CIS 105 Survey of Computer Information Systems

CIS 105 Concepts and Terminology Unit 3

CIS 105

Survey of Computer Information Systems

Essential Concepts and Terminology

Study Unit Three


File. 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.


Directory. A list of files contained on a

computer storage device.


Folders. PC. The subdirectories that can

contain files or other folders. Macintosh. Same as directories on

a PC.


Memory. The computer circuitry that holds

data waiting to be processed.


Storage. 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.


Saving. Transfer of data to a storage

device.


Read-Write Media. Storage disks that allow a

computer to both read and store (write) 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.


Random-Access. 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.


Pits. 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.


Land. 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. Typically, a hard disk is a personal 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.


Nanosecond. One-billionth of a second.


Solid State Disk. A high-capacity storage device

with rapid access time, comparable to hard disks. The device stores up to 8 GBs of data and uses 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, when open, protect disks from being overwritten or deleted.


Tracks. Concentric or spiral storage areas

created in series during formatting on storage medium.


Sectors. Pie-shaped subdivisions of tracks

on storage media.


Clusters. 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.


Fragmentation. Storage of a data 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.


Formatting. 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.


Platters. 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.


Partition. A section of a disk established 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.


Archiving. The process of moving data off a

primary storage device to a long-term storage medium such as a CD-ROM or removable magnetic medium.


Backup. A duplicate copy of data.


CD-ROM. 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. 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.


CD-R. An optical disk technology used to

create CD-ROMs and audio CDs. An acronym for compact disc-recordable.


CD-RW. 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.


DVD. 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.

CIS 105 Concepts and Terminology Unit 3 Created by James Q. Jacobs

End of Study Unit 3. Return to first slide

Move to Study Unit 4

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Documents

CIS 105 Survey of Computer Information Systems