Communicator e3000 MPE/iX Release 7.0 (C.70.00) (30216-90312)

68 Chapter5
Technical Articles
Future Support For Greater Than 8190 Concurrent Processes.
Future Support For Greater Than 8190 Concurrent
Processes.
By Scott J. McClellan
MPE/iX System Architect
Commercial Systems Division
INTRODUCTION
The maximum number of concurrent processes (sometimes refereed to as MAXPIN) is a
key constraint limiting MPE/iX in high-growth, high-end customer environments.
Removing this constraint is one of the key ingredients in Hewlett-Packard's continuing
strategy to evolve MPE/iX -- providing growth for our high-end customers.
The maximum number of concurrent processes supported by MPE/iX is 8190. This limit
has not been changed in the last several MPE/iX Releases, and is not changed in Release
7.0. However, MPE/iX Release 7.0 contains many of the changes necessary to support
greater than 8190 concurrent processes in a future release of MPE/iX. By incorporating
these changes into Release 7.0, Hewlett-Packard has ensured that Release 7.0 has an
adequate foundation to allow MPE/ix to support greater than 8190 concurrent processes in
a 7.0-based Express Release.
WHO SHOULD READ THIS ARTICLE?
• High-end customers
• System Administrators for high-end systems
• Third-party software developer (or customers) with privileged applications and/or
applications that explicitly use Process Identification Numbers.
This article contains:
• A very brief overview of internal changes to MPE/iX (and the relevant potential
external impact).
• Discussion of the BIGPIN feature
• Description of new/enhanced "Program File Event" logging feature, which logs potential
issues on a customer system.
• Description of the new MAXPIN Scaling algorithm.
• Discussion of 5-digit PIN numbers (and changes to :SHOWQ and :SHOWPROC
commands).
OVERVIEW OF INTERNAL OS CHANGES
The MPE/iX concurrent process limit has historically been limited by one of Process
Management data structures called the Process Control Block (PCB). The PCB data
structure predates MPE/iX as the key process management data structure on older
MPE/V-based operating systems. The PCB was ported to MPE/iX and has existed as a