Allow computers to store programs and information for use at a later date Storage Devices

Binary Digits Computers are Bistable Devices [It can understand two states] E.g. On/Off Yes/No True/False Computers encode and store information in binary form 1’s and 0’s

Bits & Bytes 1 bit0 bit Each digit is known as a bit either a 1 bit or a 0 bit Eight bits is known as a byte. A byte usually represents one character or letter E.g. A = B = C =

Binary Table 1024 Approx = Bits1 Byte 1000 Bytes1KiloByte (KB) 1000 KB1 Megabyte (MB) 1000 MB1GigaByte (GB) 1000 GB1 Terabyte (TB)

Main memory that is directly accessible to the CPU RAM ROM PRIMARY STORAGE

Random Access Memory Volatile (information is lost when power is off) Holds 256MB-4GB

Read Only Memory Non-volatile memory Holds 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 portable Secondary Storage

Hard Disk Drive (HDD) Read and Write information Magnetic surface Not very portable Stores 30GB-300GB or more

Floppy Disk Read and Write Magnetic storage Stores 1.44MB

Compact Disc-Read only memory (CD-ROM) Read only Optical storage Stores up to 700MB CD-RW- rewritable disc that you can erase and rewrite

Magnetic Tape Read and Write Magnetic Stores 10GB-120GB

Flash Drive Read and Write Store 64MB-16GB

Memory Cards SD Read and Write Stores 512MB-4GB

Digital Versatile Disc (DVD-ROM) Mostly read only Optical Storage Stores 4GB-16GB

Blue Ray Disc Read only Optical storage Stores 25GB-50GB

Zip Drives Read and Write