(i) 16-bit - Intel 80186, Intel 80286
(ii) 32-bit - Intel 80486, Pentium IV
(iii) 64-bit - Intel dual core, Core 2duo, core i3, Core is, Core :7
(iv) 128-bit- Power PC 460 Sx embedded processor.

(i) BIu - Ray disc was developed to enable recording, rewriting and playback of high-definition video as well as storing large amount of data.
(ii) 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.

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.