CA Dynam for VSE User Guide

Direct Access File Independence Facility (VCKD)
Direct Access File Independence Facility (VCKD)
Direct Access File Independence, which we will refer to as VCKD (Virtual-
Count Key Data), is a system that provides support for IBM's Direct Access
Method on Fixed Block Architecture (FBA) devices.
VCKD allows programs that utilize Direct Access Method, at the logical IOCS
level, to execute on FBA devices without conversion to another access method.
With VCKD, it is not necessary to make any program modifications in order to
process direct access (DA) file-dependent programs using FBA devices. After
installation, VCKD is completely transparent to the user. In addition, all
programming languages and teleprocessing monitors are supported.
For more information about the standard syntax notation used, see the
chapter "Introduction."
Utility Programs
VCKD contains the following utility programs:
• Clear Disk utility to format a Direct Access file that resides on an FBA disk
device
• Backup/Restore utility to convert current DA files on a CKD device to an
FBA device
• CKD DA disk file analyzer to assist in the allocation of the new FBA DA file
Record Formats
VCKD supports each of the following record formats:
• Fixed unblocked
• Records created by sequential disk work and nonwork files
Data Records
Data records may be accessed by any of the following:
• Relative record in the format of TTTR or TTTTTTTTRR
• Physical track addressing in the form of (MBBCCHHR)
• Key reference
Chapter 6: Controlling File Independence 6–43