HP 3000 Manuals HP 3000 Manuals
The UID/GID Databases Enhanced
by Stacy Bell
Commercial Systems Division
Overview
The UID/GID databases provide unique identification numbers for users and
accounts on MPE/iX. Each user (user.account) has their own user
identification (UID) and each account has its own POSIX group
identification (GID). The UID/GID databases have been redesigned since
MPE/iX Release 4.5 for flexibility, ease of use, and faster performance.
The databases are now updated and opened at system boot time and remain
open for the uptime of the system. This article explains the migration
of user information and the saving, updating, system boot error recovery,
and backdating of the UID/GID databases. Also, changes to the utility
PXUTIL which supports the databases are listed.
Obsoleted Directory User Nodes
The most important change in the databases is the migration of all user
information from the MPE directory structure to the UID database. This
means that directory user nodes are now obsolete. Thus, when a LISTACCT
is executed, the USER UFID field will contain zeros. Also, the disk
space used by the database files is charged to the PUB.SYS group (where
the database files reside). The following tables are an estimate of disk
space needed.
UID Database:
Disk Space (Megabytes)
# of 5.0 4.5 4.0
Users (database) (database + (user node)
user node)
----- ---------- ----------- -----------
1000 2.4 3.8 .1
2000 4.8 6.2 .2
3000 7.1 9.3 .3
GID Database:
Disk Space (Megabytes)
# of 5.0 4.5 4.0
Accounts (database + (database + (account node)
account node) account node)
-------- ------------- ------------- --------------
300 .06 .34 .04
500 .10 .56 .06
1000 .20 1.13 .13
All user information is retrieved from the databases via the database
intrinsics HPGIDINFO and HPUIDINFO.
Storing and Restoring User Information
The database files are privileged and opened exclusively at boot time so
their information is secure. In addition, the files cannot be stored
directly. Storing of the information in the UID/GID databases is allowed
through the :STORE ;;DIRECTORY command and the information can be
restored through the :RESTORE ;;DIRECTORY command. The information in
the databases is crucial to the system operation, just as it is to that
of the directory structure; therefore, backups should be done regularly.
Updating and System Boot Error Recovery
Updating and opening the UID/GID databases is done at system boot time.
When updating from a pre-4.5 system, the databases are created, the
information is transferred from the directory user nodes, and the user
nodes are deleted. When updating from a MPE/iX Release 4.5 system, the
databases are created, the information is transferred from the directory
user nodes, and the old MPE/iX Release 4.5 UID/GID databases and the user
nodes are deleted.
Problems with updating or opening the UID/GID databases at boot time are
the same with the directory structure or any other files. If the UID/GID
database files cannot be updated or opened (probably due to a disk
failure), a message is displayed on the console and default databases are
created. If the corrupted database files exist, they are renamed for
future retrieval purposes (still secure, privileged files) and the system
will continue the boot process, coming up in single user mode.
The default UID database contains one entry for MANAGER.SYS and the
default GID database contains one entry for the SYS account, which allows
the system manager to log on and fix any problems. A :RESTORE
;;DIRECTORY from a backup tape will restore all database information.
Backdating
To backdate to pre-5.0 systems, the user information must be stored
through :STORE ;;DIRECTORY and the UID/GID databases must be purged
through the PXUTIL BACKDATE command. Once the system is backdated,
:RESTORE ;;DIRECTORY will restore the user information into its proper
place (for pre-4.5 this is the user nodes in the directory structure, and
for 4.5 this also includes the UID/GID databases). The MANAGER.SYS user
node has been retained for use in the backdating process, but until the
:RESTORE ;;DIRECTORY is executed, MANAGER.SYS is the only user on the
system.
PXUTIL
PXUTIL has been enhanced to provide the commands VERSION, BACKDATE , and
PURGE along with current commands of HELP , QUIT, and EXIT. The UPDATE
command has been obsoleted due to the redesign of the UID/GID databases.
The following describes these new commands:
VERSION.
The VERSION command displays the versions of the database files, the next
UID and GID numbers to be used, and the number of valid records in the
databases. The following is an example display.
PXUTIL> version
UID DATABASE:
HPUID.PUB.SYS Version: A.01.00
HPUIDNX.PUB.SYS Version: A.01.00
Valid Records: 368
Uid Counter: 531
GID DATABASE:
HPGID.PUB.SYS Version: A.01.00
HPGIDNX.PUB.SYS Version: A.01.00
Valid Records: 122
Gid Counter: 276
BACKDATE.
The BACKDATE command purges the UID/GID databases for backdating
purposes. The user information must be saved on tape FIRST through
:STORE ;;DIRECTORY. A warning message to this effect is displayed with an
option to cancel the process. The following example illustrates this.
PXUTIL> backdate
You MUST do a :STORE ;;DIRECTORY BEFORE running
this pre-backdating operation to preserve user
information. Continue (Y/N)?
PURGE.
The PURGE command purges old UID/GID database files created from a
UID/GID system boot error (HPUIDOLD.PUB.SYS, HPUIDONX.PUB.SYS,
HPGIDOLD.PUB.SYS, HPGIDONX.PUB.SYS). For more information on system boot
errors, see the "Updating and System Boot Error Recovery" section of this
article.
HELP.
The HELP command displays instruction on the utility.
QUIT.
The QUIT command exits the utility.
EXIT.
The EXIT command exits the utility.
Summary
With the MPE/iX Release 5.0 redesign of the MPE/iX UID/GID databases, you
gain increased performance in logons, logoffs, user listings, and certain
shell commands. User information disk usage has decreased compared to
MPE/iX Release 4.5. Original externals have not changed and expansion
opportunities have been opened.