The Console Subsystem

In the old days, large computer systems often had a console processor, a separate small computer or a separate processor within the main computer. This processor controlled the larger computer; it turned the power on and off, initialized the CPU of the main computer, and performed other control functions.

Today, it is much less common to find a separate console processor, but the concept lives on in the form of a console subsystem. This usually takes the form of a program that is stored in the nonvolatile ^[1] memory of the main computer and runs on the same CPU that executes the operating system.

To start OpenVMS, it is necessary to give the appropriate instructions to the console subsystem. The console subsystem locates and loads that portion of OpenVMS dedicated to system startup, which, in turn, loads the remainder of OpenVMS.

OpenVMS uses the SRM console. If your computer is currently running ARC or some other console, you must first switch to the SRM console before using OpenVMS. This usually consists of loading a console CD-ROM and selecting the desired console from a menu. Consult your hardware documentation for details.

System Startup

When you power-on your system, the hardware will perform a series of self-tests. If no serious problems are found, it will present you with the console prompt. The SRM console prompt is three consecutive angle brackets: ">>>." You may hear it referred to as the three-arrow prompt.

The power-up sequence varies from system to system, but the following example comes from a small AlphaStation 200, which shows a display representative of typical personal systems:

     ff.fe.fd.fc.fb.fa.f9.f8.f7.f6.f50           (self-tests)     ef.df.ee.ed.ec.f4.eb.ea.e9.e8.e7.e6.....e5. (self-tests)     V7.0-9, built on Mar 18 1999 at 13:41:11     >>>     (the console prompt) 

The following is an example power-up sequence from a VAXstation 3100/76:

     KA43-A  V1.0     F...E...D...C...B...A_..9...8...7...6...5...4...3_..2_..1..     ? 6  80A1  0000.4001     >>> 

If the self-test sequence detects any errors, they will be reported here. The format and meaning of these messages varies from system to system.

Note 

In this example, the error message "? 6 80A1 0000.4001" is reported. On a VAXstation 3100 system, this means that the system can find no devices connected to the external SCSI bus. For the particular sample system shown here, this is normal.

If your system is set to autoboot (to automatically start OpenVMS from a certain disk), it will do so at this time. Otherwise you must enter the BOOT command, followed by the name of the disk device from which you wish to boot.

The Autoboot Console Feature

If your system autoboots and you would like to change the boot device or disable the autoboot feature, do so after a shutdown. Shutdowns are described in the next section. Different console versions and hardware models handle autoboot differently. Some use a SET BOOT command, while others use environment variables called auto_action and bootdef_dev. Consult the hardware documentation for your particular model.

If you enter BOOT without specifying a disk, your system may either (1) produce an error message and take no action, (2) boot from a particular prearranged disk, or (3) search for any bootable device, including requesting a downline-load of OpenVMS from another system on the network. The action taken depends on your hardware model and console settings.

A given system may have more than one disk containing an operating system, each of them a valid candidate from which to bootstrap the system.

To see available devices, use the SHOW DEVICE command (if your system is older, you may need to use a different command; consult your hardware documentation).

     >>>SHOW DEVICE     dka0.0.0.6.0          DKA0                 RZ28M  0568     dka100.1.0.6.0        DKA100                RZ26  392A     dka400.4.0.6.0        DKA400               RRD43  1084     dva0.0.0.0.1          DVA0     ewa0.0.0.11.0         EWA0     08-00-2B-xx-xx-xx     pka0.7.0.6.0          PKA0         SCSI Bus ID 7     >>> 

In the display above, devices starting with DK are disk devices (your system may use another designation, such as DU or DQ, among others; it depends on the system data bus type). On this particular system, DKA0, DKA100, and DKA400 are valid candidates. Device DKA400 is an RRD series disk, which is a CD-ROM, usually used as a boot device only during OpenVMS installations or upgrades. DKA0: and DKA100: are normal SCSI hard disks.

To boot from DKA100, issue the following command (your hardware may require a different format; see your hardware documentation):

     >>> boot dka100 

The console will attempt to load a boot block; certain data at a known location on disk that starts the bootstrap process. If a valid boot block is located, system startup begins (your hardware may show a somewhat different sequence):

     >>>boot dka100     (boot dka100.0.0.1009.0 -flags 0)     block 0 of dka100.0.0.1009.0 is a valid boot block     reading 936 blocks from dka100.0.0.1009.0     bootstrap code read in     base = 1d8000, image_start = 0, image_bytes = 75000     initializing HWRPB at 2000     initializing page table at 1ca000     initializing machine state     setting affinity to the primary CPU     jumping to bootstrap code         OpenVMS (TM) Alpha Operating System, Version V7.3     %DECnet-I-LOADED, network base image loaded, version = 05.0E.00     $!  Copyright 2001 Compaq Computer Corporation.     %STDRV-I-STARTUP, OpenVMS startup begun at 19-JAN-2003 18:36:48.54 

When the boot process is finished, the last few lines of the display will look something like this:

     %SET-I-INTSET, login interactive limit = 64, current interactive value = 0       SYSTEM       job terminated at 19-JAN-2003 18:38:45.55       Accounting information:       Buffered I/O count:               2695      Peak working set size:     5264       Direct I/O count:                 1323      Peak virtual size:       171664       Page faults:                      2412      Mounted volumes:              1       Charged CPU time:        0 00:00:10.15      Elapsed time:     0 00:02:31.76 

At this time, you may press ENTER to log into text-based machines. If your system is GUI-based, the login screen will appear after a few seconds. If it fails to appear after about one minute, you may need to start the GUI software manually. Log in as user SYSTEM, as if you were logging in from a text terminal, and enter the command

    $ @SYS$MANAGER:DECW$STARTUP 

Customizing Your System Startup

OpenVMS can automatically perform arbitrary commands at each system startup via a command procedure called SYS$MANAGER:SYSTARTUP_VMS.COM. ^[2] Do not confuse this with STARTUP.COM, which you should never modify.

As one of the final steps in system startup, OpenVMS executes SYSTARTUP_VMS.COM. You may place any commands that OpenVMS should execute at each system startup in this file. You may use this file as a way to start DECnet or TCP/IP, start batch and print queues, start a database product, configure devices, etc.

System Shutdown

As with any other operating system, it is important to shut OpenVMS down properly. If you simply turn off the power, a number of inconvenient side effects may occur. Any application data not saved to disk may be lost or incomplete, depending on the journaling capabilities of the application. Batch and print jobs underway at that moment will be interrupted and disk volumes will undergo a time-consuming consistency check at the next boot.

OpenVMS stands out for its ability to avoid data corruption as the result of interruptions, such as a sudden loss of power, but the problems listed above cannot be avoided. Therefore, you should shut OpenVMS down in a controlled manner.

Before Shutting Down

Before shutting down, you may wish to stop any batch, print, and server queues. At any given time, a number of jobs may be underway. Allowing those jobs to complete will avoid inconveniences later.

To stop batch and print queues, use SHOW QUEUE/BATCH/ALL and SHOW QUEUE/DEVICE/ALL to examine batch and printer queues, respectively. Use the STOP/NEXT queue-name command on each queue, which prevents any additional jobs from starting, but allows any jobs underway to finish. Server queues may usually be stopped in the same fashion, but whatever application is associated with a given server queue may have its own requirements; check your software documentation. You may also wish to shut down any software products that may be running. Each of these will have its own shutdown method; check your software documentation.

Finally, consider customizing the SYS$MANAGER:SYSHUTDWN.COM command procedure to include any other commands you would like to have executed at each system shutdown. This command procedure will be executed during the system shutdown, provided you answer yes to the appropriate prompt issued by the shutdown procedure (explained later).

Queues should be stopped before initiating a system shutdown because SYSHUTDWN.COM may provide insufficient time to allow jobs to finish.

Shutting Down

After you have completed any preshutdown tasks as described above, use the SYS$SYSTEM:SHUTDOWN.COM command procedure to shut down the OpenVMS operating system.

Note 

Do not modify SHUTDOWN.COM. Any customizations should be added to SYS$MANAGER:SYSHUTDWN.COM instead.

SHUTDOWN.COM will ask you a series of questions about how the shutdown is to proceed. They are as follows:

     $ @SYS$SYSTEM:SHUTDOWN             SHUTDOWN -- Perform an Orderly System Shutdown                          on node PHOEBE     Are you sure you want to shut down node PHOEBE [NO]?     How many minutes until final shutdown [0]:     Reason for shutdown [Standalone]:     Do you want to spin down the disk volumes [NO]?     Do you want to invoke the site-specific shutdown procedure [YES]?     Should an automatic system reboot be performed [NO]?     When will the system be rebooted [later]:     Shutdown options (enter as a comma-separated list):      REBOOT_CHECK        Check existence of basic system files      SAVE_FEEDBACK       Save AUTOGEN feedback information from this boot      DISABLE_AUTOSTART   Disable autostart queues     Shutdown options [NONE]: 

Let's take these questions one at a time and explain why they are asked.

Are you sure you want to shut down node PHOEBE?

This question is asked only if you are logged in from a different machine via SET HOST. Its purpose is to ensure that you have not accidentally initiated a shutdown on the wrong node. If you are logged in at a local terminal, this question is not asked. After this point, if you wish to cancel the shutdown, press CTRL/Y.

How many minutes until final shutdown?

If the system is used by more than one user, supplying a delay will give other users a chance to save their work and log out. During the countdown, OpenVMS sends periodic broadcast messages to all users, warning them of the impending shutdown.

Reason for shutdown [Standalone]:

You may enter an explanation for the system shutdown here. This explanation will be included in the broadcast messages sent to all users. The default reason "Standalone" refers to "Standalone Backup," a program used to make backup copies of disks while no operating system is running (this ensures that no files will be in transition while they are being saved).

Do you want to spin down the disk volumes [NO]?

This question asks whether system disk drives should remain spinning after the shutdown or should be stopped. Only certain disk models honor this option; many will continue to spin as long as there is power. This question has little relevance for small personal systems.

Do you want to invoke the site-specific shutdown procedure [YES]?

This asks whether SYSHUTDWN.COM (described previously) should be executed. Normally, it should.

Should an automatic system reboot be performed [NO]?

If answered yes, this option will initiate a reboot as soon as shutdown is complete. This is synonymous with restart on some personal computer systems. ^[3]

When will the system be rebooted [later]:

The answer to this question will be included in the shutdown broadcast messages sent to all users. If you have selected an automatic reboot, the default message will contain words to that effect.

Shutdown options (enter as a comma-separated list):

The options are as follows:

• REBOOT_CHECK This will ensure that certain operating system files exist. This is a rudimentary check to ensure that the system, once shut down, will be able to start again. The author recommends always choosing this option.

• SAVE_FEEDBACK OpenVMS includes a tool called AUTOGEN, which attempts to automatically tune the performance of OpenVMS over time. This question asks whether data collected since the last reboot should be saved (if your system has been under an unusual workload since the last boot, the data may not help tuning efforts and should perhaps be discarded). AUTOGEN is not covered in this book (see the OpenVMS documentation set).

• DISABLE_AUTOSTART Later versions of OpenVMS have the ability to automatically start designated queues under certain startup conditions. The autostart feature is not covered in this book (see the OpenVMS documentation set—personal systems may make little or no use of autostart queues).

After all the questions have been answered, SHUTDOWN.COM will send out a broadcast message to all users, similar to the following but based upon your answers:

     SHUTDOWN message on PHOEBE from user MIKE at _PHOEBE$OPA0:    18:32:06     PHOEBE will shut down in 10 minutes; back up in about 1 hour     Installing a new disk drive. 

At intervals, OpenVMS will send out additional messages, counting down the time remaining until shutdown. As the shutdown time approaches, OpenVMS will begin shutting down various system components and execute the SYSHUTDWN.COM, if appropriate.

Determining When the System Is Fully Shut Down

Various hardware models present different displays once OpenVMS has been fully shut down. What to look for depends on the exact hardware model you are using, but it should resemble the following example:

     %%%%%%%%%%%  OPCOM  22-JAN-2003 18:14:14.92  %%%%%%%%%%%     Message from user MIKE on PHOEBE     _PHOEBE$OPA0:, PHOEBE shutdown was requested by the operator.     %%%%%%%%%%%  OPCOM  22-JAN-2003 18:14:14.95  %%%%%%%%%%%     Logfile was closed by operator _PHOEBE$OPA0:     Logfile was PHOEBE::SYS$SYSROOT:[SYSMGR]OPERATOR.LOG;291     %%%%%%%%%%%  OPCOM  22-JAN-2003 18:14:15.03  %%%%%%%%%%%     Operator _PHOEBE$OPA0: has been disabled, username SYSTEM 

A series of messages like those above signals the very last steps of the OpenVMS shutdown sequence. After these messages appear, your system may behave in a number of different ways, depending on your hardware model.

Some models, mostly older VAX computers, will show this message:

    SYSTEM SHUTDOWN COMPLETE -- USE CONSOLE TO HALT SYSTEM 

Other models may indicate the execution of a "breakpoint" instruction:

    Brk 0 at 8000200C    8000200C!       BPT 

GUI-based systems will place the hardware back into text mode (white on black or white on blue) and may automatically display the console prompt, ">>>."

Your system may now be safely powered off.

If you wish to use the console subsystem (perhaps to reboot, perhaps to change some console setting), the method you use will depend on your hardware model.

If the console prompt does not appear, you must gain the attention of the console subsystem. Some systems use CTRL/P or BREAK from the console keyboard. Others have a HALT or RESET button, usually located on the front or the rear of the computer. Consult your hardware documentation for details.

When the console prompt (>>>) appears, you may then enter console commands.

^[1]In this context, nonvolatile memory may mean any storage medium that is not erased when power is disconnected. Today, it is usually read-only memory (ROM or EPROM).

^[2]Older versions of OpenVMS called this file SYSTARTUP.COM or SYSTARTUP_V5.COM.

^[3]Restart historically refers to restarting an operating system already in memory whose operation was suspended, perhaps because of a momentary power failure. Reboot has historically meant initializing the hardware and reloading the operating system from disk. Some personal computer systems use the term restart where reboot or reload would be more accurate.