Understanding PC Components and Startup Processes
Understanding PC Components and Startup
What is the BIOS?
The BIOS (Basic Input/Output System) is what allows the computer to start. It controls the keyboard and floppy disk, and allows control to be passed to the operating system.
What is the CMOS?
The CMOS (Complementary Metal-Oxide-Semiconductor) is a small RAM chip that stores the system’s configuration.
What is Setup?
Setup is a crucial program recorded in the BIOS chip. It’s used to change the modes of transmission and the recognition (or non-recognition) of PC devices.
The Power Supply
The power supply provides the DC voltage to each of the computer’s components, supplying the power they need. Typical supply voltages for personal computers are +5, -5, +12, and -12 volts.
Startup Process (Boot Sequence)
From the moment you press the power switch until the operating system loads, the computer performs a series of tasks to check the proper functioning of the installed hardware. The initial screening is called the POST (Power-On Self-Test). This test verifies that the hardware is working correctly. This check is performed by programs within the BIOS.
What is Cache Memory?
Cache memory is much faster than the computer’s main memory. The processor uses it to store data that may be needed in subsequent operations, eliminating the need to access the slower RAM and reducing waiting time.
General Blocks of a Microcomputer System
- Input Devices: These allow the introduction and encoding of data for the computer to process. Information is entered via devices like the keyboard, mouse, scanner, or voice input devices.
- Main Memory: This is where the computer stores running programs and the data being processed. Main memory consists of two types:
- RAM (Random Access Memory): This type of memory is read/write, and data can be read or written as needed.
- ROM (Read-Only Memory) or EPROM (Erasable Programmable Read-Only Memory): This memory is also known as the BIOS.
- Central Processing Unit (CPU): The CPU handles data, performing various arithmetic and logical operations at high speeds.
- Input and Output Units: These units communicate the system with the outside world, allowing the insertion and extraction of information. They usually consist of registers and buses operated by control and direction signals, storing information provided to or removed from the data bus.
- ALU (Arithmetic Logic Unit): The ALU performs most of the computer’s instruction set operations on data from main memory. Data can be temporarily stored in registers within the unit itself.
- Control Unit (CU): The CU is responsible for reading instructions from the code stored in main memory and generating the necessary control signals.
- Address Bus: These lines determine the sender and receiver, indicating where information should be sent or received within the computer.
- Data Bus: The set of lines through which information circulates.
- Control Bus: This bus carries synchronization signals, such as clock ticks, and signals that indicate whether the operation is a read or a write.
Software Failures
These occur as a result of the execution of another interrupt, and the hardware is not the cause of the problem.
Hardware Failures
These are produced directly by the computer’s hardware devices.
POST (Power-On Self-Test)
The POST is an automatic system test performed before the operating system loads.
The Chipset
The chipset is responsible for controlling specific functions of the computer. The northbridge chipset controls graphics and RAM, while the southbridge chipset controls storage, ports, and expansion slots.
Cache Memory
Cache memory is a relatively small amount of high-speed SRAM (Static RAM) that resides on the CPU or near the motherboard.
FireWire
FireWire is a high-speed serial bus for connecting peripherals to a computer. This interface allows up to 63 devices to be connected from sender to receiver.