Example 5:

Write 3 tapemarks.

HHC00013I Herc command: 'mt 0480 wtm 3'

HHC02800I 0:0480 wtm complete

HHC02802I 0:0480 Current file number 10

HHC02803I 0:0480 Current block number 2477

Figure 209: MT command (WTM operation)

Example 6:

Erase a tape.

HHC00013I Herc command: 'mt 0480 dse'

HHC02800I 0:0480 dse complete

HHC02802I 0:0480 Current file number 1

HHC02803I 0:0480 Current block number 0

Figure 210: MT command (DSE operation)

8.111 NUMCPU (Display or set number of emulated CPUs)

8.111.1 Function

The NUMCPU commands displays or sets the number of emulated processor engines which will be con-
figured online at startup time. The combination of NUMCPU and MAXCPU controls the behaviour of how
many CPU engines will be configured online upon startup and how many can be configured online later.

NUMCPU cannot exceed the value of MAXCPU. If NUMCPU is less than MAXCPU then the remaining
engines can be configured online later. The default NUMCPU value is 1. All processors are CP engines
unless otherwise specified by the ENGINES system parameter.

Multiprocessor emulation works best if your host system actually has more than one physical CPU, but
you can still emulate multiple CPUs nevertheless even on a uniprocessor system (and you might even
achieve a small performance benefit when you do).

There is little point, however, in specifying NUMCPU greater than 1 unless your guest operating system
(running under Hercules) is actually able to support multiple CPUs. If you do not actually need
multiprocessor emulation, then setting MAX_CPU_ENGINES to 1 at compile time might even produce a
slight performance advantage too.

Given without an argument the NUMCPU command displays the current number of emulated CPUs.

For detailed explanations on the interrelationship between NUMCPU, MAXCPU and ENGINES please
see “

8.111.2 Syntax

Descriptive

[nn]

Diagram

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nn

8.111.3 Parameter

nn

The number of emulated CPUs. NUMCPU must be less than or equal MAXCPU. If
NUMCPU is larger than MAXCPU then an error message is issued, if it is less than
MAXCPU then the remaining engines can be configured online later.