Specifications

Using Callable System Routines
10.3 System Services
Table 10–2 (Cont.) Functional Groups of System Services
Services Group Function
Input/Output I/O services perform input and output operations
directly, rather than through the file handling services
of RMS. I/O services do the following:
• Perform logical, physical, and virtual input and
output operations
• Format output lines converting binary numeric
values to ASCII strings and substituting variable
data in ASCII strings
• Perform network operations
• Send messages to system processes
Lock Management Lock management services let cooperating processes
synchronize their access to shared resources.
Logical Names Logical name services provide a generalized technique
for maintaining and accessing character string logical
name and equivalence name pairs. Logical names
can provide device independence for system and
application program input and output operations.
Memory Management Memory management services provide ways to use the
virtual address space available to a program. Included
are services that do the following:
• Allow an image to increase or decrease the amount
of virtual memory data available
• Control the paging and swapping of virtual
memory
• Create and access files in memory that contain
shareable code or data
Process Control Process control services let you create, delete, and
control the execution of processes.
Process Information Process information services let you obtain information
about processes.
Security The security services provide various mechanisms
that you can use to enhance the security of OpenVMS
operating systems.
Timer and Time Conversion Timer services schedule program events for a
particular time of the day or after a specified interval
of time has elapsed. The time conversion services
provide a way to obtain and format binary time values
for use with the timer services.
10–6