GB/T 9363-1988 Information processing - Format and recording of 9-track, 12.7 mm (0.5 in) magnetic tape group coding 246 cpmm (6250 cpi) for information exchange
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National Standard of the People's Republic of ChinawwW.bzxz.Net
Information processing
Information processing-9-Track, 12. 7mm(0. 5in)wide magnetic tape for information interchange-Format and recording ,using greup cading at 246 cprm(6250 cpi)GB9363-88
ISO 5652--1984
This standard is equivalent to IS05652-1984 "Information processing-9-track, 12.7mm(0.5in) magnetic tape for information interchange-Format and recording ,using greup cading at 246 cpmm(6250 cpi)". 1 Subject matter and scope of application
This standard makes necessary provisions for the format and record of 9-track, 12.7mm magnetic tapes used for data exchange between information processing systems, communication systems and related equipment. The seven-bit coded character set (GB1988), the extended method of the seven-bit coded character set (GB2311) and the eight-bit coded character set (GB11383) are used in these systems and equipment. The labels on the magnetic tapes shall comply with the provisions of GB7574. The magnetic tapes and reels used shall comply with the provisions of GB 9716. 2 Reference standards
GB1988 Seven-bit coded character set for information processing exchange GB2311 Extension method of seven-bit coded character nest for information processing exchange GB7574 Magnetic tape label and file structure for information processing exchange GB9716 12.7mm (0.5in) unrecorded magnetic tape for information processing exchange - recording density of 32ftpmm (800ftpi) NRZ1 system, recording density of 126ftpmm (3200ftpi) PE system, and recording density of 356ftpmm (9042ftpi) NR21 system GB11383 Eight-bit code structure and encoding rules for information processing information exchange 3 Terms
The definitions of terms used in this standard are as follows:
3.1 Magnetic tape
A tape used for input, output and storage of information on computers and related equipment, which can record and store magnetic signals. 3.2 Reference tape
A magnetic tape used for calibration and having various given characteristics. 3.3 Secondary reference tape
Magnetic tape used for daily calibration. Its characteristics are known, and the difference between it and the reference tape is also known. 3.4 Signal amplitude reference tape
Reference tape used as a signal amplitude standard.
3.5 Typical magnetic field strength
Approved by the Ministry of Electronics Industry of the People's Republic of China on June 18, 1988 and implemented on October 1, 1988
GB9363--88
The minimum write magnetic field strength when the read-out signal amplitude is equal to 95% of the maximum value under the specified physical recording density. 3.6 Reference magnetic field strength
Typical magnetic field strength of the amplitude reference tape when the recording density is 356ftpmm. 3.7 Standard reference amplitude
The average peak-to-peak value of the signal amplitude measured from the amplitude reference tape on a measurement system equivalent to the National Bureau of Standards (NBS) of the United States under the recording conditions specified in GB 9716.
3.B Reference
The tape is laid flat with the magnetic layer facing upward. During recording, the direction of movement of the tape is from left to right. The side away from the observer is the reference side. 3.9 Contact state
The working state in which the magnetic layer of the tape is in contact with the head. 3, 10 Tracks
A series of longitudinal (along the length of the tape) areas on the tape where magnetic signals can be recorded. 3.11 Rows
Nine related positions (one bit per track) on the horizontal strip of the tape where bit information is recorded. 3.12 Flux reversal position
The point in free space where the magnetic flux density is the highest perpendicular to the surface of the tape. 3.13 Physical recording density
The number of flux reversals recorded per unit length on the track (ftpmm or ftpi). 3.14 Data density
The number of data characters stored per unit length on the tape (cpmm or cpi). 3.15 Skew
The maximum longitudinal deviation of the position of information bits in a row. 3.16ECC character
A character used to detect and correct errors in a data group. 3.17Auxiliary CRC character
A character used to detect errors in the data portion of a storage block. 3.18CRC character
A character used to detect errors in the entire storage block. 3.19Preamble
A signal pattern that marks the beginning of each storage block, which is mainly used as a signal step. 3.20Postamble
A signal pattern that marks the end of each storage block. 3.21Density identification area (ID pulse)
A series of pulses recorded at the beginning of the tape to identify the encoding method of the group. 3.22Automatic gain control pulse (ARA pulse)A series of pulses recorded at the beginning of the tape to adjust the gain of the read amplifier. 3.23 Error code
refers to the missing pulse or missing pulse in the track. The definitions of missing pulse and missing pulse are respectively given in GB 9716. 4 Working environment and transportation conditions
4.1 Working environment
The working environment of the magnetic tape for data exchange should be: Temperature: 16~32℃
Relative humidity: 20%~80℃:
Wet bulb temperature: not more than 26'℃.
CB 9363-88
Adaptation time before use If the storage or transportation environment of the magnetic tape exceeds the above range, it should be adapted to the working environment for 2~12h according to the degree of excess.
4.2 Transportation conditions
During the shipment process, the consignor shall be responsible for taking appropriate damage prevention measures. See Appendix A (reference). 4.3 Winding tension
In order to ensure information exchange, the tape winding tension should be 2~3.6N. 5 Recording
5.1 Recording method
Use non-zero system (NRZ1), the magnetization direction is along the tape yaw direction, and each change of the magnetization direction represents a \"\ 5.2 Recording density
The nominal recording density should be 356ftpmm. The nominal density of the following special measurement should be 178ftpmm
119fpmm.
5.3 Average spacing of magnetic flux reversal
When the following measurement is made on the tape, its recording density should be 178ftpmm, that is, the nominal spacing of magnetic flux reversal should be 5.618 μm. 5.3.1. The long-term average (static) flux reversal spacing shall not exceed ±4% of the nominal spacing. When tested, the number of continuous flux reversals shall be at least 5x105.
5.3.2 The short-term average (dynamic) flux reversal spacing refers to any specified flux reversal spacing, where 1 is the average of the flux reversal spacings before the flux reversal spacing. The short-term average flux reversal spacing shall not exceed ±6% of the long-term average flux reversal spacing. In addition, the rate of change of the short-term average flux reversal spacing shall not exceed 0.2% of each flux reversal spacing. 5.4 Flux reversal instantaneous spacing
The flux reversal instantaneous spacing is affected by the read and write process, the recording mode (pulse crowding effect) and other factors. When tested with a standard read circuit (see Appendix B (Supplement), the flux reversal instantaneous spacing shall meet the following conditions. 5.4.1 When the maximum nominal recording density is 356ltpmm, the continuous flux reversal spacing d, shall be 48%~52% of the corresponding short-term average flux reversal spacing.
, the average displacement between the flux reversal on either side and the reference flux reversal should not exceed ±28% of the average value of d5.4.2 The information bit pattern adopts 1110011100.. In the figure, "" represents the reference reversal.
1.28d,2.d, average value ≥0.72d
1.28d,≥d, average value ≥ 0.72dl
1.28d,2d, almost average value 0.72d
1.28d,2d, average value ≥0.72d
GB 936388
The tolerance of the long-term average spacing and the short-term average spacing (see 5.3.1 and 5.3.2) is also included in this deviation range. The information bit pattern uses the average distance d between the reference flux reversals of 1110011100. The difference between the distance 5d between the calculated 6 flux reversals should not exceed 6% of d.
5. 06d, ≥ d, average value = 4. 94d5.5 skew
The deviation between any flux reversal and any other flux reversal in the same row should not be greater than 16.86um. Draw a perpendicular line through the flux turning point to the reference edge and measure the distance between the perpendicular lines to get the skew. 5.6 Signal Amplitude
5. 6. 1 Standard Reference Amplitude
The standard reference amplitude is the average peak-to-peak value of the signal amplitude measured from the signal amplitude reference band on a measurement system that meets the requirements. At this time, the recording density is 356ftpmm, and the write current is I=×1, (see (B9716). The signal amplitude should be at least the average value of 4000 flux reversals and should be measured during the writing and reading process. The reference current 1. is the current that produces the reference magnetic field strength (see 3.6). 5.6.2 Signal average amplitude
5.6.2.1 When the recording density of the information exchange tape is 356ftpmm, the deviation of the average peak-to-peak estimate of the signal amplitude from the standard reference amplitude should not exceed ±50%.
5.6.2.2 When the recording density of the information exchange tape is 119ftpmm, the average peak-to-peak value of the signal amplitude should be less than 5 times the standard reference amplitude.
5.6.2.3 When taking the average value, the flux The number of flips should not be less than 4000. For magnetic tapes used for information exchange, the average value can be obtained by block. When measuring, it should be obtained during the first reading process after the information exchange. 5.6.3 Minimum signal amplitude
On magnetic tapes used for information exchange, after the last mark control subgroup 1 (MARK1) (see 10.4), the base-peak value of the readout signal on only one microtrack is allowed to be less than 15% of half the standard reference amplitude. 5.7 Erasing
5.7.1 When erasing, the beginning of the erased area of the tape should be magnetized to the north pole. 5.7.2 Direct current should be used to erase across the entire width of the tape in the direction specified in 5.7.1. 5.7.3 The residual signal amplitude of the tape after erasure should not exceed 4% of the standard reference amplitude. 6 Magnetic avoidance
6.1 Track effect
There should be 9 tracks.
6.2 Track numbering
The tracks should be numbered in order starting from track 1 which is close to the reference edge. 6:3 Track position
The distance from the reference edge to the center line of each track should be: Track 1: 0.74±0.08mml
Track 2: 2.13±0.08mm;
Track 3: 3.53±0.08mml
Track 4: 4.93±0.08mm;
Track 5: 6.32±0.08mm
Track 6: 7.72±008mm;
Track 7: 9.12±0.08mm;
Track 8: 10. 52±0.08mm
Track 9:11.91±0.08mm.
6.4 Track width
The width of the written track should not be less than 1.09mm. 7 Data representation
GB9363-88
The characters should be represented by the seven-bit coded character set (see GB1988) or the eight-bit coded character set (see GB11383). When necessary, the extended method of the seven-bit coded character set (see GB2311) can also be used. The relationship between the information bit and the track number should be as follows: 7.1 The seven-bit coded character is shown in Table 1.
Binary weight
Information bit flag
Track number
Track 7 only records the information "0\.
Eight-bit coded characters are shown in Table 2.
Binary weight
Information bit flag
Track number
The P bit in track 4 is the parity bit. Odd parity should be used. 8 Data format preparation
Before recording, first divide the data and its check character derivative (see 8.4) into the following groups, and then arrange these data groups and the control character group in the given order. Then the data group and control character group arranged in this way are recorded on the tape according to a specific encoding method (see Chapter 9) (see Figure 1)
ErcE I cco
FRECICCCO
CRC group
GB9363
EAOO .OOD
FAO0 +CDD
EAOO 1 CODD
EAOO 1GUDD!
EAO0 IOODD
Remaining group
876 yuan
EDDI I DDDD
PPPP PPPP
EDDDDDDD
EDDD J DDdD
EDDDIDDD
Number of digits
Note that the serial information bits on each microtrack should be grouped and coded (see Chapter 9), and then the coded information stream should be recorded on the corresponding track of the tape. 8.1 Data Group
The data group should consist of the following 8 characters:
8. Position 1~7: 7 data bytes:
b. Position 8: 1 EcC character.
8.2 Remaining Group
The remaining group shall be composed as follows:
Position 1~6: If there are data bytes, then the remaining data bytes;
Position~6: If the data bytes are insufficient, the insufficient part shall be filled with blank characters ((00) bytes with odd parity);
Position 7: 1 auxiliary CRC character;
Position 3: 1 ECC character.
8.3 CRC Group
After the remaining group, there shall be a CRC group:
Position 1: If the number of preceding data groups is even, then the (00) bytes with odd parity; if it is even, then the CRC character;
Position 2~~6: CRC characters:
Position 7: Remaining characters;
Position 8: 1 ECC character.
8.4 Check Characters
8. 4. 1 ECC The character
shall be calculated as ECC character in groups (number of groups, remaining groups and CR?). Each group shall constitute D,~D,7 polynomials, and the coefficients of the polynomials shall be the 8 information bits of each byte at positions 1~7. The coefficient of polynomial D, shall be the 8 information bits at position 1. The coefficient of polynomial D, shall be the 8 information bits at position 21, and so on. The check bits in channel 4 shall be independent of the FC symbol. The relationship between these information bits and the polynomial coefficients is shown in Table 3. The microchannel number corresponding to the information bit
CB9363-88
The weight of the polynomial coefficient
The ECC character shall be obtained by the following polynomial E: EE(X'D,)
Where: t=7～1
(modG)
G=X+ X+ X'+ X+ a
All arithmetic operations shall be performed modulo 2.
The information bits of the ECC character shall be the coefficients of the polynomial E (see Table 4). Table 4
Channel number
Weights of polynomial coefficients
The odd parity bit shall be written in channel 1.
8. 4. 2 Auxiliary CRC characters
Track number corresponding to the information bit
Track number
Weight of polynomial coefficient
Weight of polynomial coefficient
Auxiliary CRC characters shall be obtained from all data bytes in the storage block. Data bytes shall be regarded as 9-bit bytes (including parity bit P). The coefficients of the generating polynomial M, shall be the information bits in each data byte. The coefficients of polynomial M, shall be the information bits in the byte at position 1 of the first data group, the coefficients of polynomial Mz shall be the information bits in the byte at position 2, and so on, until M, where n is the number of data bytes in the storage block. The relationship between these information bits and polynomial coefficients is shown in Table 5. Table 5
Track number corresponding to the information bit
Weight of polynomial coefficient
Track number corresponding to the information bit
Auxiliary CRC characters shall be obtained as follows. The asymmetric polynomial N is: N= z(X'M))
Where: i= n～1
i=1～n
Weights of polynomial coefficients
HX\+X+X+X
All arithmetic operations should be modulo 2.
GB 9363—88
Add the polynomial (X+XI+X°+X+X) and the polynomial N at the corresponding information bits using the \XOR\ operation. The relationship between the coefficients of the resulting polynomial and the information bits of the auxiliary CRC character is shown in Table 6. Table 6
Track number
Weights of polynomial coefficients
Track number
Weights of polynomial coefficients
The auxiliary CRC character should be odd parity. If the sum of the information bits of the auxiliary CRC character is an even number, the information bits of track 4 should be inverted to obtain odd parity.
8.4.3CRC character
The CRC character is obtained from all characters before the CRC character in the storage block (data, blank-filling characters, auxiliary CRC characters and the blank-filling characters that may appear in position 1 of the CRC group). These characters including their check bits should be considered as 9-bit bytes, but do not include all ECC characters in position 8 in the data group and the remaining group. The coefficients of the generating polynomial M, are the information bits in each byte. The coefficients of the polynomial M, should be the information bits of the byte in position 1 of the first data group, the coefficients of the polynomial M. should be the information bits of the byte in position 2, and so on, until the nth character M. is considered.
The relationship between these information bits and the polynomial coefficients is shown in Table 7. Table 7
Track number corresponding to information bit
Weight of polynomial coefficient
CRC character shall be obtained by the following polynomial C, C = E(X'M)
Where, i=n～1
j=1～n
(modK)
K = X\+X+ X+X+X+X\
All arithmetic operations shall be modulo 2.
Track number corresponding to information bit
Weight of polynomial coefficient
Add the polynomial (X\+X'+X\+X*+X+X+X\) to the polynomial C at the corresponding information bit by \XOR\ operation. The relationship between the coefficients of the resulting polynomial and the information bit of the CRC character is shown in Table 8. Track number
Note: Only odd parity check is used for CRC character.
8.4.4 Remaining characters
GB9363-88
The weight of the polynomial coefficient
The remaining characters are obtained from the number of data bytes n in the storage block. Rr
(mod 7)
(mod32)
R and R, are represented by binary numbers. The information bits of the remaining characters should be: R, = 0.1.2 bits
R, = 3, 4, 5, 6.7 bits
The relationship between these information bits and tracks is shown in Table 9. Table 9
The odd parity bit P should be written in track 4.
9 Recording method of each storage group on the magnetic tape
Track number
Each storage group specified in Chapter 8 is encoded and recorded on the magnetic tape according to the following method. The weights of the polynomial coefficients
Every 4 consecutive information bits on each track are converted into 5 consecutive information bits according to the following relationship. Then they are recorded on the tape. 0000→11001
0001→11011
0010-→10010
0011-→10011
0100--11101
010110101
0110--10110
0111-10111||tt| |1000-+11010
1001-01001
101001010
101101011
1100→11110
1101-01101
1110-→01110
1111→01111
GB 9363—88
After recording, the different areas on the tape are respectively called: a.
Data storage group:
Remaining storage group,
CRC storage group;
Storage row (9 information bits in the horizontal direction of the tape); data block (storage block).
10 Control subgroup
The control subgroup should consist of 5 consecutive storage rows. The information bit pattern on each track is the same except for the endpoint control subgroup 2 (TERM2).
10.1 Endpoint Control Subgroup (TERM)
Endpoint Control Group 1 (TERM1) shall be a (10101) control subgroup and shall be located at the end of each storage block toward the BOT (beginning of the mark) (see 11.2.1).
TERM2 shall be a (1010X) control subgroup in which the information bits shall restore the residual magnetism of each track to the erased state (see 5.7). It shall be located at the end of each storage block toward the E0T (end of the mark) (see 11.2.7). 10.2 First Control Subgroup (SEC)
Second Control Subgroup 1 (SEC1) shall be a (01111) control subgroup and shall be located immediately after TERM1 (see 11.2.1). The second control subgroup 2 (SEC2) shall be a (11110) control subgroup, which shall be placed immediately before TERM2 (see 11.2.7). 10.3 Synchronization control subgroup (SYNC)
SYNC shall be a (11111) control subgroup.
10.4 Mark control subgroup 1 (MARK1)
MARK1 shall be a (00111) control subgroup.
10.5 Mark control subgroup 2 (MARK2)
MARK2 shall be a (11100) control subgroup.
10.6 End mark subgroup (ENDMARK)
END MARK shall be a (11111) control subgroup, which is the same as the SYNC mode, but has a different function. 11 Memory Block
11.1 Data Section
According to the block coding method, the data section of the memory block is at least 18 data bytes and at most 8192 data bytes. However, larger memory blocks may be used by agreement between the parties to the information exchange. 11.2 Memory Block Structure
The structure of the memory block depends on the data of the data storage group. Its general structure is shown in Figure 2. Synchronization
11.2.1 Preamble
MARK 1
Last-·
Data Storage
The structure of the preamble is shown in Figure 3
Data Storage Group
End mark
11.2.2 MARK1
MARK1 immediately follows the preamble.
11.2.3 Resynchronization Pulse (RESYNC)
The structure of RESYNC is shown in Figure 4.
11.2.4 Number of data storage groups N
GB 9363~-B8
Valid data storage group
Remaining storage groups
RESYNC
CRC storage group
14 SYNC
Number of storage groups
MARK 2
Last step
When N ≤ 158, END MARK should be located after the last data storage group and before the remaining groups. In this case, there should be no RESYNC.
When N>158, a RESYNC should be inserted after every 158 data storage groups, and ENDMARK should be inserted after the last data storage group. However, if N is a multiple of 158, there should be no RESYNC after the last data storage group, but only ENDMARK.
Note that RESYNC is attached, and MARK1 and MARK2 are placed before and after each 158 data storage groups arranged in sequence. 11.2.5 Remaining storage groups and CRC storage groups
Remaining storage groups and CRC storage groups should be placed immediately after ENDMARK. 11.2.6 MARK2
MARK2 should be located after the CRC storage group and before the post-step. 11.2.7 Post-sync
The post-sync structure is shown in Figure 5.
14 SYNC
1111-0
11.3 Inter-block spacing
There should be an inter-block spacing between storage blocks:
Nominal length: 7.6 mm;
Minimum length: 7.1 mm;
Maximum length: 1.6 m.
GB 9363B8
The inter-block spacing of the magnetic tape should be erased according to the provisions of 5.7. 11.4 Maximum Data Density
Since an ECC character is inserted after every 7 data bytes, 4 bits are converted to 5 bits, and RESYNC is inserted after every 158 data storage groups, the maximum data recording density shall be the maximum physical recording density 356ftpmm multiplied by the factor 4158
8 ^ 5 × 160
, i.e. 246 data bytes per millimeter (6250 data bytes per inch). 12 Tape Format
The beginning of the tape before the first preamble shall have a specific area as specified in 12.1 to 12.5 (see Figure 6). 292 mm maximum, 241 mm minimum
10 mm maximum, 38 mm minimum
ARA Area
First Memory Fin Block
12.1Density identification area (ID pulse)
ARA ID pulse
Electrical half pulse
111:1(11111(111
1111111
1111111111111
-11111111
111111111
111111111
43mmMinimum value
00100100100100100
86.36m m maximum value
The information pattern of the ID pulse is 100100100.*, and the recording density is 119±12ftpmm. The ID pulse is only written on track 6, and all other tracks are erased. The starting point of the ID pulse should be before the trailing edge of the BOT. The distance between them should not be less than 43mm, and it should continue after the trailing edge of the BOT.
: 12.2 Interval G1
Interval G1 should be immediately after the ID pulse, and its maximum value is 86.36 mm. 12.3 Automatic readout amplifier (ARA) area
The ARA area should consist of an ARA level pulse and an ARA identification pulse immediately following it. 12. 3. 1 ARA level pulse
The ARA level pulse is immediately after the interval G1, and its information pattern on all tracks is 1111, and its recording density is
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