HP 3000 Manuals HP 3000 Manuals
Recovery Procedures
Information Access consists of several components, one of which is Access
Server. Disruption of any one component affects the data flow of all.
This section explains the effects of an interruption, and describes the
recovery steps necessary. Note that because Access Server does not
modify IMAGE databases but only reads from them, a database is protected
from corruption in these situations.
Host Power Failure
If the host HP 3000 experiences a power failure, MPE's normal power
failure recovery procedures take place when power is restored (assuming,
of course, that the power failure is sufficiently short).
If The Administrator or Translator Utility Was in Use.
If your PC or terminal's power did not fail when the host's did, Access
PC will still be running. It was not suspended, and therefore need not
be resumed. The MPE "powerfail" message appears on your screen. To
refresh the screen, start at Step 2 below.
If the PC or terminal's power failed as well as the host's, you'll notice
that the screen being worked on in the Administrator Utility or
Translator Utility was not refreshed. Follow the recovery procedures
described below to resume operation.
Although the screen is blank, the original MPE session is still running.
Press Return to display the colon prompt. If the colon prompt does not
appear, press Break, then Return again. When the colon prompt appears,
follow these steps to restore the screen display:
1. At the colon prompt, type :RESUME and press Return.
This resumes the application program's processing, which was
suspended by the power failure as though by the Break key.
2. Press function key f8.
This key directs the application to move out of the current
function and up one level. The screen for the next higher level
appears, and the screen that was being worked on when the power
failed can then be returned.
3. If the power failure also affected the PCs running Access PC, type
the UDC command CLEARAC.
This disables Access Server and immediately re-enables it,
cleaning up the active users list and deleting leftover work
files.
If Access PC Was in Use.
If Access PC was running and a power failure occurs on the host, or on
both host and PC, the original MPE session may still be running on the
host. The discussion just below describes how to restart Access PC.
Check the status of work that was in progress when the power failed. The
data may or may not have been affected, depending on the transaction
status at the exact moment the power failed. For example, if a table was
being saved or reformatted on the HP 3000, check the status of the saved
table or the SD, DIF, ASCII, binary, or BRW file.
Data in IMAGE/3000 databases on the HP 3000 is not affected, since it is
available for read transactions only.
If a host-to-PC transmission was in progress when the power failed, the
data sent to the PC could be incomplete, corrupted, or lost. Clean up
any data left after a power fail interrupt, and start the transaction
again.
PC Power Failure While Running Access PC
The "Host Power Failure" discussion included an explanation of how to
return to the Administrator or Translator Utility after a PC power
failure. The discussion below explains how to return to Access PC after
a PC power failure.
NOTE The steps given below apply only to basic serial connections. If
HP OfficeShare networking software is used, the session ends when
the power fails.
Returning to Access PC on an HP Vectra, IBM PC, or Compaq and PC.
If the PC is logged on across a modem, Access Server closes its files and
lines, then stops the Access Server process. You need only access the
PAM. screen and restart Access PC. If the PC is connected directly to the
host, Access Server may still be running but Access PC is not. The
procedures listed below explain how to return to work.
1. Restart the PC. If the host's power failed as well as the PC's,
normal MPE recovery takes place on the host when power is
restored.
2. When the PAM screen appears, go into AdvanceLink (or other
terminal emulator) and press Enter. The colon prompt should
appear. If there is no response, or if the response is other than
the colon prompt, press the appropriate Break key(s). If there is
still no colon prompt, abort the session and restart Access PC.
3. At the prompt, type the MPE command, :SHOWME. If the host's
response shows IN BREAK, type the MPE command :ABORT to stop the
server process. If the :ABORT command is unsuccessful, free the
port and restart Access PC. Since normal communication between
Access PC and Access Server is with echo off, you may have to type
ESC : to turn echo back on for this port.
4. If the PC is not in break, access the PAM screen and restart
Access PC.
Here are some special things to consider when restarting Access PC on an
HP Vectra, IBM PC, or Compaq PC after a power failure:
* If a host session was established through AdvanceLink: Run
AdvanceLink again. It is likely that the noise on the line will
abort the current server process, freeing the original MPE
session. If it does not, abort the session and start over. Since
normal communication between Access PC and Access Server is with
echo off, you may have to type ESC : to turn echo back on.
* If a host session was initiated using another terminal emulator:
You may need to abort the original session before Access PC can be
restarted. Session recovery varies from one terminal emulator to
another. Since normal communication between Access PC and Access
Server is with echo off, you may have to type ESC : to turn echo
back on.
* If a host session was established through the Access PC Remote
Connection screen: Run Access PC again. It is likely that the
noise on the line will abort the current server process, freeing
the original MPE session. If it does not, abort the session and
start over.
* If a host session was established with a basic serial connection
file: Execute the connection file again. It is likely that the
noise on the line will abort the current server process, freeing
the original MPE session. If it does not, send a connection file
containing a &SENDBREAK command to abort the session and start
over. The procedure for session recovery may vary depending on
the connection path that you established. Using a terminal
emulator program might be the only practical way to clean up
RS-232 connections.
Host System Failure
In a disorderly system halt, all HP 3000 processes are terminated in an
unpredictable state, including the server processes, the Administrator
Utility, and the Translator Utility.
If the Administrator or Translator Utility Was in Use.
Because the HP 3000 processes are terminated ungracefully in a system
failure, it is possible that the data being worked on is corrupt. When
the system is again running, the Administrator Utility's List and Show
screens can be used to review what was being wored on. It may be
necessary to delete any entries made and start over.
If Access PC Was in Use.
The host's data communications are shut down in an ungraceful halt, and
the PC's data communication software times out trying to communicate with
the host. It is probable that any data manipulation taking place on the
host at the PC's request is lost. When the system is running again,
review the Access PC work. The PC user might have to restart his or her
operations.
If Host-Remote Connection Is Broken
Disruption of data communications between the host HP 3000 and a remote
HP 3000 can be caused by an operator command, mechanical line failure, or
loss of transmission timing synchronization. If the link is broken,
Access Server on the host times out trying to communicate with the remote
HP 3000. The host stops processing current requests and returns an error
message to the requester PC.