Computer Hardware Components and Boot Process

IPL (Initial Program Load)

IPL (Initial Program Load) -> Power On Self Test (POST)

BIOS (Basic Input/Output System)

BIOS: A set of input and output routines. It handles the communication between the operating system and hardware.

Types of Memory

• RAM (Random Access Memory): For both reading and writing.
• ROM (Read-Only Memory): For reading only.

Types of ROMs

• ROM: Read-Only Memory.
• PROM: Programmable Read-Only Memory. A digital memory where each bit's value depends on a fuse that can be burned only once.
• EPROM: Erasable Programmable Read-Only Memory. Read sequentially. Less reading provides a greater margin for error.
• EEPROM: Electrically Erasable Programmable Read-Only Memory. The signal is updated and erased with the BIOS.

RAM and ROM Classification

• Dynamic ----> RAM (Read/Write)
• Static -----> SRAM (Read/Write)
• ROM
  • Not Erasable: PROM
  • Erasable:
    • UV ---> EPROM
    • Electrically ---> EEPROM

EPP (Enhanced Parallel Port)

EPP: An improved parallel port. It has 8 input and 8 output threads. The connector has 25 pins.

Bus Connections

• ISA: Industry Standard Architecture.
• EISA: Extended Industry Standard Architecture. An improved version of ISA.
• Local Bus: An extension of EISA. It has a direct connection to the CPU. Used by video cards.
• PCI: Peripheral Component Interconnect. A type of local bus.
• AGP: Accelerated Graphics Port. A local bus specifically for video cards.

Drive Bays

Drive Bays: The location where floppy and hard drives are connected.

Computer Case Types

• Slim Cases: Smaller form factor cases.
• Desktop Cases: Horizontal cases, larger than slim cases, and usually taller. Designed for home use.
• HTPC: Home Theater PC. Designed for a home media center (stereo).
• Micro ITX: Particularly low power. Small power supply. Reduced mechanical strength. ITX motherboard with low power.
• ICT Box: Informatics and Communications Technology Box. Contains telecommunications channels, through which all the cables of a house pass.
• AT: The motherboard format used by the IBM AT and clones, in full desktop and full tower format. Its size is 12 inches. Released in 1984.

Computer Boot Process

1. The power switch supplies power to the motherboard and electromechanical devices.
2. The microprocessor resets its internal registers to zero.
3. The BIOS wakes up and performs the POST (Power On Self Test).
4. The microprocessor receives POST commands and tests the connected devices.
5. The video card and RAM are initialized and set to 0.
6. The keyboard is initialized, and access to the setup (IRQ configuration) is enabled.
7. The microprocessor checks the connected components and verifies their proper functioning. Afterward, it passes control to the OS and loads the MBR (Master Boot Record) into memory.