QIO Configuration and Management Manual

Configuring the QIO Subsystem
QIO Configuration and Management Manual—424717-008
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Process Globals and Process Heap Space
Process Globals and Process Heap Space
Process globals represent global variables defined by processes for use by the entire
process environment.
The process heap (C/C+) is flat memory space for a program to use for temporary
storage of data structures.
Process globals and the process heap share the area of flat memory between
0x0800.0000 and 0x2000.0000. Within their segment, process globals and the process
heap grow dynamically as required by a program. When a program fills up the globals
and heap segment, it fails and issues an error. The error displayed depends on the
process that is running. Runtime error messages are:
18 Extended stack overflow
31 Cannot obtain data space
Figure 2-1. Default Configuration of User-Addressable Data Space
2000.0000
0800.0000
QIO Shared Memory
Segment
(default 512 MB)
QIO IOperm (32 MB)
Main Stack and
Flat Segment Memory
Space Reserved for
Programs
Base Addresses
4000.0000
4200.0000
VST011.vsd
Process Heap and
Process Globals
Flat Memory Space
(User Addressable
Data Space)
4E00.0000
5000.0000
Unassigned Flat
Memory Space