Storage and memory devices

STORAGE AND MEMORY DEVICES

Made by: Muhammad Hassaan Arif

STORAGE DEVICES

A data storage device is a device for recording (storing) information (data).

1


MAGNETIC TAPE

MAGNETIC DISK


A plastic tape coated with iron oxide for use in magnetic recording.

Magnetic tape is a serial access medium, similar to an audio cassette, and so data cannot be quickly located.

However large amounts of information can be stored within magnetic tape. This characteristic has prompted its use in the regular backing up of hard disks.

MAGNETIC TAPE


The primary computer storage device. Like tape, it is magnetically recorded and can be re-recorded over and over.

Disks are rotating platters with a mechanical arm that moves a read/write head between the outer and inner edges of the platter's surface.

MAGNETIC DISK


Common types are:– Hard disks– Floppy disks– Zip disks

It can take as long as one second to find a location on a floppy disk to as little as a couple of milliseconds on a fast hard disk.

MAGNETIC DISK


MEMORY VS STORAGE

HARD DRIVE- STORAGERAM- MEMORY(RANDOM ACCESS MEMORY)


RAM- MEMORY(RANDOM ACCESS MEMORY)

Memory is a temporary workplace where the computer transfers the contents of a file while it is being used.

Random Access Memory (RAM) is a computer storage location that allows information to be stored and accessed quickly from random locations.


Storage, also known as mass media, refers to the various media on which computer system can store data.

Hard drive is one of them. There are some features such as:

High capacity disk. Most common media of storage. Use one or more metal magnetic disks.

HARD DRIVE - STORAGE


CATEGORIES

The type of operations they perform.

The method they use to access the information.

The technology they use. Their capacity and speed.

2


SEQUENTIALACCESS STORAGE

VS

RANDOM ACCESS STORAGE


SEQUENTIAL ACCESS STORAGE

Storage devices that read and write data in a serial fashion.


RANDOM ACCESS STORAGE

Storage devices that read and write data without going through a sequence of locations.


STORAGE TECHNOLOGIES


MAGNETIC STORAGE

OPTICAL STORAGE CD/DVD DRIVE


MAGNETIC STORAGE

Storage devices use disks or tapes that are coated with magnetically sensitive material.


OPTICAL STORAGE CD/DVD DRIVE

Storage devices that use laser beams to read patterns etched into plastic disks.


MAGNETIC DISK STORAGE

3


MAGNETIC DISK STORAGE

A disk is formatted; it is divided into tracks and sectors, and a file allocation table (FAT) is created.

Track – circular band

Sector – pie shaped section

Cluster – two or more adjacent sectors

FAT – keeps tracks of specific locations of files



STORAGE CAPACITY &

SPEED


STORAGE CAPACITY &

SPEED

Floppy DiskCapacity – 720 KB to 1.44 MB

Hard DriveCapacity – up to 1000 GB ( 1 TB)

CD ROM/DVDCapacity – CD ROM 650 MB – DVD 17 GB


FLOPPY & ZIP DISKS &DRIVES


3.5’’ – FLOPPY DISKS & DRIVE

High – density floppy disks that are commonly used today store 1.44MB and 2.8MB of data.

A disk or diskette is a portable storage medium.

Low capacity removable disk.

Not widely used today.Made by: Muhammad Hassaan Arif

ZIP DISKS

Zip disks store up to 750 Mb of data and are not downwardly compatible with floppy disks.


CD-ROM DISCS & DRIVES

CD-ROM stand for compact disc read only memory.

CD-ROM drives can not write data to disc.

They are capable of storing 650 MB of data.

They are used for operating system; large application programs.

4


CD-R & CD-RW & RECORDERS

CD-R Discs can only

be written to “once”

CD-R drives are capable of reading and writing data.

CD-RW Discs are erasable

Discs can be written to many times

CD-RW drives are capable of reading, writing and erasing data


DVD stand for Digital Video Disc.

DVD technology is similar to CD-ROM technology.

DVDs are capable of storage up to 17GB of data.

DVD-R and DVD-RW drives have the ability to read and write data.

DVD-ROM DISCS & DRIVES


SOLID STATE STORAGE DEVICES

Solid state storage devices use nonvolatile memory chips to retain data.

They do not have moving parts.

They are small, lightweight, reliable and portable.



Education

Storage and memory devices