PC hardware tutorials: a complete guide from scratch

If you've ever thought "I'd like to understand How PC hardware really works"But every book you open sounds like gibberish, don't worry: you're not alone. The world of hardware can seem like a jumble of acronyms, numbers, and electrical concepts, but with a clear explanation and simple examples, it becomes much easier to understand."

In this guide you will find a complete tour of the physical components of a computer, its internal language, and how everything fits togetherFrom the most basic concepts (what is a bit or a byte) to specific components like the motherboard, RAM, CPU, ports, and hard drives, covering key aspects such as system speed, data bus, and cache memory. It's designed so you can read it at your leisure, without rushing and without needing any prior knowledge.

How a computer communicates: bits, bytes, and measurement systems

To understand PC hardware, you have to start from the beginning: the computer only “speaks” electricityInternally, it all boils down to whether there is current (1) or not (0) in millions of tiny switches integrated into chips.

Each of those possible states, on or off, is called bit, the smallest unit of information that a computer handles. A bit can only be worth 0 or 1, but when we put several bits together we start to be able to represent letters, numbers and symbols.

The next step is byte, a group of 8 bitsWith 8 switches (bits) we can form many different combinations of zeros and ones, and each combination is assigned a character. For example, in the well-known ASCII code, the letter A can be represented with a specific 8-bit sequence, such as 10100001.

When you press a key on the keyboard, the computer doesn't "see" the letter as such, but rather receives a combination of 0 and 1 corresponding to that keyThe hardware translates your keystroke into bits, and the screen ends up displaying the letter thanks to that encoding system.

Since a byte is too small to measure large amounts of data, its multiples are used. The most common storage units in computer science are:

• 1 bytes = 8 bits (a character, number, or space).
• 1 Kilobyte (KB) = 1024 bytes.
• 1 megabytes (MB) = 1024 KB.
• 1 Gigabyte (GB) = 1024 MB.
• 1 Terabyte (TB) = 1024 GB.

Notice that multiples of are always used 1024 and not 1000For example, a 1 KB document actually occupies 1024 characters, counting letters, numbers, symbols, and spaces.

Besides capacity, in hardware there is a lot of talk about data transmission rateHere you'll see units like B/s, KB/s, MB/s, or GB/s (bytes per second). And sometimes you'll find bits per second (b/s, Kbps, Mbps), which are 8 times smaller than the values ​​in bytes per second because 1 byte is 8 bits.

The idea of frequencywhich is measured in hertz (Hz, MHz, GHz). A component operating at 1 MHz performs one operation per million times per second. In modern processors, we speak of gigahertz (GHz), that is, billions of cycles per second.

What determines the actual speed of a computer

When someone says "this PC is very fast" they usually only look at the processor, but in reality The speed of a computer depends on several factors combined.The microphone is important, yes, but it's not the only one.

First is the number of internal bits the CPU works withThis indicates how much information it can process at once (its internal bandwidth). Previously, there were 16-bit or 32-bit processors; today, virtually all home computers are 64-bit, which allows for handling more data simultaneously and making better use of memory (see performance comparison).

The second key factor is the operating frequency or machine cycleInside the computer, there's a "clock" that sets the pace at which instructions are executed. A 2 GHz processor, for example, is capable of performing around 2.000 billion cycles per second. The higher the frequency, the more instructions per second... provided the rest of the system keeps up.

The following also have a significant influence data busesThese are the "highways" along which information travels from one component to another (CPU, RAM, disk, graphics card, etc.). The wider the bus (the more bits it can carry at once) and the higher its frequency, the smoother the data traffic will be within the computer.

To use an agricultural analogy, it's like a combine harvester: if it can cut several rows of corn in each pass and unload them into large, fast trucks, the job gets done sooner. If buses were cramped or slow, Bottlenecks would form even if the processor were very powerful.

In summary, the team's overall speed is determined by the combination of:

• Number of internal bits of the microprocessor (internal bandwidth).
• Working frequency of the processor (MHz or GHz).
• Data bus speed and width that connects the components.
• Hard drive performance or SSD drive and the motherboard chipset.
• Amount and speed of RAM.

The case, the power supply, and the motherboard

Every desktop computer starts with a tower or case with sufficient space and ventilationThe size of the case determines how many bays and slots you will have to install storage drives, fans, and other components.

Inside the box we found the power supplyThe power supply transforms the alternating current from the electrical grid (for example, 220V) into lower, more stable voltages that the computer can use, typically +5V and +12V. A good power supply is key to the stability of the equipment and to avoid unexpected problems caused by insufficient power or voltage spikes.

The central component where virtually everything connects is the motherboardThe motherboard houses the processor, RAM, expansion cards, SATA connectors for hard drives, USB ports, BIOS, chipset, and many other components. The motherboard must be compatible with the processor (socket type, etc.). motherboard compatibility, memory support, etc.).

On the plate you will find different expansion slotswhich are plastic connectors with metal contacts where the cards are inserted:

• PCI and PCIe slotsThe modern standard. Most current cards, including 3D graphics cards, connect to PCI Express (PCIe). They are faster and come in various sizes (x1, x4, x8, x16) depending on the number of pins and data lanes.
• DIMM slots: for RAM memory modules. Older SIMMs are now obsolete.
• SATA connectors: for connecting modern hard drives and optical drives using SATA cables.
• IDE connectors: the old standard for PATA disks, practically extinct in current PCs.

In addition to the slots, the motherboard integrates various Controllers or controllers that manage data traffic between the CPU, RAM, disks, and peripherals. Previously, there were many separate controllers; today, most are grouped into the chipset.

El chipset It's a chipset that determines how the microprocessor, memory, cache, USB ports, PCIe buses, etc., communicate with each other. Its quality and characteristics affect things like:

• The actual performance you get from the CPU.
• Maximum RAM capacity that can be installed.
• Compatibility with modern technologies (RAM types, disk types, advanced ports).
• The possibility of future upgrades and the support of certain processors.

Memory: ROM, BIOS, RAM, cache, and virtual memory

A computer doesn't have just one type of memory, but several, each with its own function. Understanding them helps a lot in seeing Why does my PC sometimes run fast and other times it's slow?.

The old one ROM memory (Read Only Memory) It was a read-only memory where the manufacturer stored the basic system boot and configuration instructions. Its contents were not erased when the computer was turned off. Today, that role is almost entirely assumed by the BIOS/UEFI.

La BIOS (Basic Input / Output System) It's a program stored on a chip on the motherboard. It runs as soon as the computer is turned on, detects the memory, disks, CPU, and other devices, and performs initial checks before... load the operating systemPart of its configuration is modifiable by the user (boot order, hardware parameters, etc.).

To ensure the BIOS retains its settings even when the PC is turned off, the motherboard has a battery or small accumulatorWhen this battery runs out, the date, time, or boot settings start to be lost, and it's usually a sign that it needs to be replaced.

La main memory or RAM (Random Access Memory) It is the space where the computer temporarily stores the data and programs currently in use. It is fast memory, but volatile: when the computer is turned off, all its contents are erased.

When choosing RAM, it's important to look at its capacity (for example 8 GB, 16 GB, 32 GB) and in its transfer speed, usually expressed in MHz or using the DDR nomenclature (DDR2, DDR3, DDR4…). The faster and wider the communication between the RAM and the CPU, the more responsive the system will be.

If you install multiple RAM modules with different speeds, Everyone will work at the speed of the slowest person.That's why it's best to use similar modules. Original DRAM and early DDR memory are no longer used; nowadays, DDR3, DDR4, or higher are the norm.

In addition to the main RAM, the processors have cacheA special type of very fast memory located inside or very close to the CPU. It stores frequently used data and instructions, avoiding the need to constantly access the slower RAM.

We can imagine the cache as a bulletin board where you post notes that you consult at all timesIf what you're looking for is there, you read it instantly; if not, you have to go to the cache (RAM), which takes longer. Thanks to the cache, the CPU can work at speeds very close to its maximum frequency.

There are several levels of cache:

• L1 cacheThe fastest and smallest memory chip, located next to each CPU core. Its typical size ranges from 256 KB to 512 KB or 1 MB per core.
• L2 cache: somewhat slower and larger in size, between a few hundred KB and several MB.
• L3 cache: larger (from a few to tens of MB) and somewhat slower than L1 and L2, but still much faster than RAM.

When RAM starts to run out, the The operating system reserves a portion of the hard drive to simulate additional memory. When physical RAM doesn't fit, Windows (or another system) moves recently unused data to the hard drive.

This allows you to continue opening programs even if there is not enough RAM, but it comes at a price: The hard drive is much slower than RAMIf virtual memory is overused, the computer becomes sluggish because it is constantly swapping data between RAM and disk (page file).

Configuring the virtual memory size is possible from the advanced system options, but the real solution for intensive use is install more physical RAM, instead of relying on the disk as a patch.

The microprocessor (CPU) and its cooling system

El microprocessor or CPU It is the "brain" of the computer. It is responsible for performing calculations and coordinating what the other components do, reading data from RAM or cache and executing instructions one after another at full speed.

Internally, the CPU is mainly composed of two functional blocks:

• Arithmetic-Logic Unit (ALU): performs mathematical operations (addition, subtraction, multiplication, division) and logical operations (comparisons, conditions such as "IF this, then that").
• Control unitIt is responsible for deciding the order in which instructions are executed, what data is read or written, and how information flows within the processor.

When choosing a processor, it's important to consider several details: CPU type and family (Intel, AMD, specific range), (physical socket, chipset), operating frequency, number of cores, 64-bit support, and internal cache size.

The CPU generates a lot of heat, especially when working at high frequencies, so a good cooler is essential. dissipation and ventilation systemThe usual practice is to mount a metal heatsink in direct contact with the processor and a fan on top that expels the heat.

If the processor frequency is increased beyond the specification (overclocking), the temperature rises even moreAnd if the cooling isn't sufficient, crashes, errors, and a reduced lifespan for the components can occur. That's why thermal paste and proper fan installation aren't just a luxury, but essential.

Ports, connections and data transmission

In order for the computer to communicate with the outside world it needs inlet and outlet portsThese are the physical connectors where we plug in mice, keyboards, monitors, printers, external drives, networks, etc.

Some of the most common ones you can find on a modern PC are:

• Audio ports (RCA or minijack)Inputs and outputs for microphones, speakers, and other sound devices. Each color usually indicates a function (output, line input, microphone, etc.).
• PS/2 PortsOld round connectors for keyboard and mouse. Virtually obsolete, replaced by USB.
• USB port (Universal Serial Bus)USB is the de facto standard for almost all types of peripherals. It supports hot-swapping (plug and play), so you can connect and disconnect devices while the PC is on. Versions such as USB 1.1, 2.0, 3.0, and higher differ in speed: the higher the number, the faster the transfer.
• Ethernet port (RJ45): the wired network connector for accessing the Internet or local networks.
• External SATA ports: used to connect external hard drives compatible with this standard.
• FireWire Port (IEEE 1394): designed for fast data transmission, widely used in its day for digital video cameras.
• VGA, DVI and HDMI connectorsVideo outputs for monitors and projectors. VGA is analog and older; DVI offers digital quality; HDMI has become the most widely used because it transmits high-definition digital audio and video over the same cable, with high bandwidth.

In addition to physical ports, modern laptops and computers are full of... wireless technologies such as infrared (older), Bluetooth, or Wi-Fi. They allow data to be transmitted wirelessly using electromagnetic waves or light, with receivers and antennas integrated into the board itself or as add-on cards.

Peripherals and storage devices

The peripherals These are all the external devices that connect to the computer to communicate with it or expand its capabilities: keyboards, mice, printers, scanners, speakers, cameras, etc. They can be input devices (mouse, keyboard), output devices (monitor, printer), or input and output devices (touchscreens, external hard drives, multifunction printers).

In terms of internal storage, the star component is the HDDTraditionally, magnetic disk drives (HDDs) have been used, consisting of several aluminum platters coated with magnetizable material that rotate at high speed inside a sealed casing.

These dishes are divided into concentric trackswhich in turn are broken down into sectors (usually 512 bytes). Several sectors together form a cluster or allocation unit, which is the smallest portion of disk space reserved for a file.

If the cluster size is 4 KB and you save a file of only 1 KB, It will actually take up 4 KB on diskIf it occupies 5 KB, it will use two clusters (8 KB). That's why it's important that the cluster size not be too large, to avoid wasting space with small files.

When choosing a classic hard drive, two things are important: its capacity in GB or TB and Rotation speedThe older models rotated at 3.600 rpm, then those of 7.200 rpm became popular, and there are even faster units of 10.000 rpm or more, intended for demanding uses.

For years, hard drives and interfaces coexisted. IDE/EIDE/ATA and discs SCSI or FireWireIDE has been disappearing in favor of SATA standards, while SCSI and FireWire have remained for more specialized environments or have been replaced by other technologies.

Today, they are also very common SSD drivesThese features, which were not described in detail in the original text, but are worth mentioning, store data on flash memory chips instead of rotating platters, offering much shorter access times and a read/write speed far superior to traditional mechanical disks.

Regarding optical media, many towers still include CD/DVD readers and writersThey differ in their read, write, and rewrite speeds, expressed as a number followed by "x" (for example, 52x/24x/52x). DVDs also offer different speeds for CDs and DVDs, and the option to record in [configuration missing]. double layer, which practically doubles the disk capacity.

Another interesting parameter in recorders is the internal buffer sizeA small memory that stores data while it is being recorded. If the PC momentarily stops sending data, the drive uses this buffer to avoid interrupting the recording and prevent errors.

Monitors and screens

The computer's visual output is displayed in the monitorAnd here too there are several important hardware concepts. CRT (tube) monitors were the first to become popular; their quality depended on the size in inches, the resolution, and the refresh rate (times per second the image is "redrawn").

A very low refresh rate (for example, 60 Hz) can cause eye strain and noticeable flickering, while at higher rates the image appears more stable. Over time, CRTs have gradually given way to flat-screen displays.

The TFT/LCD screens They operate using liquid crystal technology and offer a much thinner and lighter design. In this type of monitor, the following becomes important: response time, which is the time it takes a pixel to change from one state to another. Values ​​below 20 ms are considered acceptable to avoid trails in fast movements.

These screens also have a native resolution (for example, 1920×1080). If different resolutions are used, the image is rescaled and may lose definition. When choosing a monitor, it's advisable to consider the panel type, the maximum supported resolution, the response time, the refresh rate (in gaming models), and the pixel pitch or pixel density.

The industry has continued to move towards technologies such as LED, OLED, 3D screens and high-definition televisionswhich improve contrast, color reproduction and energy efficiency, although these details fall more into the realm of consumer electronics than basic PC hardware.

Ultimately, when you look at an open desktop computer, all you see are different parts that, together, form a system: The tower that provides space and ventilation, the power supply that provides stable energy, the motherboard that connects everything, the CPU that orders and calculates, the RAM and cache that feed data to the processor, the disks that store your information, the graphics card and monitor that display it to you, and the ports and peripherals that allow you to interact.Understanding each of these parts and how they relate to each other is the most direct way to master hardware from scratch, without needing to be an engineer or suffer through impossible courses.