ISO/IEC 14417:1999 情報技術— IEC1016に準拠した磁気テープカセット用のデータ記録フォーマットDD-1 | ページ 5

4.1

Auxiliary data

Optional information of secondary importance.

4.2

Annotation record

The magnetization pattern or associated information recorded in the annotation track.

4.3

Annotation tracks

Two longitudinal tracks one each at each tape edge.

4.4

Average Signal Amplitude

ASA

The average peak-to-peak value of the signal output of the read head measured over a minimum of 280 000 flux transitions, exclusive of dropouts.

4.5

azimuth

The angular deviation, in degrees and minutes of arc, of the recorded flux transitions on a track from the line perpendicular to the track centerline.

4.6

block

A group of bytes transported between host and controller as a unit and considered a minimum locatable unit; containing one or more logical records or portions of logical records.

4.7

byte

An ordered set of 8 bits acted on as a unit.

4.8

Codeword Digital Sum

CDS

The digital sum variation from the beginning to the end of a NRZI(1) symbol's waveform. The CDS is calculated assuming that the NRZI(1) waveform starts at a negative level, the binary −1 and +1, and the waveform transitions are centred relative to the corresponding bit cells.

4.9

Data area

An area on tape that is defined by the end points of all possible helical track center lines.

4.10

Data area reference line

A basic dimension which shall be exactly 1,8075 mm from the tape reference edge (no tolerence).

4.11

Data area reference point

The point on the centreline of a helical track at the boundry between preamble run-up and preamble sync pattern.

4.12

Data field

A continuous string of bits that is error protected.

4.13

Digital Sum Variation

DSV

The accumulated sum of the CDS values of the NRZI(1) symbols.

4.14

Dropout

The point of read signal amplitude below a given threshold.

4.15

Erase

The removal of all magnetically recorded information from the tape.

4.16

Erasing field

An a. c. magnetic field of sufficient strength to remove the recorded signals from the tape.

4.17

Equivalent reference edge

For measurement of the recorded track format, the average location of the reference edge over a given length.

4.18

flux transition spacing

The distance along a track between successive flux transitions. The spacing is derived from the inverse of flux transitions per millimeter (ftpmm) (See physical record density.)

4.19

Helical (data) record

The magnetization pattern or associated information recorded in all possible helical tracks.

4.20

Helical track

An area on tape, inclined at a small angle to the reference edge of the tape.

4.21

Home track ID

A recorder manufacturer defined field used to identify the scanner head recording the first track of a track set.

4.22

Inner code

Of the sequential error detection and correction codes, the first encountered on playback from tape (C1).

4.23

Leader

A nonmagnetic length of transparent tape joined to each end of the magnetic tape to provide strength and convenience. At the beginning of the tape, it identifies the storage position of the tape. At the end of the tape, it indicates that the permissible recording area has been exceeded.

4.24

Logical volume

A collection of related files, without regard to physical container size.

4.25

magnetic tape

A tape which will accept and retain the magnetic signals intended for input, output, and storage purposes on computers and associated equipment.

4.26

Master Standard Reference Tape

The tape selected to establish the standard for tape properties essential to data interchange.

Note 1 to entry: A master standard reference tape has been established. It has been agreed that Sony Corporation will maintain the master standard reference tape. (See secondary standard reference tape.)

4.27

Outer code

Of the sequential error detection and correction codes, the second encountered on playback from tape (C2).

4.28

physical recording density

The number of recorded flux transitions per unit length of track, e.g., flux transitions per millimeter (ftpmm).

4.29

Postamble

A sequence of bits recorded at the end of each helical track on a magnetic tape to provide flux transitions and special padding area to clear the decoding circuitry and provide tolerance area.

4.30

Preamble

A sequence of bits recorded at the beginning of each helical track on a magnetic tape to provide electronic synchronization.

4.31

reference edge

The lower edge of the tape when viewing the recording surface with the supply reel to the observer's right.

4.32

reference field

The typical field of the master standard reference tape.

4.33

Resolution

The ratio of the average signal amplitude at the physical recording density of 2252 ftpmm to that at the physical recording density of 280 ftpmm.

4.34

Secondary Standard Reference Tape

A tape, the performance of which is known and stated in relation to that of the master standard reference tape.

4.35

Sector

The helical record pertaining to a single helical track.

4.36

Sector recording tolerance

The maximum allowable distance of the data area reference point from the intersection of track center line and data area reference line.

4.37

Standard Reference Amplitude

The average peak-to-peak signal amplitude output from the master standard reference tape when it is recorded with the standard reference current. The signal amplitude shall be averaged over at least 280 000 flux transitions. Traceability to the standard reference is provided by the secondary standard reference tape.

4.38

Standard Reference Current

The current required to produce the reference field.

4.39

Sync pattern

A magnetization pattern defining the start of each sync block and the postamble or, following the preamble run-up.

4.40

Tape mark

A special block recorded on magnetic tape to serve as a separator between files and file labels, or to define the end of recorded data.

4.41

Tolerance zones

Narrow zones established to contain completely the track center lines of six consecutive helical tracks.

4.42

track

A narrow, defined area on tape along which a series of magnetic signals may be recorded.

4.43

track angle

The angular deviation, expressed in degrees and minutes of arc calculated from arcsine of (16/170), of the centerline of the recorded helical track from the equivalent reference edge of the tape.

4.44

Track Set

Four consecutive helical tracks uniquely identified by a track set ID.

4.45

Track Set ID

TSID

A 23 bit binary field which is a common identifier for a set of four consecutive helical tracks. Each track set ID is recorded at the start of the helical tracks as part of the control record, and also recorded on the control track.

4.46

Volume set

A collection of logical volumes.