From: PSULCS::TRI 11-MAY-1993 10:28:44.26
To: JLW
CC:
Subj: Fwd: OPENIN, DNF, NOSUCHFILE Errors Using Search List Logicals For DIRECTORY
OPENIN, DNF, NOSUCHFILE Errors Using Search List Logicals For DIRECTORY
Last Technical Review: 22-APR-1992 Size: 105 lines
COPYRIGHT (c) 1988, 1989, 1990 by Digital Equipment Corporation.
ALL RIGHTS RESERVED. No distribution except as provided under contract.
COMPONENT: Record Management Services (RMS) OP/SYS: VMS
LAST TECHNICAL REVIEW: 22-APR-1992
SOURCE: Customer Support Center / USA
VERSION INFORMATION:
Information Applies To: VMS, Versions 4.n and above
SYMPTOM:
A DIRECTORY operation is performed using a search list logical name
containing several rooted directory specifications. When no files
are found, the operation completes with the following message, as
expected:
%DIRECT-W-NOFILES, no files found
However, under some circumstances, the operation completes with the
following message:
%DIRECT-W-NOFILES, no files found
-RMS-E-DNF, directory not found
-SYSTEM-W-NOSUCHFILE, no such file
EXAMPLE:
For example, given the following devices and directories:
DSA1:[PROJECT_A]
DSA2:[PROJECT_A]
DSA2:[PROJECT_A.TEST]
DSA3:[PROJECT_A]
DSA3:[PROJECT_A.TEST]
And the following series of commands:
$ DEFINE /TRANSLATION=(CONCEALED,TERMINAL) TEST -
DSA1:[PROJECT_A.], -
DSA2:[PROJECT_A.], -
DSA3:[PROJECT_A.]
$ DIRECTORY TEST:[TEST]NOSUCHFILE.DAT
The result is:
%DIRECT-W-NOFILES, no files found
However, if the order of search list elements is changed:
$ DEFINE /TRANSLATION=(CONCEALED,TERMINAL) TEST -
DSA3:[PROJECT_A.], -
DSA2:[PROJECT_A.], -
DSA1:[PROJECT_A.]
$ DIRECTORY TEST:[TEST]NOSUCHFILE.DAT
The result is:
%DIRECT-E-OPENIN, error opening TEST:[TEST]NOSUCHFILE.DAT as input
-RMS-E-DNF, directory not found
-SYSTEM-W-NOSUCHFILE, no such file
ANALYSIS:
This behavior occurs because the directory [TEST] is not present
in all of of the roots in the search list specified in the above
command.
The fact that the error is sensitive to where the missing
directory falls in the search list is the expected behavior under
the circumstances described. The "directory not found" (DNF)
error is reported when:
o The specified file is not found in any of the existing
directories in the search list.
o The specified directory cannot be found in the last
root in the search list.
Otherwise, a "file not found" (FNF) error is reported.
Note that in addition to the DIRECTORY command, this behavior
applies to the routines LIB$FIND_FILE, LIB$FILE_SCAN and the
$SEARCH system service.
SOLUTION:
When referencing a directory using a search list of rooted
directories, ensure that the specified directory exists in all of
the directory roots in the search list.
From: PSULCS::TRI 11-MAY-1993 10:33:50.94
To: JLW
CC: TRI
Subj: more on search lists
Lance, note the second paragraph from the bottom.
Overview of Search List Logicals
Last Technical Review: 21-FEB-1992 Size: 494 lines
COPYRIGHT (c) 1988, 1989, 1990 by Digital Equipment Corporation.
ALL RIGHTS RESERVED. No distribution except as provided under contract.
COMPONENT: Search List Logicals OP/SYS: VMS
SOURCE: Customer Support Center/Colorado Springs USA
VERSION INFORMATION:
Information Applies To: VMS, All Versions
OVERVIEW:
This article provides an overview of using searchlist logicals and
contains approximately 520 lines. Due to the length of this article,
it is recommended that you get a hardcopy before attempting to read it.
DISCUSSION:
What is a Searchlist?
A searchlist is a logical name assigned to a list of equivalence
names. Typically, a searchlist consists of two device or device
and directory specifications. However, the searchlist is not
limited to just two components.
Searchlists became part of VMS with the advent of VAXclusters in
VMS Version 4.0. The searchlist is an important part of managing
the files on the system disk. The logical names SYS$MANAGER,
SYS$SYSTEM, SYS$LIBRARY and others are all implemented as
searchlists. Actually, these searchlists are implemented through
the use of the logical name SYS$SYSROOT which is defined as a
searchlist AND as a rooted directory.
A searchlist can be viewed as a series of containers. Generally,
the rules for using a search list are the following:
o On a read operation involving a searchlist, RMS uses the first
container that provides a match for the file specification
unless a wildcard is specified. When a wildcard is specified,
all matching files are used. If no matches are found, the
command terminates with a "file not found" error message.
o On a write operation to a searchlist which creates a new file,
RMS uses the first container in the list.
o On a read/write operation (such as editing or renaming an
existing file), the structure of the searchlist is preserved.
The new version of the file is written to the same container
in which the existing file was found.
NOTE: A searchlist provides only a logical definition for the
series of containers; just because a container is named in
a searchlist does not guarantee that it exists or is
accessible. Any problem that occurs using a component of a
searchlist is revealed only when the component is accessed.
(Examples deleted)
Summary -
In summary, several considerations go into the use of a
searchlist.
First of all, it may be important to know that a searchlist is
being used by default. New files (including directories) that
are created will be inserted into the first component of the
searchlist. The system logical names that use SYS$SYSROOT
(e.g. SYS$SYSTEM, SYS$MANAGER, SYS$LIBRARY, etc.) are searchlists.
Access to the components of a searchlist are transparent only if
all components have the same access (protections, existence). If
the searchlist components are defined with different
characteristics, command execution can become inconsistent.
Finally, it is often useful to have additional logical names
defined to reference the individual components of a searchlist.
The logical names SYS$SPECIFIC and SYS$COMMON permit references
to the components of the SYS$SYSROOT searchlist.
REFERENCES:
"VMS User Manual", (AA-LA98B-TE), June 1989, Section 11.8
"VMS DCL Concepts Manual", (AA-LA10A-TE), April 1988, Section 4.7