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How I passed the compTIA A+

Guide to conquer compTIA A+

This is the guide to conquer compTIA A+ made by Said Neder, this is what am doing to study and get certified!

Here I documented everything that I learned when preparing for the exam, this are my notes to study and remember what I did, and I passed!

Am taking this exam on 11th and 13th of april, 2022!

What is compTIA A+? Is the Computing Technology Industry Association, being vendor-neutral, they have been around since the 80’s. The A+ is a test designed for IT technicians anywhere from 6-9 months of experience, being one of the most popular certification.

This cert consist of two exams:

Details of the exam

If you pass these two exams you will become A+ certified.

Why get A+ certified? The best way to start in the IT industry, being the entry-level certification, and that gives a feel of your skills and scope to companies that are trying to hire you, a lot of companies require A+ or strongly suggest it, and A+ certified technicians have higher paying salaries that does who don’t. BUT IT DOESN’T GUARANTEE A JOB but it will help you a ton to get your foot in the door.

Just to keep that in mind.

Disclaimer! am already into the IT world and I have previous knowledge on the majority of this topics, but that doesn’t mean I know them deeply, take it with caution


This is what I used for studying and getting certified, a video course and pratice tests.

Domains covered by the 220-1001 exam

Domains covered by the 220-1002 exam

How to pass the exam

Schedule the exam right away! the majority of the exams are multiple-choice but some questions are performance based questions (PBQs) that are fill in the blank, drag and drop, etc…

Study a ton of the resources that am using, a month is enough, and go through the practice exams, that will help you to know where you need to focus more your studying, then take notes!

You have 2 hours for each exam, read carefully and have patience, this exam is made to trick you, after the exam you need to complete a large survey of the quality of service you were given and finally you get a big passed on the screen!

Don’t worry about the grade if you pass you are golden!

Chapter 1: Safety and professionalism

Professional communication

  1. Be on time!!
  2. Actively listening
  3. Clarify customer statements
  4. Maintain positive attitude
  5. Don’t use technical words, speak human
  6. Set and meet expectations

How to treat your customers

Physical safety

Tools of the trade

Troubleshooting theory (compTIA loves this)

This is the theory behind trying to solve a user’s problem, remember that certain companies have policies, procedures or agreements, and some time strict ones to follow.

Remember the OSI model


  1. Identify the problem
  1. Establish a theory of the probable cause (question the obvious)
  1. Test the theory to determine cause
  1. Establish a plan of action to resolve the problem and implement the solution
  1. Verify full functionality, and if applicable, implement preventative measures.
  1. Document findings, actions, and outcomes.

Escalate the issue if necessary, but try harder first

Chapter 2: The visible computer

External connections

System unit connections

System unit connections in older hardware

Laptop connections

Inside the pc

Question that could appear in the exam:

Given the scenario, install and configure motherboards, CPUs, add-on cards.

What is a computer?

Is machine that let’s us get stuff done, thanks to each part of the computer that accomplish their functionality.

What is an operating system?

An operating system is the program that runs the programs to say it like that, and the most important thing about it is the kernel, is the core part of the OS that handles memory management, so it assigns RAM to every program.

You need to check the version of your CPU architecture to handle memory, because it can handle it with 32bits or 64bits, so you can install OSes, and programs based on your architecture.

Your OS needs device drivers to talk to different devices like keyboards, mice, webcams, etc…

Every OS store everything in hierarchical order by backslashes (windows) or slashes (Linux FTW)

Users and super users

Everything has a user account, because everything needs authentication, since something we don’t want to happen could happen in our name if we didn’t have any type of authentication so is a security feature, and the way that superuser works (sudo) is a root account which have all the permissions on the system, he is able to do everything, and you as a user can’t do that type of things since you don’t have permission to do so, this way we control the environment to prevent unwanted accidents and let our system secure, this is called UAC in windows.

Since windows is difficult to maintain, you need to pay for it, you need to have anti-malware to prevent unwanted processes, is pure spyware, just why?

It’s just based on a good salesman named bill gates that made it that popular, that was the per processor agreement, for every sale of a computer you got a copy of windows with it.

Active directory was really a blast on the enterprise side so it made it even more popular, since windows owns SSO (Single sign on)

Windows versions and editons



Touring Mac OS

It has a dock, global menu, and for it’s file explorer is named finder, if you want to configure something you need to go to the system preferences or the terminal.

Touring Linux

Linux is everywhere, is free as in freedom and free as in free beer! You have liberty to create what you want, there’s tons of distros out there, tons of desktop environments, window managers, you name it, make it your own, one of the most special things to check is the package manager, since they are four right now:

Linux is the most powerful tool made, so play with it! And it respect your privacy under the GNU license.

Chapter 3: CPUs

What is a CPU?

The CPU (Central Processing Unit) is the brain of the computer, which we need to instruct it to process and calculate our problems, and we do that with a programming language, and thanks to that a spreadsheet can appear on your screen or a video can reproduce, and what a programming language does is to convert the source code to machine language, that is 1 and 0’s being a byte, and a bit being 8 bytes, known as an octet of bytes.

The CPU has registers, that is made to store information that is going to be calculated.

To summarize:

CPU speed and cores

The most predominant and top notch companies of CPU’s are:

(Both have the same code books)

They are quartz crystals that are osciloscopes that calculates the timing for the cpu, and they are placed on the motherboard, and the cpu inside will multiply the time, this is called clock multiplying.

Overclocking is an enthusiast thing that is to push the speed power of the CPU to it’s maximum level, and there are motherboards that are able to to this, but is not recommended because on the long run the CPU will be damaged faster, the system will be unstable and not worth it.

Hyper-threading is a pipeline that can handle to pieces of code incoming at the same time.

A cpu have a lot of cores, and those cores are like a exact CPU, and inside of those cores it has their own threads.



Caching is just pieces of the program saved on SRAM (inside the CPU) to use frecuently.

Most CPUs comes with three caches:

The most controversial dilemma is how AMD and Intel handles their caching since Intel handles low storage on their caches but extremely fast, when AMD at is side it handles high storage on their cache but not that fast.

CPU caching works between RAM and CPU.

CPU sockets

CPU socket is where the cpu is mounted and connected to the motherboard.

CPU microarchitecture is the circuit diagram that is inside of the CPU, and Intel and AMD has their own way to make it, and the companies use the microarchitecture to apply it to a bunch of new CPU lines.

This takes much importance in place since a high-end CPU of 5 years ago doesn’t mean that is better that today’s CPU, probably a low-end CPU of today would be much faster than that.

Socket names:

There are different motherboards for each CPU company (AMD & Intel) being that the socket is different, for AMD is called AM4 (PGA) and for intel is called 1151 (Depending of each motherboard since the number means the quantity of pins they are in the socket) (LGA)

The most common CPU sockets are:

Installing a CPU

Please use an antistatic wristband!

Of course before installing a CPU we need to buy a motherboard that is with a socket and speed-rate compatible with the CPU we are planning to buy.


Then we need to notice the orientation notch (a little triangle on the CPU) and we need to align it to the orientation notch of the motherboard (a little mark on one corner of the socket) and just place it gently, like letting it go, if is installed correctly you will feel it that just entered in place, but if not you will see that is a bit wobbly or that is something wrong, just lift it up and try again carefully.

The majority of the OEM CPU’s comes with an OEM fan, and that’s really cool since the company that made the CPU is guaranteeing you that the fan will support the heat that the CPU can produce.

Every fan has a thermal paste applied, and that is a barrier between the fan and the CPU that makes the cooling process much easier since it absorbs the heat easier, the way to put these fans are tricky, is recommended to watch a video tutorial on how to do it since it depends on the build you are doing but you will get it right, or just try it and see how it goes, make sure is really tight, look out for any type of orientation.

Then connect the 4-pin connector of the fan into the motherboard.

New term: delidding

Delidding is when the metal plate of the cpu is taken off to improve the perfomance of it.

Liquid cooling

The OEM fans that comes with the CPU are great and guaranteed to work but if you do weird things like:

You can opt out for other alternatives (third-party coolers) that are designed for taking more heat than usual, the majority of them are better than the OEM ones, and they are great!

If you want to be a cool kiddo you will want liquid cooling, and is about a box that is attached to the CPU with fluids running that is water with alcohol, and what it does it lets the cool liquid absorb the heat, then return the hot liquid to the radiators fans to cool it out and send them back over, now if you don’t know what you are doing and you install it not the proper way, get ready to get all of you computer soaked in water, so it’s a great option if you know what you are doing, the best thing of liquid cooling is that is really quiet, and it can take more heat than any other fan.

Liquid cooling uses a pump, a radiator, a cooling block with liquid to remove heat.

32bits vs 64bits computing

This worked by counting how many connections did the CPU had with the MCC (memory control chip) and it that way, 32bit worked great until the 2000’s, where 32 bit couldn’t handle more than 4gb of RAM, and you need to check the version of your operating system if is for your 32bit processor, as well for your programs, so:

x64 is compatible with x86, but not the other way around.

Chapter 4: RAM

RAM technologies

The first ram technology was the SDRAM (synchronous DRAM) synchronous meaning that is timed with the quartz crystal that times the CPU as well, these type of ram has 168 pins in their stick with two notches on it, these type of ram is the only RAM that you will find with two notches nowadays, and these type of RAM as it was timed with the quartz crystal, the speed of it just went as the crystal went, so could be 66MGz or 100MGz.

The second technology was the big leap, introducing the DDR SDRAM (Known only as DDR) meaning Double-Data-Raid, being that for any one given click of the clock (quartz crystal) it can send back two bits of data, being this really fast.

Now before you buy the RAM you need to research that the speed of the RAM is compatible with the speed of the motherboard, or known better as DDR speed rating and PC speed rating, there are charts that can help you with these but for matching the DDR speed to the PC speed just multiply it by eight since the DDR speed is in bytes and the PC speed is in bits, the DDR memory had 184 pins and just one notch on the stick.

The third technology to enter is the DDR2 RAM, with 240 pins and with one notch on the stick as well but more centered instead of on the left side as DDR, this is made because they don’t want you to confuse yourself and insert a DDR ram into a motherboard that only accept DDR2 technology, with the DDR2 speed chart as well you need to compare the core RAM clock speed (system crystal) and then multiply by 2 the DDR ratings, and then check the PC speed rating (multiplying by 8) then checking the PC speeds, the PC- is for DDR and PC2- is for DDR2, just by looking the speed rating.

Then it comes the DDR3 that uses the 240 pin as well and one notch but little off to side to not be confused with DDR2 as well, and then as technology moves on, motherboards get faster so the clock speed of the DDR is now multiplied by 4 and then for DDR3 multiply the DDR rating by 2, as well the PC rating is now PC3-.

The nowadays standard is DDR4 using a 288 pin stick with one notch off-set of DDR3, to differentiate between those technologies, and DDR4 is the fastest RAM described on the compTIA A+ exam, but not in the real world since DDR5 is already out but not the standard by any means and it will take a lot of years to be available to normal users, so the fastest ram by now is the DDR4, is the gold standard is it has outrageous speeds, remember the speed chart, being the PC rating by now PC4-, now how it’s calculated is different, since is metered in MT/s (megatransfers per second) and that is how is rated DDR4, and then for the PC speed rating we need to multiply by 8 as you already know.

Now DDR4 yes indeed is the gold standard but don’t let that fool you, DDR3 & DDR2 are still used on many hardware as laser printers or dedicated systems, so don’t be surprised if you catch older RAM.

Remember we measure RAM speeds using DDR or PC ratings, and the technologies on the exam are DDR, DDR2, DDR3, DDR4, and multiply the DDR speed by eight to get the PC speed.

RAM Capacity

RAM is based on a square-chip, and they are ram sticks that have squares on one side (single-sided RAM) and other sticks that would have squares on each side (double-sided RAM) being double-sided ram the standard, which is why is very common, but you need to check if your motherboard supports it.

Most motherboards have 4 slots that can handle RAM, and RAM is almost sold in pairs these days, so that’s why we have channels, and specifically dual-channel memory, that is to insert the same ram (same capacity and speed) into these dual-channel memory, that is combining the two sticks of ram so that the motherboard can used them at it’s fullest, which makes the computer a lot faster, and the slots which should be placed is in your motherboard manual.

RAM features

Installing RAM

Before installing RAM we need to consult the motherboard’s manual to check if what type of technology does the motherboard support, and what size is it’s maximum, could be that the motherboard supports DDR4 and a maximum of 64gb, and those 64 GB is divided into the ram slots, that the motherboard has, for example a 4 slots, the maximum you can put into each slot is 16gb of RAM.

The installation process is really easy, just verify what channel you should put the ram (read the motherboard manual) and just slide the ram into the slot and press it lightly until you hear to clicks, and that’s it.

Then check in the bios if all the RAM is correctly installed, if it’s not installed correctly then reinstall the RAM, check the channels if they are in the correct order and check the speed of the RAM if is conflicting with the motherboard, and then try again.

Virtual RAM

Virtual RAM is just swap, and swap is a partition in your hard drive that is set aside when you run out of memory that partition can be used and save you of a crash, remember that your storage is way slower than RAM, not even comparable, so don’t think is a viable option to increase speed, if you wamt speed just install more RAM!

Chapter 5: Firmware

All of the devices that are connected to the motherboard need to speak to communicate themselves after the OS boots up, and that happens thanks to the BIOS (Basic Input Output Services) and these are code, because is a program that is built into the motherboard itself, so every motherboard has a bit of programming itself.

This is very important, but very, since with the BIOS everything can communicate so that’s why we have two BIOS chips, one for use and the other for backup (MBIOS, BBIOS) and the BIOS is the best tool for troubleshooting.

Into the BIOS we have the Power-On-Self-Test (POST) (More on that later)

Other thing that is built into the bios is the CMOS (System setup, more on that later)


The Power-On-Self-Test (POST) is a program that checks all of the motherboard’s add ons, runs a diagnostic test to check that everything is working and then it replies to cpu to boot up since everything is great and it reports it by a little speaker that is built into the motherboard as well.

What happens if the post doesn’t get as expected? You get “beep codes” that is the most primitive way to advise the user something specific is going wrong, so let’s imagine that the post didn’t found your video card, it will output one beep and two long beeps, if the post didn’t found RAM it will output a beep code that will repeat until you power down the system.

If the problem you have is so much bigger that even post can report the errors you will need to get a POST card, that is an adapter that shows an hexadecimal number meaning each code an specific error, and the meaning of each error should be in the motherboard’s manual, and the post codes are only valid when the computer is booting up, after that it doesn’t mean anything.

System setup

The BIOS is an ancient program which only weighs around 16 bits, after all these years the BIOS has been updated, and is now called UEFI (Unified Extensible Firmware Interface) and is a much better bios that is graphical and can be navigated with your mouse, and before the system boots up there it will be the “system setup” that is a menu for changing some setting into the bios, although not every computer ships with a system setup, much of them does, so be on the look out when you turn on your computer and it says “Press F12 to enter system setup”, for example my computer doesn’t says that, it just have the UEFI screen and from there you can change verything you want, and my computer is a 2020 gamer laptop model.

Now in the bios you can set up and administrator password, and you need to set up the password because in the bios there are very delicate stuff that you don’t want anyone to touch on, so if someone enters the BIOS it would need to enter the password, and then is user password, that for the computer to boot they will need to enter a password, no matter what.

In the BIOS you can troubleshoot, enable or disable ports, and so on and so forth, if you need to update the bios then you will need to flash it, so in order to flash it you should refer to yours motherboard manual, flashing can be dangerous, so please read the documentation and know what you are doing, if you don’t know what you are doing in every bios they are the advanced menu and the EZ or basic menu, and depending of the motherboard how you can access those menus.

How to flash the bios properly

This is the way to convert a 300 bucks motherboard into an ashtray in a minute if you do it improperly so follow this guidelines:

Troubleshooting firmware

Firmware itself is really stiff and secure meaning it shouldn’t break at all, in the past we had two chips, one being the CMOS (Complementary metal oxide semiconductor) and the BIOS updated the CMOS, but now we have a Single flash ROM chip, meaning ROM Read Only Memory, and in computers we have a RTC (real-time-clock) and is really critical, that ticks thanks to electricity, but what happens if you unplug the whole thing? Then the CMOS battery being the technical name CR2032 ,comes into place, where this battery fuels the RTC to not stop, being the battery a rounded golden “coin” to say it like that, built into the motherboard, and if the battery is presenting problems very negative things may happen, like your clock is falling behind, any type of settings may disappear, or it wouldn’t detect some hardware, and all these type of problems could be for a battery that cost 4 bucks that you just need to replace.

If you have any type of problems just reset system setup for defaults and it will boot your machine.

Chapter 6: Motherboards

Motherboards have standards to fit inside all cases, and that is thanks to the form factors standards.

Form factors

All motherboards have the same, for example the I/O area has the same dimensions as the other motherboards, and they are different sizes of motherboards:

Those are the majority of sizes that are seen in motherboards, and thanks to the standards that are in the hardware industry, it connects the same way all of the sizes so depending on what amount of electricity you will consume you can buy a power supply and that power supply can fit all, since it has an standard.

Every motherboard has connections and the way to display those connections in the case is through and I/O shield, and every motherboard has them, and the ports may be different but the size itself of the shield is extremely fixed, so it can fit many cases, of course the motherboard should fit tho.


In motherboards that are 20-30 years old, had a lot of chips in it, and one chip took care of an specific action, like hard drives, or a sound card, and so on, but now they are chipsets that manages all of that and work together to take care of everything in the motherboard, those chips are called:

But now, most CPU’s take care of what the Northbridge did, so nowadays in actual motherboards there’s only one chipset and that is the southbridge and is one of the most important things to know what your system can do, these are so important that their own names of the motherboard announces the name of the chipset that is built-in, since is what cares, since it defines how many ram it can support, how many video card you can install, or how much of speed it can handle, and how many usb & sata ports, and their speeds, etc…

When you are out buying a CPU you need to know which chipset does this CPU supports, it can make a huge difference, so make your own research.

Touring the motherboard

First, please keep your workbench nice and clean, with anti-static protection, being that a bracelet or an anti-static mat or just keep the motherboard in it’s anti-static bag which it came with.

The manual of the motherboard is really important, but really important, you need to have some documentation, being that a PDF by looking up the name of the motherboard or the manual book.

The I/O shield that comes with the motherboard keep it near and don’t lose it.

The cables that the motherboard can include could be some SATA cables, and the SATA ports are small, that’s why it can include up to 6-8 sata ports depending of your motherboard.

Then they are the power connectors, the most known is the 24 pin connector.

The motherboard manages a lot of different voltages and thanks to this capacitors it can handle the energy, but when these capacitors tend to be damaged it bubbles up and it shows like they are going to explode, so that’s how you know that the motherboard is damaged and it needs a replacement, unless you are really good at soldering.

Today’s they still are expansions slots and are known as PCIe expansion slots, so there you can connect a graphics card into it, and the connector is a 16 lane PCIe connector (PCI express).

There’s also a single lane PCIe port, and all of the PCIe ports are serial ports, and there’s a 4-lane PCIe too.

There’s usb connectors port, where you can connect a dongle to have usb ports, that often is the case that includes them.

Touring the case

There are different sizes for cases but the really big ones are named tower cases, and it supports a lot of hard drives for storage, and a lot of space for airflow, the majority of cases have a front panel connections, like and on/off switch, usb’s, audio connectors, etc.

Inside the case we have the standouts, being where we place the motherboard and is really fixed by the standards.

The back of the case is where all of the cables are managed, cable management is really important since it separates the pros from the amateurs, making the inside look clean.

There’s a power supply area where you can mount it.

There’s a hard drive bay where you can place all of your hard drives.

There’s is the fan area where is pretty standard.

Mounting the motherboard

Before anything you should connect everything without mounting it up on a case since something could be damaged and being your effort to mount everything up worthless since you need to disassemble everything to fix what is wrong, so keep that in mind.

Now the I/O shield is a flimsy metal case is really easy to install but really difficult to remove without bending it so be careful and check the right orientation.

Drop in your motherboard and match the I/O with the shield, that is very important since it can make a difference when screwing the motherboard up, then just screw the motherboard and connect all of the cables from the case.

Chapter 7: Power Supply

The PSU (power supply) really is a step-down transformer that convert AC power from the wall to DC power for the computer, and a PSU provides 12 volt, 5 volt and 3.3 volt of energy and includes a ton of connection including:

Old PSUs had their cables soldered into the box itself, so if you didn’t need one cable you can’t remove it, you will need to hide it at your best but nowadays the PSUs are modular, being that have ports and you can connect the cables into the PSU and you are done!

The cables that the PSU has are really easy to connect so if you are forcing it, you are doing it wrong.

Mounting a PSU

The way to mount a PSU depends of the case but the majority of the cases is a special space for it that it needs to be screwed in at the back of the PSU.

Check the airflow of the power supply, so the fans draw air from the system and blows it off it.

Choosing a PSU

When buying a PSU we buy it based on watts being the formula (volts X amps = watts) but when converting the electricity a percentage of it is lost in heat, resistance, etc…

So you need to do your own research based on the parts that you have chosen for your pc build, being the motherboard, graphics card, or how many hard drives, and to solve that problem go online to a watts calculator determining the need of watts by using the parts you have chosen, and then add a bit more to the result just in case, since the majority of times the PSU will run on less-than-optimal situation.

Here is where the 80 plus rating comes into place, where efficiency improves when the rating is better, being the rates available:

Beware of the PSU sizes since they are smaller form factors.

Cooling the system

To disipate heat we will need a heat sink, being that it takes heat from another device, the majority of cases is made of copper.

The majority of PSU will cool themselves by drawing cool air from the bottom and blowing it out to the back.

Beware that some graphics cards can obstruct the air flow inside the case, since the way to keep cool the system is by making air move.

If your system is overheating it will reboot, so that is how you know is overheating.

The downside is that fans = noise, but liquid cooling solves that problem and noctua special fans as well.

You can control the speed of the fans in the BIOS or from your OS, since the default speed of the fans is full speed and it does make noise.

Troubleshooting the PSU

The PSU is the item that suffers the most since it’s abused from your electricity providers, and it can die two ways, fast or slow, and when it’s fast you will have horrible burnt smells, or smoke, and pray that the PSU didn’t damage other things.

The slow death is the most difficult way to diagnose, if you are having this problems unexpected shutdowns, no power suddenly, etc…

Now if you think that you are having a slow death, you will need to test the PSU, and you can test the power supply by doing so with a PSU tester, yea that simple, or a multimeter and the majority of the manufacturers will send the PSU over volted like 12.3V, and that’s okay, and if it’s undervolted like 11.8 or similar it’s okay enough to run the system but if the number is going down well is time to replace the PSU.

Troubleshooting core components

Power protection

You can get sag from your electricity provider, meaning sag short term voltage dip, or far more dangerous is overvolting, known as a spike, so to protect from spikes there are surge supressors, that are big boxes that will eat it off instead of your computer being killed, so go buy a UPS (Uninterrupted power supply) that will protect you from sags and spikes.

Chapter 8: Mass storage technologies

Mass storage boards media itself in different ways:

And so much more, but these are based on LBA (logic block addressing) and it is circuitry, where is how the OS stores data in the drive, based on blocks of 4096 bytes, so inside the drive there could be up to more than 1 billion blocks!

The way to count storage is the following:

And for computers would be:

And storage have many sizes!

Magnetic disk drives

They are drives that haves platters inside them that stores binary code thanks to magnetisim and it works by having a little arm that makes contact with it by milimeters

How the OS talks to the drive is by ATA (Advanced technology attachment) but what we see a ton in nowadays is SATA (Serial ATA) which is taking place of the old and deprecated PATA (Parallel ATA)

eSATA is a way to connect sata externally (external SATA) in storage devices, and eSATA has it’s own port and connector, but USB has been blowing up lately so eSATA is not longer popular.

Solid state drives

SSD’s are managed by chipsets, and inside those chipsets there are pages, and within those pages stores tons and tons of blocks, and the chip can store tons and tons of pages, and there’s tons of chips in the ssd.

The most popular sizes for ssd’s are:

SSD’s are really but really fast! but if connected to a SATA port is not going to be as fast as an NVMe (non volatile memory express) that is directly connected to the motherboard.


SCSI (small computer system interface) is a 25-30 year old drive that used the PATA interface, so it had a wide cable, so this drives are old and deprecated, and we use serial connection, but there’s a SAS (serial attach SCSI) so watch out, since SCSI itself could be in some places with the ISCSI technology meaning SCSI connected by ethernet cable, so they still are alive in servers, but completely dead in desktop.

Boot order

If your system has a ton of drives, you need to specify the boot order of the computer so that it can boot of a specific drive, so this can happen if you want to boot up a linux iso or some utilities.

Chapter 9: Implementing mass storage

What do you do with a brand new storage device with no OS on it? Just boot from the ISO and click next, really that is it.


The RAID system (redundant array of inexpensive disks) is a system that makes drives to work together, was invented by some college students in Berkeley which provides:

RAID 0 (Striping)

Is common for two or more drives, where what it does it partitions the data to save it in pieces on those two drives gaining speed but the downside is that there’s no data safety at all so is really easy to lose the data.

RAID 1 (Mirroring)

Is common for 4 drives or more, and what it does as the word says, it mirrors the data and saves it on each disk, having backups of the data, so you gain redundancy but lose speed.

RAID 5 (Parity)

It requires three drives or more, and is the combination of the two leves we have described, where it saves multiple pieces of the data but with a parity program does a type of backup of one piece of the data, meaning that if one drive dies, you can revert the parity file to it’s original type, having speed and data safety, but if you lose more than one drive youwill lose data.


It requires 4 drives, and does much the same as level 5, but with two drives, so you can afford to lose 2 drives before losing any type of data.

RAID 10 (Stripping mirrors)

It requires as well a minimum of 4 drives, so the two pairs will be mirroring, but it stripes the data, meaning it divides the data, and saves the data twice on different pairs.

RAID 0+1

It requires a minimum of 4 drives, having both pair striped, but the thing is that one pair of drives is mirroring the striped data, so you can afford to lose one complete pair, but if you lose one on each pair that could lead to data loss.

Difference between RAID 10 and 0+1

The RAID 10 needs 4 drives, what it does it divides the data and saves one piece of data in one drive of one pair, and the other drive of the pair mirrors it, and the other piece of data is stored on the other drive of the other pair, and the following drive of the pair is mirroring as well, while RAID 0+1 what it does it splits the data and saves the split data in one pair, and the second pair mirrors the first pair.

Proprietary RAID

Those are types of RAID created by companies that won’t tell you how they did it or show the source code (watch out absolutely proprietary)

How you can create RAID?

By two ways:

Hardware RAID

The majority of desktop motherboard include RAID support built-in, just go into BIOS and look for the RAID setting, now reboot and look for the sticky key, it pops up on the screen to enter the RAID setup, and you can create the array, but don’t expect you will have the best customization ever, since for doing that the majority of manufacturers will sell you a license, so is limited, and for the OS it will appear as a one big drive, I prefer creating a RAID in a linux OS.

Software RAID

You can start RAID on windows with the storage spaces tools, you need windows professional tho, with linux just install mdadm.

MBR partitioning

Master Boot Record (MBR) is the oldest type of partition still in use today, consisted of a bootloader and up to four partitions with one set as an active partition. has limitations to only 4 primary partitions, the way to go around this is in the fourth partition create something called logical volume or also known as extended partition, also MBR limitated the amount of storage of your disk to a maximum of 2 TB

GPT partitioning

THe Guid partition table (GPT) was meant to take full potential of UEFI systems, based on global unique indentifiers (GUID) so it’s secure, you can have 128 partitions, and each can be 18.8 terabytes per partition so we have ton of space.

GPT uses a protective MBR but the GPT starts at the primary GPT header and includes a secondary GPT header.

File systems

When you create a GPT table of partitions on a disk you need to format those partitions to a specific file system, the most famous are:

File systems are needed to organize and know where each file is stored this is made thanks to a data structure.

Fragmentation could be a problem with some file systems.

Dynamic disks

Is a windows feature, that gives you more options to control drives, and apply simples RAID schemes, microsoft recommends to do this before anything:

  1. Keep the boot drive basic (not dynamic)
  2. Set boot drive to GPT
  3. Be Careful to convert to dynamic

Encrypting mass storage

First you need to check the TPM (Trusted Platform Module) is turned on in the bios, then you need to choose how you are going to encrypt, by doing File-based encryption or Disk-based encryption, in windows bitlocker is the tool that is used by default to both ways of encrypting, altough is only available for windows professional, your best bet is veracrypt since is FOSS.

For linux you have LUKS (Linux unified key setup) and GPG keys for files.

Troubleshooting mass storage

Possible problem: RAID not found/not working

Possible problem: Read/Write Failure

Possible problem: Slow perfomance

Possible problem: Loud clicking (click of death[physically destroying itself])

Possible problem: Failure of boot

Possible problem: Drive not recognized

Possible problem: OS not found

Possible problem: Attempts to boot incorrect device

If you have continuous reboots, it means that the OS is borked (corrupted) and the best option is to reinstall the OS.

Remember you can turn off/on ports on the system BIOS, check that first always.


Chapter 10: Essential Peripherals

Optical media:

Optical media is nothing more than CD’s, being the famous CD-ROM (compact disk - read only memory) being the file system of the CD ISO-9660 or more known as the CDFS

And there are too CD-R, where we can ‘burn’ (write) data into it, but then it came the CD-RW (cd rewritable) where you can burn it and then rewrite it.

But then the DVD came (digital versatile disc) and it was way superior than the CD, being made for movies because it came with surround sound, and the most famous option of optical media is DVD-ROM.

But the best form of optical media is Blu-ray, being really fast and made for movies as well.


The Universal serial bus is the new standard for any type of connection, and this type of standard has been evolving, being the first one the USB 1.1 (1.5 mbps/ 12 mbps), then it came the USB 2 (480 mbps) but the USB 3.0 came and demolished the other standards with the speed of 5.0 gbps! but the downside is that the compatibility with this standard wasn’t great so they came with USB 3.1 Gen1 being the same speed but fixing compatibility issues but the Gen2 runs at 10 gbps!

This is really important for the exam so we will organize it in a chart:

StandardMaximum speed
USB 1.01.5 mbps
USB 1.112 mbps
USB 2.0480 mbps
USB 3.05 gbps
USB 3.1 Gen 15 gbps
USB 3.1 Gen 210 gbps

USB connectors may come in many types:

And USB often use color to show versions White = USB 1.0 Black = USB 2.0 Blue = USB 3.0 Red = USB charging port

Understanding USB

USB had terminology where the cable had two sides, the upstream and the downstream being the upstream a type B connector soldered into the device on most cases and the downstream the type A everyone knows, but that terminology is gone since the arrival of USB 3.0, where you can plug it either side and is handled by the root hub of your motherboard (the southbridge)

Configuring USB

Before plugin things up you should check if your machine has the proper drivers for it, but that’s not longer the case anymore since tons of drives come preinstalled on the majority of linux distros because are built into the kernel, and windows 10.

But USB has a big security risk like keyloggers, rubber duckies and so much more, so one way to tackle this is by disabling USB ports on BIOS, or use a USB lock, that is a software that would let you know what is happening with your ports.

Thunderbolt and lightning

Thunderbolt is a everything-you-want port, charge something, connect displays, you name it, Thunderbolt will do it! At the fast speed of 10 Gbps for Thunderbolt 1, Thunderbolt 2 runs at 20 gbps, and Thunderbolt 3 runs at 40 gbps! That is crazy fast, and Thunderbolt 1 & 2 is just good mini display port, but the Thunderbolt 3 technology is using USB Type-C!

Lightning is a Thunderbolt alternative made by apple that is absolutely Proprietary, so no no for me, but still Lightning is great, you will only see them on apple products tho, but lightning is really slow at 5 gbps.

Keyboard and mice

Keyboards and mice are essential to the pc setup, and making it’s return with this devices is the PS2 port, being really but really old but it came back since it has a very low latency for gamers who need really high speed.

There’s something called KVM switches (being Keyboard, video, mouse) that if you have multiple computers you can share the same keyboard, monitor and mouse and with this switcher you just switch to your desired computer

Sight and sound

For sound there are tons of systems to order sound but the most common is a 2.1 speaker system having two little speakers and then a big one for low frequencies, and the sound card that the majority of motherboard includes are great! you need to be a quite audiophile for requiring more quality sound, and you can do so easily by buying an add on sound card for your motherboard.

If you don’t have sound coming out of your speakers the majority of the problems is if the speakers has energy, if the are connected properly or volume settings in the computer OS.

Readers and scanners

Cards that include a chip to authenticate themselves in systems are called smart cards, and there are smart readers that is a usb device that reads the information that the smart card is holding, the most common example are credit cards when paying something with it on site, the other case is a magnetic reader, that is when you swipe the credit card for example from it’s magnetic band in the back of the card.

Flash memory readers are able to read SD cards, mini SD, micro sd, and a weird size that covers the exam is the Olympus xD picture card, being very popular in the old days for the Olympus cameras.


Flatbed scanners just scans paper documents and convert into a digital document, but it only reads one paper at a time, but there’s other type of scanners being the ADF scanner (Automatic Document Feeder), where you place the pages face up and it will scan them automatically.

Other type of scanners are barcode/QR scanners, that are really common on inventory of a business, and the scan those barcodes with a tool known as a gun scanner, but QR codes are common to share a website to others, and you can read QR codes with your cellphone

Using expansion cards

That is what is amazing of building your own PC, you make it to fit your needs and that’s why there are expansion cards, being placed on the PCIe slot, the majority of the times the most common expansion card is your dedicated GPU, but there’s others like:

To insert this type of add on cards, is just as easy as plugin them into PCIe slot, then screwing into the case, and giving it power to the card itself, and to troubleshoot this cards, check always the device drivers for it and check compatibility issues, and the use them.

Chapter 11: Building a PC

Understand what type of computer should fit a specific client by knowing the different cases of clients

The thick client

Is the basic office computer, it should first meet the recommended requirement specs of the OS (middle of the road) (intel i3 with integrated graphics, ssd, windows, office)

Thin client

Most common in enterprise, is really focused on network connectivity, so meet the recommended requirement of the OS, could be a motherboard with gigabit, windows, basic applications.

Graphic/CAD/CAM/Design workstation

Good powerful motherboard, ssd, a multicore processor (tons of cores), a dedicated graphics card (high-end video card), tons of RAM.

Virtualization workstation

Maximum RAM and CPU cores, the majority of the cases is a server hypervisor with proxmox installed, and you need a good amount of storage, ssd as a boot drive and then hdd as storage drive.


Is a headless system attached to the network that handles drives to share files, Gigabit NIC, RAID array. (4 drives are great)

Gaming PC

Games makes computers struggle so if you want to game right make it top of the line! A great multicore processor (Ryzen 7) a really good motherboard and a beefy PSU (750 gold watts and up) and you need a really high end cooling (liquid cooling) and a great dedicated graphics card, and add on could be a special sound card (not recommended tho), a must is an ssd, and a big chunk of RAM (16gb and up)

Audio and video editing

A great high end graphics card, a good ssd as boot drive and tons of hard drives, a specialized sound card, and dual monitors, but if you want to make your life easier, just get those bois a mac.


Booting from anything

Installing windows

  1. Check minimum requirements for windows
  2. Back up
  3. Download the .iso from microsoft
  4. Flash it with microsoft tool or ventoy
  5. Boot from it
  6. Install it

Post installation task

Steps to do after installing windows

  1. Go to device manager and check all drivers
  2. Update windows to the latest version
  3. You can setup a recovery drive
  4. You can setup a restore point as well
  5. Setup windows security

Windows installation option

Clean install: reformat the drive and clean install it Upgrade install: You keep your data and it upgrades the version of windows (win10 > win11) Dual-boot: you can boot different OSes, like linux, freebsd, hackintosh or windows servers Unattended installation: Is a template already made for the installation setup of windows, configured with .xml file made in the Windows System Image Manager. Image deployment: If you have identical hardware, you can setup one computer with what you want and then redistribute it to all of the other computers connected to the network, this is made with windows’s User State Migration Tool (USMT) or ghost.

Chapter 12: Windows under the hood

What is the registry?

A registry stores settings, and those registries need to be read by some programs, the registry is a binary file, and to edit it, you need to use regedit, and the registry is really critical, if you don’t have the registry your computer won’t boot! That’s why windows has 4 different copies of it just in case.

It bases from 5 keys:


Processes are applications that run in the background, everything is a process really, and you can check them with their PID (Process ID) and kill them if you want with htop in linux, or task manager in windows.


Services are background apps that runs on startup, like networking, backup, and so much more, you can use the services app in windows to enable/disable services, in Linux you use systemD’s systemctl.A

Windows toolset

Windows 7 task manager

You can start a technical menu where you can go to the task manager with ctrl+alt+delete and you can go straight into it with ctrl+shift+esc and you can check resource monitor since is a good tool as well.

Windows 10 task manager

Is the same but with a better GUI.

Information and configuration tools

Performance Monitor

Is a tool that logs your performance to see how many resources you use on your daily use and then to calculate how to counter that.

Event viewer

Event viewer is a log viewer to see what is happening in your computer, and you can customize it, with local security policy that creates audit policies for your system, and with that we can create more logs.

Tools for programmers

There are tools used for programmers in windows for example Open Database connectivity (ODBC) for SQL databases, and you can use component services to edit COM features (component object model)

Chapter 13: Users and groups

Managing Users and groups

In windows users can be involved in two groups:

An administrator has admin permissions in his account and standard user is just a user, you can create this users and groups in control panel, and in local users and groups you have the most control over.

NTFS Permissions

You can go to properties and check security and sharing options, there are different NTFS permissions but are really based on RWX (Read, Write, eXecute), inheritance is stopped with deny keyword.

Linux and MacOS permissions

This is based on the scheme of:

Based on the RWX scheme.

Sharing resources

Network shares anounces folders and files that will be shared in the network with share permissions, is a quick solution, since NTFS permissions are most powerful, and shared resources can be mapped to a drive letter.

Security policy

These are security rules that are followed, you can open local security policy to find:

Here you can create passwords policies, and more, if you are connected to a domain you can’t change some policies is because your domain administrator created domain policies.

Chapter 14: Maintaining and Optimizing operating systems

Patch managment

That is to setup automatic updates and patches, in windows update section, in Linux you can use your package manager of your distro to update.

Working with disks

You should do error checking and optimization in disks often, in windows this is made with chkdsk

Working with applications

To remove programs you can go to control panel in programs and features, it can lead to residue in the system, then you can clean it with software like CCleaner.

System restore

You can access it’s properties in system properties and create/remove restore points, create strategic restore points to not bloat the system, this is useful since you can access restore point in winRE.

Backing up files

You can schedule back ups (snapshots) and a external backup to save the data, then you can go to windows backup and restore page and set it up, finally you can restore from it in winRE as well.

Task scheduler

This is a program that able us to schedule tasks to do like back ups, cleaners, and more.

Chapter 15: Working with the terminal

Am not going to take notes of this because I already know this really but really well, going to take notes here and there.

Working with drives

Troubleshooting operating systems


You can go to winRE with a bootable image of windows, and you can troubleshoot a ton with it, you can get a terminal if you want.

Advanced window startup options

You can go to recovery > advanced startup and you will be on the automatic repair screen, it will allow you to boot from safe mode and much more stuff!

Troubleshooting boot problems

Troubleshooting at the GUI

Troubleshooting applications

Kernel Panic

The famous kernel panic or windows BSOD (blue screen of death) and is just something that the OS couldn’t handle and it just dies in front of you or sometiimes is funny and says things like “bailing out, you are on your own, good luck” in case of linux.

BSOD are caused by hardware in most cases, do research. update the hardware and/or firmware, boot into safe boot and check event viewer.

Chapter 17: Display technologies

LCD breakdown

Inside a monitor, there’s the LCD screens with really thin layers that are it’s wires that connects into the monitor itself, and then before that there’s a big white layer that behind are the fluorescent tubes (CCFL), that needs AC power, so inside the monitors there are mini power supplies, but as the CCFL needs AC, it changes AC from the wall to DC and inverts it to AC again, so this process is called inverter, so when a monitor is an inverter you know it has CCFL tubes inside it, when LED don’t need inverters, so you have:

  1. Panel
  2. Backlight unit
  3. Connectors
  4. Input from data
  5. Power connection

Graphics cards and connections

The graphics processing unit (GPU) AKA video card, and those GPU’s need RAM to keep track of every single pixel electronically and that’s called frame buffering, but in today’s world instead of pixels are figures itself that the computer uses a lot, so it keeps it on memory, and inside the card itself there’s is the memory chips.

There’s three big competitors:

Although intel does not sell dedicated gpu’s, they do sell iGPU’s (integrated graphics) meaning that the graphics itself are integrated into the CPU itself, so that’s why you see a HDMI port soldered into the motherboard, for those cases, and AMD does it too and when they do they call it APU.

It’s common to see a lot of GPU’s with tons of memory like 8gb (known as VRAM) in high end GPU’s, and you have to connect them some point to the monitor so the most common connections are:

Connecting a GPU

The same thing with expansion cards, connect into a PCIe slot, screw it in, and connect into a monitor, check the bios that you are booting from that specific PCIe slot, then check the resolution in your settings, and finally update the drivers of the GPU, or/and install the utility software from the GPU company.


Is just like a monitor, and they use for technologies DLP, and LCD, being the most common ones, but they have a special spec, being the lumens, a lumen is the brightness quantity of the projector, so if you don’t have enough lumens is not going to look good.

You need to check the ’throw’ of the projector being the range of distance the projector should be on to have a quality image, so check that to suit your needs.

There are geometrical figures like pincushion, keystone, and skew, that is the way the projector shows the image onto the screen, so if you have those errors, you need to check the menu that is on the projector itself.

Resolution and aspect ratios

4:3 =

16:10 golden ratio =

4K ratios =


In settings you can go to display settings and setup the master monitor and organize your workflow by extending or duplicating.

Troubleshooting monitor

Chapter 18: Networking

Let’s go baby!


The local area network, and the majority of the cases are computers, printers, and laptops all connected to a switch or if it’s wireless a WAP (wireless access point) being cabled by ethernet, the standard in today’s age, and with ethernet you can only send 15 mb chunks of data, and that’s called a frame.

We Identify every device in the network with the MAC adress (media access control) which is a 48 bit address, and is always manifested as 12 hexadecimal characters, and the first 6 decimal characters are called the OEM ID, use ipconfig on windows or ifconfig(deprecated) (ip) on linux

Hub vs switch

In short words, switches and hubs look alike, but hubs are dumb since if one computer sends a packet through the network to a specific computer, it will not only send the packet to the receiver but to all of the rest in the network as well, it just repeats and sends it to everyone when a switch sends it to the specific computer by using MAC addresses.

The problem with hubs is that if there’s other computers talking to each other it will make the connection really slow since the hub just repeats, so it will make insignificant replies.

Switches are really smart because the switch knows the mac addresses of each device on the network automatically, so it knows exactly where to send it, and provide full bandwidth for all nodes.

Hubs are deprecated.


Is a base-16 numbering system, so if we check the combinations of a 4 digit binary system (only ones and zeroes), it will sum up til 16, so you can replace each combination with a letter until the f, being hexadecimal counted like so: 0123456789abcdef since we don’t want two digit numbers like 10 since it could mean “on and off” so that’s why, and hexadecimal remember, represents 4 binary values, so if you have a mac address which hexadecimal value is 12 characters long, that means is a 48 bit address.

WANs and routers.

The ethernet standard says that you will not put more that 1024 computers on the same switch or interlinked switches, because the network will become overloaded, but really that problem will occur with 20-30 computers.

There the WAN comes into place (wide area network) and is based on the idea that what happens when different LANs want to connect each other without overloading the network, then we will create a WAN with a router, being the router who connects those LANs together and know what data needs to go to which LAN.

We need to configure the router to know what computers are from what LAN, and that is called logical addressing, being the logical addressing IP addressing in the local area network, where the three first octects are the same, but the final octect determines which device is which, and when a device wants to communicate to another device that is not on the network it will connect to another LAN, being from the ISP that will connect you where you need to go.

This sounds complicated but all of this is already automated, with a DHCP server that assign automatically IP addresses of the devices on the network.

So addressing is divided by two things, mac addresses (physical addressing) and IP addresses (logical addressing) and a router can connect multiple LANs to make a WAN.

Cables and connectors

Ethernet is the go to in today’s age, but there’s DOCSIS (used for cable modems), and there’s different versions of ethernet like 10BaseT (10 mbps baseband twisted pair) or 1000BaseT, or 10gbBaseT, and so on.

Let’s start from oldest to newest:

Coaxial cable

Is still common to see coaxial cables, and coaxial have RG rating like:

And this type of cables are connected with and F-type connectors, that are your typical cable coming through the wall to connect your TV and such, but for RG-58, there’s the BNC connector which is old and it was thinner and you need to twist it to connect.

Twisted pairs

The predominant type of cable is twisted pair and there’s different types of this cables like UTP (Unshielded twisted pair) where is no protection for the 4 twisted pairs, or telephone cable with two pairs and its connector is a RJ-11, where compared with the still standard RJ-45, the RJ-45 has 8 contacts where the RJ-11 only has 4 and they are twisted in pairs so it can propagate the signal better, and they run till 100m, being from your switch to your router.

Another type of twisted pairs are STP (Shielded twisted pairs) where there’s metal covering the inside and the connector of the cable managing interference just great, and don’t forget CAT ratings (category ratings) where is designed to know how much load it can support:

The new kid of the block uses fiber optic, which is the best option since it uses light, so it goes to the speed of light literally, by reflecting inside of the cable with really tiny fiber glass, and for the provider of the light could be multimode (LED) common for houses, or singlemode (Lasers) for many kilometers of distance, and fiber just accomplish one function, sending or receiving, so one cable for one of those.

The majority of these cables are covered in plastic, and plastic can burn so there’s plenum ratings (being plenum what is between your drop ceiling and the actual ceiling) rated on how much they can resist fire:

Crimping cable

Crimps are the connectors, and you should be comfortable with crimping cable, and you need to match up the connector with the category the cable is, so RJ-45 for cat 5 with a cat 5 cable, and there’s specific colors that match a standard, being for example:

Most connectors have a tab, and starting from the right you read the pins of the connector, check online the chart of each standard on how to do it, and if you make one side type A and the other side type B that’s called crossed cables and they are quite handy because that way you can connect two computers without a switch, and they would be able to communicate, and the same type on both ends is called straight-through, and all of this is made with a punchdown.

Structured cable

This is that you need to put your cables inside the walls since you don’t want cables all over the place nor people stepping on your cables damaging the reliability of the data, so structured cable starts with the MDF (Main distribution frame) where all of the equipment will be, and it’s a rack where the most standard is 19 inch rack, and you can size the rack with ‘u’ which is the standard size of a switch in a rack, and we will have horizontal runs that really is ethernet ports on your wall outlet to the back of the rack that is called a patch panel that are numbered ports that connect to your switch, and the maximum horizontal run is 90 mts, and you can test your cables with a cable tester.

If you have no idea where the cables are going you need a fox and a hound, being the fox a tone generator and the hound a tone probe.

If you need to know how long the cable is you will need a TDR (Time domain reflectometer) and it uses the speed of light to know how long is the cable, and this test is handy to know if a cable has broken down.

And the cable that we put to the walls itself are solid core, that is solid piece of copper and is reliable, and for the patch is stranded so is flexible and it won’t be broken.

Network card Troubleshooting

Install the NIC and go to device manager to check the drivers of the NIC, so you can configure half-duplex or full-duplex speeds (leave it on auto) and Wake-On-LAN that is if a computer is sleeping and it receives a packet wake the computer on, that is with a special packet called magic packet, check the bios if the NIC is enabled.

If your computer is connected to a switch it will have three lights:

So check the lights in your NIC and in your switch!

Chapter 19: Local Area Networking


The IP number is made of 4 octets, meaning that an octet could go from 1, to 255, so the IP adress following the quantity differentiate in classes like:

IP examplesClasses
192.168.93.xClass C (home routing)
192.12.x.xClass B (Businesses)
9.x.x.xClass A (enterprise)

Meaning the octet how many devices they can actually have, so a Class C addressing can have up to 254 devices, and class B can have 65,534 hosts, and the class A are in the millions.

An IP address never ends on 255, or 0, and no more than 254, since if you put a 0 it means as an identifier of an entire LAN.

The internet was created with the ARPANET basis, and TCP/IP was adopted as protocol for ARPANET.

Networks IDs and subnets masks.

IP addresses (internet protocol) version 4 is what built the internet itself but now we have an improved version being IPv6, but let’s save that for later, being the subnet the amount of devices that we can have on the network or know as netmask, and then the default gateway that is our router, and knowing that we can configure our first static ip address, where we need to input the values ourselves, in windows you can go to control panel and you will find what you need, so manual settings means static IP.

Special addresses

How to identify classes in IP addresses in an old fashioned way:

But there’s two more classes:

Being a class D multicast, and class E is reserved.

Private IP addresses are the folks who wants their own TCP/IP protocol at home, their own internet without the big internet:

And we can’t forget about Loopback IP address, the famous and it refers to your own system, to your own network card.


IPv4 addresses ran out in the 90’s, that quick, so thanks to Network address translation (NAT) we made magic possible, before in the 80’s, 90’s, each device was assigned a public IP, and that was wasteful, and complex since it was public so a firewall needed to be configured as well, but then NAT came in, that made it possible to make private IP addresses talk to the internet, since private IP addresses are just for the LAN, it can’t go outside, so when they need to the send the packet to the default gateway, and the default gateway replaces the private IP with his own public IP to communicate, and when the packet comes back the router remembered and logged what private IP sent the packet to give it to the proper IP, and that’s how it works, so what an ISP is selling you is an public IP, and not tons of public IPs for each of your devices, the down side is that you can’t host any type of web server or other type of servers since the LAN is invisible to the internet, and every home router comes with NAT enabled by default.


The dynamic host configuration protocol address IP to each device on the LAN automatically, and this is completely automatic, so no need to worry to configure manually IP addresses, but what happens if your DHCP server goes down? You have APIPA (Automatic private IP addressing) that is a fallback from your OS to assign you an IP address.

APIPA will always give 169.254.X.X so check that in your IP settings, and if you have limited connectivity, that means you have a DHCP server problem.


Is an IP address with 8 octets meaning they use a 128-bit scheme, and with hexadecimal notation, and for each octet that has 4 zeroes on it is just simplified to just 1 zero, for example: 2001:0:0:1:0:0:0:8a2e And if it was 3 following octets with zeroes on it, that would be: 2001:0:0:1::8a2e

The IPv6 protocol will create a minimum of two IP’s for you system:

In the exam you need to differentiate an IPv4 from an IPv6:

Port numbers

So when sending and receiving data back and forth you need the IP of the other computer, and you need the port number so we can send that information to the correct application for example a web server (80, 443) and port numbers go through 0 all the way up to 65535, and for ports is similar with IP addresses, you need the source port and the destination port, for example visiting a web site in your browser opens a source port, being 23-337 and the server of the website you are visiting to being HTTPS will be listening on port 445, and when the data arrives the server switches the IP’s, and the ports and that’s how it works.

The number of ports running from 0-1024 are “well known” ports, running things like the web, file servers, mail servers, and many things that no one never wants them to run this port numbers without fulfilling it’s purpose.

The other range from 1024-49151 are registered ports, where other applications registered their ports for specific things, for example steam, so no one use those types of ports either.

The last range between 49152-65535 is a dynamic/ephemeral port number.

Port numbers you need to know


This are protocols, that are the specific rules and how to do a specific task, to make an standard between all devices, for example the Transmission Control Protocol (TCP) is a very common protocol for the majority of things we use, because TCP is a connection based protocol, being very reliable for getting data sent and received, it’s purpose is to not get data loss at any point since it’s based on connection, if both computers are ready to connect and have a well established connection, they can talk, where’s UDP is connectionless protocol (User datagram protocol) so the UDP protocol doesn’t care if the server is not ready it just goes for it and see if it get a response, and ICMP (Internet control message protocol) is only a single packet trasnfer, and that is what the ping command uses for protocol for example.

When establishing a connection over one of these protocols, the data that the protocol cares about is a PDU (Protocol data unit) since these type of protocols doesn’t care about MAC addresses or stuff like that so it only takes the frame it needs, in this case a PDU.


The Domain Name System is really a name to get to an IP address, for example is really an IP address behind it, as everything in the digital world, so we have DNS to remember more easily names of webpages, or phone numbers instead of remembering IP addresses everywhere.

Before the DNS server came around we had host files (see yours right now! in linux: cat /etc/hosts) and there you can create names of your preferred IP’s to visit.

So DNS resolves fully-qualifed domain names (FQDN) to IP addresses, and all internet connected hosts have a DNS server, a FQDN is a domain name that was verified and fully-qualifed with the requirement that is not taken and that is maximum 255 characters long with dots included.

Working with DNS

To troubleshoot DNS problems you can:


Is the name of the computer to be recognized in the LAN, and for windows this is useful with AD (Active Directory) and workgroups.

In windows:


Routers connect the LAN to the ISP (Internet service provider) and it’s work is to connect you to the internet.

To configure most SOHO routers (Small Office/Home Office) that those types of routers include a switch, a router, and a WAP (wireless access point) they have a web interface, so in your browser you go to the specific IP of the router and from there you can configure them, most routers have in their back the IP address and their admin default password.

Some routers need to be configured through the terminal with console ports, you connect yourself to the router with a specific cable and with a terminal you configure them.

Router configurations

Advanced router configuration

Bandwidth is a thing to calculate in your LAN, since some devices require it more than others so the QoS is a toolset that meters how much bandwidth requires a certain IP, if more or less than others, or a certain MAC address, and is really up to you to take advantage of this option.

UPnP (Universal plug and play) shows it every OS, so you can see your router in your options and configure it from your OS, in windows that’s called Link Layer Discovery Protocol, but there’s a much more powerful tool called SNMP (Simple network managment protocol) used by network administrators, is great!


Virtual Local Area Network, takes a switch and digitally creates a virtual LAN, and that’s really useful if you have a lot of services going and you need them more organized but you don’t want to buy another switch, and by creating a VLAN you give an IP address to a switch, and a switch support that is called a managed switch, because switches are layer 2, so it just knows MAC addresses, so a switch that doesn’t have a IP address is an unmanaged switch, but a managed switch is more expensive.

If you have connected devices to a switch and they aren’t talking to each other you might have a problem with VLAN configuration by default.

In managed switches you can setup port security which is great because what it does is it remembers the MAC addresses of the connected devices in those specific ports, and if it changes, don’t enable the port at all, and send a notification about it, this is configured on the web interface of the managed switch.

Working with connections

To check the status of your connection you can run netstat on your windows machine and it will show you network connections that you are having, what ports and protocol is using.

Working with workgroups

With workgroups you can share SMB/Samba servers to share folders and so much more, by default you should leave the share to everyone and leave it on read/write but use NTFS permissions instead that are more powerful to configure your sharing, you must have an account on a remote system to access shared folders, security is an issue on workgroups if is used in an enterprise scale, the best way is to set up an active directory.

Working with Active Directory

You need to create a domain controller that is a computer that runs windows server and it handles the domain accounts with SSO, is great by being security-focused with security policies that propagates on the whole domain, you can run login scripts and roaming profiles.

Now you can share based on domain accounts, be careful of giving domain admin privileges since it has full power of the AD, so we use organizational units to tidy up the AD.

Windows sharing with Mac and Linux

Sharing across OSes is made the microsoft way with SMB (Server Message Block) or commonly known as Samba, you just need to give it a name and you can start sharing folders and files!

The net command

Is a old tool but still rocking and it will give you information with the following flags

Firewall configuration

To configure a firewall we need to follow the principle of least privileage, giving only the permissions that the user need to continue working, you can create access control list, whitelist/blacklist, you can set up a DMZ (DeMilitarized Zone) that is a LAN host exposed to the WAN.

There are two types of firewalls:

Windows Firewall

You can configure your windows defender firewall, so you set up profiles and block certain PID, ports and more, you can create exceptions on the three profiles (domain, public, private)

Port forwarding

You can setup ports that are available on the WAN by setting up port forwarding, you configure the ip, the port that the client connects and the port that it will forward to, we use nonstandard port numbers for security reasons and we can use DDNS to configure devices.

Network Troubleshooting

Chapter 20: Wireless networking

The standard in the wireless world is the IEEE 802.11 that defines how all the wireless stuff talks.

If you have a WAP there’s different modes of running them and most of us use the infrastructure mode since it’s required to have a WAP to set it up, and to connect to it you will need a network card and there’s different ways to get it:

The WAP will be configured to create a SSID (Service set identifier)

With Ad Hoc mode, is a way to create a LAN with wireless without a WAP, being one computer the WAP in this case.

Antennas are really important in the wireless world and there’s different types of them:

Wi-fi standards

The 802.11 standard is based on the ISM radios bands (Industrial, scientific and medical) and your WAP will use one or both of differents bands:

With a band being a range of radio frequencies, where the 2.4 band goes from 2.412 up to 2.4884 GHz of frequencies, and to make it simple they made channels, so each channel takes place on this range, being from 1 up to 14 but that differentiate if you are in Japan where is 14, if you are in Europe it will have only 13 and in the US only 11.

With the 5 GHz band: will go on from 5.150 up to 5.875 GHz, but the channels are weird coming from 36 up to 165, skipping a ton of numbers, check the standard, it just means that is really great.

IEEE extensions

802.11n100mbps2.4/5 GHz

b, n and g are compatible since they run on the same band but not in a, except for n since it can run on both bands.

Most 802.11n WAP have MIMO (Multiple in/multiple out) on by default that is that it can direction the radiation to the device.

But there’s other: 802.11ac, and it’s blazing fast! and it has MUMIMO (Multi user MIMO) it’s 2.4/5GHz for backwards compatibility, this standard is also called Wi-Fi 5, the thing is that Wi-Fi 5 is not compatible with Wi-Fi 4 NICS (Network cards) so that is the catch.

Basic WAP setup

For channel configuration you can see the how busy is the network with external applications (like wifiman made by ubiquity) and select your channel of preference, check that 1,6,11 are the preferred ones since they don’t overlap, and 5GHz just leave it to automatic.

Configure an SSID (the name of the wifi), and you can configure to broadcast it or to hide it, when hidden it will not show and you will need to enter it manually, this is a security feature according to compTIA (but not that secure tho)

Check the mode and set the channel width in auto as well as the channel itself, you can adjust the wattage where it can improve the radius where the signal covers, set it to your liking.

Connecting to a wi-fi network

If you have problems connecting with Wi-Fi:


The wireless mesh network (WMN) is really ad hoc but on steroids, were you setup a WAP, and then with Wi-Fi extenders configure it to extend the signal of one SSID with multiple devices, and is really but really easy to configure for SOHO environments.

Beyond Wi-Fi

There’s things like RFID (Radio frequency identification) is very important in cards to authenticate for doors in a building, or RFID stickers in a warehouse, RFID use tiny radios activated by the energy of the scanning device, and RFID for non nerds is NFC (Near Field Communication) and you see it on smartphones, credit cards, etc to connect, NFC is very low powered and you need to make them really close to each other to make them able to connect.

Bluetooth is like 802.11 but is a PAN connection protocol (Personal Area Network) where is point to point.

Wireless encryption

Enterprise wireless

In an enterprise environment is a bit the same, just much bigger, and the way to handle wireless in the enterprise side is with WAPs that support PoE (power over ethernet) with a PoE switch of course, and you will be ready to go! just put those WAPs on the walls and connect them with ethernet and it will be turned on since it’s PoE, that is it!

For the authentication side you will need to use RADIUS, or TACACS+ boxes, that will implement the AAA standard (Authorization, Authentication, Accounting) that will ask an account (username and password) and you for the SSID creation you will need to use a ESSID (Extended SSID) so that every WAP uses the same SSID so that way you don’t need to sign in and out everytime.

For security you can setup isolation, that permits the users to only access the internet and not the LAN itself, it would not let them ping other devices or share folders for example.

Troubleshooting Wi-Fi

Chapter 21: The internet

Internet tiers

Dial-Up connections

Or known as POTS (Plain Old Telephone Service) is the old school telephone where you pay monthly for a cable to connect to a telephone, this is legacy but you can use it with a modem, being two RJ-11 ports, where one goes to your computer and other went to the modem, so that way you can use your telephone to send digital packets, but this is deprecated since it’s max speed is 56kbps.

Broadband connections

Wires, wireless, satellites you name it! This is about connections, let’s get them organized:


Digital Subscriber Line is the type of broadband that you used to get into the internet with a telephone cable with a modem, modern routers still supports this with PPPoE (Point-to-Point Protocol Over Ethernet)


Cable uses DOCSIS (Data Over Cable Service Interface Specification) where you can have TV signal and internet at the same time


Is great! it has up to 25 mbps for download and upload speeds, but it has latency tho, but you can have it wherever you want!


Some ISP companies will give you the option to just have your own antenna that receive signals from your ISP towers.

Firewalls and servers

Firewalls are just rules over ports, to enable them or accept connection over them with the incoming vs outgoing concept.


FTP (File transfer protocol) bases on the port 21 and works with repositories of data you want to transfer and you can access them through your web browser or a FTP client like filezilla is better, port triggering could be problem since there are two modes of FTP:

The thing is that in the client it has never started the communication on port 20 so every router will block it, so you need to enable the exception on your router settings.


There are different ports for different e-mail protocols like:

SMTP Is used on every e-mail protocol since it’s the base to sending and receiving mail, where it changes is in the last two protocols (IMAP & POP)


It will have all of your mail stored on your own computer.


It will copy over the information from the server to your computer, the majority of the cases it will just display it.

Proxy Server

Proxy servers are a MITM (Man in the middle) on your outgoing connections, so it can filter webpages that are restricted, or filter keywords that shouldn’t be sent, and that way it increases security and privacy, and proxy servers can do caching, proxy servers are expensive though.


Virtual Private Networks, are a way to virtualize a connection between a device and your LAN, if you are far from home you can connect to your LAN by using VPNs and use your LAN services as you where home, so this is really powerful, you need to know the IP of the VPN server to connect as well as a VPN client.


The most common Internet of Things cases are in home automation, and they connect through 802.11, Zigbee or Z-Wave, IoT requires a hub to be controlled from, could the one that came with the product or an Arduino! Alexa, Google Home or Apple Siri are able to control IoT.

Telnet and SSH

Telnet was the way to get a reverse shell on your computer, to get a terminal from a computer remotely but the problem with telnet is that is unsecure because is not encrypted, so there is when SSH comes into place meaning ‘Secure SHell’ and it runs on port 22.

Remote Desktop Connections

When connecting remotely with GUI in the windows world we use RDP (Remote Desktop Protocol) running on 3389, this is the way to go if you want to connect to a windows server for example.

For linux and other OSes VNC (Virtual Network Computing) is the way to go, is pre-installed on mac and linux, but really VNC works everywhere even on windows to windows connections.

The World Wide Web

If you want to connect to the WWW, using a web browser like firefox, brave, icecat or other you will be using HTTP and HTTPS ports (80 for http and 443 for https) and you need to look out for http since is really insecure because is not encrypted, so only go for https page.

Troubleshooting internet connections

Before anything check always your physical! your address and gateway also.

Chapter 22: Virtualization

The VM (Virtual Machine) is just a machine with their own allocated memory, CPU, storage, etc from the host machine resources, being the host the real machine, this is not emulation since you are not trying to appear as some hardware that you don’t have, instead you are sharing your resources.

You need to activate the VT-X setting in the BIOS to enable virtualization, and to virtualize you need a hypervisor, there’s two types:

Virtualization is isolated from the host, but you can configure it extensible.

Installing a VM

This is really easy because I have background on this type of stuff, but if you anon are reading this and don’t have a clue well, install virtualbox, just google it, then go to linux mint’s website and download an ISO, which is a boot file to install linux mint, then create the VM in virtualbox with easy steps and you are ready to go!

Advanced configuration

You can configure everything, like create more virtual hard drives, or create a shared folder between your real drive and the virtual drive, you can isolate the networking of the VM or bridge into your network as if it was a real machine in your LAN!

Cloud Computing

The cloud is someone else computer where you don’t know where is it, and probably that someone is google (GCP) or microsoft (Azure) or Amazon (AWS) and you can control them, the great point is you have rapid elasticity, so you can duplicate your VM, or you can add more memory or CPU’s in a click of a button or increment the power of your VM on-demand, and the majority is paid on monthly bills, these are the business model:

Cloud Ownership

They are different clouds:

Cloud-Based Applications

Cloud storage and synchronization we use everyday like google drive, one drive, icloud, this made shared folders really easy! and email as well as ton of things as well to put things off-side.

Streaming applications are really famous of using the cloud, like netflix, or web based office, gaming, etc.

Chapter 23: Portable computing

Functions keys are really important! So check the what functions you have and what can you do.

Laptops have Keningston locks so you won’t take the laptop elsewhere, also they have docking stations but they aren’t that common anymore, there’s port replicators too that is a USB hub.

Laptop Troubleshooting

Be careful with the screws since they are really tiny, check your model’s manual online to see how to disassemble the specific model, and go for it with a goal in mind.

IfixIt kit is really great and a anti-static mat as well!

Laptop Hardware: CPU & Motherboard

Best way to get to those places is by taking off the monitor, read the manufacture manual, and take pictures of your process to guide yourself.

Laptop displays

Use the right tools, remember that a monitor has a webcam, antennas, and more things built-in so check for that.

Power managment

Be careful with AC adapters, In the most cases buy from the manufacturer, if your battery die you just replace it, like any other battery.

ACPI (Advanced Configuration and Power Interface) enable us to suspend, sleep, hibernate and much more our laptops! This is where power managment was born 20 years ago.

ACPI has levels:

Chapter 24: Mobile Devices

They are:

  1. Single, sealed unit
  2. Runs specific mobile OS
  3. Wireless connectivity

Connecting our mobile devices

You can connect them wire or wireless, wired with USB micro B, or Type C or Lightning, to charge them or synchronize files, and wireless will be NFC, Bluetooth, Infrared, and wifi.

Virtual reality

Gaming is the real purpose for consumers, or useful purposes are medical, military, etc… Remember the difference between VR and AR.

Mobile - Email

Ports to remember:


Mobile device security

You need:

Troubleshooting mobile security

Troubleshooting mobile devices

Chapter 26: Printers and multifunction devices

Laser printers

In laser printing you use a laser to hit a photosensitive drum to print into the paper with the laser, by following these steps:

  1. Processing (Stores the print job on local memory)
  2. Charging (Negative charge)
  3. Exposing (Writing with laser)
  4. Developing (The toner prints the words)
  5. Transferring (Charges the paper)
  6. Fusing (Heat and pressure)
  7. Cleaning

Laser printers are really easy to mantain, and if you have problem just replace the toner cartridge and then clean it, read the manual.

Inkjet printers

Printing for the masses, you put the ink in the jet that is a separated box where you put the cartridges of ink, and if you have problems you can:

Impact Printers

Impact printers are really old that used tractor feed paper, they aren’t common except on shipping businesses, and to maintain one you need to replace the ribbon and keep cleaning them.

Thermal printers

Thermal printers are the ones that are used in stores for your receipt, and work with a special type of paper that is thermal sensitive so when you apply heat to the paper it changes colors, to maintain them you need to:

Installing a local printer

Connect a printer by one of two ways:

You can install utitlies from the manufacturer to know what is happening with the printer.

Sharing a printer

Is really trivial while using windows, is like a shared folder.

Installing a wireless and cloud printers

Troubleshooting printers

3D Printing

You can use blender or cura to make 3D designs, and every 3D printer needs thermal plastic filament that is the plastic that will melt and dry really fast.

Chapter 27: Securing computers


Be on the look out for MiTM, DDOS, DOS, Spoofing by checking system files, logs, and more.

Physical security

This is really important, security guards, locks, biometric locks, badge readers, smart readers doors, man traps, cable locks, privacy screen, server locks, usb locks, and much more is important.

Passwords and authentication

  1. Strong passwords
  2. Looong passwords
  3. Password expiration
  4. Screensavers!!
  5. BIOS passwords!!!
  6. Passwords everywhere!!
  7. Multifactor auth



Is malware that it’s job is to replicate everywhere


The first generation of malware that replicated on the network, emails, messages, etc


Like the trojan horse, is a malware that appears as something legit but what it does it zombiefies your computer.


Is malware that was stored on specific sectors of the storage to be sneaky, it isn’t anymore but is good to know, that is the compTIA way, but the real way is that a rootkit is a collection of malicious software designed to get access to a computer.


Is a program that encrypts your files and if you want them back you need to pay the hacker in crypto, and the most cases it will not tell you the key to decrypt the files


It registers your keystrokes.


Is malware that spies on you but is really common like google, amazon, microsoft and more.



Things to take note:

7 steps of dealing with malware:

  1. Identify and research malware symptoms
  2. Quarantine infected systems
  3. Disable system restore (Windows)
  4. Remediate the infected systems
    • Update the anti-malware and signatures
    • Scan and use removal techniques (safe mode)
  5. Schedule scans and run updates
  6. Enable system restore and create a restore point (delete the old points)
  7. Educate the end-users

Social engineering

Be careful of:


Everyone have deal with the EULA and proprietary software, like microsoft, or games with DRM to protect copyright, there’s difference between personal license and enterprise license, where it changes the way to use the product, but what if I can show you the way of FOSS, the free and open source software world where there’s no spyware and everyone is happy, that is thanks to the GNU public license, (GPL) and richard stallman, and with servers is complicated the pre-processor way to license windows since in servers you can pay up to more than 2 licenses of windows server for the same machine! so use linux.

Incident response

An incident is a problem that happens in the office that needs documentation and a special procedure, could be infected computers, a hacked router and so much more.

  1. Know your responsibility
  2. Identify the problem
  1. Keep chain of custody

Environmental controls

  1. Make sure you are compliance to your government regulations
  2. MSDS (Material safe data sheet) to know how to handle devices
  3. Temperature and humidity levels, make it very cold and dry!
  4. Battery backup and get a ups
  5. Clean dust and debris (consider enclosures and compressed air)

Dealing with threats

The intrusion detection system (IDS) is a software or could be a box that detects threats and notify the agents about it, but is deprecated because of the intrusion preventiton system (IPS) that replaced it, the difference between IDS and IPS is that the IDS notifies but the IPS notifies and tries to kill the threat by closing ports or blacklisting domains, these types of equipment is expensive tho.

But specially for smaller business there’s UTM’s (Unified Threat Managment) that is a service or a box that will combine a firewall, anti-malware and/or intrusion protection, and are available on the cloud.

Chapter 28: Operational procedures

Documents you need to know

Data you need to know

Change managment

Is the organized, smart, careful system to make changes in the enterprise level and keeps them from losing money, or personel and such.

  1. Change board
    1. Documented business practices
    2. Purpose of the change
    3. Scope of the change
  2. Risk analysis
  3. Plan for the change
  4. End user acceptance
  5. Backout plan
  6. Document the changes (lessons learned)

The zen of backup

Backup and recovery:

Recycling and data destruction

You can recycle:

You can sell:

If you want to destroy your data your put 5 holes on it and you are good to go! or run drive-wiping software if you want to reuse the drive.

Good luck!

Sorry for any typo since this are quick notes of what I studied, you will pass! You got this!