Storage Devices

Allow computers to store programs and information for use at a later dateStorage DevicesBinary DigitsComputers are Bistable Devices [It can understand two states]E.g. On/Off Yes/No True/FalseComputers encode and store information in binary form1s and 0s

Bits & BytesEach digit is known as a bit either a 1 bit or a 0 bitEight bits is known as a byte.A byte usually represents one character or letterE.g. A = 10000000 B = 11000000C = 11100000

Binary Table1024 Approx =10008 Bits1 Byte1000 Bytes1KiloByte (KB)1000 KB 1 Megabyte (MB)1000 MB 1GigaByte (GB)1000 GB 1 Terabyte (TB)Main memory that is directly accessible to the CPU RAMROM

PRIMARY STORAGERandom Access MemoryVolatile (information is lost when power is off)Holds 256MB-4GB

Read Only MemoryNon-volatile memoryHolds the instructions needed for the computer to boot up when power is off

Stores information that is not directly accessible to the CPU. It is usually removable or portableSecondary StorageHard Disk Drive (HDD)Read and Write informationMagnetic surfaceNot very portableStores 30GB-300GB or more

Floppy DiskRead and WriteMagnetic storageStores 1.44MB

Compact Disc-Read only memory (CD-ROM)Read onlyOptical storageStores up to 700MB

CD-RW- rewritable disc that you can erase and rewriteMagnetic TapeRead and WriteMagneticStores 10GB-120GB

Flash DriveRead and Write Store 64MB-16GB

Memory Cards SDRead and WriteStores 512MB-4GB

Digital Versatile Disc (DVD-ROM)Mostly read onlyOptical StorageStores 4GB-16GB

Blue Ray DiscRead onlyOptical storageStores 25GB-50GB

Zip DrivesRead and Write