18-Byte Communications Blocks › Overview

Overview

As an alternative to using the 16-byte IDMS DB communications blocks, you can specify 18-byte blocks. The difference between 16-byte blocks and 18-byte blocks is that an 18-byte block contains an additional 18-byte filler field, and the following fields are 18 bytes instead of 16 bytes:

• RECNAME
• AREANAME
• ERRORSET
• ERRORREC
• ERRAREA

This appendix describes where to specify an 18-byte communications block and contains figures showing these blocks.

Note: For more information about the fields in IDMS DB communications blocks, see Communications Blocks and Error Detection.

Where to Specify the 18-Byte Block

For Assembler, you specify an 18-byte communications block by using the @SSC120 statement in place of the @SSCTRL statement.

Note: For more information, see @SSCTRL.

18-Byte IDMS-DB Block

The following figure shows the 18-byte IDMS DB communications block:

                  ┌───────────────────────────┐
                  │ IDMS COMMUNICATIONS BLOCK │
                  └───────────────────────────┘

                                                Length      
                   Field           Data Type   (bytes)      Initial Value
  ┌──────────┐
 *│ 0      7 │     PROGRAM-NAME    Alphanumeric  8           Program Name
  ├────────┬─┘
  │ 8   11 │       ERROR-STATUS    Alphanumeric  4           '1400'
  ├────────┤
  │ 12  15 │       DBKEY           Binary        4(Fullword) 0000
  ├────────┴───┐
  │ 16      33 │   RECORD-NAME     Alphanumeric  18          Spaces
  ├────────────┤
  │ 34      51 │   AREA-NAME       Alphanumeric  18          Spaces
  ├────────────┤
  │ 52      69 │   FILLER          Alphanumeric  18          Spaces
  ├────────────┤
  │ 70      87 │   ERROR-SET       Alphanumeric  18          Spaces
  ├────────────┤
  │ 88     105 │   ERROR-RECORD    Alphanumeric  18          Spaces
  ├────────────┤
  │ 106    123 │   ERROR-AREA      Alphanumeric  18          Spaces
  ├─────────┬──┘
**│ 124 127 │      PAGE-INFO       Binary        4(Fullword) 0000
  └─────────┘
  ┌─────┬───┬────┐
  │ 124  ... 223 │ IDBMSCOM        Alphanumeric  100         Spaces
  ├─────┴───┴┬───┘
  │ 224  227 │     DIRECT-DBKEY    Binary        4(Fullword) 0000
  └──────────┘
  ┌──────────┐
  │ 228  234 │     DATABASE-STATUS Alphanumeric  7           Spaces
  ├─────┬────┘
  │ 235 │          FILLER          ...           1           ...
  ├─────┴────┐
  │ 236  239 │     RECORD-OCCUR    Binary        4(Fullword) 0000
  ├──────────┤
  │ 240  243 │     DML-SEQUENCE    Binary        4(Fullword) 0000
  ├──────────┴──┐
  │ 244     299 │  FILLER          Alphanumeric  56          Spaces
  └─────────────┘
*  word aligned
** PGINFGRP overlays bytes 124 and 125 and PGINFDBK overlays bytes
   126 and 127. Both of these fields are binary datatype each
   having a length of two bytes. Suggested initial values for
   both are 00. Together these two fields represent PGINFO.