GLOSSARY
SOFTERROR
A data error which can be overcome by rereading the data or repositioning the head.
SOFTSECTORED
A technique where the controller determines the beginning of a sector by the reading of format information from the disk. This is contrasted to hard sectoring where a digital signal indicates the beginning of a sector on a track.
SOFTWARE
Applications programs, operating systems, and other programs (as opposed to hardware).
SPINDLE
The rotating hub structure to which the disks are attached.
SPINDLEMOTOR
The motor that rotates the spindle and therefore the disks.
SPUTTEREDMEDIA
Magnetic disk or tape that has the magnetic layer deposited by sputtering means.
STEPPERMOTOR
A motor that has known detent positions where the rotor will stop with the proper control in some cases. The digitally controlled motor moves the head positioner from track to track in small,
STORAGECAPACITY
The amount of data that can be stored in a memory location, usually specified in kilobytes for main memory and floppy drives and megabytes for mass storage devices.
STORAGE DENSITY
Usually refers to recording density (BPI, TPI, or a combination of the two.)
STORAGELOCATION
A memory location, identified by an address where information may be read or written.
STROBEOFFSETSIGNAL
A group of digital input signal levels which cause the read PLL and/ or data decoder to shift the decoding windows by fractional amounts. Often early/late are modified when two signals are used.
T
THIN-FILMHEAD
A magnetic transducer manufactured by deposition of magnetic and electrical materials on a base material contrasted with prior art mechanical methods. Read/write heads whose read/write element is deposited using integrated circuit techniques rather than being manually wound.
See plated thin film media.
TRACK
One surface of a cylinder. A path which contains reproducible information left on a magnetic medium by recording means energized from a single channel.
TRACK-FOLLOWINGSERVO
A
TRACKS PER INCH (TPI)
A measurement of radial density. Tracks per inch of disk radius.
TRACKPOSITIONING
The method, both mechanical and electrical, used to position the heads over the correct cylinder in a disk drive system.
U
An error that is not able to be overcome with Error Detection and Correction.
UNFORMATTEDCAPACITY
Storage capacity of disk drive prior to formatting; also called the gross capacity. (See format.) The raw capacity of a drive not taking into account the capacity loss due to storage of the format control information on the disk surfaces.
UNRECOVERABLEERROR
A read error falling outside the capability of an ECC mechanism to correct, or not able to be overcome by rereading the data in question, with or without repositioning the head.
V
VOICECOILMOTOR
A positioning motor that uses the same principle as a voice coil in a loudspeaker. The motor has no detent positions. The mechanical motion output of it can be either rotary or linear.
W
WHITNEYHEAD
A successor to the original Winchester read/write head design. The primary change was to make the flexure smaller and more rigid. First used in IBM 3370/3380.
WHITNEYTECHNOLOGY
A method of constructing a read/write head in a rigid disk drive using a Whitney head. In all other details it is the same as Winchester technology.
WINCHESTERHEAD
The read/write head used in Winchester technology,
WINCHESTERTECHNOLOGY
A method of constructing a rigid disk drive using concepts introduced in the IBM model 3340 disk drive. The primary changes from prior technology was to lower the mass of the slider, use of a monolithic slider, radically changing the design of the flexure and having the slider come to rest on a lubricated disk surface when disk rotation ceases. In addition to the above, a totally sealed chamber containing the read/write heads and disks was used to protect against contamination.
WINDOWMARGIN
The amount of tolerance a read/write system has for transition jitter at a specified error rate level.
WORD
A number of bits, typically a multiple of eight, processed in parallel (in a single operation). Standard word lengths are 8, 16, 32 and 64 bits (1, 2, 4, or 8 bytes).
WRITE
The recording of flux reversals on a magnetic media.
WRITEPRE-COMPENSATION
The intentional time shifting of write data to offset the effects of bit shift in magnetic recording.
WRITEGATESIGNAL
A digital input signal level which causes the drive circuitry to record (write) data.
GL – 6