1Q. The DUMMY feature for VSAM data sets is not supported and should
not be used at program execution time. Specifying this option on
the DLBL command will cause an execution-time OPEN error 20. The 3066 is supported as a 3215. It is not supported as a graphics
editor; therefore, it is recommended that the NODISP option of the
EDIT command be used when editing in a 3066. 21. The Program Controlled Interruption (PCI) FETCH option for load
module retrieval is not supported for OS/MFT or VS1. MSS Restrictions
1. There are two os/vs system data sets associated with Mass Storage System: The mass storage volume inventory and the mass storage
volume control journal. There is one copy of each data set per Mass storage System, not necessarily one per opera ting system. If more than one oS/vs on either native or in a virtual machine) is connected to a common Mass Storage System, then
the OS/VS systems must share a common inventory and journal.
2. When a real 3330V device is dedicated to a virtual machine as a
virtual 3330V, the prbgramming support in the virtual machine must
recognize and access the virtual device as a 3330V. 3. The following must be compatible; the definition of 3330V addresses
in the MCS tables; the DMKRIO module; and the IOGEN for any as/vs
system running in a virtual machine with a dedicated MSC port. The
reason for this, and the way to ensure it, is explained in the 4. Fach active volume in the MSS must have a unique volume number. If
you wish to have two or more user volumes having the same volume
serial (such as different versions of an OS/VS2 system residence
volume both having a volume serial of VS2037), then create two MSS volumes having different volume serials and allocate the user
volumes as minidisks.
5. Mass Storage System volumes may not be used for VM/370 residence,
paging, spooling, or temporary disk space.
6. You must not change the volume of a real 3330V volume (the volume
serial as known by the MSC) except by using the OS/VS access method
services utilities. If, for example, cylinder 0 of a 3330V is
dedicated to a virtual machine and that virtual machine alters the
volume serial using DDR, then the volume cannot be mounted. eMS Restrictions
The following restrictions apply to CMS, the conversational subsystem of VMI 3
7 0: 1. eMS executes only on a virtual IBM System/370 provided by VM/370. 438 IBM VM/370 Planning and System Generation Guide

2. The maximum sizes (in cylinders) of CMS minidisks are as follows: 2314/2319 3330 Model 1 3330 Model 11 3340 Model 35 3340 Model 70/3344 3350 Series 203 246
492
349
682
115 200 404 808 349
698
555
3. CMS employs the spooling facilities of VM/370 to perform unit
record I/O. However, a program running under CMS can issue its own SIOs to attached dedicated unit record devices.
4. Only those as and DOS facilities that are simulated by CMS can be
used to execute as and DOS programs produced by language processors
under eMS. 5. Many types of object programs produced by CMS (and OS) languages
can be executed under eMS using CMS's simulation of as supervisory
functions. Although supported in as and .DOS virtual machines under VM/370, the writing and updating of non-VSAM OS data sets and DOS files are not supported under eMS. 6. CMS can read sequential and partitioned as data sets and sequential DOS files, by simulating certain as macros.
The following restrictions apply when CMS reads as data sets that
reside on as disks: • Read-password-protected data sets are not read unless they are VSAM data sets. • BDAM and ISAM data sets are not read. • Multivolume data sets are
End-of-volume is treated
end-of-volume switching.
read as single-volume data
as end-of-file and there
sets.
is no • Keys in data sets with keys are ignored and only the data is
read, except for VSAM. • User labels in user-labeled data sets are bypassed.
The following restrictions apply when eMS reads DOS files that
reside on DOS disks: • Only DOS sequential files can be read. CMS options and operands
that do not apply to as sequential data sets (such as the MEMBER and CONCAT options of FILEDEF and the PDS option of MOVEFILE) also do not apply to DOS sequential files. • The following types of DOS files cannot be read: --DOS DAM and ISAM files.
--Files with the input security indicator on. --DOS files that contain more than 16 extents. 1!Qte: User labels occupy the first extent; therefore, the file can hold
only 15 additional data extents.}
Appendix F: V8/370 Restrictions 439