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

Chapter 5 69
Technical Articles
Future Support For Greater Than 8190 Concurrent Processes.
Compatibility Mode data structure. The PCB is very heavily referenced by various
components of the Compatibility Mode Operating System.
Over the years, there have been many changes to the PCB data structure that have
expanded its capacity. The current MAXPIN limit is a function of PCB capacity, and is
limited by 16-bit CM addressing restrictions. In Release 7.0, the PCB has been
rearchitected as Native Mode data structure.
The PCB changes have been designed for maximal backward compatibility. As a result,
existing CM or NM code which accesses the PCB should function correctly, (without
modification) provided there are less than 8190 processes on the system.
BIGPIN Concept
Release 7.0 introduces the concept of "BIGPIN." The term BIGPIN refers to a system’s
ability to support greater than 8190 concurrent processes. In Release 7.0, the CORE OS is
BIGPIN capable; but the BIGPIN feature (which is Configurable) will not be enabled. In a
future release of MPE/iX, customers will be notified how to turn on the BIGPIN feature.
EVENT LOGGING
MPE/iX has been enhanced to log, at runtime, certain events where programs execute
operations that will not function correctly if the BIGPIN feature is enabled. Customers are
encouraged to make sure that this event logging facility is enabled (which it should be by
default) when they upgrade to Release 7.0. In particular, high-end customers who are
potential candidates for turning on the BIGPIN feature (in a future release of MPE/iX) are
encouraged to examine their system log files -- looking specifically for the new BIGPIN
related events (described below).
If any BIGPIN events are logged on a customer's system, the customer will need to contact
the company responsible for the software in question. Hewlett-Packard will be making
changes to some additional software products in future release of MPE/iX. There should be
no BIGPIN related events logged by the MPE/iX operating system. If there are any events
logged by MPE, please contact your HP support representative with all the details.
For software supported by third-party software vendors, contact the vendor directly.
Hewlett-Packard will be working with our software vendors to ensure they can make any
necessary changes to support greater than 8190 concurrent processes.
NOTE The event logging facility is designed to catch specific runtime events that
will cause a problem ON SYSTEMS WITH GREATER THAN 8190
PROCESSES. None of these events represents issues on systems with less
than or equal to 8190 processes. Furthermore, these events are expected to be
relatively rare. For the most part, the kinds of operations that can potentially
cause problems are fairly obscure. It is not "common" for third-party or
customer software to reference the PCB (or other OS internal data
structures) directly. Such references are limited to lower-level privileged
mode applications. This is not expected to be a significant issue for customers
as we move forward with a plan to support greater than 8190 processes. The
event-logging facility should be viewed as a "safety net,” designed to give HP
and our customer's "piece of mind" as we make this transition.