Hercules V4.00.0 - User Reference Guide

8.100 MEMLOCK (Lock Hercules memory)

8.100.1 Function

The MEMLOCK console command is used to lock Hercules memory in storage. It defines the locking
state of the allocated Hercules memory (page lock by host operating system). Given without argument
MEMLOCK displays the current setting. If Hercules memory is locked in storage it cannot be paged out
by the host operating system. This may result in some performance improvements.

This console command is available if Hercules is built with option “_HAVE_MLOCKALL”. Currently
MEMLOCK is only supported under Linux host operating systems.

8.100.2 Syntax

Descriptive

OFF]

Diagram

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OFF

8.100.3 Parameter

ON indicates that the memory is to be locked into storage.

OFF

OFF indicates that the memory is not to be locked into the storage.

8.100.4 Examples

Example 1:

Do not lock Hercules memory in storage.

HHC00013I Herc command: 'memlock off'

Figure 189: MEMLOCK command

8.101 MESSAGE (Display message on console like VM)

8.101.1 Function

The MESSAGE command is actually a VM CP command. It is used to transmit message text to the virtual
console of other active users.

However, some programmers also use this command as a simplified way to display messages on the
own virtual machine console by using "MESSAGE * <message text>". One program that uses this is the
IBM "System z" port of Solaris which is only capable of running under z/VM.

So basically, all the MESSAGE command does is to display a message on the Hercules console with VM
like headers. Therefore the MESSAGE command is not really intended to be used directly from the Her-
cules console as shown in the example below, although it does not hurt doing so.