MT - Maximum CPU Time

This Natural profile and session parameter determines the maximum amount of CPU time which can be used by a Natural program.

In server environments where the server itself runs without any operating system controlled CPU time limit, it is strongly recommended to set the profile parameter MT to a non-zero value to prevent the formation of endless loops caused e.g. by application errors. This recommendation applies to Natural RPC and Natural Development Server servers.

Possible settings 1 - 9999999 Maximum amount of CPU time in seconds.


  1. If Natural Security is installed, the profile parameter MT can be overridden within Natural Security.
  2. With Natural Security, the maximum value for the profile parameter MT is 32767.
  3. To use a higher value as specified with the MT profile or session parameter, specify MT=0 within Natural Security.
0 MT=0 defines that no Natural CPU time limit is to be in effect.
Default setting 60  
Dynamic specification yes  
Specification within session yes  
Applicable statements SET GLOBALS  
Applicable command GLOBALS  
Application programming interface USR1005N See SYSEXT - Natural Application Programming Interfaces in the Utilities documentation.


  1. This Natural profile and session parameter only applies to programs executed in batch mode, under Natural Development Server (SPoD) or under Natural for TSO.applies only to mapped mainframe environments (SPoD).
  2. This Natural profile and session parameter applies only to mapped mainframe environments (SPoD).
  3. CPU time measurement starts when a Natural program is started from NEXT mode or by means of a FETCH statement, that is, on program level 1. In non-batch mode (Natural Development Server, Natural for TSO), CPU time measurement is restarted at every terminal I/O.
  4. The limit for programs operating in interactive mode is controlled by the TP monitor in use.
  5. The maximum value that can be used is determined by the operating system environment. Any setting in excess of the maximum is reduced to the maximum supported by the operating system.
  6. In system environments which do not support CPU time measurement, the limit is interpreted as elapsed time. The CPU time limit is ignored for systems without timer support.
  7. Within a Natural session, the MT profile parameter can be overridden by the session parameter MT.
  8. When running zIIP-enabled under z/OS, the MT profile parameter applies separately to both TCB (except under CICS) and SRB (zIIP) processing modes. If MT=0 is set in SRB mode, Natural uses the existing z/OS TCB time limit to avoid endless loops because there is no z/OS CPU time limit (for example, the JCL TIME parameter) for SRBs.
  9. The MT parameter is supported under CICS SRBs (zIIP), but not under CICS TCBs. If MT=0 is set, Natural uses the CICS runaway time as CPU time limit in SRB mode. Note: CPU timeout abends cannot be recovered under CICS OTE TCBs, but cause an immediate AICA abend of the CICS task and the Natural session to abort.