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LJDC 681.327.64.042
IS0
O RG A N I Z AT1 O N FOR STA N DA RDl Z AT1 O N
I NT ERN AT1 O N A L
IS0 RECOMMENDATION
R 1001
MAGNETIC TAPE LABELLING AND FILE STRUCTURE
FOR INFORMATION INTERCHANGE
1st EDITION
March 1969
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 1001, Magnetic tape labelling and file structure for information interchange,
was drawn up by Technical Committee ISO/TC 97, Computers and information processing, the Secretariat of
which is held by the American National Standards Institute (ANSI).
Work on this question led to the adoption of a Draft IS0 Recommendation.
'/
In September 1967, this Draft IS0 Recommendation (No. 1323) was circulated to all the IS0 Member Bodies
for enquiry. It was approved, subject to a few modifications of an editorial nature, by the following Member Bodies :
Austrdia Israel Sweden
Belgium Italy Switzerland
Canada Japan Turkey
Czechoslovakia Korea, Rep. of U.A.R.
Denmark Netherlands United Kingdom
New Zealand
France U.S.A.
Germany Portugal
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council, which decided,
in March 1969, to accept it as an IS0 RECOMMENDATION.
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ISO/R 1001-1%9 (E)
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IS0 Recommendation R 1001 March 1969
MAGNETIC TAPE LABELLING AND FILE STRUCTURE
FOR INFORMATION INTERCHANGE
INTRODUCTION
The basic reason for producing an IS0 Recommendation for magnetic tape labelling is to give protection, via an
operating system, against procedural and human errors in handling data from magnetic tape. When a tape is read
a check can be made of the identification on the tape against that supplied by the operator/programmer and writing
or reading stopped before any damage has been done.
In producing this IS0 Recommendation cognizance has been taken of the fact that the data on tape may be sent
from tape to data link and the control characters have been excluded from the characters allowable in labels.
However, it should be noted that no restriction has been placed upon the information that may be recorded in
data blocks and that, in particular, if the record length is given in binary, control characters could be encountered.
It cannot be overstressed that this IS0 Recommendation, in its present form, is a Recommendation for magnetic
tape labelling. Even though other media, as the data transmission example above, have been considered, the Recom-
mendation does not have universal applicability.
Although this IS0 Recommendation was written to be used specifically with the IS0 7-bit code, the principles
contained herein are equally applicable with other code structures.
1. SCOPE
This IS0 Recommendation relates to information interchange utilizing magnetic tape, by providing magnetically
recorded labels to identify and structure files, and by providing a standard structure for the blocks containing
the records that constitute a file.
2. DEFiNITIONS OF TERMS
As used in this IS0 Recommendation, the following items have the meanings indicated. When a term is in common
use in a context related to the subject-matter of this IS0 Recommendation, the definition conforms to common
usage; when a term has been used in related IS0 Recommendations, the definition conforms to its usage there.
2.1 Record. Collection of related terms of data which for operating systems logic purposes is treated as a unit
of information. Conceptually, a record corresponds (in the context of business data) to a transaction, a
customer’s account, etc. In other contexts, the delineation of a record may be relatively arbitrary, and is
determined by the designer of the information formats.
Block. Group of contiguous characters recorded on and read from magnetic tape as a unit. A block may
2.2
contain one or more complete records.
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2.3 File. Major collection of information, consisting of all the records pertaining to a general subject.
Conceptually, this term (in the context of business data) relates to such collections as a Payroll File,
an Inventory File, etc. In other contexts, the delineation of a file may be relatively arbitrary.
2.4 File set. Collection of one or more related files recorded on one or more volumes. A file set may consist of
- one file recorded on a single volume,
- more than one file recorded on a single volume,
-- one file recorded on more than one volume,
- more than one file recorded on more than one volume.
2.5 Volume. Physical unit of storage media. The word volume, as used in this IS0 Recommendation, is
completely synonymous with “reel of magnetic tape”.
2.6 Label. Block at the beginning or end of a volume or a file which serves to identify and/or delimit that
volume or file.
2.7 Label Group. Collection of contiguous labels of the same type (see clause 3.1.3 for label types).
2.8 Tape Murk. Special configuration recorded on magnetic tape, essentially indicating the boundary between
files and labels, and also between certain label groups. The Tape Mark configuration is defined in the
relevant IS0 Recommendations for recorded magnetic tape.
2.9 Operating System. Programme or set of programmes, usually provided by the manufacturer, which, among
other things, handles the functions of reading and writing blocks on tape, label handling and related
functions.
3. LABELLING
3.1 Elements of the labelling scheme
3.1.1 The labels. Each label shall be an 80-character block.
9
ClaSS
me
Operating System User
(None) 1 UuvTL:;p 1
Volume
EOVl EOV2-9
I I I
Required Optional
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ISO/R 1001 -1969 (E
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3.1.5 Tape Murk. Tape Marks shall be used only where specified in this 1SO Recommendation.
3.2 Structuring the file
3.2.1 Use of Required Label and Tape Marks. Required Labels and Tape Marks shall be used to establish
the file structure according to the following rules, as illustrated in Figure 1. In that Figure, the
beginning of the tape is at the left, and the end of the tape is at the right. Required Labels are indicated
by the first three characters of their identifiers, and Tape Marks are indicated by asterisks (*):
The rules and the Figure are presented as though there were no Optional Operating System Labels or
User Labels. Rules for using these optional classes of labels are set forth in clauses 3.2.3 to 3.2.8.
Single-Volume File
VOL HDR * --- Data Blocks --- * EOF **
Multi-Volume File
VOL HDR * --- First Volume Data --- * EOV **
VOL HDR * --- Last Volume Data --- * EOF **
Multi-File Volume
VOL HDR * -- File A -- * EOF * HDR * --- File B --- * EOF **
Multi-Volume Multi-File
VOL HDR * -- File A -- * EOF * HDR * -- File B --- * EOV **
VOL HDR * --- Continuation of File B -------- * EOV **
VOL HDR * -- End of File B -- * EOF * HDR * -- File C -- * EOF **
~~~ ~
FIG. 1 - Structure of Magnetic Tape Files
(* means Tape Mark)
VOLUME HEADER LABEL. Every volume shall have a Volume Header Label as the first block in the
volume. The Volume Header Label shall not be used at any other place in the volume.
FILE HEADER LABEL. Every file shall be preceded by a File Header Label. Whenever a volume ends
within a file, the continuation of that file in the next volume shall also be preceded by a File Header.
Every File Header shall be immediately followed by a Tape Mark. (See clause 3.2.6.)
END OF FILE LABEL. The last block of every file shall be followed by an End of File Label. A Tape
Mark shall immediately precede, and another Tape Mark shall immediately follow, every End of File
Label. The End of File Label that appears at the end of the last (or only) file in a volume set shall be
followed by two Tape Marks, rather than one. (See clause 3.2.6.)
END OF VOLUME LABEL. Whenever a volume ends within a file, the last block of the file in that
volume shall be followed by an End of Volume Label. One Tape Mark shall inimediately precede, and
two Tape Marks shall immediately follow, every End of Volume Label. (See clause 3.2.6.)
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3.2.2 Coincidence of End-of- Volume and End-of-File. Whenever end-of-volume and end-of-file coincide, the
labelling configuration shall be one of the following :
__- File A ___ * EOV **
VOL HDR ** EOF * HDR * --- File B ---
(A) (A) (BI
FIG. 2
~~ ~ ~
--- File A --- * EOF * HDR ** EOV **
(A) (BI
VOL HDR * --- File B ---
(B)
3.2.2.1 By agreement between the interchange parties, it is allowable to arrange that any file of a set
may start at the beginning of a volume. If this procedure is used the labelling configuration
shall be as set out in clause 2.2.6 of the Appendix.
3.2.3 Fitting Optional Labels with the File Structure. Optional Operating System Labels and User Labels
shall be fitted into the file structure as described in clauses 3.2.4 to 3.2.8, without otherwise modifying
the relationship between the Required Labels and the files. When these optional classes of labels are
used, any reference to a label within clause 3.2 shall be construed to mean the entire label group.
3.2.4 Optional Operating System Labels. Optional Operating System Labels of a given type, when used, shall
directly follow a Required Label of the same type. The fourth character of consecutive Optional
Operating System Labels in a group shall be the numbers 2, 3, 4, 5,6,7,8 and 9 respectively.
3.2.5 User Labels. User Labels of a given type, when used, shall directly follow a consecutive group of
Operating System Labels of the same type. When no Optional Operating System Labels are used in
the label group, the User Labels shall directly follow a Required Label of the same type.
3.2.6 No Tape Mark within a Label Group. There shall be no Tape Mark within a group of labels. Wherever
Figures 1, 2, 3, and the descriptions in clauses 3.2.1 and 3.2.2, indicate a Tape Mark following a
Required Label, that Tape Mark shall actually follow the last label of the entire group.
3.2.7 Label Group compiere on one Volume. Every label group shall be completed on the volume where
the first label of the group was recorded.
3.2.8 Example of the Grouping of Optional Labels
*
or IF BEGINNlNG OF TAPE HDRl HDR2 -.
.- HDRn
UHLl UHL2---- UHLa * ------- FILE DATA - - -*
EOVl EOV2 - - - - EOVn
UTLl UTL2 ---- UTLa **
or
EOFl EOF2 - - - - EOFn
FIG. 4
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3.3 Format and contents of labels
In this IS0 Recommendation, “n” means any numeric digit O to 9. An “a” means any of the characters
occupying the central four columns of the IS0 7-bit code table, except position 511 5 and those positions
where there is provision for alternative graphic representations.
The limitation on “a” characters is intended as a guide to provide maximum interchangeability and
consistent printing especially when international interchange is a possibility. Checking for conformity
to this limitation is not implied.
The word “optional” is sometimes used in the name or description of fields in this IS0 Recommendation.
When used, “optional” means that the field may, but need not, contain the information described. If an
optional field does not contain the designated information, it shall contain spaces (or zeros if so indicated).
Fields which are not described as “optional” are considered to be “mandatory”. “Mandatory” fields must
be written as specified.
Although this IS0 Recommendation does not require any particular label processing on reading, certain
desirable processing is implied.
3.3.1 Volume Header Label
Field Name Length Description
Label Identifier 3 Must be VOL.
Label Number 1 Must be 1.
Volume Serial Number 6 Six “a” characters permanently assigned by the owner
to identify this physical volume (i.e. reel of tape).
Accessibility 1 An “a” character which indicates any restrictions on
who may have access to the information in the volume.
A “space” means unlimited access; any other character
means special handling, in a manner agreed between
the interchange parties.
Reserved for future 20
Must be “spaces”.
standardization
Reserved for future
6 Must be “spaces”
standardization
Owner Identification 14 Any “a” characters, identifying the owner of the
physical volume.
Reserved for future 28 Must be “spaces”.
standardization
Label Standard Level 1
1 means the labels and data formats on this volume
conform to the requirements of this IS0 Recommen-
dation. “Space” means the labels and data formats on
this volume require the agreement of the interchange
parties .
3.3.1.1 Anyone recording on a magnetic tape that he does not own must preserve the entire Volume
Header Label unchanged, except as authorized by the owner. This is not intended to preclude
the rewriting, unchanged, of the Volume Header Label.
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3.3.2 First File Header Label
-
Description
Length
Field Name
3 Must be HDR.
1 Label Identifier
1 Must be 1.
2 Label Number
my “a” characters agreed on between the interchange
3 File Identifier 17
parties.
6 my “a” characters to identify the set of files of which
4 Set Identification
this is one. This identification must be the same for all
files of a multi-file set.
4 The File Section Number of the first Header Label of
5 File Section Number
each file is 1. This applies to the first or only file on a
volume and to subsequent files on a multi-file volume.
This field is incremented by one on each subsequent
volume of the file.
Four “n” characters denoting the sequence (i.e.
6 File Sequence Number 4
0001, 0002, etc.) of files within the volume or set of
volumes. In all the labels for a given file, this field will
contain the same number.
Generation Number 4 Four “n” characters denoting the current stage in the
7
succession of one file-generation by the next. When a
(optional)
file is first created, its generation number is 1.
8 Generation Version 2 Two “n” characters distinguishing successive iterations
of the same generation. The generation version number
Number (optional)
of the first attempt to produce a file is O (zero).
9 Creation Date 6 A “space” followed by two “n” characters for the
year, followed by three “n” characters for the day
(O01 to 366) within the year.
10 Expiration Date 6 Same format as field 9. This file is regarded as
“expired” when today’s date is equal to, or later than
the date given in this field. When this condition is
satisfied, the remainder of this volume may be over-
written. To be effective on multi-file volumes therefore,
the expiration date of a file must be less than, or equal
to the expiration date of all previous files on the volume
11 Accessibility 1 An “a” character which indicates any restrictions on
who may have access to the information in this file.
A “space” means unlimited access; any other character
means special handling, in a manner agreed between
the interchange parties.
12 Block Count 6 Must be “zeros”.
13 System Code 13 Thirteen “a” characters identifying the Operating
(optional) System that recorded this file.
14 Reserved for future 7 Must be “spaces”.
standardization
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IW/R 1001-1969 (E)
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3.3.3 Second File Header Label (optional). Further explanations concerning the fields in this label are
given in Section 4.
Description
Name Length
Fieid
3 Must be HDR.
Label Identifier
1 Must be 2.
Label Number
1 F = Fixedlength.
Record Format
D = Variable with the number of characters in the
record specified in decimal.
V = Variable with the number of characters in the
record specified in binary.
U = Undefined.
5 of
Block Length Five “n” characters specifying the maximum number
characters per block.
5 Five “n” characters specifying :
Record Length
- If “Record Format” is F, Record Length;
- If D or V, Maximum Record Length including
any countfield;
- If U, undefined.
Reserved for Operating 35 Reserved for Operating Systems use. Any “a”
Systems characters.
Buffer Offset 2 Two “n” characters specifying the length in characters
(optional) of any additional field inserted before a data block
(viz. Block Length). This length is included in the block
length (Field 4).
Reserved for future 28 Must be “spaces”.
standardization
3.3.4 First End of File Label
Field Name Length Description
1 Label Identifier 3
Must be EOF.
2 Label Number 1 Must be 1.
Same as corresponding
...