Data bus is used to transfer data between the memory and the CPU.

Ultra-violet-rays is used to erase the content of a EPROM.

High-Definition Multimedia Interface is an audio/ video interface which transfers the uncompressed video and audio data from a video controller, to a compatible computer monitor, LCD projector, digital television etc.

The Program Counter (PC) is a special register in the CPU which always keeps the  address of the next instruction to be executed.

A command which is given to a computer to perform an operation on data is called an instruction

A Microprocessor's performance depends on the following characteristics:
(a) Clock speed
(b) Instruction set
(c) Word size

(i) The microprocessor which is an Integrated Circuit. Microprocessors were first introduced in early 1970s. The first general purpose microprocessor, 4004 was developed by Intel Inc.
(ii) The microprocessor is a programmable multipurpose silicon chip. It is driven by clock pulses. It accepts input as a binary data and after processing, it provides the output data as per the instructions stored in the memory.

The various types of ports are given below
Serial Port : To connect the external devices, found in old computers.
Parallel Port : To connect the printers found in old computers.
USB Ports : To connect external devices like cameras, scanners, mobile phones external hard disks and printers to the computer.

PROM can be written only and cannot be erased. EPROMS are used widely in personal computers because they enable the manufacturer to change the contents of the PROM to replace with updated versions or erase the contents before the computer is delivered.

The two types of microprocessors which are based on their instruction sets.
(i) Reduced Instruction Set Computers (RISC)
(ii) Complex Instruction Set Computers (CISC)

Microprocessors can process instructions. The microprocessors can be classified as follows based on the size of the data.
1. 8-bit microprocessor
2. 16-bit microprocessor
3. 32-bit microprocessor
4. 64-bit microprocessor

Computer architecture deals with the engineering considerations involved in designing a computer. Computer Organization deals with the hardware components that are transparent to the programmer.

(a) Bus: A bus is a collection of wires used for communication between the internal components of a computer.
(b) Data bus:
(i) Data busis a collection of wires to carry data in bits.
(ii) A data bus is used to transfer data between the memory and the CPU.
(iii) The data bus is bidirectional.
(c) Address bus:
(i) Address bus is a collection of wires to carry data in bits.
(ii) The address bus is used to point a memory location.
(iii) The address bus is unidirectional.
(d) Control bus:
(i) Control bus is a control line/collection of wires to control the operation/functions.
(ii) The control bus controls both read and write operations.

(i) The size of the instruction set is another important consideration while categorizing microprocessors.
(ii) Initially, microprocessors had very small instruction sets because complex hardware was expensive as well as difficult to build.
(iii) As technology had developed to overcome these issues, more and more complex instructions were added to increase the functionality of the microprocessor,
(iv) Let us learn more about the two types of microprocessors which are based on their instruction sets.
(v) RISC stands for Reduced Instruction Set Computers. They have a small set of highly optimized instructions.
(vi) Complex instructions are also implemented using simpler instructions, thus reducing the size of the instruction set.
(vii) Examples of RISC processors are Intel P6, Pentium IV, AMD K6 and K7.
(viii) CISC stands for Complex Instruction Set Computers. They support hundreds of instructions. Computers supporting CISC can accomplish a wide variety of tasks, making them ideal for personal computers.
(ix) Examples of CISC processors are Intel 386 & 486, Pentium, Pentium II and III, and Motorola 68000.