Stability of the System
While the DPS8M development team has been running Multics on the emulator for several months now, and those of us with long-running systems have enjoyed long periods of up-time, you should take care to not store anything of value on your Multics system unless you also have that data backed up somewhere else.
Warning: We have experienced emulator crashes where the contents of the Multics storage system is damaged. Salvaging the storage system allows Multics to be rebooted, but any data written in the bootload prior to the crash may be lost. Please see the following sections for recommendations to ensure the safety and integrity of your Multics storage system.
Run with DIRW Configuration Setting
By default, a cold boot of Multics (and by extension a QuickStart image) does not have the DIRW parameter enabled. This parameter causes "dirty" (written to) directory pages to be periodically flushed from memory to disk. We will probably enable this in the next version of the QuickStart image, but we strongly recommend you enable this parameter. To enable this parameter, boot your Multics system to BCE or shut down a running Multics to BCE. Use the "config" command to add a PARM card to the config deck. Here is an example of how to shut down your running Multics system and add this card:
M-> logout * * * Ready M-> CONSOLE: RELEASED 1210 as LOGOUT IO.SysDaemon.z dmn cord 0: 0 $0.06 (looc) 1210 as LOGOUT Backup.SysDaemon.z dmn bk 0: 1 $0.08 (looc) 1210 as LOGOUT IO.SysDaemon.z dmn prta 0: 0 $0.06 (looc) 1210 as LOGOUT Utility.SysDaemon.z dmn ut 3: 9 $14.35 (looc) 1210 as LOGOUT Volume_Dumper.Daemon.z dmn vinc 0: 1 $0.08 (looc) M-> shut 1210 as act_ctl_: shutdown, 9 0.21 0.13 0.00 0.34 80:37:47 $19601.79 1210.9 shutdown complete bce (boot) 1210.9: M-> config M-> /parm/ Search failed. M-> $a M-> parm dirw M-> \f M-> w M-> q bce (boot) 1211.5: M-> reinit bce (boot) 1211.6: M-> boot star
Run Incremental Hierarchy Backups
While ideally, you should run both Volume and Hierarchy backups, and you should run complete, consolidated/catchup, and incremental backups, we recommend, at minimum, that you run an incremental hierarchical backup while your system is up.
To do this, once you boot your system, type the following at the Initializer console:
x inc <operator initials> <tape-label>
x inc ejs ih0001
Here, I'm using the convention that tapes beginning with "ih" are "incremental hierarchy" backup tapes.
You will see the following output:
sc_command r bk start_dump sys_dirs "ejs" 1 60 sc_command r bk "ih0001" Ready M-> CONSOLE: RELEASED 1215 bk Begin at 03/22/16 1215.6 pst Tue 1215 bk 1215 bk >user_dir_dir 1215 bk 1215 bk Type primary dump tape label: 1215 bk Mounting tape ih0001 for writing 1215.7 RCP: Attached tapa_01 for Backup.SysDaemon.z 1215.7 RCP: Note (tapa_01) - ih0001,sys CONSOLE: ALERT 1215.7 RCP: Mount Reel ih0001 with ring on tapa_01 for Backup.SysDaemon.z <ih0001.tap> attachTape selected unit 1 TAPE: creating new file CONSOLE: ALERT 1215.7 RCP: Authenticate tapa_01. It has blank label . M->
Authenticate your tape, by issuing the following command:
x auth tapa_01 ***
Substitute, of course, the correct tape drive if tapa_01 is not the one chosen for your tape mount.
You will see output similar to the following:
Ready M-> CONSOLE: RELEASED 1215 bk Mounted blank volume "ih0001" on device tapa_01 1215 bk Begin at 03/22/16 1215.6 pst Tue 1216 bk Normal termination 03/22/16 1216.1 pst Tue. 1216 bk 1216 bk >system_control_1 1216 bk Begin at 03/22/16 1216.1 pst Tue 1216 bk Error file attached to file "start_dump.03/22/16.1216.ef". 1216 bk Normal termination 03/22/16 1216.3 pst Tue. 1216 bk 1216 bk >documentation 1216 bk Begin at 03/22/16 1216.3 pst Tue 1216 bk Normal termination 03/22/16 1216.4 pst Tue. 1216 bk 1216 bk >library_dir_dir 1216 bk Begin at 03/22/16 1216.4 pst Tue 1216 bk Normal termination 03/22/16 1216.4 pst Tue. 1216 bk 1216 bk >daemon_dir_dir 1216 bk Begin at 03/22/16 1216.4 pst Tue 1216 bk Normal termination 03/22/16 1216.5 pst Tue. 1216 bk 1216 bk >site 1216 bk Begin at 03/22/16 1216.5 pst Tue 1216 bk Normal termination 03/22/16 1216.5 pst Tue. 1216 bk 1216 bk >dumps 1216 bk Begin at 03/22/16 1216.5 pst Tue 1216 bk Normal termination 03/22/16 1216.5 pst Tue. 1216 bk 1216 bk Dump finished. 1216 bk Dumper going to sleep. 1216 bk 1216 bk r 12:16 36.335 2784 1216 bk --> bk
The incremental hierarchy backup daemon (Backup.SysDaemon) will wake up periodically and dump changed segments/directories to tape. When the current tape is filled up, the Initializer console will prompt for another tape.