CIS 105 -- Survey of Computer Information Systems

Essential Concepts and Terminology -- Study Unit Three.

A named collection of data (such as a computer program, document, or graphic) that exists on a storage medium such as a hard disk, floppy disk, or CD-ROM.
A list of files contained on a computer storage device.
PC. The subdirectories (a subdivision of a directory) that can contain files or other folders. Macintosh. Same as directory on a PC.
The computer circuitry that holds data waiting to be processed.
The area in a computer where data is retained to be used again later. Storage devices retain information after the device is turned off.
Volatile Memory.
Memory contents that are erased when a computer is shut off.
Transfer of data to a storage device.
Read-Write Media.
Storage disks that allow a computer to both read and store data. Examples are CD-RW and floppy disks.
Sequential Access.
A form of data storage, such as a computer tape, that requires a device to read or write data one record after another starting at the beginning of the medium.
The ability of a storage device to go directly to a specific location rather than searching sequentially from a beginning location.  Magnetic disks are random-access storage media.
Microscopic indentations on optical storage media used by laser beams to read patterns of data on the surface of disks. The light-sensing reading device receives no light from a pit and returns a "0" signal.
Flat, reflective areas on optical storage media the bounces laser light, returning a "1" signal.
Online Storage.
Immediately available storage which does not require a user action, such as inserting media. A hard disk is a persoanls computer's online storage device.
Near-Online Storage.
Secondary storage that requires insertion of media. Storage readily made available by user action.
Access Time.
The estimated time for a storage device to begin reading data on a disk, usually measured in milliseconds for disks and nanoseconds for RAM.
One-billionth of a second.
Solid State Disk.
A high-capacity storage device with rapid access time comparable to hard disks. The devices store up to 8 GBs and use batteries to provide data involatility.
Double-Density (DD) Floppy Disk.
A type of disk with a higher storage capacity (800 K) due to increased disk density.
High-Density (HD) Floppy Disk.
A disk that stores more data than a double-density disk, up to 1.44 MB.
Write-Protect Tab.
A sliding notch on floppy disks that protect disks from being overwritten or deleted when open.
Concentric or spiral storage areas created in series on storage medium during formatting.
Subdivisions of tracks on storage media. Pie-shaped subdivisions of tracks on floppy disks.
Groups of sectors on a storage medium that, when accessed as a group, speed up data access.
File Allocation Table (FAT).
A table of information recording the physical location of files on storage medium.
Storage of data in a file in non-contiguous clusters.
Activity Light.
An indicator that illuminates while the head is reading or writing data on a disk, indicating not to press the eject button.
The process of preparing a magnetic disk to store information. The process of a disk drive's head laying down the magnetic pattern of tracks and sectors.
Hard Disk.
One or more magnetic disk platters providing high-capacity, high-speed online storage.
Fixed, rapidly-rotating magnetic storage component disks of a hard disk.
Head Crash.
A collision between the read-write head and the surface of a hard disk platter, resulting in disk damage.
A section of a disk establish to operate as if it were a separate disk.
Positioning Performance.
The speed at which a drive can position the read/write head to begin transferring data.
Transfer Performance.
The speed at which a drive can transfer data.
Spindle Speed.
The number of revolutions per second at which hard disk platters rotate.
Hard Disk Controller.
A circuit board on the mother board, on an expansion card, or in a hard drive that acts as an interface between the CPU and the hard disk.
Small Computer System Interface (SCSI).
An interface standard used for attaching peripheral devices such as drives, scanners, and other peripherals. Pronounced "scuzzy."
Disk Cache.
A type of RAM used to temporarily store information read from a disk, dramatically improving up hard disk performance.
The process of moving data off a primary storage device to a long-term storage medium such as a CD-ROM.
A duplicate copy of data.
A read-only, optical disk storage medium that uses laser technology to read data.  An acronym for compact disc read-only memory.
CD-ROM drive.
A device that uses laser technology to read data from a CD-ROM. Drive speed is stated in multiples of 150,000 bits per second, such as 2x or 4x.
Multisession CDs.
A CD that allows a device to write (burn) data during more than one session.
An optical disk technology used to create CD-ROMs and audio CDs. An acronym for compact disc-recordable.
An optical disk technology that allows data to be written onto a CD, then changed much like on a floppy or hard disk.  An acronym for compact disc-rewritable.
An optical storage medium similar to CD-ROM, except with higher storage capacity (up to 17 GB). The acronym for "digital video disc" or "digital versatile disc."  DVD-ROM drives are downwardly compatible with CD-ROM.
PC Card (PCMCIA Card).
A credit-card-sized circuit board, typically used to connect a modem, memory, network card, or storage devices to a notebook computer.


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