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

A program counter (PC) is a CPU register in the computer processor which has the address of the next instruction to be executed from memory. It is a digital counter needed for faster execution of tasks as well as for tracking the current execution point.

Instruction is a command which is given to the computer to perform an operation on a piece of data.

It depends on
(a) Clock speed
(b) Instruction set
(c) Word size

Word size determines the amount of RAM that can be accessed by a at one time and the total number of pins on the microprocessor. Total number of input and output pins in turn determines the architecture of the microprocessor.

(i) Data transfer
(ii) Arithmetic operations
(iii) Logical operations
(iv) Control flow
(v) Input/output

PROM	EPROM
Can be Programmed only once.	It is reusable and can be programmed multiple times.
This has Permanent memory.	EPROMs memory can be erased using UV light.
Enclosed in plastic package so that not visible to UV light.	EPROMs are fused with quartz window.
Uses high Voltage.	Also use high Voltage but not enough to alter the semiconductor layer permanently.

Classification of Microprocessor based on the Instruction set:
(a) RISC-Reduced Instruction Set Computers
(b) CISC-Complex Instruction set Computers

Depending upon the size of the data the microprocessor can be classified as
(a) 8 bit microprocessor
(b) 16 bit microprocessor
(c) 4 bit microprocessor
(d) 32 bit microprocessor
(e) 64 bit microprocessor.

Differences between computer organisation and Computer Architecture:

Computer Organisation	Computer Architecture
Often called micro architecture (low level)	Computer architecture (a bit higher level)
Transparent from programmer (ex. a programmer does not worry much how addition is implemented in hardware)	Programmer view (i.e. Programmer has to be aware of which instruction set used)
Physical components (Circuit design, Adders, Signals, Peripherals)	Logic (Instruction set, Addressing modes,Data types, Cache optimization)

Flash Memory Devices
Flash memory is an electronic (solid-state) non-volatile computer storage medium that can be electrically erased and reprogrammed. They are either EEPROM or EPROM. Examples for Flash memories are pendrives, memory cards etc. Flash memories can be used in personal computers, Personal Digital Assistants (PDA), digital audio players, digital cameras and mobile phones. Flash memory offers fast access times. The time taken to read or write a character in memory is called access time. The capacity of the flash memories vary from 1 Gigabytes (GB) to 2 Terabytes (TB).

BIu-Ray Disc
Blu-Ray Disc is a high-density optical disc similar to DVD. Blu-ray is the type of discussed for PlayStation games and for playing High-Definition (HD) movies. A double-layer Blu-Ray disc can store up to 50 GB (gigabytes) of data. This is more than 5 times the capacity of a DVD, and above 70 times of a CD. The format was developed to enable recording, rewriting and playback of high-definition video, as well as storing large amount of data. DVD uses a red laser to read and write data. But, Blu-ray uses a blue-violet laser to write. Hence, it is called as Blu-Ray.

Ports and Interfaces
The Motherboard of a computer has many I/O sockets that are connected to the ports and interfaces found on the rear side of a computer. The external devices can be connected to the ports and interfaces. 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. USB 3.0 is the third major version of the Universal Serial Bus (USB) standard to connect
computers with other electronic gadgets. USB 3.0 can transfer data up to 5 Giga byte/second. USB 3.1 and USB 3.2 are also released

SCSI Port:
To connect the hard disk drives and network connectors.