HP 3000 Manuals HP 3000 Manuals
Creating Pre-POSIX Compatible Tapes
by Jim Nissen
Commercial Systems Division
With the addition of HFS syntax files and other new POSIX-related
features, mechanisms exist in STORE to allow tapes to be created on a
POSIX system and restored on a pre-POSIX system (4.0 or earlier).
There are two general scenarios when files would need to be transferred
to a pre-POSIX system:
* Planned Transport
You store off a set of files from one system, to be restored on
another system right away.
* Unplanned Transport
The data stored off from a system (usually a system backup) is
suddenly required to be restored on the same or a different
system. This kind of transport is usually done to recover lost
data and may require a POSIX system's backup to be restored on a
pre-POSIX system.
With these two cases in mind, STORE has the following objectives with
respect to data transport:
* The media created on a POSIX system should be restorable on a
pre-POSIX as well as a post-POSIX release.
* The planned transport operation should be as simple and easy as
possible.
* A default name conflict should not exist. This means that the
naming of non-MPE syntax files on a transport to a pre-POSIX
system should occur such that you do not inadvertently overwrite
previously transported files.
* For each of the transport situations, the security should be at
least equal to or more restrictive than required on the target
system.
Following are the features in Store which address these objectives.
HFS Name Mapping
Every POSIX Store media is created such that any HFS syntax file can be
restored to a pre-POSIX system with a unique MPE syntax name. When
restoring a tape to a pre-POSIX system, the file set of @.@.@HFSACCT
contains all HFS syntax files on that media. These files are named with
the MPE syntax of:
F#######._HFSGRP._HFSACCT
The #'s represent numbered files starting at 0000001.
A mapping file is also on the media. This file specifies the mapping
between the _HFSACCT name and the actual HFS name. The name of this file
is HFSMAP._HFSGRP._HFSACCT. Sample entries in the file would look similar
to this:
F0000001._HFSGRP._HFSACCT <- /SYS/PUB/dir1/file_a
F0000002._HFSGRP._HFSACCT <- /SYS/PUB/dir1/file_b
F0000003._HFSGRP._HFSACCT <- /SYS/PUB/dir1/file_c
Since _HFSGRP and _HFSACCT are illegal MPE filenames, special steps must
be taken when attempting to restore these files on a pre-POSIX system.
The LOCAL option can be used to restore the HFS files into your logon
group. For example, on a pre-POSIX system, issue:
:FILE T;DEV=TAPE
:RESTORE *T;@.@.@HFSACCT;SHOW;LOCAL
Alternately, you can specify a specific group and account to place the
HFS files, using the CREATE, GROUP, and ACCOUNT options:
:FILE T;DEV=TAPE
:RESTORE *T;@.@.@HFSACCT;SHOW;CREATE;GROUP=NEWGRP;ACCT=MYACCT
This restores all of the HFS syntax files to the group NEWGRP.MYACCT. The
HFSMAP file lets you identify the real names of the F####### files.
If you want to only restore MPE syntax files from the tape, that can be
accomplished by the following command:
:FILE T;DEV=TAPE
:RESTORE *T;@.@.@ - @.@.@HFSACCT;SHOW;CREATE
\ \ \ Important Details \ Please Read There are certain types of files
that exist on a POSIX system that
have no equivalent on a pre-POSIX
system, such as symbolic links and
device links. It is not
recommended that you attempt to
restore these files on a pre-POSIX
system. They contain no useful
information for that system, and
may be difficult to use or purge.
Preserving File Security
An argument of the TRANSPORT option allows POSIX style ACDs to be
translated to pre-POSIX systems, while maintaining the correct security.
Using TRANSPORT=MPEXL causes STORE to write out the pre-POSIX format
ACDs. If a POSIX media is created without TRANSPORT=MPEXL, and then
restored to a pre-POSIX system, the ACDs are not understood and the
system enforces a "creator only" security. This provides a more
restrictive security.