TAPE SERVICE REQUESTS
6.1 MESSAGE SUMMARIES
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Each message text consists of one or more tables, described in subsection 6.2. This subsection describes the different kinds of messages and
identifies the tables used in each. The function code shown after each heading is an octal representation of the FC field from the station message. Each message has a request version and a reply version. The two versions use the same format, so that when a front end does not accept these message types, the request message can act as a reply in which no processing occurred.
6.1.1 MOUNT REQUEST (100) AND REMOUNT REQUEST (102)
The Mount and Remount Requests indicate that a tape volume should be mounted on a particular drive. TQM sends the message to the servicing front-end andlor Master Operator station. The message does not invoke
any auxiliary servicing other than issuance of a message to an operator console. The servicing front end can transform the information in the message into a displayable operator message which is equivalent to an operator message on the host system. TQM provides an ASCII-displayable default message for stations which do not format the information.
Table Word Count Description
FSH Variable Front-end service message header
R~ Variable (Re)mount auxiliary information table
6.1.2 MOUNT REPLY (101) AND REMOUNT REPLY (103)
The Mount Reply and Remount Reply tell TQM that the operator has intervened. The reply is sent by the servicing front end or Master Operator station. TQM honors the RESELECT or ABORT options; for other values TQM reissues the original Mount or Remount Request.
Table Word Count Description
REP 1 Operator response:
'ABORT'L Abort job
'RESELECT'L Select different device
6.1.3 DATASET ENQUIRY REQUEST (200)
The Dataset Enquiry Request tells the servicing front end that a certain job requests a certain tape dataset. The message is issued when TQM processes an ACCESS request.
Table Word Count Description
FSH Variable Front-end service header
DEX 2 Dataset Enquiry Information Table LOT Variable Label Definition Table
6.1.4 DATASET ENQUIRY REPLY (201)
The Dataset Enquiry Reply returns information, including DEX and LOT, to TOM after a TOM request. DEX contains servicing statuses; the returned LDT, which overwrites the user LDT, can contain new information about the
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dataset and its characteristics. For example, i t can contain a VSN list or change the block size of the dataset. The supplementary logfile message, i f present, is sent to the user or system logfile; this message is independent of the return status.
Table Word Count Description
FSH Variable Front-end service header
DEX 2 Dataset Enquiry Information Table LDT Variable Label Definition Table
TMSG Variable Supplementary logfile message
6.1.5 DATASET UPDATE REQUEST (202)
TQM sends the Dataset Update Request to the front end when the dataset is released. This message contains the following information:
• Volumes used
• Catalog function to be performed, derived from the SAVE, DELETE, or ACCESS statements
• Characteristics used while the dataset was being accessed
• Error conditions existing while the dataset was being accessed Table Word Count Description
FSH Variable Front-end service header
DUX 3 Dataset Update Auxiliary Information Table LDT Variable Label Definition Table
6.1.6 DATASET UPDATE REPLY (203)
The Dataset Update Reply tells TQM whether the requested update was successful. An error status causes TQM to abort the job. The
supplementary logfile message, if present, is sent to the user or system logfile; this message is independent of the return status.
Table Word Count Description
FSH Variable Front-end service header
DUX 3 Dataset Update Information Table
TMSG Variable Supplementary logfile message
6.1.7 VOLUME ACCESS REQUEST (300)
The Volume Access Request from TQM tells the servicing front end that TQM is about to perform its first 1/0 operation on the volume, and requests that the front end allow COS to read or write the volume. Every field in the LDT contains a value, which is either a system default, a user
specification, or a value from the first volume label group.
Table Word Count Description
FSH Variable Front-end service header
VAX 3 Volume Access Auxiliary Information Table LDT Variable Label Definition Table
LBL Variable Label Group Table
6.1.8 VOLUME ACCESS REPLY (301)
The servicing front-end sends the Volume Access Reply in response to a Volume Access Request. The reply includes the following:
• Access information
• Indication of the existence of the volume in a tape management catalog (TMC)
• Expiration of the volume
• Protection status of the volume
• A supplementary set of logfile messages concerning the request The supplementary logfile message, if present, is sent to the user or system logfile; this message is independent of the return status.
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Table Word Count Description
FSH Variable Front-end service header
VAX 3 Volume Access Auxiliary Information Table TMSG Variable Supplementary logfile message
6.1.9 VOLUME UPDATE REQUEST (302)
TQM sends the Volume Update Request after processing the Beginning of Volume (BOV) label group, indicating that the job will process the specified volume. For read mode datasets, the message is sent after BOV label processing is complete; for write mode datasets, i t is sent after the new label group is written.
Table Word Count Description
FSH Variable Front-end service header
wx
4 Volume Access Auxiliary Information Table LDT Variable Label Definition Table6.1.10 VOLUME UPDATE REPLY (303)
The Volume Update Reply tells TQM whether the requested update was successful. An error status causes TQM to abort the job. The
supplementary logfile message, if present, is sent to the user or system logfile; this message is independent of the return status.
Table Word Count Description
FSH Variable Front-end service header
vux 4 Volume Update Auxiliary Information Table TMSG Variable Supplementary logfile message