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How to start and stop ITS

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Lars Brinkhoff edited this page Mar 12, 2024 · 4 revisions

Except on KL10, starting ITS goes like this:

  • Start DSKDMP.
    • On a KA10 this is most often done from paper tape, but magnetic tape is also possible.
    • On a KS10, use the BT console command to boot off disk into DSKDMP.
  • DSKDMP will announce itself eponymously.
  • Select an ITS core image. Conventionally it should be @ ITS. Type F$ to see a file listing.
  • To load and run ITS, type the file name and enter. If the first file name is @ that can be omitted.
  • First DDT is entered. Here's a chance to debug ITS, set breakpoints, etc.
  • To start ITS running, type $G.
  • The Salvager will check the disks and then ITS IN OPERATION is printed.

On the KL10, there is no DSKDMP. DDT is used to load a core image and start:

  • Start non-timesharing DDT.
    • On a real machine this is done with the PDP-11 front end, but on an emulator it's done automatically for you.
  • Select an ITS core image. Conventionally it should be @ ITS. Type ^F to see a file listing.
  • To load ITS, type $L, the file name, and enter. If the first file name is @ that can be omitted.
  • You are still in DDT. Here's a chance to debug ITS, set breakpoints, etc.
  • To start ITS running, type $G.
  • The Salvager will check the disks and then ITS IN OPERATION is printed.

Stopping ITS goes like this:

  • Log in and run LOCK.
  • Type 5DOWN, without Enter, to have ITS shut down in 5 minutes. This is the minimum.
  • Type Y to confirm.
  • Type a message terminated by a ^C.
  • Type Q to exit LOCK.
  • When all users are logged out, ITS will shut down immediately regardless of the grace period.
  • ITS will soon print ITS NOT IN OPERATION, but it will still take a while to synchronize the disks.
  • When SHUTDOWN COMPLETE is printed, it's safe to power off.
  • Optionally you can restart ITS from DDT, or go back to DSKDMP by typing $U.

A transcript of starting ITS, logging in, and stopping. It has been edited for brevity.

 DSKDMP
its
$G
SALVAGER.317
ITS 1649 IN OPERATION
ITS 1649 SYSTEM JOB USING THIS CONSOLE.
^Z
ITS.1649. DDT.1547.
TTY 0
You're all alone, Fair share = 99%
:lock
 LOCK.156
_5down
DO YOU REALLY WANT THE SYSTEM TO GO DOWN?
Y
PLEASE ENTER A BRIEF MESSAGE TO USERS, ENDED BY ^C
Bye.
^C
ITS 1649 NOT IN OPERATION
SHUTDOWN COMPLETE
PI LEVEL 7 BUGDDT.  TYPE <ALTMODE>P TO CONTINUE.
YOU ARE NOW IN DDT.
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