I-O-CONTROl Paragraph

TAPE.lfdname·\!~1

4.4.2. I-O-CONTROl Paragraph

Function

7004 4490-000

The I-O-CONTROL paragraph specifies the points at which rerun is to be

established and the main storage area to be shared by different files. In addition, this paragraph specifies the location of files on a multifile reel for sequential file organization as well as special inputJoutput techniques for file processing using the APPLY clauses.

4-27

Environment Division

4-28

Format

Rules

[I -O-CONTROL.

iRERUN ON

[{~~~~ -lfdname-{~}l

^EVERY

TAPE

r----,

lfdname L ___ -'

integer-1 RECORDS OF file-name-1 ...

[

RECORD

1

AREA FOR file-name-2{,file-name-3} . . . . SORT

SORT-MERGE

[;MULTIPLE FILE TAPE CONTAINS fite-name-4 [POSITION integer-2]

[,file-name-5 [POSITION integer-3]] ... J •••

r - - - l

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[:APPLY BLOCK-COUNT ON {file-name-6 [file-name-7] .. _}] ...

TAPES

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[;APPLY CYLINDER-INDEX AREA OF integer-4 INDICES ON file-name-8.

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f ile-name-9] ... ] ..•

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[;APPLY CYLINDER-OVERFLOW AREA OF integer-5 PERCENT ON file-name-10

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^Ifile -name -11] ••• ] •••

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[;APPLI VERIFY ON file-name-12 [,file-name-13] ... ] ...

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[;APPLY INDEX-AREA OF integer-6 CHARACTERS ON file-name-14

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[, file-name-15]. .. J. . . . ]

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1. The I-O-CONTROL paragraph is optional.

2. The RERUN clause specifies when and where the rerun information is recorded. The rerun information is recorded on the device specified whenever integer-l records of file-name-l are processed. File-name-l may be any type of file with any organization or access except a sort or merge file.

3. The value of integer-l in the RERUN clause must be within the range of 1 to 8,388,607.

4. There are two forms of the implementor-name in the RERUN clause.

a. The form specifies a dedicated rerun receiver.

{

DISC -lfdname-{l}

DISK f

TAPE

7004 4490-000

Environment Division

• DISC, DISK, and TAPE are the types of devices supported for a user file dedicated for receiving checkpoint records.

• The lfdname field is a 1- to 8-character alphanumeric field. This field specifies the lfdname of the dedicated receiver file.

.. The field

{i}

is a I-character field, where the value 1 indicates that all

checkpoint records are to be written consecutively on one dedicated receiver file, and the value 2 indicates that checkpoint records are to be written alternately on two dedicated receiver files, each file containing only the latest alternate checkpoint record. When two dedicated receiver files are specified, the INIT parameter must be designated in the LFD job control statements for both receiver files.

b. The form [lf4l2?~~ specifies the name of an output data file on which both data records and checkpoint records are to be written. The name specified must be the lfdname of a standard sequential EBCDIC tape file described by an FD entry with standard system labels.

Note: This form of the implementor-name is not supported in the mixed mode or consolidated data management mode.

5. The file-name of a dedicated rerun receiver file is generated by the compiler by using the lfdname specified in the Ifdname field of the RERUN clause.

If one dedicated receiver file is specified, the If dname is used as the file-name of the rerun receiver.

If two dedicated receiver files are specified, a suffix, A or B, is appended as the last character of a given If dname of seven or fewer characters, or the suffix replaces the last character of an 8-character If dname to form a unique file-name for each receiver file. The file-names for the two receiver files are IfdnameA and lfdnameB.

Odd-numbered checkpoints are written on the file:

lfdnameA

Even-numbered checkpoints are written on the file:

lfdnameB

6. More than one RERUN clause may be specified; but no two of them may specify the same file-name-I.

7004 4490-000 4-29

7. The SAME AREA clause specifies that two or more files that do not represent sort or merge files are to use the same main storage area during processing. The area being shared includes all storage areas assigned to the files specified; therefore, only one file may be open at any given time. (See rule 9c.)

8. The SAME RECORD AREA clause specifies that two or more files are to use the same main storage area for processing of the current logical record. All the files may be open at the same time. A logical record in the SAME RECORD AREA is considered as: 1) a logical record of each opened output file whose file-name appears in this SAME RECORD AREA clause, and 2) a logical record of the most recently read input file whose file-name appears in this SAME RECORD AREA clause. This is equivalent to an implicit

redefinition of the area; i.e., records are aligned on the leftmost character position.

9. More than one SAME clause may be included in a program; however, the following rules also apply:

a. A file-name must not appear in more than one SAME AREA clause.

b. A file-name must not appear in more than one SAME RECORD AREA clause.

c. If one or more file-names of a SAME AREA clause appear in a SAME RECORD AREA clause, all the file-names in that SAME AREA clause must appear in the SAME RECORD AREA clause. However, additional file-names not appearing in that SAME AREA clause may also appear in that SAME RECORD AREA clause. The rule that only one of the files mentioned in a SAME AREA clause can be open at any given time takes precedence over the rule that all files mentioned in a SAME RECORD AREA clause can be open at any given time.

10. The files referenced in the SAME AREA orlSAME RECORD AREAlclause need not all have the same organization or access.

11. The SAME SORT AREA or SAME SORT-MERGE AREA clause is for documentation purposes only.

12. The MULTIPLE FILE clause applies to sequential files only and is required when two or more files share the same physical reel of tape. Regardless of the number of files on a single reel, only those files that are used in the object program need be specified. If all file-names are listed in consecutive order, the POSITION clause need not be given. If any file in the sequence is not listed, the position relative to the beginning of the tape must be given.

Not more than one file on the same tape reel may be open at one time.

~30 7004449~OOO

7004 4490-000

13. All files sharing the same physical reel of tape must specify the LABEL RECORDS STANDARD or data-name clause in the associated FD entries;

the LABEL RECORDS OMITTED clause is not permitted.

14. The REVERSE phrase of the OPEN statement must not be used for files sharing the same physical reel of tape.

~---I 15. The APPLY BLOCK-COUNT clause is used only for tape files. For each file-name specified, this clause inserts a 3-byte block number at the of

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each block on tape.

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If the TAPES option is specified, all tape files present are affected. This clause must be specified for all input tape files that contain a block count.

16. The APPLY CYLINDER-INDEX AREA clause is used only for ISAM files (ORGANIZATION IS ISAM). The clause indicates that sufficient main storage area should be allocated to contain integer-4 top index entries.

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The method for calculating the value of integer-4 is described in detail in the

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Consolidated Data Management Macroinstructions Programming Guide

(7004 4607).

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If the file already exists, use the following formula to determine the value of

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integer-4:

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Is integer-4 of the APPLY clause.

Signifies bytes that are required for main storage and that can be obtained from a display of VTOC. The number of bytes is shown under the heading Bytes Required for Main Storage.

Signifies size of the record key.

If the remainder of the divide operation in the formula is not equal to zero, add 1 to the quotient (i.e., add 1 to

nJ.

17. The APPLY CYLINDER-OVERFLOW AREA clause is used only for ISAM files. Integer-5 indicates the percentage of each cylinder in the prime data area will be reserved for cylinder overflow.

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If this clause is omitted, 20 percent of the cylinders specified as prime data

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area are automatically allocated. If no cylinder overflow is desired, 0 percent

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should be specified. If no overflow area exists, new records cannot be added

L_~~~_·

__________________ _

4-31

Environment Division

118~h-;

APPLY VERIFY clause is used for any mass storage files. It request;

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verification of disk records after they have been written (read after write). Ifl

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this clause is omitted, no verification is performed.

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1,19.

The APPLY INDEX-AREA clause is used only for indexed files

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(ORGANIZATION IS INDEXED). The clause specifies the size of the index-

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area used by MIRAM data management during the loading and retrieving of

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indexed MIRAM files. The size of the index-area for file retrieval, therefore, I must be the same as the size when the file was created.

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Integer-6 must be a multiple of 256.

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If the clause is not specified, an index-area of 256 characters is provided for

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-=-ach indexed file defined in the File Section~ _ _ _ _ _ __ _ ~

4-32 70044490-000

Section 5 ata ^IVISlon

^III ¹¹¹¹ ^ill

Im Dokument U I • System 80 (Seite 81-87)

TAPE.lfdname·\!~1

4.4.2. I-O-CONTROl Paragraph

[{~~~~ -lfdname-{~}l

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118~h-;

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1,19.

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Section 5

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