Planning Considerations for CKS Spanned records for buffered files . Sort-merge
Checkpoint-restart ASCII data sets
Track overflow
The DOS/VS COBOL and DOS PL/I Optimizing compilers execute in the CMS/DOS environment of CKS. The CKS/DOS environment does not support
the execution of DOS programs that use: • sort exits. The DOS/VS COBOL and DOS PL/I Optimizer SORT verbs are
not supported in CKS/DOS. • Teleprocessing, indexed sequential access method (ISAK), or direct
access method (DAM). CMS/DOS supports only the sequential access
method (SAK, and virtual storage access method (VSAK). • Kultitasking. CKS/DOS background partition. CMS TEXT PROCESSING FACILITY supports only a single partition, the
Text processing facilities that can create formatted output from one or
more CKS files containing text and/or control words are available
through the SCRIPT command. SCRIPT/370 is an IBM Installed User Program that must be ordered separately.
Limited Support of OS and DOS in eMS Object programs (TEXT files) produced under CMS and under OS in real or
in virtual machines can be executed under CKS if they do not utilize
certain OS functions not simulated by CKS. Object programs using
nonsimulated OS macro functions must be transferred to an appropriate
real or virtual OS machine for execution.
Sequential and partitioned data sets residing on as disks can be read
by OS programs running under CMS. Also, certain CMS commands can be used
. to process data sets on as disks. CMS simulates the control blocks, supervisor and I/O macros, linkage
editor and fetch routines necessary to compile, test, and execute DOS/VS programs under CMS. The support for the DOS user is comparable to that
for the OS user. CMS supports VSAM and access method services for DOS and OS users. CMS supports VSAM for the following." compilers: OS/VS COBOL, OS PL/I, VS BASIC, DOS/VS COBOL, and DOS PL/I. CMS does not support VSAM for
assembler language programs or VS APL. The application programmer who normally uses CMS to interactively
create, modify, and test his programs may require facilities not
supported in CMS (for example, an OS program using ISAM). He can
alternately execute CKS and another operating system in the same virtual
machine. A description of the actual processes for reading as or DOS files is
in the !11Ll1Q A description of alternating operating
systems is in !1!L37Q in 24 IBM VM/370 Planning and System Generation Guide

Planning Considerations for CMS DL/I IN THE CMS/DOS ENVIRONMENT Batch DL/I application programs can be written and tested in the CMS/DOS environment. This includes all batch application programs written in COBOL, PL/I, or Assembler language.
You can also execute any data base description generation and program
specification block generation. The data base recovery and
reorganization utilities must also be executed in a DOS/VS virtual
machine.
For more information, see the CMS and DL/I Infofmati2n, GH20-1246. eMS Disk and File Management CMS can manage up to ten virtual disks for each user. These disks may
be minidisks or full packs. Moreover, they may be in: • eMS format • as or DOS format • VSAM format When the VM/370 MSS support is installed, and the VM/370 processor is
attached to an MSS, any CMS virtual disk can be located on an MSS 3330V volume. eMS disks are formatted with the CMS FORMAT command; files contained
on these disks are in a format unique to CMS, and cannot be read or
wri tten using other operating systems.-
as and DOS disks or minidisks may be used in CMS. as or DOS programs
executing in CMS may read data sets or files on as or DOS disks, but may
not write or update them: as and DOS minidisks may be formatted with
the IBCDASDI service program, or with an appropriate OS/VS or DOS/VS disk initialization program, if the disk is a full pack. VSAM disks used in CMS are fully compatible with as and DOS VSAM disks. Minidisks for use with VSAK must be formatted with the IBCDASDI
program; full disks must be initialized using the appropriate as/iS or DOS/VS disk initialization program. DISK ACCESS Disks can be accessed in two ways: read-only, where files on that disk
can only be read; and read/write, where files can be read and written.
Both CP and CMS can control read/write access. If a disk is
designated read/write by CP, then the CMS access determines its
read/write status. If a disk is desi9nated read-only by CP, then it can
only be accessed read-only in CMS. Part 1. Planning for System Generation 25