eMS/DOS Storage Requirements CMS/DOS requires
EXEC files. This
required for CMS is: DASD space to contain its source, text, module, and DASD requirement is in addition to the space already
system residence. The DASD space required by CMS/DOS 21 cylinders on a 2314/2319 12 cylinders on a 3330 33 cylinders on a 3340/3344 6 cylinders on a 3350
A simulated DOS/VS nucleus, eight DOSLIB directories, and
simulated DOS/VS control blocks (approximately 1300 decimal bytes)
located in the CMS nucleus.
are CMS/DOS also uses the CMS user area. CMS/DOS executes the Des
compilers, linkage editor, and librarian programs in the CMS user area.
The virtual storage requirements are: 60K plus buffers for the DOS/VS COBOL compiler 44K plus buffers for the DOS PL/I optimizing compiler 20K for the CMS/DOS linkage editor 3K for the RSERV library program 2K for the PSERV library program 2K for the SSERV library program CMS also uses the user area for its own purposes when processing CMS/DOS programs. For specific information on CMS use of free storage,
refer to the section "Free storage Management."
When the DOS/VS System must be Online Most of what you do in the CMS/DOS environment requires that the DOS/VS system pack and/or the DOS/VS private libraries te available to CMS/DOS. In general, you need these DOS/VS volumes whenever: You use the DOS/VS COBOL compiler or DOS PL/I The compilers are executed from the system or
Optimizing compiler.
private core image Your source programs contain COPY, LIBRARY, or CEL
statements. These statements copy books from your system or the
private source statement library. You invoke one of the library programs: DSERV, RSERV, SSERV, PSERV, or ESERV. You execute DOS programs that use LIOCS modules. eMS/DOS fetches most
of the LIOCS routines directly from DOS/VS system or private
A DOS/VS system pack is usable when it is: Defined for your virtual machine Accessed Specified, by mode letter, on the SET DOS ON command 308 IBM 1M/370 System Programmer's Guide
A DOS/VS private library is usable when it is: Defined for your virtual illachine Accessed Identified via ASSGN and DLBL commands
Although you can use the CMS/DOS library services to place the DOS/VS COBOL compiler, DOS PL/I compiler, and ESERV program in a CMS DOSLIB, it
is recommended that you do not use this method with VM/370. CMS/DOS can
fetch these directly from the DOS/VS system or private libraries faster
than from a DOSLIB. Execution Considerations and Restrictions
The eMS/DOS environment does not support the execution of DOS programs
that use: Sort exits. The DOS/VS COBOL and DOS PL/I SORT verbs are net
supported in CMS/DOS. Teleprocessing or indexed sequential (ISAH) access methods. eMS/DOS supports only the sequential (SAM) and virtual storage (VSAM) access
methods. Multitasking. CMS/DOS background partition.
supports only a single partition, the CMS/DOS can be executed in a CMS Batch Facility virtual machine. If
any of the DOS programs that are executed in the batch machine read data
from the card reader, you must ensure that the end-of-data indication is
recognized. Be sure that (1) the program checks for end of data and (2)
a /* record follows the last data record.
If there is an error in the way you handle end of data, the Des
program could read the entire batch input stream as its own data. The
result is that jobs sent to the batch machine are never executed and the DOS program reads records that are not part of its input file.
Part 3. Conversational Monitor System (CMS) 309
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