SASSIST have been exhausted. The maximum number of page frames reserved is limited by the size of the virtual machine. The OFF operand returns the reserved pages to the system. {
ON } [[ PROC ]nn ] OFF controls whether virtual machine assist, a facility available
on most VK/370 supported System/370 processors, is activated
or deactivated for the entire system. In VK/370 attached
processor applications, virtual machine assist may be set
either ON or OFF for the desired processor by selecting the PROC nn operand. If PROC nn is not selected then SET SASSIST ON or OFF determines the setting of virtual machine assist for
both the main and the attached processor. The values of nn
are processor addresses (hexadecimal values 00 to 3F)
established when the System/370 is installed. If nn equates
to a value that is not the address of the main processor or
attached processor, an error message is issued. Virtual
machine assist increases the efficiency of CP processing of
certain instructions, privileged instructions, and interrupts
reflected to CPa SET SASSIST in conjunction with CPASSIST also controls whether
the VK/370 Extended Control-Program Support provided by System/370 Kodels 135-3, 138, 145-3, and the 148 is in an
active or inactive state. For details on how this is
accomplished, refer to the CPASSIST operand previously
described. VK/370 Extended Control-Program support simulates
the CP processing ot additional privileged instructions and
extends the level of handling of other privileged instructions
not covered by virtual machine assist. SET SASSIST ON or OFF also controls whether the virtual interval timer assist
function of ECPS, a hardware updating' facility for the
interval timers of virtual machines, (virtual location X'50') is available to users. Use of this timer hardware update
facility by the virtual machine is controlled by the class G
command SET ASSIST TKR or SET ASSIST 10TKR; for details, see
the !!L37Q Upon system initialization, the default value SET SASSIST is ON for VK/370 processors except the system/370 Kodel 155 II
and the 165 II .. For details on the extent of virtual machine assist and the VK/370 Extended Control-program Support, refer to the PRIORITY userid nn
sets the priority of the specified user (userid) to the
desired value This value affects the user's dispatching
priority in relation to other users in the system. The
priority nn value is one of the factors considered in VK/370's dispatching algorithm. Generally, the lover the value of nn,
the aore favorable the user's position in relation to other
users in VK/370's dispatch queues.
Section 3. CP Commands 141

The format of the Class B SET co.mand is: r , SET LOGllsg Inn I INULLI L .J 1 r , ) DUMP {AUTO } ICP I raddr IALLI --'-"'.,."'".=-- L 1";;S;:: =
r , LOGMSG Inn I INULLI L .J LOGMSG or LOGMSG nn causes CP to respond with the message LOGMSG: followed by a console read to allow the operator to
enter the line. The maximum log message length per line is 76
characters, including spaces. Use LOGftSG with no operand to
start a new log message or add to a log message. LOGftSG nn
specifies that a change is to be made. to existing line number nn in the log message. A null line entered terminates the LOGMSG entry (for adding or initializing) or deletes line nn
if that option is used. LOG8SG NULL deletes the entire
existing LOG8SG allowing a new LOG8SG to be created.
Preceding the message text with an asterisk automatically displays the message on the console as soon as a user logs on
to VM/370. r , DUMP {AUTO } ICP I raddr IALLI L .J
designates the unit to receive the '8/370 system ABEID dump, where raddr is a real printer or a 9-track tape address. If
the dump unit is a tape drive, the dump data must fit on one
reel because '8/370 does not support multiple tape volumes. If AUTO is specified, the system unit is disk. The CP
option dumps only storage occupied by the control prograa-;­ whereas the option dUllps all storage.
142 V8/370 Operator's Guide