NonStop Systems Introduction

The NonStop Kernel
NonStop Systems Introduction—527825-001
6-3
Application Services
•
Manage memory such that when a process needs more memory, it can request a
block of memory; when the process is finished with the memory, it can release it
back to the operating system
•
Debug programs at both a high (symbolic) level and a low (machine) level
•
Compile and execute programs
Applications written for the Guardian environment fully support the NonStop principles.
Open System Services (OSS) is HP’s environment for open systems development on
NonStop systems. It provides an open alternative to the proprietary Guardian
environment. OSS provides an interface to many of the services of the NonStop
Kernel.
The OSS environment is similar to the standard UNIX programming environment.
Applications written for OSS are easily ported to other UNIX environments (provided
that they do not use HP extensions to OSS), and by the same token, UNIX applications
from other environments can be easily ported to OSS. Furthermore, programming
skills are transferable; programmers familiar with UNIX can readily develop
applications in the OSS environment.
Open System Services supports a multilevel file system similar to a UNIX file system,
as shown in Figure 6-2 on page 6-3.
As Figure 6-2 shows, the multilevel file system is composed of directories,
subdirectories, and files (a subdirectory is a directory within a directory). At the top of
the hierarchy is the root directory. Thus, every other directory is a subdirectory of the
root directory. You reference a file or directory within the hierarchy by specifying the
Figure 6-2. UNIX Multilevel File Structure
/ (root directory)
dev
bin
bfile1 bfile2
bfile3
src
myfile
filea
fileb
VST072.vsd
A directory can contain files and other directories.
Directories are shown in boldface.