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1、r 11630 PT*2 87 m 4853903 0536853 822 m INTERNATIONAL STANDARD IS0 8630-2:1987 TECHNICAL CORRIGENDUM 1 Published 1992-11-15 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION. MDKAYHAPOAHAR OPrAHM3AAL(MR Il0 CTAHAAPTH3AQMH. ORGANISATION INTERNATIONALE DE NORMALISATION INTERNATIONAL ELECTROTECHNICAL COMM
2、ISSION * MEMYHAPO b) a flux transition shall be written at each cell boundary between consecutive bit cells containing ZEROS. Exceptions to this are defined in 4.12. 1 COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organizat
3、ion for Standardization Licensed by Information Handling Services ISO 8630-2 : 1987 (E) 4.2 Track location tolerance of the recorded flexible disk cartridge The centrelines of the recorded tracks shall be within k 0,042 5 mm ( f 0.001 67 in) of the nominal positions, over the range of operating envi
4、ronment specified in IS0 8630-1. 4.3 Recording offset angle At the instant of writing or reading a magnetic transition, the transition shall have an angle of Oo f 18 with the radius. NOTE - As tracks may be written and overwritten at extremes of the tolerances given in 4.2 and 4.3, a band of old inf
5、ormation may be left at one edge of the newly written data and would constitute unwanted noise when reading. It is therefore necessary to trim the edges of the tracks by erasure after writing. 4.4 Density of recording 4.4.1 The nominal density of recording shall be 13 262 ftprad”. The resulting nomi
6、nal bit cell length for track 00, side O is 151 Clrad, and for all the other tracks it is 75,5 prad. 4.4.2 The long-term average bit cell length shall be the average bit cell length measured over a sector. It shall be within k 2 , O % of the nominai bit cell length. 4.4.3 The short-term average bit
7、cell length, referred to a par- ticular bit cell, shall be the average of the lengths of the preceding eight bit cells. It shall be within f 8 % of the long- term average bit cell length. 4.5 Flux transition spacing The instantaneous spacing between flux transitions may be influenced by the reading
8、and writing process, the bit sequence recorded (pulse crowding effects) and other factors. The locations of the transitions are defined as the locations of the peaks in the signal when reading. Tests should be carried out using a peak-sensing read amplifier (see annexes B and C). 4.5.1 Flux transiti
9、on spacing for track 00, side O (see figure 1) 4.5.1.1 The spacing between two clock flux transitions sur- rounding a data flux transition or between two data flux transi- tions surrounding a clock flux transition shall be between 90 % and 140 % of the nominal bit cell length. 4.5.1.2 The spacing be
10、tween two clock flux transitions not surrounding a data flux transition or between two data flux transitions surrounding a missing clock flux transition shall be between 60 % and 110 % of the nominal bit cell length. 4.5.1.3 The spacing between a date flux transition and the preceding clock flux tra
11、nsition (when not missing) or between a clock flux transition and the preceding data flux transition (when not missing) shall be between 45 % and 70 % of the nominal bit cell length. 4.5.2 Flux transition spacing for all tracks excluding track 0 0 , side O (see figure 2) 4.5.2.1 The spacing between
12、the flux transitions in a sequence of ONES shall be between 80 % and 120 % of the short-term average bit cell length. C 1 C 1 C O C I 1 I 1 1 1 O Figure 1 O 1 O 1 8O0/0 to 120% koo/0 to 165 0 / bit-position B8 shall be recorded with bit ZERO. 6.4.2 Data Field The relationship shall be as shown in fi
13、gure 5. This field shall comDrise a number of bvtes as defined bv the sector length byte (see 6.2.2.3) in the Sector Address: No Bits of the 7-bit combination O b7 b6 b5 b4 b3 b2 bl requirements are implied beyond the correct EDC for the con- tent of this field (see also 7.4.2.4.2). Bit-positions in
14、 the byte B8 R7 B6 B5 B4 B3 B2 BI 6.4.3 EDC Figure 5 These two bytes shall be generated as defined in 4.13 using the Each 8-bit coded character shall be recorded in bit-positions B8 bytes of the Data Block starting with the first (Al)*-byte of the to B1 of a byte. Data Mark (see 6.4.1) and ending wi
15、th the last byte of the Data Field (see 6.4.2). The relationship shall be as shown in figure 6. 6.5 Data Block Gap I Bits of the 8-bit combination I b8 I b7 1 b6 I b5 I b4 1 b3 I b2 I bl I This field shall comprise a number of initially recorded I Bit-positions in the byte I B8 1 B7 I B6 I B5 I B4 I
16、 B3 I B2 I BI 1 (4El-bytes. The number is dependent on the number of bytes in the Data Field (see 6.4.2) as given in table 7. Figure 6 6 COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organization for Standardization License
17、d by Information Handling Services 7.2 Good and bad cylinders A good cylinder is a cylinder which has both tracks formatted according to 7.4. A bad cylinder is a cylinder which has both tracks formatted according to 7.5. 7.3 Requirements for cylinders Cylinder 00 shall be a good cylinder. There shal
18、l be at least 74 good cylinders between cylinder O1 and cylinder 76. 7.4 Layout of the tracks of a good cylinder References to clause 5 are for track 00, side O. References to clause 6 are for all other tracks. 7.4.1 Index Gap Description : see 5.1 and 6.1. 7.4.2 Sector Identifier 7.4.2.1 Identifier
19、 Mark Description : see 5.2.1 and 6.2.1. 7.4.2.2 Address Identifier This field shall comprise 6 bytes. 7.4.2.2.1 Track Address This field shall comprise 2 bytes: a) Cylinder Address (C) This field shall specify in binary notation the Cylinder Address from O 0 for the outermost cylinder to 74 for the
20、 innermost cylinder. NOTE - A unique Cylinder Number is associated with each cylinder (see 4.10). Two of these cylinders are intended for use only when there are one or two defective cylinders. Each good cylinder possesses a unique Cylinder Address; a defective cylinder does not possess a Cylinder A
21、ddress. Cylinder Addresses are assigned con- secutively to the good cylinders in the ascending sequence of Cylinder Numbers. b) Side Number (Side) Description : see 5.2.2.1 and 6.2.2.1. 7.4.2.2.2 Sector Number (S) Description : see 5.2.2.2 and 6.2.2.2. 7.4.2.2.3 4th byte of the Sector Address Descri
22、ption: see 5.2.2.3 and 6.2.2.3. IS0 8630-2 1987 (E) 7.4.2.2.4 EDC Description: see 5.2.2.4 and 6.2.2.4. 7.4.2.3 Identifier Gap Description: see 5.3 and 6.3. These bytes may subsequently become corrupted due to the overwriting process. 7.4.2.4 Data Block 7.4.2.4.1 Data Mark For track 00, side O this
23、field shall comprise 6 (00)-bytes 1 byte The 7th byte shall be (FBI“ indicating that the data are valid and that the whole Data Field can be read; (F8)“ indicating that the first byte of the Data Field shall be interpreted according to IS0 7665. For all other tracks this field shall comprise 12 (00)
24、-bytes 3 (Al )*-bytes 1 byte The 16th byte shall be (FBI indicating that the data are valid and that the whole Data Field can be read; (F81 indicating that the first byte of the Data Field shall be interpreted according to IS0 7665. 7.4.2.4.2 Data Field This field shall contain a number of bytes as
25、specified in 5.4.2 and 6.4.2. If it comprises less than the requisite number of data bytes, the remaining positions shall be filled with (00)-bytes. Data fields in cylinder 00 are reserved for operating system use, including labelling. 7.4.2.4.3 EDC Description: see 5.4.3 and 6.4.3. If the last byte
26、 of the data mark is (F8)“ or (F81 and the first character of the Data Field is capital letter F, the EDC may or may not be correct, as the sector contains a defective area. If the first character is capital letter D, then the EDC shall be correct. On cylinder 00, only capital letter D is permitted.
27、 7 COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services IS0 8630-2 : 1987 (E) 7.4.2.5 Data Block Gap This field is recorded after each Data Block and it pr
28、ecedes the following Sector Identifier. After the last Data Block it precedes the Track Gap. It comprises initially 27 (FFI-bytes (see 5.5) or a number of (4E)-bytes (see 6.5). These bytes may subsequently become ill- defined due to the overwriting process. 7.4.2.6 Track Gap Description : see 5.6 an
29、d 6.6. 7.5 Layout of the tracks of a bad cylinder 7.5.1 Contents of the fields The fields of the tracks of a bad cylinder should have the following contents. 7.5.1.1 Index Gap This field should comprise 146 (4Ebbytes. 7.5.1.2 Sector Identifier This field should comprise an Identifier Mark and an Add
30、ress Identifier. 7.5.1.2.1 Identifier Mark This field should comprise 16 bytes: 12 (OOI-bytes 3 (Al )*-bytes 1 (FEI-byte 7.5.1.2.2 Address Identifier This field should comprise 6 bytes: 4 (FFI-bytes 2 EDC-bytes These two EDC bytes shall be generated as defined in 4.13 using the bytes of the Sector I
31、dentifier starting with the first (Al)*-byte (see 7.5.1.2.11 of the Identifier Mark and ending with the above 4 (FFI-bytes. 7.5.1.3 Other fields The contents of the remaining fields are not specified and may be ill-defined. 7.5.2 Requirements for tracks Each track of a bad cylinder shall have at lea
32、st one of its Sector Identifiers with the content specified in 7.5.1.2. If this condition is not satisfied the cartridge shall be rejected. 8 COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organization for Standardization Li
33、censed by Information Handling Services 8630 PT 2-87 4853703 0063734 7 r IS0 8630-2 : 1987 (EI Annex A EDC implementation (This annex does not form part of the standard.) Figure 7 shows the feedback connections of a shift register which may be used to generate the EDC bytes. Prior to operation, all
34、positions of the shift register are set to ONE. Input data are added (exclusive OR) to the contents of position C , , of the register to form a feedback. This feedback is in its turn added (exclusive OR) to the contents of position C4 and position C,. On shifting, the outputs of the exclusive OR gat
35、es are entered respectively into positions Co, C , and CI2. After the last data bit has been added, the register is shifted once more as specified above. The register then contains the EDC bytes. If further shifting is to take place during the writing of the EDC bytes, the control signal inhibits ex
36、clusive OR operations, To check for errors when reading, the data bits are added into the shift register in exactly the same manner as they were during writing. After the data, the EDC bytes are also entered into the shift register as if they were data. After the final shift, the register con- tents
37、 will be all ZERO if the record does not contain errors. Control (for EDC writing) Figure 7 9 COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services 8b30 PT
38、2-87 “ 3 4853703 0063735 7 r IS0 8630-2 : 1987 (E) Annex B Procedure and equipment for measuring flux transition spacing (This annex does not form part of the standard.) B.l General This annex specifies equipment and a procedure for measuring flux transition spacing on 130 mm (5.25 in) flexible disk
39、 cartridges using MFM recording at 13 262 ftprad on both sides. B.2 Format The disk to be measured shall be written by the disk drive for data interchange use. Testing shall be done on tracks O 0 and 76 on both sides. Track 00, side O shall have the test patterns 001OooOO (20) and 11 101 11 1 (EF) w
40、ritten repeatedly. On all other test tracks the test patterns 1101 101 1 (DB) and 1101 1100 (DC) shall be written repeatedly. B.3 Test equipment B.3.1 Disk drive The disk drive shall have a rotational speed of 360 r/min, with a tolerance of k 3 r/min, averaged over one revolution. The average angula
41、r speed, taken over 32 rns, shall not deviate by more than 0,5 % from the speed averaged over one revolution. B.3.2 Head 8.3.2.1 Resolution The head shall have an absolute reedution of 55 % to 65 % at track 76 on side O and at track 68 on side 1, using the reference material RM 8630, applying the ca
42、libration factor of the reference material, and recording with the appropriate test recording current. The resonant frequency of the head shall be at least 500 O00 Hz. The resolution shall not be adjusted by varying the load impedance of the head. The resolution shall be measured at the output of th
43、e amplifier defined in 8.3.3.1. 8.3.2.2 Offset angle The head shall have a gap offset angle of Oo f 6 with the disk radius on the testing drive. B.3.2.3 Contact Care shall be taken that the heads are in good contact with the media during the tests. B.3.3 Read channel B.3.3.1 Read amplifier The read
44、amplifier shall have a flat response from 1 O00 to 375 O00 Hz within f 1 dB, and amplitude saturation shall not occur. 8.3.3.2 Peak sensing amplifier Peak sensing shall be carried out by a differentiating and limiting amplifier. 10 COPYRIGHT International Organization for Standardization Licensed by
45、 Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services 8630 PT 2-87 4851903 O063936 O r IS0 8630-2 : 1987 (E) 8.3.4 Time interval measuring equipment The time interval counter shall be able to measure 2 ps to at least 5 ns re
46、solution. A triggering oscilloscope may be used for this purpose. B.4 Procedure for measurement B.4.1 Flux transition spacing measurement The transition locations shall be measured by the locations of the peaks in the signal when reading. The flux transition spacing shall be measured by the pulse ti
47、ming intervals after the read channel amplifier defined in B.3.3. B.4.2 Flux transition spacing for track 00, side O Measure time intervals fl to t8 as shown in figure 8. 20 EF Af A 0010000011101111 -f3,-17 + c f l and t2 correspond to sub-clause 4.5.1 .I t3 and t4 correspond to sub-clause 4.5.1.2 t
48、g, 16, f , and t8 correspond to sub-clause 4.5.1.3 Figure 8 B.4.3 Flux transition spacing for all other tracks Measure time intervals tl to f5 as shown in figure 9. OB OC / 110110111101110 A 4- O 1 tl and t2 correspond to sub-clause 4.5.2.1 t3 and t4 correspond to sub-clause 4.5.2.2 f5 corresponds t
49、o sub-clause 4.5.2.3 Figure 9 i COPYRIGHT International Organization for Standardization Licensed by Information Handling Services COPYRIGHT International Organization for Standardization Licensed by Information Handling Services IS0 8630-2 : 1987 (E) Annex C Data separators for decoding MFM recording (This annex does not form part of the standard.) c.1 On track 00, side O the two-frequency recording results in nominal flux transition periods of t for a ONE cell b 2t for a ZERO cell where t = 2 PS. The data separator shall be capable of resolving a difference of 2 PS. This can