IBM Professional Series User Manual page 381

CMS Mac1ibs
The macro libraries which are on the CMS 100 minidisk
contain a subset of the macros available on a VM/SP
Release 2 CMS system. The CMS and OS maclibs are
named 'CMSPCLIB MACLIB' and 'OSPCLIB
MACLIB', respectively.
I/O interface changes.
VM/SP CMS uses the SIO instruction to support the
console. Since VM/PC does not support this instruction,
VM/PC CMS has changed the console support to use
the DIAGNOSE X'20' support in VM/PC CPo
Storage Keys
Although storage protection is not performed, the
storage keys have been retained to provide compatibility
for programs that use the storage keys to determine
system and user area partitioning.
Interval Timer
Since VM/PC does not support the interval timer, the
timer routines in OS Simulation have been modified to
use the CPU timer.
• File System
You cannot create or access local minidisks formatted in
800-byte blocks. You may access remote minidisks
formatted at this size, however. VM/PC supports CMS
minidisks in 512, 1024,2048, and 4096-byte sizes.
VM/PC chose these as the best sizes for minidisks, since
they must be mapped into Personal Computer DOS files,
which are maintained in 512 byte blocks.
In addition, the support for remote minidisks and remote
files has changed the CMS file system somewhat. The
FSTs for remote minidisks which you access are not
copied to your local session storage. Rather, all requests
for file system functions are sent to the remote server
program. The results of these requests are passed back
C-4
VM/PC Users
Guide