is placed in a queue and will be serviced by the first available thread (eg. by which-
ever thread becomes idle first).

This option was created to address a threading issue, possibly related to the Cyg-
win phtreads implementation on Windows systems. On Windows systems positive
DEVTMAX values are currently not honoured and are treated identically as if the
value 0 had been specified. The default for non-Windows systems is 0.

8.54.4 Examples

Example 1:

Display the maximum allowed device threads along with the current statistics.

HHC00013I Herc command: 'devtmax'

HHC02241I Max device threads: 0, current: 5, most: 5, waiting: 4, max exceeded: 0

Figure 110: DEVTMAX command (list maximum allowed device threads)

Example 2:

Set the maximum allowed device threads to 25.

HHC00013I Herc command: 'devtmax 25'

Figure 111: DEVTMAX command (set maximum allowed device threads)

8.55 DIAG8CMD (
Display or set DIAGNOSE 8 command option)

8.55.1 Function

The DIAG8CMD command specifies whether a command issued through Diagnose 8 will be executed by
Hercules as a Hercules commands or not. An optional second argument can be specified to request
whether the commands issued using the Diagnose 8 interface will be traced at the console. This may be
useful for programs that routinely issue console commands using the Diagnose 8 interface. If no argu-
ment is given, DIAG8CMD displays the current settings.

Caution: Enabling this feature may have security consequences. When this feature is enabled it is
possible for guest operating systems running under Hercules to issue commands directly to the host
operating system by means of the Hercules ‘sh’ (shell) command. This ability may be disabled via the
SHCMDOPT statement.

Note: There are some commands that are being prevented from being used by the Diagnose 8 interface.
The list of commands that may not be executed by means of Diagnose 8 can be found in “

8.55.2 Syntax

Descriptive

[ ]]

Diagram

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8.55.3 Parameter

DISABLE

Commands issued through the Diagnose 8 interface will generate a Specification
Exception program interrupt on the issuing CPU. This is the default together with
NOECHO.

ENABLED

Commands issued through the Diagnose 8 interface will be executed by Hercules
as Hercules commands.

ECHO

When ECHO is specified, a message is issued as the console is about to issue the
command, the command is redisplayed as if it was entered through the console in-
put line, and a final message is issued to indicate the command completed.