The OSS Development Environment

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Open System Services (OSS) is an interface, similar to UNIX, to the Tandem NonStop Kernel. The OSS environment coexists with the Guardian environment and provides an independent alternative to it. OSS conforms to open computing industry standards, specifically to the POSIX specification.

Unlike UNIX, OSS is not an operating system. The Tandem NonStop Kernel is the operating system for both OSS and Guardian file systems.

OSS consists of the following major components:

• File system. The OSS file system has a hierarchical structure similar to that of UNIX, composed of directories, subdirectories and files. The OSS file system uses the flat Guardian file system.
• Command interpreter (OSS shell). The OSS shell (osh) is the user interface for OSS. It uses the UNIX Korn shell.
• User commands and utilities.
• Application Programming Interfaces (APIs).
• C++ run-time libraries.

Most OSS commands have direct counterparts in UNIX, although some commands and utilities are unique to OSS. In some cases, OSS extends a UNIX command to provide access to features of the NonStop Kernel.

To get on-line information about OSS commands and utilities, you can use the OSS command called man (an abbreviation for "manual"). For example, to get more information about the gtacl command, you can type:

man gtacl

By default, OSS processes run as unnamed Guardian processes. However, you can use the OSS run command to run an OSS process as a named Guardian process.

You can use Guardian commands from osh through the OSS gtacl command. The following examples show how you would run the Guardian fileinfo and status commands through gtacl:

 gtacl -c fileinfo
 gtacl -c `status $ztc0'

You can also use Guardian files from osh by following a standard naming convention: in the OSS file system, the string "/G" designates the Guardian file system. The following shows how you would use the OSS ls command to list the contents of the Guardian subvolume $data1.nsdom:

 ls /G/data1/nsdom

The OSS run command lets you run a process with Tandem attributes. For example, you could use the following syntax to run a named process:

 run -name=Guardian-process-name program-name

A shell typically has environment variables, which you can set and display. Processes started from the shell can use the OSS API for access to the environment variables. For example, NonStop DOM processes and utilities use environment variables when you configure the system, develop a component, or run an application. The environment variables that NonStop DOM uses are stored in the env.sh file and are loaded into the osh environment as a configuration step.

A subset of the variables in the env.sh file, which are relevant for building NonStop DOM applications are described below:

export NSD_ROOT=/usr/tandem/nsdoms
export MY_ROOT=$NSD_ROOT
add_define =_SRL_01 class=map file=$NSD_SRL_SUBVOL.NSDSRL

export NSDOM_CFG_DBM=$MY_SUBVOL.NSDCFGDB
export PATH=$PATH:$NSD_ROOT/bin:$COMP_ROOT/usr/lib:$JAVA_HOME/bin

Note: If you installed the Software Development Kit (SDK) version of NonStop DOM, your files are installed into the subdirectory ZDOMSD20. If you are using the runtime version of NonStop DOM, your NonStop DOM fileset is located in the subdirectory ZDOMRT20.

NSD_ROOT designates the root directory where NonStop DOM files will reside. This manual sometimes refers to directory names relative from NSD_ROOT; in these cases, the notation NSD_ROOT means your setting of the NSD_ROOT variable.

The add_define sets a Guardian define from OSS to point to the NonStop DOM SRL. Guardian uses this define to associate an executable with an SRL when the executable runs.

NSDOM_CFG_DBM specifies the location of the configuration database.

PATH specifies the order in which to search directories for a command typed at the osh prompt.

The Administration Guide contains much more information about all aspects of NonStop DOM installation and configuration.

You use the following OSS commands and utilities to develop your application:

make

This utility helps you build and maintain an application that consists of multiple, interdependent modules. You use a file, called makefile or Makefile by default, to describe the dependencies among program modules. Thereafter, when you modify a module on which other modules depend, the make utility automatically initiates recompilation of the dependent modules. The NonStop DOM sample programs use a makefile to perform all the steps for building and configuring applications: running the IDL compiler, compiling and linking application programs.

c89

This utility is the front end for the C++ compiler. You can invoke c89 from within the make file.

nld

This utility is the native (TNS/R) linker. It links one or more TNS/R native object files to produce an executable or relinkable native object file. You can run the nld utility from either the Guardian or the OSS environment. c89 automatically invokes the nld utility. Therefore, in most cases you need not use nld explicitly when creating application executables.

noft

The noft utility reads and displays information from native object files. For example, the utility lets you list SRL references or unresolved references in an object file. It is very useful for developing and debugging NonStop DOM programs. The noft utility runs in both the Guardian and the OSS environment.

vi

This utility is the OSS editor used to create and update OSS files.

inspect

OSS does not provide a native debugger. You must use the Guardian INSPECT debugger to debug your NonStop DOM application programs. To start an INSPECT session from osh prompt, use the run command as shown below:

  run -debug program-name

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