disk(redirected from Placido disk)
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1. The two-dimensional projection of the surface of a star or planet.
A flat, circular, raised ornament, carved as a series of disks adjacent to each other.
Also spelled disc.
A relatively thin layer of material distributed in the central plane of a spiral galaxy, in contrast to the nucleus or halo.
Any of various rounded and flattened animal and plant structures.
A rotating circular plate having a magnetizable surface on which information may be stored as a pattern of polarized spots on concentric recording tracks. Also known as magnetic disk.
The region in the plane consisting of all points with norm less than 1 (sometimes less than or equal to 1).
diskA direct access storage device. See floppy disk, hard disk, magnetic disk, optical disc, CD-ROM and DVD.
|Disk and Memory Work Together|
|On the disk, data are stored in sectors, which hold a chunk of data (typically 512 bytes) and are the smallest unit that can be read or written. Memory is broken up into squares like a checkerboard, each square holding one byte. The contents of any single byte or group of bytes can be calculated, compared and copied independently. That is how fields are put together to form records and broken apart when read back in.|