1、0 British Standards Institution. No part of this publication may be photocopied or otherwise reproduced without the prior permission in writing of BSI British Standard Specification for File structure and labelling of magnetic tape for information interchange IS0 title: Information processing - File
2、 structure and labelling of magnetic tapes for information interchange BSI BS*4?32 88 Lb24bb9 O085022 8 = BS 4732 : 1988 IS0 1 O01 -1 986 UDC 681.327.6361.638 : 006.915.3 O O O British Standards Institution Etiquetage des bandes magntiques et structure des fichiers dchange dinformations - Spcificati
3、ons Kennstze und Dateianordnung auf Magnetbndern fr den Informationsaustausch BSI ES*4732 A8 Lb24669 8085023 T I BS 4732 : 1988 Contents Page National foreword Inside front cover Committees responsible Back cover Specification 1 Scope and field of application 2 Conformance 3 References 4 Definitions
4、 5 Notation 6 Arrangement of labels and files 7 File structure for data interchange 8 Format and contents of the labels and label sets 1 1 1 1 2 2 . 4 .L 5 9 Levels of interchange 10 Requirements for the description of systems 11 Requirements for an originating system 12 Requirements for a receiving
5、 system Annexes A IRV code table for IS0 646 B Initialized volumes C Main differences between the first edition (1979) and the present (second) edition of this International Standard Page 12 12 12 14 15 16 17 National foreword This British Standard has been prepared tinder the direction of the Infor
6、mation Systems Technology Standards Committee. it is identical with IS0 1001-1986 Information processing - File structure and labelling of magnetic tapes for information interchange published by the International Organization for Standardization (ISO). This British Standard supersedes BS 4732 : Part
7、 2 : 1979 which is withdrawn, IS0 1001-1986 is a revision of IS0 1001-1979. The main differences between this edition and the 1979 edition of IS0 1001 (with which BS 4732 : Part 2 : 1979 was identical) are given in annex C. Terminology and conventions. The text of the international standard has been
8、 approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. For metric units the comma has been used as a decimal marker. In British Sta
9、ndards it is current practice to use a full point on the baseline as the decimal marker. Wherever the words International Standard appear, referring to this standard, they should be read as British Standard. Cross-references International standard Corresponding British Standard IS0 646-1983 IS0 2022
10、 -1986 BS 4730 : 1985 Specification for UK 7-bit coded character set (Identical exercising national options) BS 6856 : 1987 Specification for code extension techniques for United Kingdom 7-bit and 8-bit coded character sets (Identical) BS 6006 : 1987 Specification for structure and rules for impleme
11、ntation of United Kingdom 8-bit coded character set (Identical) IS0 4873-1986 There are no corresponding British Standards for IS0 962, IS0 1862, IS0 1863, IS0 1864, IS0 3788 and IS0 5652 but since they are referred to in the text for information only the validity of the standard is not affected. Co
12、mpliance with a British Standard does not of itself confer immunity from legal obligations. BSl BS*4732 88 I 1b2qbb9 008502Y 1 m BS 4732 : 1988 British Standard Specification for File structure and labelling of magnetic tape for information interchange 1 Scope and field of application This Internati
13、onal Standard specifies the file structure and the labelling of magnetic tapes for the interchange of information between users of information processing systems. This International Standard also smcifies 0 - volume and file structure; - basic characteristics of the blocks containing the records con
14、stituting the file; - recorded labels for identifying files, file sections and volumes of magnetic tapes; - four nested levels of interchange. Furthermore, this International Standard specifies require- ments for the processes which are provided within information processing systems, to enable infor
15、mation to be interchanged between different systems, utilizing recorded magnetic tape as the mddium of interchange. For this purpose it specifies the functions to be provided within systems which are intended to originate or receive magnetic tape volumes which conform to this International Standard.
16、 o * 2.1 Conformance of a magnetic tape volume set A magnetic tape volume set conforms to this International Standard when all information recorded on it conforms to the specifications of this International Standard. A statement of conformance shall identify the lowest level of interchange to which
17、the contents of the magnetic tapes conform. A prerequisite to such conformance is conformance of each volume of the volume set to the same International Standard for information interchange on magnetic tapes. 2.2 Conformance of an information processing system An information processing system confor
18、ms to this Inter- national Standard if it meets all the requirements specified in this International Standard either for an originating system, or for a receiving system, or for both types of system. A state- ment of conformance shall identify which of these sets of re- (I) quirements can be met by
19、the system. 3 References IS0 fi46, Informationprocessing - IS0 7-bit coded character set for information interchange. IS0 962, Information processing - Implementation of the 7-bit coded character set and its 7-bit and 8-bit extensions on Strack, 12,7 mm (0.5 in) magnetic tape. IS0 1862, Information
20、processing - Strack, 12,7 mm (0.5 in) wide magnetic tape for information interchange recorded at 8 rpmm (200 rpi. IS0 1863, Information processing - Btrack, 12,7 mm (0.5 in) wide magnetic tape for information interchange recorded at 32 rpmm (800 rpi). IS0 1864, Information processing - Unrecorded 12
21、,7 rnm (0.5 in) wide magnetic tape for information interchange - 35 ftpmm (800ftpi) NZ7,126 ftpmm (3 200 ftpi) phase encod- ed and 356 ftpmm (9 042 ftpi), NZ7. IS0 2022, Information processing - IS0 7-bit and 8-bit coded character sets - Code extension techniques. IS0 3788, Information processing -
22、Strack, 12,7 mrn (0.5 in) wide mgnetic tape for information interchange recorded at 3 rpmm (1 600 rpi), phaseencoded. IS0 4873, Information processing - 8-bit coded character set for information interchange. IS0 5652, Information processing - Strack, 12,7 mm (0.5 in) wide magnetic tape for informati
23、on interchange - Format and recording, using group coding at 246 cprnm (6 250 rpi). 4 Definitions For the purpose of this International Standard, the following definitions apply. 4.1 application program : A program that processes the contents of records belonging to a file, and may also process sele
24、cted attribute data relating to the file or to the volumes) on which it is recorded. NOTE - An application program is a specific class of user as defined in this international Standard. 1 - BSI BS*4732 A8 W lib24bb9 0085025 3 m BS 4732 : 1988 4.2 block : A group of bytes recorded consecutively in ac
25、cordance with the relevant International Standard for infor- mation interchange. NOTE - The minimum and maximum lengths of a block are specified in the relevant International Standard for information interchange. 4.3 blocked : An attribute of records and record segments that indicates that they may
26、begin at a byte that is not the first byte of a block. 4.4 unit. byte : A string of eight binary digits operated upon as a 4.5 zero or more records. file : A named collection of information consisting of 4.6 one volume. file section : That part of a file that is recorded on any 4.7 file set : A coll
27、ection of one or more files recorded con- secutively on a set of volumes. 4.8 which all records must have the same length. fixed-length record : A record contained in a file in 4.9 implementation : A set of processes within an informa- tion processing system which enable that system to behave as an
28、originating system, or as a receiving system, or as both types of system. 4.10 installation : A person or other entity which controls the use of one or more implementations which process and interchange magnetic tapes. NOTE - An installation is a specific class of user as defined in this Internation
29、al Standard. 4.11 label : A record that identifies and characterizes a volume, or a file section on a volume. 4.12 originating system : An information processing system which can record a file set on a volume set for the pur- pose of data interchange with another system. 4.13 commands to an originat
30、ing system. originator : A person who is responsible for issuing 4.14 receiving system : An information processing system which can read a file set from a volume set which has been recorded by another system for the purpose of data inter- change. 4.15 commands to a receiving system. recipient : A pe
31、rson who is responsible for issuing 4.16 record : Related data treated as a unit of information. 4.17 segmented record : A record contained in a file which is assigned to contain records that may have different lengths and that may be recorded entirely in one block or over more than one block. 4.18
32、International Standard for information inter- change : A standard that specifies the recording method and the track format of a magnetic tape (for example IS0 1863). 4.19 Tape Mark : A control block used as a delimiter. NOTE - The structure of Tape Marks is specified by the relevant International St
33、andards for information interchange. 4.20 tion of the services provided by an implementation. user : A person or other entity that causes the invoca- 4.21 which the records may have different lengths. variable-length record : A record contained in a file in 4.22 volume : A dismountable reel of magne
34、tic tape. 4.23 which a file set is recorded. volume set : A collection of one or more volumes, on 5 Notation The following notation is used in this International Standard BP : Byte position within the label L: Length of the field in number of byte positions a-character(s1 : Any of the allowed charac
35、ters (see 8.1) Digit(s) : Any digit from ZERO to NINE. With the exception of SPACE, a group of capital letters in the content column of a table specifying label contents indicates that these characters shall appear in the order given and in the corresponding byte positions of the field specified, fo
36、r example VOL in BP 1 to 3 of the Volume Header Labels. In the tables and thoughout this International Standard, SPACE signifies the character coded in position 210 of IS0 646. 6 Arrangement of labels and files 6.1 A volume shall be recorded with a sequence of blocks and Tape Marks. The sequence sha
37、ll commence with a block, and shall terminate within the usable recording area. Arrangement of data on a volume 6.2 Arrangement of label groups 6.2.1 Labels A label shall be a record that shall have a length of 80 bytes. Each label shall be recorded within the first or only 80 byte pos- itions of a
38、block. If the block contains any additional bytes, they shall be recorded with any desired bit combinations. 2 ES1 BS*4732 88 Lb24bb 0085Zb 5 I BS 4732 : 1988 Each label shall be of one of the following types : Volume Header Installation Volume File Header User File Header End of File End of Volume
39、User File Trailer 6.2.2 Label sets A sequence of one or more labels of the same type, recorded in consecutive blocks, shall be a label set of that type. All labels in a set shall be numbered consecutively starting from 1, except those labels in the User File Header and User File Trailer Label Sets.
40、The labels in the User File Header and User File Trailer Label Sets may be identified in any order and may contain duplicate identifiers within a set. 6.2.3 Label groups A label group shall consist of a mandatory label set, optionally followed by a second label set of a different type. Each label gr
41、oup shall be of one of the types listed in table 1, and shall in- clude only those label sets listed in the corresponding entry of the table. The first set listed in each table entry is the man- datory set, and the second set listed is the optional set. Table 1 Label group Beginning of Volume Beginn
42、ing of File Section End of File Section End of File Label sets Volume Header Installation Volume File Header User File Header End of Volume User File Trailer End of File User File Trailer 6.3 Arrangement of file sections 6.3.1 File section A file section shall be recorded in a sequence of one or mor
43、e blocks, or no blocks. If no blocks are recorded, the file section is regarded as empty. 6.3.2 Labelled-Sequence 6.3.2.1 A Labelled-Sequence shall consist of the sequence of blocks and Tape Marks as listed below, recorded consecu- tively : . a) Beginning of File Section Label Group; b) Tape Mark; c
44、l a file section; d) Tape Mark; e) either an End of File Label Group or an End of File Sec- tion Label Group, as required in 6.3.2.2: f) Tape Mark. 6.3.2.2 If the file section is the last or only file section of a file, then the label group that follows it shall be an End of File Label Group. Otherw
45、ise the label group shall be an End of File Section Label Group. NOTE - An End of File Section Label Group can only be the last label group on a volume because of the requirements of 6.5.1. 6.3.2.3 Within a Labelled-Sequence the information con- tained in the File Header Label Set, and in the End of
46、 File or End of Volume Label Set, shall apply to the file section that is recorded within the sequence. 6.3.2.4 Within a Labelled-Sequence the number of labels in an End of Volume or End of File Label Set shall be equal to the number of labels in the File Header Label Set. Within all Labelled-Sequen
47、ces in which the file sections of a file are recorded, the number of File Header Labels shall be the same. 6.4 Relationship of file sections to a volume The information on a volume shall consist of the sequence of blocks and Tape Marks as listed below, recorded consecutively: - Beginning of Volume L
48、abel Group; - one or more Labelled-Sequences; - Tape Mark. Any recording following the last Tape Mark of the sequence shall be ignored in interchange. The information that identifies and describes the volume shall be contained in the Volume Header Label Set, within the Beginning of Volume Label Grou
49、p. 6.5 Arrangement of files and file sets 6.5.1 Files If a file is recorded entirely within one volume it shall consist of only one file section. If a file is recorded over more than one volume, then only one file section of the file shall be recorded on any one volume, and - the first file section shall be recorded as the last or only file section on a volume; - any intermediate file section shall be recorded as the only file section on a volume; - the last file section shall be recorded as the first or only file section on a volume. All sections of a file shall b
