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1、INTERNATIONAL STANDARD ISO/IEC 14833 First edition 1996-03-I 5 Information technology - Data interchange on 12,7 mm 1284rack magnetic tape cartridges - DLT 3 format Technologies de /information - ichange de don + - -z ; + - -z z z G4 2f G5 G4 2f G5 ii ii ; m g 2 x a- , ; mgn,a -3 g -3 g -2 -2 2 zz p
2、 2 zz p 5 5 g P g P- : : c) 5 c) 5 z - E z - E 2 2 5 5 2 .!z 2 .!z G6 G6 a v c1 a v c1 ; ; Reverse Data Tracks Reverse Data Tracks G5 2f G4 G5 2f ” ” G4 2f G4 2f G5 G5 Forward Data Tracks Forward Data Tracks 4 .4 Calibration and Directory Area Data Area 4 .4 b Calibration and Directory Area Data Are
3、a Figure 20 - Tape layout Figure 20 - Tape layout 12.4 Calibration and Directory Area The Calibration and Directory Area shall be partitioned as shown in figures 21 and 22. It shall extend from the leader splice to the BOT over 8 690 mm f 150 mm and comprise the following zones. 27 Copyright Interna
4、tional Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/05/2007 02:47:51 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO/IEC 14833:1996 (E) OISO/IEC Unless otherwise indicated
5、, the tolerance is + 50 7 Scratch Area 3 Reference Edge Directory Area - 2692 - . 86902 150 94-0092-A Figure 21 - Calibration and Directory Area Scratch Area 12.4.1 The Scratch Area shall start at the leader splice and shall end at a distance of 2 692 mm f 50 mm from the BOT. It is intended for use
6、by the drive for setting gains, write current, etc. 12.4.2 Guard Area Gl Guard Area Gl shall start at the end of the Scratch Area and shall end at a distance of 2 388 mm + 50 mm from the BOT. 12.4.3 Calibration Tracks Area The Calibration Tracks Area shall start at the end of the Guard Area Gl and s
7、hall end at a distance of 914 mm f 50 mm from the BOT. The Calibration Tracks Area shall contain four Calibration Tracks the width of which shall be 0,215 9 mm f 0,012 7 mm. They are defined as follows. Forward Calibration Track 2 (FCT2) The centreline of FCT2 shall be at a distance of 2,280 mm * 0,
8、030 mm from the Reference Edge. FCT2 shall be recorded with 2j starting at the end of Guard Area Gl and ending at a distance of 2 108 mm + 50 mm from the BOT. Following this section, FCT2 shall be recorded with lfending at a distance of 914 mm + 50 mm from the BOT. Forward Calibration Track 1 (FCTl)
9、 The centreline of FCTl shall be at a distance of 5,334 mm + 0,030 mm from that of FCT2. FCTl shall be recorded as specified for FCT2. Reverse Calibration Track 2 (RCT2) The centreline of RCT2 shall be at a distance of 1,505 mm f 0,030 mm from the Reference Edge. RCT2 shall be recorded with 2f start
10、ing at Guard Area G2 and ending at a distance of 1 219 mm f 50 mm from the BOT. Following this section RCT2 shall be recorded with lfending at a distance of 2 388 mm + 50 mm from the BOT. 28 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS
11、Employees/1111111001, User=Wing, Bernie Not for Resale, 04/05/2007 02:47:51 MDTNo reproduction or networking permitted without license from IHS -,-,- OISO/IEC ISO/IEC 14833:1996 (E) Reverse Calibration Track 1 (RCTl) The centreline of RCTl shall be at a distance of 5,334 mm +: 0,030 mm from that of
12、RCT2. RCTl shall be recorded as specified for RCT2. 2108 l 5o +-1219*50 -q FCTl lf RCTl 1 lf I 2f - FCT2 I_ 2f 1 - 1-f -_- RCT2 -_ lf - I 2f- - 1,505 Reference Edge f 0,030 Figure 22 - Calibration Tracks Area 12.4.4 Guard Area G2 Guard Area G2 shall start at the end of the Calibration Tracks Area an
13、d shall end at a distance of 762 mm f 50 mrn from the BOT. 12.4.5 Directory Area The Directory Area shall start at the end of the Guard Area G2 and end at a distance of 152 mm + 50 mm from the BOT. It shall be recorded on two physical tracks (see 12.5.1) having their centrelines 3,379 mm f 0,030 mm
14、above those of RCTl and RCT2. The Directory Area is intended for recording manufacturers information about the recordings on the tape. This information shall be recorded in the reverse direction, starting at its end specified above. The content of the Directory Area shall be ignored in interchange.
15、12.4.6 Guard Area 63 Guard Area G3 shall start at the end (see 12.4.5) of the Directory Area and shall end at the BOT. 12.5 Data Area The Data Area shall contain data which is transmitted by the host to the drive and recorded according to the format specified in clause 13. The quantity of recorded d
16、ata may be such that the total capacity of the maximum number of physical tracks, 29 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/05/2007 02:47:51 MDTNo reproduction or networki
17、ng permitted without license from IHS -,-,- ISO/IEC 14833:1996 (E) OISO/IEC viz. 128, is required in order to contain it. It may, under other circumstances, be less in which case fewer than 128 physical tracks will be required (see also 14.5). The following specifications are based on the former cas
18、e. 12.51 Physical tracks There shall be 128 physical tracks in the Data Area each identified by a Physical Track Number. Physical track No. 128 shall be that farthest from the Reference Edge and physical track No. 1 shall be that nearest to the Reference Edge. 12.5.2 Width of the physical tracks The
19、 width of a physical track shall be 0,076 2 mm f 0,012 7 mm. 12.53 Logical tracks A logical track shall consist of two physical tracks the Physical Track Numbers of which are m and m+64, where: I I m I 64. The two tracks of a logical track shall be recorded simultaneously. Logical tracks are identif
20、ied by a Logical Track Number from 0 to 63. They are recorded in ascending order of their Logical Track Numbers, starting with logical track No. 0. Logical tracks with an even Logical Track Number shall be recorded in the forward direction. Logical tracks with an odd Logical Track Number shall be re
21、corded in the reverse direction. The allocation of physical tracks to logical tracks shall be as specified in table 2. Table 2 - Allocation of physical tracks to logical tracks 12.5.4 Locations of the physical tracks The locations of the centrelines of the physical tracks are related to those of the
22、 centrelines of the Calibration Tracks. The locations of the physical tracks of logical tracks with an even Logical Track Number shall be related to those of FCTl and FCT2. The locations of the physical tracks of logical tracks with an odd Logical Track Number shall be related to those of RCTl and R
23、CT2. The positions of the centrelines of the physical tracks relative to those of the Calibration Tracks shall be as specified in table 3. A positive offset indicates that the physical track is above the referenced Calibration Track, a negative offset that it is below the referenced Calibration Trac
24、k. Physical tracks with Physical Track Numbers 1, 64, 65 and 128 may be wider than the other physical tracks. The centre line of the usable part of these tracks is at a distance of 0,076 2 mm from the centre line of the previously written adjacent track. 30 Copyright International Organization for S
25、tandardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/05/2007 02:47:51 MDTNo reproduction or networking permitted without license from IHS -,-,- OISO/IEC ISO/IEC 14833:1996 (E) Table 3 - Locations of the physical tracks Physical
26、 Track Calibration Offset Number track Tolerance: f 0,012 7 n 1 to 15 FCT2 -l,lll 2-(n-1)0,0762 16 to 32 0,044 4 + (n-16) 0,076 21 33 to64 RCT2 2,279 6 + (n-33) 0,076 21 65 to 79 FTC1 -l,lll 2-(n-65)0,0762 80 to 96 0,044 4 + (n-80) 0,076 21 97 to 128 RTCl 2,279 6 + (n-97) 0,076 21 12.5.5 Layout of t
27、racks in the Data Area The layout of tracks in the Data Area shall be as shown in figure 23. Logical Track No.3 Logical Track No.2 Tolerance: f 76 d 3073 I Reverse Data Tracks G5 2f G4 Forward Data Tracks c EOT Reverse Data Tracks G5 2f G4 G4 2f GS -:p- Forward Data Tracks G6 f 1219 1803 P-4 / ;24 3
28、073 Reference Edge 94-0094-A 12.5.5.1 Forward tracks Figure 23 - Layout of the tracks of the Data Area The layout of tracks recorded in the forward direction, i.e. all pairs of physical tracks forming the logical tracks having an even Logical Track Number, shall be as follows. Guard Area G4 Guard Ar
29、ea G4 shall start at the BOT and end at a distance of 1 219 mm f 76 mm from the BOT. 31 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/05/2007 02:47:51 MDTNo reproduction or netwo
30、rking permitted without license from IHS -,-,- ISO/IEC 14833: 1996 (E) OISO/IEC 2f Zone The track shall be recorded with 2f starting at Guard Area G4 and ending at a distance of 1 803 mm + 76 mm from the BOT. Guard Area G5 Guard Area G5 shall start at the 2f Zone and end at a distance of 3 073 mm f
31、76 mm from the BOT. Guard Area G6 The track shall end with a Guard Area G6 which shall start at a distance of 1 524 mm min. from the EOT and end at the EOT. 12.552 Reverse tracks The layout of tracks recorded in the reverse direction, i.e. all pairs of physical tracks forming logical tracks with an
32、odd Logical Track Number, shall be as follows. Guard Area G4 This Guard Area G4 shall start at the EOT and end at a distance of 1 219 mm f 76 mm from the EOT. 2f Zone The track shall be recorded at the physical recording density of 2f starting at Guard Area G4 and ending at a distance of 1 803 mm f
33、76 mm from the EOT. Guard Area G5 This Guard Area G5 shall start at the 2f Zone and end at a distance of 3 073 mm i 76 mm from the EOT. Guard Area G6 The track shall end with a Guard Area G6 which shall start at a distance of 1 524 mm min. from the BOT and end at the BOT. 13 Data format The host tra
34、nsmits to the drive data in the form of Records, each comprising one or more 8-bit bytes the interpretation of which is outside the scope of this International Standard and is a matter of agreement between sender and recipient of the data. The maximum size of a Record permitted by the format is 224
35、- 1 bytes. 13.1 Data Bytes Data Bytes shall be - User Bytes transmitted by the host - Groups of 8 bytes for MAP entries (see 13.6.3.3) - Pad Bytes which are bytes set to all ZEROS. 13.2 Logical Blocks A Logical Block shall consist of the two physical blocks recorded simultaneously on the physical tr
36、acks of a logical track. 13.3 Data Blocks After having been received from the host, Records shall be arranged in groups of 8 216 Data Bytes. Each such group shall be split into two sets of 4 108 bytes. To each of these 4 lo - if the first physical block has a page of type Tape Mark, the second physi
37、cal block shall have a first page of type Filler; - if the first physical block contains the last Record received from the host, then the second physical block shall have a first page of type Filler; - within either physical block: . there shall be no page of type Data nor of type Tape Mark after a
38、page of type Filler, . there shall be no page of type Data nor of type Filler after a page of type Tape Mark. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/05/2007 02:47:51 MDTNo
39、 reproduction or networking permitted without license from IHS -,-,- ISO/IEC 14833: 1996 (E) OISO/IEC 13.6.4 EDC The Data field shall be followed by a 2-byte field containing a 16-bit EDC computed over the 4 108 bytes of the Data Field as follows. Each EDC character is a 16-bit word computed over 2
40、054 16-bit Data Words formed from the 4 108 bytes of the Data Field. The first Data Byte constitutes the least significant part of the first Data Word, the second Data Byte constitutes its most significant part, and so on. With these 2 054 Data Words identified by 1 I i I 2 054, the EDC word is obta
41、ined by the following algorithm. Set EDC, to (00)(45) Set EDC, to EDCi_, $ (Data Word)i Shift EDC, leftwards by one bit position, with the most significant bit moved to the least significant bit position. where: stands for Exclusive OR. This algorithm yields EDC, us4 which is the 16-bit pattern reco
42、rded in byte positions 4 182 and 4183 of the Block format. 13.6.5 Control Field 1 (CFl) CFl is a 160-bit field. It specifies attributes of a Logical Block, thus both physical blocks of a Logical Block have an identical CFl . The content of CFl shall be as shown in figure 26. When recorded on the tap
43、e, this field shall be formatted as specified by annex F. Number of bits Field 30 Reserved 6 Format 24 Tape Mark 8 Compression 32 Object Number 16 Logical Block Number 12 Sequential File Mark Number 4 Sequential File Mark Offset 3 Block Type 1 Early Warning 24 Back Link Figure 26 - content of Contro
44、l Field 1 This format is not applicable to ECC Blocks (see 14.5). 13.6.5.1 Reserved field The bits in the Reserved field shall be set to all ZERO. 13.6.5.2 Format This field shall be set to 000010. 13.6.5.3 Tape Mark This field shall be set to ZERO for all Logical Blocks prior to the first one conta
45、ining a page of type Tape Mark. For Data Blocks this field shall specify in binary notation the ordinal number of the previous Data Block containing a page of type Tape Mark. For Filler Blocks, EOTR and EOD Blocks, this field shall be set to all ZEROS. 36 Copyright International Organization for Sta
46、ndardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 04/05/2007 02:47:51 MDTNo reproduction or networking permitted without license from IHS -,-,- OISO/IEC ISO/IEC 14833:1996 (E) 13.6.5.4 Compression This field shall express in bina
47、ry notation a numerical identifier of the compression algorithm, where applicable, else it shall be set to all ZEROS. 13.6.5.5 Logical Block Number This field shall specify in binary notation the ordinal number of each Data Block which contains one or more Records and/or a part of a Record, starting
48、 with 0 and incremented by 1 for every successfully written Data Block of the Record. This field shall be set to all ZEROS in Filler Blocks. The content of this field in EOTR and EOD Blocks is not specified by this International Standard and shall be ignored in interchange. 13.6.5.6 Object Number This field is a count of all Records and pages of type Tape Mark on the tape, starting with 1 and incremented by 1 for each Record and each page of type Tape Mark. This count shall include the object in which it is recorded. This field shall be set to all ZEROS in Filler