ROM Read Only Memory
rom is fast permanent memory used for holding instructions needed to start the computer up
rom is held on a copuer chip, called non- volatile memory because it does not lose its content when the power is turned off, it used tohold instrcutions to start the computer, contents cannot be altered by the user.
RAM Read Only Memory
RAM is a fast tempory memory where programs and data are stored only when the power is supplied.
- held on a computer chip
- called volatile memory because the contents disappear when the power is turned off
- read/write, so can be altered by the user
Importance of memory size
having large amounts of memory is important. having more memory means.
- applications run faster on their own
- more applications able to runat the same time
- able to quickly move between application
Digital media refers to a storage device that holds digital data. Digital data is normally generated and stored in a computer. Digital media data can be in form of data, voice and video
Digital media refers to audio, video, and photo content that has been encoded (digitally compressed). Encoding content involves converting audio and video input into a digital media file such as a Windows Media file. After digital media is encoded, it can be easily manipulated, distributed, and rendered (played) by computers, and is easily transmitted over computer networks.
optical disk are flat cirular disk on which data is stored as a series of bumps. the way the bumps reflect laser beam light is used to read the data of the disk
magnetic tape stores the data on a plastic coated tape which is stored on a reel. sometimes the tape is in a plastic case a bit like the old fashioned music cassest tape.
- has a huge storage capacity 800gb
- is used for the backup of data and programs in large systems
- is not used for storage needed quickly because of the large access time.
Magnetic Disk Drive
magnetic disk drives can be classified acording to wether the media containing the data is hard or soft.
floppy disk and drives
floppy disk are flexible plastic disk which are coated with a material which can store data as a magnetic pattern. the disk are removeable and can be transferred from one computer to another.
- slow transfer speed
- very low storage capacity
hard drives consiste of a series of disk with a magnetic coating and a series of read/ write heads which put the data onto or record it off each surface.
- very high transfer rate
- a very high storage capcity
A piece of computer equipment on which information can be stored.
The data storage devices come in several sizes and shapes and some are non-removable while other are removable. Some of the storage devices in a computer include: floppy diskette, CD-ROM disc, CD-R disc, hard disk drive and USB flash drive.
The device that saves data onto the storage medium, or reads data from it, is known as the storage device.