Initialization of the eMS Virtual Machine
Environment
There are four steps involved in initializing aCMS virtual machine: • Processing the IPL command for a virtual card reader. • Processing the IPL command for a disk device or a named or saved
system.• processing the first command line entered at the CMS virtual console. • Setting up the options for the virtual machine operating environment. DMSINI and DMSINS are the two routines that are mainly responsible
for the one-time initialization process in which the virtual card reader
is initialprogram loaded. DMSINI also handles the IPL process when a
named or saved system is loaded. TheC!S command interpreter, DMSINT, processes the first line entered from the console as a special case; the
processing performed by this code is a part of the initialization
process.DMSSET sets up the user-specified virtual machine environment
features;DMSQRY allows the user to query the status of these settings. Initialization: Loading a CMS Virtual Machine from
Card ReaderWhen a virtual card reader is specified by the IPL command, for exaaple OOC, initialization processing begins. Initialization refers to the
process of loadingfrom a card reader as opposed to reading a nucleus from a cylinder of a CMS minidisk or reading a named or shared system
(description follows).
IPLOOC invokes the CMS module DMSINI, which requests that the
operator enter information sucb as the address of theDASD where the
nucleus is to be written, the cylinder address where the write operation
is to begin, and which version ofCMS is to be written (if there is more than one to choose fro.). When all questions are answered, the requested nucleus is written to
theDASD. Once written on the DASD, a copy of the nucleus is read into virtual
.achine storage.One track at a tiae is read from the disk-resident
nucleus into virtual storage.DMSINS is then invoked to initialize
storage constants and to set up the disks and storage space required by
this virtual machine.DMSINS performs three general functions: • Initializes storage constants and system tables. • Processes IPL command line parameters (SEG= and BATCH). • Initializes for as SVC processing, in the case where a saved segment
is not available for use in processing ossimUlation requests. CMS Method of Operation and progras OrganiZation 2-57
Environment
There are four steps involved in initializing a
system.
for the one-time initialization process in which the virtual card reader
is initial
named or saved system is loaded. The
processing performed by this code is a part of the initialization
process.
features;
Card Reader
process of loading
(description follows).
IPL
operator enter information sucb as the address of the
nucleus is to be written, the cylinder address where the write operation
is to begin, and which version of
the
.achine storage.
nucleus into virtual storage.
storage constants and to set up the disks and storage space required by
this virtual machine.
is not available for use in processing os
