CMS VSAM and Access Method Services IBM 3350 Direct Access storage When VM/370 MSS support is installed, and the VM/370 processor is
attached to an MSS, the CMS disk may be defined as a 3330 Model 1
which is mapped by VM/370 to all or part of a 3330V volume.
Programming Languages Supported CMS supports VSAM for programs written for the following compilers: OS/VS COBOL Compiler and Library as COBOL Interactive Debug VS Basic Processor as PL/I Optimizing Compiler and Libraries as PL/I Checkout Compiler DOS/VS COBOL Compiler and Library DOS PL/I Optimizing Compiler and Library
Data Set Compatibility Considerations 1.2. 57qO-CB1 573q-CBq 57q8-II1 5734-PL3 5734-PL2 57q6-CBl 5736-PL3 CMS can read and update VSAM data sets that vere created under DOS/VS or OS/VS. In addition, VSAM data sets created under CMS can be read and
updated by DOS/VSE or OS/VS. However, if you perform allocation on a minidisk in CMS, you cannot
use that minidisk in an os virtual machine in any .anner that causes
further allocation. DOS/VS VSAM (and thus CMS) ignores the format-5,
free space DSCB on VSAM disks when it allocates extents. If allocation
later occurs in an as machine, os attempts to create an accurate
format-5 DSCB. However, the format-5 DSCB created by os does not
correctly reflect the free space on the minidisk because os expects it
to be a full pack. In CMS, allocation occurs whenever data spaces or
unique data sets are defined, and space is released whenever data
spaces, catalogs, and unique data sets are deleted. ISAM INTERFACE PROGRAM (lIP) CMS does not
program that
method) data
sets.
support the VSAM ISAM Interface Program (lIP). Thus, any
creates and accesses ISAM (indexed sequential access
sets cannot be used to access VSAM key sequential data
There is one exception to this restriction. If you have (1) os PL/I programs that have files declared as ENV(INDEIED) and (2) if the library
routines detect that the data set being accessed is a VSAM data set,
your programs will execute VSAM I/O requests.
32 IBM VM/370 Planning and System Generation Guide
CMS VSAM and Access Method Services
User Requirements and Considerations
Because the CMS support of VSAM and access method services is based on DOS/VS access method services, you must order a DOS/VS system (Release
31 and above and use the DOS/VS starter system when you install the eMS VSAM support. In order to install CMS VSAM from the DOS/VS Release 33
starter system, you must be sure to use the current level of VM/370 installation files (Release 3 PLC 8 or later). Also, the CMS/DOS support must be installed before you install VSAM under CMS. Distribution of VSAM and CMS VM/370 does not distribute the DOS/VS VSAM and access method services
routines that it uses. You are responsible for ordering Release 31 and
above DOS/VS systems. The VM/370 starter system has an installation EXEC procedure, VSAMGEN, that generates CMS support for VSAM and access
method services using a restored DOS/VS starter system. Part 1. Planning for system Generation 33
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