6 VM/HSC 6.0 System Programmer’s Guide
1st ed., 6/30/04 - 312579601
VM Environment
The VM version of the HSC product is the implementation of the ACS Host Software
Component (HSC) product on VM. The principal interfaces and components under VM
are:
• VM Operating System (CP and CMS)
• The System Control Program (SCP)
• The Host Software Component (HSC)
• The tape management system (TMS)
• Operators and utility users.
VM Operating System (CP and CMS)
VM HSC requires relatively few system services. The VM system services that are used
are:
• Spool files
• Inter-User Communications Vehicle (IUCV)
• IUCV-based services *MSG and *BLOCKIO
• Diagnose
•RSCS
• VMDUMP Storage Dumps
• Interactive Problem Control System (IPCS) for VM/SP, or Dump Viewing Facility
for VM/XA and VM/ESA
• CMS (at initialization only).
CMS
The first portion of the SCP initialization process is executed under CMS. During this time
various files are read and some control data set locations are noted for reference. After the
program modules have been loaded into storage and the major control blocks have been
created, CMS is replaced by the SCP.
