--- - -...l ---- ----- ---"' 3850 MSS Therefore, the following rule must be used when defining (via IOGEN) 3330V devices in a VS system to run in a virtual machine to which an KSC in ter face is dedicated.
For each 3330V defined in the VS system there must be a corresponding 3330V defined to VM/370 and allocated to the virtual machine.
For example, if you wish to dedicate real 3330Vs 240 through 27F to
virtual CPUID 22222 as virtual devices 140 through 17F, then only 3330Vs 140-17F can be defined (via IOGEN) in the OS/VS system running in CPUID 22222. I SPECIAL CONSIDERATIONS FOR THE VS1/VS2 CENTRAL SERVER VIRTUAL MACHINE At detach time, the VM/370 control program destages changed cylinders on a'volume when the use count for the entire volume reaches zero. The
destaqe function is accomplished by a relinquish order to the MSS throuqh the central server. A relinquish order iR for volume-IDs mounted on SYSVIRT and VIRTUAL virtual unit addresses
which have had a volume mounted on them by VM/370 on behalf of the guest
operating system. No data are destaged for VIRTUAL units that were not
mounted by VM/370. The following VS1/VS2 APARs must be applied to the central server
virtual machine operating system when VM APAR 11344 (relinquish
function) is applied to the VM/370 control program. The following APARs
should be applied regardless of whether the new function is desired: COMEQNENT SC.1]] SC1CI SC1DP VS1 APAR OX27455 OX27456 OX27453 OX27454 VS1 SPE BASE UX90058 UX90059 UX90054 UX90056 VS1 SPE MSSE UX90055 UX90057 VS2 APAR OZ49650 OZ49655 OZ49642 OZ49643 VS2 SPE BASE UZ90134 UZ90135 UZ90130 UZ90132 VS2 SPE MSSE UZ90131 UZ90133 VM/370 APAR 11342 permits general use volume sharing on 3330 virtual
unit addresses between a VM/370 system and a native VS1/VS2 system when
the unit control blocks are not generated in the VS1/VS2 central server
virtual machine. The following VS1/VS2 APARs must be to the
central server virtual machine operating system when this fUnction is
desired: VS1 VS2 APAR PTF APAR PTF OX24117 UX15678 OZ48289 UZ33530 If general use volume sharing is not desired, these APARs do not
have to be applied.
74 IBM VM/370 Planning and System Generation Guide
Page of GC20-1801-10 As Updated April 1, 1981 by TNL GN25-0837 3850 MSS DEFINING THE MSS COMMUNICATION DEVICE The VM/370 control program initiates an MSS mount or demount request by generating an attention interruption on a specified device. This device
must be specified in the directory of the virtual machine as a unit
record output device, for example: SPOOL 017 2540 PUNCH The same device address must be specified on the job control language
used to start DMKMSS in VS, for example: //MSSCOMM DD UNIT=017 This device address must be constructed in VS at the same time as the IOGEN for the 3330Vs. The address chosen must not correspond to an
actual device that VS will attempt to use for any other purpose: This
is done by specifying the device as a DUMMY in the VS IOGEN. For
example: IODEVICE ADDRESS=017,UNIT=DUMMY,DEVTYPE=nnnnnnnn The value of nnnnnnnn
requirement to provide
example:
is any valid hexadecimal code.
a UNITNAME statement for this UNITNAME NAME=017,UNIT=017 T.HE MASS STORAGE CONTROL TABLES It is a
device, VS for
This topic is provided for those installations that intend to run VS systems in a virtual machine and access the MSS (under control of VS) from those systems. If you run only one VS virtual machine that has MSS support, and that virtual machine will access the MSS only upon request
from VM/370, then this section does not apply. However, you must follow
the guidelines in this topic if you have a virtual machine that has 3330Vs dedicated to it (that is, you intend to run more than one MSS virtual machine or to run VS MSS jobs in the MSS communication virtual
machine).
The MSC is driven from tables that reside on DASD. These tables are
used, among other things, to define the MSS configuration. This
configuration includes such items as the addresses to be used for all
components of the system, and the available paths from all connected
hosts to all these component devices. Thus, the MSC tables define the
allowable paths from any host (as defined by that host's CPUID to a 3330V where the 3330V is defined in terms of the Staging Adapter address
and the specific S/370 channel attachment to the Staging Adapter). Part 1. Planning for System Generation 74.1
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