Module 1: Introduction to Personal Computer Hardware

PC Safety

Electrostatic Discharge (ESD):

ESD is a buildup of an electric charge that exists on a surface that comes into contact with another differently charged surface. It takes 3000 volts of static electricity for a person to feel ESD, but 30 volts or less can damage PC components.

ESD Prevention:

To prevent ESD damage, follow these recommendations:

• Keep all components in antistatic bags until you are ready to install them.

• Use grounded mats on workbenches.

• Use grounded floor mats in work areas⁵.

• Use antistatic wrist straps when working ^on computers.

Electrical Safety:

• Electrical equipment must be grounded⁷.

• Exchanging AC adapters with a different type of laptop may cause damage to both the AC adapter and the laptop⁸.

Cases and Power Supplies

Computer Cases:

The case holds the internal components of a computer, such as the power supply, motherboard, CPU, memory, and drives9. The physical design of a case is its form factor10.

• Common form factors include: horizontal case, full-size tower, compact tower, and All-in-one¹¹.

Power Supplies (PSU):

A power supply converts AC (alternating current) power to a lower voltage DC (direct current) power required by internal computer components12.

• PSU Form Factors:

  • AT (Advanced Technology): An obsolete power supply for legacy systems¹³.

  • ATX (AT Extended): An updated but still obsolete version of the AT supply¹⁴.

  • ATX12V: The most common power supply on the market today¹⁵.

  • EPS12V: Originally designed for network servers but is now used in high-end desktop models¹⁶.

Power Supply Connectors:

• 20-pin or 24-pin slotted: Connects to the motherboard¹⁷. The 24-pin connector has two rows of 12 pins each ¹⁸, and the 20-pin has two rows of 10 pins each¹⁹.

• SATA keyed connector: Connects disk drives and is wider and thinner than a Molex connector²⁰.

• Molex keyed connector: Connects hard drives, optical drives, or other devices²¹.

• Berg keyed connector: Connects to legacy floppy drives and is smaller than a Molex connector²².

• 4-pin to 8-pin auxiliary power connector: Supplies power to different areas of the motherboard²³.

• 6/8-pin PCIe power connector: Supplies power to internal components²⁴.

Power Supply Voltage and Rails:

• Common voltages are 3.3 volts, 5 volts, and 12 volts²⁵.

• 3.3V and 5V supplies are typically used by digital circuits²⁶.

• 12V supplies are used to run motors in disk drives and fans²⁷.

• A "rail" is the printed circuit board (PCB) inside the power supply²⁸. A single-rail PSU has all connectors on one PCB, while a multi-rail PSU has separate PCBs²⁹.

Motherboards

Motherboard Overview:

The motherboard is the backbone of the computer30. It is a PCB that contains buses (electrical pathways) to interconnect components31. Components can be soldered directly or added via sockets, slots, and ports32.

• Common Components: CPU, RAM, Expansion Slots, Chipset, BIOS/UEFI chip, SATA connectors, Internal USB connector³³.

Motherboard Chipset:

The chipset consists of integrated circuits on the motherboard that control how system hardware interacts with the CPU and motherboard34.

• Northbridge: Controls high-speed access to RAM and the video card³⁵.

• Southbridge: Allows the CPU to communicate with slower devices like hard drives, USB ports, and expansion slots³⁶.

Motherboard Form Factors:

This pertains to the size and shape of the board37.

• ATX (Advanced Technology eXtended): The most popular form factor, measuring 12 in x 9.6 in³⁸.

• Micro-ATX: A smaller form factor popular in desktops, measuring 9.6 in x 9.6 in³⁹.

• ITX: A family of form factors including Mini-ITX (6.7 in x 6.7 in), designed for small devices like thin clients⁴⁰.

CPU and Cooling

Central Processing Unit (CPU):

The CPU is responsible for interpreting and executing commands41. It is a small microchip that resides within a CPU package42.

• CPU Socket: The connection between the motherboard and the processor⁴³.

  • Pin Grid Array (PGA): The pins are on the underside of the processor package⁴⁴.

  • Land Grid Array (LGA): The pins are in the socket instead of on the processor⁴⁵.

Cooling Systems:

Computer components perform better when kept cool using active and passive solutions46.

• Active solutions require power, like a case fan⁴⁷.

• Passive solutions do not require power, like heat sinks⁴⁸.

Memory

Types of Memory (ROM vs. RAM):

• Read-Only Memory (ROM): Located on the motherboard, it contains basic instructions like booting the computer⁴⁹. Its contents are not erased when the computer is powered off (non-volatile)⁵⁰.

• Random-Access Memory (RAM): Temporary storage for data and programs being accessed by the CPU⁵¹. RAM is volatile, meaning its contents are erased when power is off⁵². Adding more RAM can enhance system performance⁵³.

Types of ROM:

• PROM (Programmable ROM): Manufactured blank and can be programmed once⁵⁴.

• EPROM (Erasable Programmable ROM): Non-volatile but can be erased by exposing it to strong ultraviolet light⁵⁵.

• EEPROM (Electrically Erasable Programmable ROM): Can be erased and rewritten ("flashed") without removing it from the device⁵⁶. EEPROMs are often used to store a computer's BIOS⁵⁷.

Types of RAM:

• SRAM (Static RAM): Very fast RAM often used for cache memory⁵⁸. It is the fastest type of RAM⁵⁹.

• SDRAM (Synchronous Dynamic RAM): DRAM that operates in synchronization with the memory bus⁶⁰.

• DDR SDRAM: Transfers data twice as fast as SDRAM⁶¹. It has a 184-pin connector⁶².

• DDR2 SDRAM: Runs at higher clock speeds than DDR and has a 240-pin connector⁶³.

• DDR3 SDRAM: Doubles the clock rate of DDR2 and has a 240-pin connector^64646464.

• DDR4 SDRAM: Quadruples DDR3's maximum storage capacity and has a 288-pin connector⁶⁵.

• DDR5 SDRAM: More than doubles the speed of the fastest DDR4 modules and has a 288-pin connector that is not compatible with DDR4^66666666.

• GDDR SDRAM: RAM specifically designed for video graphics and used with a dedicated GPU⁶⁷.

Memory Modules:

• DIMM (Dual Inline Memory Module): A circuit board that holds various types of SDRAM chips for desktops⁶⁸.

• SODIMM (Small Outline DIMM): A smaller, condensed version of DIMM ideal for laptops, printers, and other devices where space is a concern⁶⁹.

Cache Memory:

The fastest memory is typically Static RAM (SRAM), which is used as cache memory70.

• L1 cache: Integrated into the CPU⁷¹.

• L2 cache: Now integrated into the CPU, but was originally on the motherboard⁷².

• L3 cache: Used in some high-end workstation and server CPUs⁷³.

Memory Error Checking:

• Non-parity: Does not check for errors in memory⁷⁴.

• Parity: Contains 8 bits for data and 1 bit for error checking⁷⁵.

• ECC (Error Correction Code): Can detect multiple-bit errors and correct single-bit errors in memory⁷⁶.

Adapter Cards and Storage

Adapter Cards:

Adapter cards increase a computer's functionality and are installed in expansion slots on the motherboard77. The card's connector must match the expansion slot78.

• Common expansion slots include: PCI, Mini-PCI, PCI-X, PCIe, and Riser card⁷⁹.

Storage Device Interfaces:

• SATA (Serial AT Attachment): The modern connection for internal storage devices⁸⁰. SATA 1, 2, and 3 have different data transfer speeds (1.5 Gb/s, 3.0 Gb/s, 6.0 Gb/s respectively)⁸¹.

• PATA (Parallel ATA) / IDE: The legacy interface standard⁸².

Magnetic Media Storage:

• Hard Disk Drive (HDD): Traditional magnetic disk devices with capacities from gigabytes (GBs) to terabytes (TBs)⁸³.

• Tape Drive: Most often used for archiving data, using a removable tape cartridge⁸⁴.

Semiconductor Storage:

• Solid State Drive (SSD): Stores data as electrical charges in semiconductor flash memory⁸⁵. SSDs are much faster than HDDs, have no moving parts, and are more energy efficient⁸⁶.

  • Form factors include: disk drive, expansion cards, and mSATA or M.2 modules⁸⁷.

• NVMe (Non-Volatile Memory Express): A standard interface developed to allow computers to take greater advantage of SSD features by providing a standard interface between SSDs and the PCIe bus⁸⁸.

• Solid State Hybrid Drives (SSHDs): A compromise between an HDD and an SSD, combining a magnetic HDD with onboard flash memory as a non-volatile cache⁸⁹.

Optical Storage Devices:

These are removable storage devices that use lasers to read and write data90.

• CD: Can be CD-ROM (read-only), CD-R (recordable), or CD-RW (rewritable) with a capacity of about 700 MB⁹¹.

• DVD: Can be DVD-ROM, DVD-R, or DVD-RW with a capacity of 4.7 GB (single-layer) or 8.5 GB (dual-layer)⁹².

• BD (Blu-ray Disc): Can be BD-ROM, BD-R, or BD-RE with a capacity of 25 GB (single-layer) or 50 GB (dual-layer)⁹³.

Ports, Cables, and Peripherals

Video Ports and Cables:

• DVI (Digital Visual Interface): A usually white connector with up to 24 pins for digital signals⁹⁴.

• DisplayPort: Designed to connect high-end graphics-capable PCs and displays⁹⁵.

• HDMI (High-Definition Multimedia Interface): Developed for HDTVs but also a good candidate for computers⁹⁶.

• Thunderbolt 3: Uses the same connector as USB-C, has twice the bandwidth of Thunderbolt 2, and can provide video to two 4K monitors⁹⁷.

• VGA (Video Graphics Array): A 15-pin connector for analog video⁹⁸.

• RCA: Used to carry audio or video, often found in groups of three (yellow for video, red and white for audio)⁹⁹.

Other Ports and Cables:

• PS/2: Connects a keyboard or a mouse to a computer¹⁰⁰.

• Network (RJ-45): Has 8 pins and connects devices to a network¹⁰¹.

• SATA: Connects SATA devices using a 7-pin data cable¹⁰².

• IDE: A ribbon cable used to connect storage drives, typically with 40 pins for hard drives¹⁰³.

• USB (Universal Serial Bus): A standard interface that connects peripheral devices and is hot-swappable¹⁰⁴.

Input and Output Devices:

• Input Devices: Allow a user to communicate with a computer, such as a keyboard, mouse, and scanner¹⁰⁵.

• Output Devices: Take binary information from the computer and convert it into a form that is easily understood by the user, such as monitors, printers, and speakers¹⁰⁶.

Monitors, Projectors, and Headsets:

• Monitors use LCD, LED, or OLED technology¹⁰⁷. Projectors typically use LCD or DLP (Digital Light Processing) technology¹⁰⁸.

• Virtual Reality (VR): Creates a simulated, three-dimensional environment with a headset that completely encases the user's upper face¹⁰⁹.

• Augmented Reality (AR): Superimposes images and audio over the real world; the headset usually does not close off ambient light^110110110110.

Printers:

Printers are output devices that create hard copies of files111. Different types include inkjet, laser, impact, thermal, and 3D printers112.