5. FILES › 5.2 VMC Information Area Files › 5.2.2 VM Device Accounting File (VMCDAC)

5.2.2 VM Device Accounting File (VMCDAC)

The VM Device Accounting File identifies the allocation of
dedicated devices and temporary disk virtual machine (user).

This file is created from VM Account data types 02, C2, 03,
and C3 records (dedicated device, foreground and CMS Batch,
temporary disk, foreground and CMS Batch).

At the DETAIL time-span, this file contains one observation
per virtual device allocated by a virtual machine.  Each
observation contains the variable VMCRCODE, which can be used
to determine which of the following Account record types
provided the data:

       Type:  02 - Dedicated Device (Foreground)
              C2 - Dedicated Device (Background)
              03 - Temporary Disk   (Foreground)
              C3 - Temporary Disk   (Background)

A dedicated device can be a tape drive, disk drive, terminal,
channel-to-channel adapter, or any other device that is
allocated to a virtual machine for its exclusive use.

A temporary disk is one that is allocated from the VM T-DISK
pool defined to the Control Program (CP) using the CP DEFINE
command.

VM supports both count-key-data (CKD) and fixed-block
architecture (FBA) DASD.

CKD devices are organized using cylinders, tracks, and
records.  Data on CKD devices is referenced by cylinder,
head, record (CCHHR).  The architectural boundary of CKD DASD
that is used by VM is the cylinder.  Minidisks are provided
to virtual machines in cylinder increments.

FBA devices are organized into blocks (currently 512 bytes in
length) and the data is referenced by logical block number.
Minidisks are provided to virtual machines in block
increments.

The following sections describe the file's organization, list
the data elements maintained, and provide usage hints.

   1 - File Organization
   2 - Data Elements List
   3 - Usage Considerations
   4 - Retrieval Examples