| slovo | definícia |
floppy disk
(encz) | floppy disk,disketa n: [it.] |
floppy disk
(encz) | floppy disk,pružný disk n: [it.] |
floppy disk
(gcide) | magnetic disc \magnetic disc\, magnetic disk \magnetic disk\n.
A ditical memory device consisting of a flat disk covered
with a magnetic coating on which information is stored; a
hard disk, floppy disk, and diskette are typically
magnetic disks.
Syn: disk, disc.
[WordNet 1.5] |
floppy disk
(wn) | floppy disk
n 1: a small plastic magnetic disk enclosed in a stiff envelope
with a radial slit; used to store data or programs for a
microcomputer; "floppy disks are noted for their relatively
slow speed and small capacity and low price" [syn:
diskette, floppy, floppy disk] |
floppy disk
(foldoc) | floppy disk
crunchy
diskette
double density
floppy
HD
high density
(Or "floppy", "diskette") A small,
portable plastic disk coated in a magnetisable substance used
for storing computer data, readable by a computer with a
floppy disk drive. The physical size of disks has shrunk from
the early 8 inch, to 5 1/4 inch ("minifloppy") to 3 1/2 inch
("microfloppy") while the data capacity has risen.
These disks are known as "floppy" disks (or diskettes) because
the disk is flexible and the read/write head is in physical
contact with the surface of the disk in contrast to "{hard
disks}" (or winchesters) which are rigid and rely on a small
fixed gap between the disk surface and the heads. Floppies
may be either single-sided or double-sided.
3.5 inch floppies are less floppy than the larger disks
because they come in a stiff plastic "envelope" or case, hence
the alternative names "stiffy" or "crunchy" sometimes used to
distinguish them from the floppier kind.
The following formats are used on IBM PCs and elsewhere:
Capacity Density Width
360K double 5.25"
720K double 3.5"
1.2M high 5.25"
1.44M high 3.5"
Double denisty and high density are usually abbreviated DD and
HD. HD 3.5 inch disks have a second hole in the envelope and
an overlapping "HD" logo.
(1996-08-23)
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| | podobné slovo | definícia |
floppy disk drive
(foldoc) | disk drive
FDD
floppy disk drive
floppy drive
(Or "hard disk drive", "hard drive",
"floppy disk drive", "floppy drive") A peripheral device
that reads and writes hard disks or floppy disks. The
drive contains a motor to rotate the disk at a constant rate
and one or more read/write heads which are positioned over the
desired track by a servo mechanism. It also contains the
electronics to amplify the signals from the heads to normal
digital logic levels and vice versa.
In order for a disk drive to start to read or write a given
location a read/write head must be positioned radially over
the right track and rotationally over the start of the right
sector.
Radial motion is known as "seeking" and it is this which
causes most of the intermittent noise heard during disk
activity. There is usually one head for each disk surface and
all heads move together. The set of locations which are
accessible with the heads in a given radial position are known
as a "cylinder". The "seek time" is the time taken to
seek to a different cylinder.
The disk is constantly rotating (except for some floppy disk
drives where the motor is switched off between accesses to
reduce wear and power consumption) so positioning the heads
over the right sector is simply a matter of waiting until it
arrives under the head. With a single set of heads this
"rotational latency" will be on average half a revolution
but some big drives have multiple sets of heads spaced at
equal angles around the disk.
If seeking and rotation are independent, access time is seek
time + rotational latency. When accessing multiple tracks
sequentially, data is sometimes arranged so that by the time
the seek from one track to the next has finished, the disk has
rotated just enough to begin accessing the next track.
See also sector interleave.
Early disk drives had a capacity of a few megabytes and were
housed inside a separate cabinet the size of a washing
machine. Over a few decades they shrunk to fit a terabyte
or more in a box the size of a paperback book.
The disks may be removable disks; floppy disks always are,
removable hard disks were common on mainframes and
minicomputers but less so on microcomputers until the mid
1990s(?) with products like the Zip Drive.
A CD-ROM drive is not usually referred to as a disk drive.
Two common interfaces for disk drives (and other devices) are
SCSI and IDE. ST-506 used to be common in
microcomputers (in the 1980s?).
(1997-04-15)
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