ISO IEC 1863-1990 Information processing 9-track 12 7 mm (0 5 in) wide magnetic tape for information interchange using NRZ1 at 32 ftpmm (800 ftpi) 32 cpmm (800 .pdf
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1、INTERNATIONAL STANDARD ISOIIEC 1863 Second edition 19904541 Information processing - g-track, 12,7 mm (0,5 in) wide magnetic tape for information interchange using NRZI at 32 ftpmm (800 ftpi) - 32 cpmm (800 cpi) Traitement de linformation - Bande magnbtique B 9 pistes de 12.7 mm (0,5 in) de large, p
2、our / b) The spacing between the first detected bit and the last detected bit of a row shall be less than IO,8 urn (425 pin); 4.1 Operating environment Tapes used for data interchange shall be operated under the following conditions: c) There shall be a minimum apparent spacing between any bits of s
3、uccessive rows of 11,2 urn PI40 pin). 5.5 Static skew - temperature: 16 OC to 32 OC (60 OF to 90 OF); - relative humidity: 20 % to 80 %; - wet bulb temperature: not greater than 25 “C (78 OFI. Conditioning before operating: If a tape has been exposed during storage and/or transportation to condition
4、s outside the above values, it should be conditioned for a period of 2 h to 12 h depending upon the extent of exposure. 4.2 Storage and transportation The recommendations for storage and transportation environ- ment are specified in annex C. Responsibility for ensuring that adequate precautions agai
5、nst damage are taken during shipment shall be with the sender (see annex Cl. 4.3 Wind tension For interchange, the tape winding tension shall be between 2,0 N and 3.6 N (7 ozf to 13 ozf). 5 Recording 5.1 Method of recording The “non return to zero change-on-ones recording” (NRZl) method of recording
6、 shall be used where a ONE is represented by a change of direction of longitudinal magnetization. 5.2 Density of recording The nominal density shall be designated by 32 ftpmm (800 ftpi). The actual density shall be 31,5 ftpmm (800 ftpi). The resulting nominal flux transition spacing is 31,75 urn (1
7、250 uin). The static skew shall be less than 3,81 urn (150 pin). This con- dition is required to be satisfied for both flux transition polarities. 5.6 Signal amplitude 5.6.1 Standard Reference Amplitude The Standard Reference Amplitude is the average peak-to-peak signal amplitude derived from the Ma
8、ster Standard Reference Tape on the qualified measurement system at the density of 32 ftpmm BOO ftpi) and the recording current Zr of 2,l x Zf. The signal amplitude shall be averaged over 4 000 flux tran- sitions, and shall be measured on the read-while-write pass. The reference current Zr is the mi
9、nimum current which produces the Reference Field. 5.6.2 Average signal amplitude The average peak-to-peak output signal amplitude of an inter- changed tape at 32 ftpmm (800 ftpi) shall be between 70 % and 115 % of the Standard Reference Amplitude. Averaging shall be done over a minimum of 4 000 flux
10、 tran- sitions which, for the interchange tape, may be segmented into blocks. Averaging shall be done on the first read pass after interchange. 6.6.3 Maximum signal amplitude An interchanged tape shall contain no flux transition the base- to-peak signal amplitude of which exceeds 120 % of one-half t
11、he Standard Reference Amplitude on the first read pass after interchange. 2 ISO/IEC 1863 : 1990 (El 5.6.4 Minimum signal amplitude An interchanged tape shall contain no flux transition the base- to-peak signal amplitude of which is less than 35 % of one-half the Standard Reference Amplitude on the f
12、irst read pass after interchange. 5.7 Erasure 5.7.1 Erase direction When erased, the rim end of the erased area of the tape shall be magnetized so that it is a North-seeking pole and the hub end of the erased area is a South-seeking pole (see annex B). 5.7.2 Erase width The full width of the tape sh
13、all be d.c.-erased in the direction specified in 5.7.1. 5.7.3 Residual signal The tape shall be erased so that any residual signals, including NRZl at 32 ftpmm (800 ftpi) and 356 ftpmm (9 042 ftpi) and phase encoding at 126 ftpmm (3 200 ftpi) are less than 4 % of the Standard Reference Amplitude at
14、32 ftpmm (800 ftpi). 7 Data representation 7.1 Coded representation of characters Characters shall be represented by means of the -I-bit coded character set (see IS0 6461, the 8-bit coded character set (see IS0 4873) or, where required, of an extension of the -/-bit coded character set (see IS0 2022
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- ISOIEC18631990INFORMATIONPROCESSING9TRACK127MM05INWIDEMAGNETICTAPEFORINFORMATIONINTERCHANGEUSINGNRZ1AT32FTPMM800FTPI32CPMM800PDF

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