9.1 Computer Memory Terms

Byte  - A unit of measure of computer data containing one character of information. Used when quantifying memory size.

Fixed Media  - Refers to a type of storage device that is permanently mounted in its drive (its reading/writing mechanism). An example is a "hard disk" or "fixed disk." Contrast this with removable media, which can be removed from the drive.

Gigabyte (GB)  - Approximately one billion bytes. A common multiple for computer memory for newer computers.

Kilobyte (KB)  - A memory measurement of about one thousand bytes. Example: 64K bytes is 65, 536 bytes.

Megabyte (MB)  - Approximately one million bytes. A common multiple for computer memory.

Random Access Memory (RAM)  - Volatile memory used for short-term storage. The processor uses the programs (loaded into RAM) to direct its calculations on the data stored in RAM. RAM does not retain its contents when the PC is turned off.

Removable Media  - Refers to a type of storage device that can be inserted and removed from the PC. This includes floppy disks, CD-ROMs, DVD-ROMs, PC Card and PCMCIA (Personal Computer Memory Card International Association) cards. Removable media is nonvolatile.

Storage Media  - Nonvolatile memory retains its data even after power is removed from the PC. Mass memory refers to a large quantity of memory used for storing data. Typically in the tens to hundreds of MByte range. Common forms of nonvolatile mass memory are: USB Data Sticks, SD Cards, Compact Flash, floppy disks, hard disks, CD ROMs, DVD devices and PCMCIA cards. Programs and data are permanently stored in nonvolatile mass memory, and loaded into RAM when they are used.

Terabyte (TB)  - Approximately one trillion bytes. A common multiple for hard drive sizes.