(i) Address Bus
(ii) Data Bus
(iii) Control Bus

(i) Address Bus
(ii) Control Bus
(iii) Data Bus

Ultra violet rays are used to erase the contents of EPROM. EPROM retains its contents until it is exposed to ultraviolet light. The ultraviolet light clears its contents making it possible to reprogram the memory.

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

(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 microprocessor is made up on main units. They are:
(i) Arithmetic and Logic unit (ALU): 
To perform arithmetic and logical instructions based on computer instructions.
(ii) Control unit : 
To control the overall operations of the computer through signals.
(iii) Registers (Internal Memory):
They are used to hold the instruction and data for the execution of the processor.

Flash memory	EEPROM
It is faster	It is slower
Flash memory is read/write memory	EEPROM is read only memory
Flash memory can store 4GB to 2TB of data	EEPROM can store only less data
Flash memory is used in PDA'S, Digital camera to store data.	It is used to store critical programs.

CD	DVD
CD stands for Compact Disc	DVD stands for Digital Versatile Disc
Can store up to 700 MB	Capacity of DVD is 4.7 GB of data
CD's are single sided	DVD's are single or double sided
Due to capacity constraint, CD's cannot store movies of good quality	DVD's are used for storing movies with good quality
CD players cannot play DVD's	DVD players can play CD's

1. Interfaces are HDMI interface port, USB 3.0 port,
2. Ports available in the computer: Serial Port, Parallel port, USB ports, VGA connector, Audio plugs, PS/2 port, SCSI Port.

(a) Bus:
A bus is a collection of wires used for communication between the internal components of a computer.
(b) Data bus:
(i) Data bus is 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.

Read-only memory (ROM):
1. Read only memory refers to special memory in a computer with pre-recorded data at manufacturing time which cannot be modified.
2. The stored programs that start the computer and perform diagnostics are available in ROMs. ROM stores critical programs such as the program that boots the computer.
3. Once the data has been written onto a ROM chip, it cannot be modified or removed and can only be read.
4. ROM retains its contents even when the computer is. turned off. So, ROM is called as a non-volatile memory.
Programmable Read-Only Memory (PROM):
1. Programmable read-only memory is also a nonvolatile memory on which data can be written only once. Once a program has been written onto a PROM, it remains there forever.
2. Unlike the main memory, PROMs retain their contents even when the computer is turned off.
3. The PROM differs from ROM. PROM is manufactured as a blank memory, whereas a ROM is programmed during the manufacturing process itself.
4. PROM programmer or a PROM burner is used to write data to a PROM chip. The process of programming a PROM is called burning the PROM.
Erasable Programmable Read-Only Memory (EPROM):
1. Erasable Programmable Read Only Memory is a special type of memory which serves as a PROM, but the content can be erased using ultraviolet rays.
2. EPROM retains its contents until it is exposed to ultraviolet light. The ultraviolet light clears its contents, making it possible to reprogram the memory.
3. An EPROM differs from a PROM, PROM can be written only once and cannot be erased.
4. 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.
Electrically Erasable Programmable Read Only Memory (EEPROM)
1. Electrically Erasable Programmable Read Only Memory is a special type of PROM that can be erased by exposing it to an electrical charge.
2. Like other types of PROM, EEPROM retains its contents even when the power is turned off.
3. Comparing with all other types of ROM, EEPROM is slower in performance.