1. Topic ---------Storage Devices
Storage devices of Computer
Submitted By
Pravesh Kumar
UPS Beetia
Baliakheri
Saharanpur

2. Computer storage refers to the data stored in an electromagnetic form to be used by the processor .
The storage capacity define the amount of data that can be stored on a storage device.
In a computer system, only two digits, 0,1, are used.
The 0’s and 1’s in binary system are known as bits(binary digits).

3. A bit is the smallest unit of measurement of storage capacity.
A set of eight bits is called a byte.
8 bits byte
1024 bytes kilobyte(KB)
1024 KB megabyte(MB)
1024 MB gigabyte(GB)
1024 GB terabyte(TB)

4. Computer use two types of storage:
1) Internal storage
2) External storage
Internal storage:
Its stores data and instruction for processing. Its also called primary storage is main memory. It also stores the output data temporarily before it is sent to an appropriate output device.

5. There are two type of internal storage: Random Access Memory(RAM)
Read Only Memory(ROM)
RAM
ROM
Storage area used for temporarily holding programs and data for processing.
Storage area used for holding instruction needed for starting a computer. These instruction are stored permanently.
Data stored is lost the moment the power supply is turned off.
Information stored is not lost even after the computer is turned off.

6. External storage: A computer’s primary storage or main memory is volatile. This means that the content in memory will be lost when the computer is turned off. Therefore, a permanent storage are is required to store data and programs that are not needed immediately by the computer. This kind of storage is called the secondary or external storage.

7. 3)Compact disk- Read Only Memory (CD-ROM) drives and CD writers
Some of commonly used external devices are:
1)Hard disk drives
2)Floppy disk drives
3)Compact disk- Read Only Memory
(CD-ROM) drives and CD writers
4)Digital Video Disk(DVD) and DVD writers

8. Hard Disk Drive: A hard disk drive is a very typical external storage device found in almost any PC. The hard disk is attached to the system unit from within, but it is possible to remove a hard disk drive from a computer if necessary. The storage capacity of hard disk drives varies up to a capacity of terabyte. In schools, student PC’s typically have a capacity of less than 80 gigabytes.

9. Floppy Disk Drive: Floppy disk drive is an external storage device used to from and write t0 a floppy disk. Floppy disk is a portable storage medium that can store a small amount of data. The storage capacity of a floppy disk is usually 1.44 MB. One disadvantage of a floppy disk is that is prone to damage by heat , dust and magnetic fields.

10. Compact Disk: The CD-ROM drive is an external storage device used to read from a CD-ROM. The storage capacity of most CD-ROM is approximately 650MB or 700 MB, which is also the reason why large software programs usually come with an installation CD-ROM. The advantage of a CD-ROM is that the data stored on it is less prone to damage because the data present on a CD-ROM cannot be changed.

11. Digital Video Disk(DVD) Drive: A DVD drive is an external storage device used to read from a DVD-ROM although DVD drives also able to read CDs. A DVD-ROM is similar to a CD-ROM except that it can store larger amounts (at least 4.7 GB) of data. DVDs that can store up to 17 GBs are also available.

12. Thank You!