DOS /VS Support under eMS eMS supports interactive program development for DOS/VS Release 31, 32. 33 and 34. Tbis includes creating, compiling, testing. debugging. and
executing commercial application programs. The DOS/VS programs can be executed in a eMS virtual machine or in a CMS Batch Facility virtual
machine. DOS/VS files and libraries can be read under eMS. VSAM data sets can
be read and written under CMS. The eMS DOS environment (called CMS/DOS) provides many of the same
facilities that are available in DOS/VS. However, CMS/DOS supports only
those facilities that are supported by a single (background) partition.
The DOS/VS facilities supported by CMS/DOS are: • DOS/VS linkage editor • Fetch support • DOS/VS Supervisor and I/O macros • DOS/VS Supervisor control block support • Transient area support • DOS/VS VSAM macros
This environ.ent is entered each time the eMS SET Des ON command is
issued; VSAM functions are available in CMS/DOS only if the SET DOS ON (VSAM) command is issued. In the CMS/DOS environment, CMS supports many DOS/VS facilities, but does not support OS simulation. When you nO longer need DOS/VS support under CMS, you issue the SET DOS OFF co •• and
and DOS/VS facilities are no longer available. CMS/DOS can execute programs that use the sequential (SAM) and virtual storage access method (V SAM) , and can
libraries.
access lIethod access DOS/VS CMS/DOS cannot execute programs that have execution-time
restrictions, such as programs that use sort exits, teleprocessing
access methods, or multitasking. DOS/VS COBOL, DOS PL/I, and Asse.bler
language programs are executable under CMS/DOS. All of the CP and CMS online debugging and testing facilities (such
as the CP ADSTOP and STORE commands and the CMS DEBUG environment) are
supported in the CMS/DOS environment. Also, CP disk error recording and
recovery is supported in eMS/DOS. With its support of a CMS/DOS environment, ces becomes an important
tool for DOS/VS application program development. Because CeS/DOS was
designed as a DOS/VS program development tool, it assumes that a DOS/VS system exists, and uses it. The following sections describe what is supported, and what is not.
284 IBM VM/370 System Guide

Hardware Devices Supported CMS/DOS routines can read real DOS disks containing DOS data files and DOS private and system libraries. This read support is limited to the
following disks supported by DOS/VS: • IBft 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 • IBft 3344 Direct Access storage • IBM 3350 Direct Access storage
Also, under CMS/DOS you can write VSAM data sets. VSAM data sets can
only be written to disks that are supported by DOS/VS. The following devices, which are supported by BOS/VS, are not
supported by CMS/DOS: • Card Readers: 1442, 2560P, 2560S# 2596, 3504, 5425P, and 5425S • Printers: 2560P, 2560S, 3203 Models 1 and 2, 3525, 5203, 5425P, and 5425S • Disks: 2311
Also, CMS uses the CP spooling facilities and does not support
dedicated unit record devices. Each CMS virtual machine supports only
one virtual console, one reader, one punch, one printer, four tapes, and
ten disks. Programs that are executed in eMS/DOS are limited to the
number of devices supported by CMS. eMS Support of DOS/VS Functions
In addition to the CMS SET command used to invoke the CMS/DeS environment, there are a number of CMS/DOS commands and CMS commands
with special CMS/DOS operands that provide CMS support of the following DOS/VS functions: • Assignment of logical units to particular physical devices. • Associating DOS files with particular logical units. • DOS/VS Librarian Services. • Compilation and testing of DOS/VS COBOL and Des PL/I programs. • Execution of DOS/VS COBOL and DOS PL/I programs. Figure 32 summarizes these new commands and the new operands fer
existing commands. A detailed description and command format can be
found in the !ttLl1Q Part 3. Conversational Monitor System (CMS) 285