Subsystem Control Point (SCP) Management Programming Manual

SPI Programming Considerations for SCP

Subsystem Control Point (SCP) Management Programming Manual—520619-001

3-9

Interprocess Communications Restrictions

These restrictions apply to communications among processes on a D-series node or in a

mixed C-series and D-series network. They are relevant to all instances of requester-

SCP-server communications.

•

No process on a C-series node can be opened by a high-PIN process on a D-series

node. For example, a management application running at a high PIN cannot open an

SCP process running on a C-series node, nor can an SCP process running at a high

PIN open a subsystem manager process on a C-series node.

•

A high-PIN process on a D-series node can open an unconverted low-PIN process

on a D-series node if the low-PIN process has the HIGHREQUESTERS object-file

attribute set during compilation or binding. From the perspective of communication

subsystem management, this is of interest only if you have developed a subsystem

because Compaq provides converted versions of its subsystems and the SCP

program.

For more information on these restrictions and how to overcome them, see the Guardian

Programmer’s Guide.

Converting Management Applications

Old management applications need not be converted to run on a D-series or G-series

system or in a mixed network, so long as all related processes run at low PINs. (Related

processes include the management application, the managed subsystem processes, and

the intermediate SCP process.)

However, if you decide to convert a management application:

1. For an overview of conversion and its benefits, see the Guardian Application

Conversion Guide. This guide also provides details of the conversion process.

2. Modify your management application to use the D-series tokens described in this

manual and in the SPI Common Extensions Manual.

3. For D-series SCP process startup methods and parameters, see Starting an SCP

Process on page 2-2. For more commands supported by the D-series SCP process,

see Commands and Responses on page 5-7. For more event and error messages

issued by the D-series SCP process, see Section 6, Event Messages, and

Appendix A, Errors.

4. For information on converting the sections of your application that process event

messages, see the EMS Manual.