DEC 3000 800 Owner's Manual page 285

diagnostics
Programs, located in read-only memory, that detect and identify
abnormal system hardware operation.
digital data
Information recorded and transmitted in binary coded form.
direct memory access (DMA)
A transfer of data directly from one memory to another without
going through the main processor.
disc
See compact disc.
disk
A flat circular plate with a magnetic coating on which data is
magnetically stored in concentric circles (tracks). A fixed disk
resides permanently inside a disk drive, whereas a diskette is
removable.
disk drive
A device that holds a disk. The drive contains mechanical
components that spin the disk and move the read and write
heads that store and read the information on the surface of the
disks.
diskette
A flexible disk contained in a square jacket. Diskettes can be
inserted and removed from diskette drives.
diskette drive
A disk drive that reads from or writes to a removable diskette,
such as an RX26 diskette.
disk fragmentation
The writing of files in noncontiguous areas on a disk.
Fragmentation can cause slower system performance because of
repeated read or write operations on fragmented data.
diskless system
A system that has no storage capacity of its own.
Glossary–11