| SAS/C Cross-Platform Compiler and C++ Development System User's Guide, Release 6.50 |
When working in a distributed environment without file sharing, the barrier between systems can become problematic. Files that are needed on one system often reside on another. The solution of
transferring the entire file, using File Transfer Protocol (FTP) for example, is practical if the file is small and seldom changes, but becomes much more laborious when this is not the
case.
Traditionally, programs running on MVS and CMS have had little or no access to files located on PCs, workstations, and other non-mainframe computers. The
SAS/C CSL NFS client support changes this situation. For example, in the cross-development environment you can run the
SAS/C Debugger on the mainframe while your source and debugger files reside on a workstation.
The SAS/C CSL NFS client transient libraries enable a new filename style prefix,
path:
, in SAS/C filenames. In the same way that an MVS program can use the
dsn:
prefix to open a file by data set name, the program can now open
an NFS file with
the
path:
prefix. Thus, files that are accessed using NFS are placed in a separate name space from traditional MVS or CMS files. This separation is due to differences in file system organizations, such as
directories versus partitioned data sets, rather than the fact that one group is local and the other is remote.
SAS/C CSL functions and configuration files are available to mount directories in the mainframe environment. As multiple mounts are established from one or more remote machines,
the CSL NFS client library maintains a unified hierarchical view of the resultant directory structure. With the CSL NFS client, mounts are the responsibility of the individual user, not of a system
administrator.
For example, a configuration file with the following line can be used if the user wants to access a UNIX root directory / on a machine named
acct.langdev.abc.com
.
acct.langdev.abc.com:/ / nfs
This indicates that the root of the
acct.langdev.abc.com
machine should be mounted as the root directory on the mainframe, thus enabling a debugger user to specify
set search
commands relative to the mount point. (See Chapter 9, "Cross-Debugging" for information about the SAS/C
Debugger's
set search
command.)
To continue our example, suppose the user now invokes the debugger on the mainframe and enters the following
set search
command:
set search userinclude =
"path:/usr/name/project/headers/%leafname"
The debugger will now look for user include files in the
/usr/name/project/headers
directory on the remote workstation named
acct.langdev.abc.com
.
In a more complicated setup, many different UNIX workstation file systems can be mounted together. The overall organization is the responsibility of the mainframe user,
and the pathname for a particular file will often differ from what would be used on any of the systems individually.
The CSL NFS client enforces security controls that prevent unauthorized access to files on the server. Before the user can access an NFS file, the user identification must be authorized by the local
RACF compatible security system, if one is available, and by a login server running on a UNIX system. If a local security system is available, this login process can be invoked automatically by the
CSL library. If not, the user must supply a UNIX, or other NFS server operating system, username,
and password.
In either case, the NFS client software maintains the standard UNIX, or POSIX, User Identification (UID) and Group Identification (GID) numbers for the duration of the user's session. The NFS client
software controls access to remote files based on the user identification and the file's permissions.
Copyright © 1998 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
