eMS Support for OS and DOS VSAM Functions CMS supports interactive program development for
using VSAM. CMS supports VSAM for as proqrams OS/VS COBOL, or as PL/I programming languages; or
in DOS/VS COBOL or DOS PL/I programming languages. VSAM for as or DOS Assembler language programs.
as and DOS programs
written in VS BASIC, DOS programs CMS does not support CMS also supports Access Method Services to manipulate as and Des VSAM and SAM data sets. Under CMS, VSAM data sets can span up to nine DASD volumes. CMS does
not support VSAM data set sharing; however, CMS already supports the
sharing of minidisks or full pack minidisks. VSAM data sets created in CMS are not in the CMS file format.
Therefore, CMS commands currently used to manipulate CMS files cannot be
used for VSAM data sets that are read or written in CMS. A VSAM data
set created in CMS has a file format that is compatible with as and Des VSAM data sets. Thus, a VSAM data set created in CMS can later be read
or updated by as or DOS. Because VSAM data sets in eMS are not a part of the CMS file system, CMS file size, record length, and minidisk size restrictions do not The VSAM data sets are manipulated with Access Method Services programs executed under CMS, instead of with the CMS file system
commands. Also, all VSAM minidisks and full packs used in CMS must be
initialized with the IBCDASDI program; the CMS FORMAT command must not
be used. CMS supports VSAM control blocks with the GENCB, MODCB, TESTCB, and SHOWCB macros.
In its support of VSAM data sets, CMS uses BPS (rotational position
sensing) wherever possible. CMS does not use RPS for 2314/2319 devices,
or for 3340 devices that do not have the feature.
Hardware Devices Supported
Because CMS support of VSAM data sets is based on DOS/VS VSAM and DOS/VS Access Method Services, only disks supported by DOS/VS can be used fer VSAM data sets in CMS or for CMS disk files used as input for Access Method Services. These disks are: IBM 2314 Direct Access Storage Facility IBM 2319 Disk Storage IBM 3330 Disk Storage, Models 1 and 2 IBM 3330 Disk Storage, Model 11 IBM 3340 Direct Access storage Facility IBM 3344 Direct Access Storage IBM 3350 Direct Access storage 310 IBM VM/370 System Programmer's Guide
April 1, 1981 DOS/VS Supervisor Macros and Logical Transients Support for VSAM CMS supports VSAM is based VSAM for OS on DOS/VS. and DOS users. However, the eMS support of
The DOS/VS supervisor macros shown in Figure DOS/VS VSAM routines, are supported by eMS. 41, which are used by the r- I 1 Macro 1 ICDLOAD I 1 1 I I 1 IFREE I 1 FREEVIS 1 I GETVIS HOLD POST RELEASE SECTVAL USE L- ISVC I INumberl Extent of eMS Support 65 DOS/VS macro for internal use only. Loads a VSA! core image phase. CMS searches the VSAM saved
segment for the phase instead of the DOS/VS SVA area. If an anchor table entry does not exist, CMS fetches the phase, creates an anchor table entry,
and sets register values as DOS/VS would set them.
36 No operation is performed by CMS. 62 CMS invokes its free storage handler to return
35 40 64
the storage that is no longer needed. CMS follows
the DOS/VS register and return code conventions. CMS invokes its free storage handling routines
to obtain free storage; it follows the DOS/VS register and return code conventions. The SVA operand does not apply to CMS and is not supported.
The PAGE and POOL operands are ignored by CMS. No operation is performed by CMS. When a POST macro is issued for an ECB, Byte 2 Bit 0 is set on. The SAVE=savarea operand is ignored by CMS. CMS reduces the RURTBL counter for the resource
by one. CMS uses the data in registers 0 and 1 to calculate
the sector number and returns the sector number in
register O. If any errors occur
CMS returns I'FF'
in reqister o. DOS/VS macro for internal use only. CMS supports
this macro only to the extent necessary to support VSAM. If a counter for a particular resource is
zero, CMS increments the counter by one and returns
a zero in register o. If a counter is greater than
zero, CMS increments the counter by one and returns
an eight in register o.
Fiqure 41. DOS/VS VSAM Macros Supported by CMS CMS distributes the DOS/VS transients that are needed in the VSAM support. Thus, OS users do not need to have the DOS/VS system pack
online when they are and executing VSAM programs. CMS uses all of the DOS/VS VSAM except those that build
and release JIBs (job information blocks). The JIB is not supported in CMS and, thus, neither are the B-transients ($$BJIBOO, $$BJIBFF, and $$BOVS03) that control the JIB. Part 3. Conversational Monitor System (eMS) 311
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