Forgot TOPS-20 operator password?

Dan Cross

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Jul 30, 2021, 3:30:17 PM7/30/21

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Someone surely knows the answer to this, but I can't find
it easily.

I have forgotten the OPERATOR password on my Panda TOPS-20
instance; I have also forgotten the password for my "normal"
user account. Surely there is some way to reset it (manually
setting some contents of the switch register?), but I can't
find it. Where should I look? Thanks!

- Dan C.

Rich Alderson

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Aug 1, 2021, 11:45:14 PM8/1/21

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cr...@spitfire.i.gajendra.net (Dan Cross) writes:

> Someone surely knows the answer to this, but I can't find
> it easily.

It was never easy to find, intentionally. It requires physical access to the
console of the DEC-20, and the ability to boot the monitor into DDT.

> I have forgotten the OPERATOR password on my Panda TOPS-20
> instance; I have also forgotten the password for my "normal"
> user account. Surely there is some way to reset it (manually
> setting some contents of the switch register?), but I can't
> find it. Where should I look? Thanks!

I'm in the middle of a move, so the disk with my personal writeup of the method
is out of my reach for a couple of weeks. However, I knew I had something on
the LCM+L Toad-1 and Toad-2, and I was right. Courtesy of my late friend Mark,
you have the following:

> Date: Mon, 30 Nov 2009 08:26:37 -0800 (PST)
> From: Mark Crispin <M...@Lingling.Panda.COM>
> To: C.... S.... <.......@gmail.com>
> cc: ALDE...@xkleten.paulallen.com
> Subject: Re: tops-20 EDDT

> Boot the monitor into EDDT. Breakpoint at GOTSWM. Start. When the
> breakpoint is hit, patch location CHKPSW to be JRST RSKP. You may have to
> do <ESC>W to enable patching. Remove the breakpoint, then do
> 1,,GOTSWM<ESC>G (not <ESC>P).

> You now have a running system that will accept any password.

> -- Mark --

> http://panda.com/tops-20
> TOPS-20: a great improvement over its successors

Mark's version is slightly less elegant than mine, but you don't care about that.

--
Rich Alderson ne...@alderson.users.panix.com
Audendum est, et veritas investiganda; quam etiamsi non assequamur,
omnino tamen proprius, quam nunc sumus, ad eam perveniemus.
--Galen

Dan Cross

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Aug 2, 2021, 1:59:36 PM8/2/21

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In article <mdda6m0...@panix5.panix.com>,

Rich Alderson <ne...@alderson.users.panix.com> wrote:
>> Boot the monitor into EDDT. Breakpoint at GOTSWM. Start. When the
>> breakpoint is hit, patch location CHKPSW to be JRST RSKP. You may have to
>> do <ESC>W to enable patching. Remove the breakpoint, then do
>> 1,,GOTSWM<ESC>G (not <ESC>P).
>
>> You now have a running system that will accept any password.
>
>> -- Mark --
>
>> http://panda.com/tops-20
>> TOPS-20: a great improvement over its successors
>
>Mark's version is slightly less elegant than mine, but you don't care about that.

Nice. Thank you, Rich; I really appreciate it.

- Dan C.

Dan Cross

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Aug 3, 2021, 7:41:00 AM8/3/21

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In article <se9bq7$4up$1...@reader1.panix.com>,

Just a quick follow-up on this. I was able to follow Mark's
instructions, as relayed by Rich, and get patch the monitor on
my instance and reset my password.

I did have to modify slightly in that, breaking on GOTSWM, I found
that the page containing CHKPSW was not (yet?) loaded. However,
breaking on SWPINI and following essentially the same procedure
yielded the desired results. That is, the exact sequence of steps:

GO
/e
$w
SWPINI$b
dbugsw/2
147$g
(at the breakpoint...)
$b
CHKPSW/$<JRST RSKP
$>
1,,SWPINI$g

and then login as normal (^C log operator foo once TOPS-20 is up).

Thanks again, Rich!

- Dan C.

Rich Alderson

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Aug 4, 2021, 10:41:50 PM8/4/21

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Good catch, Dan! Swappable monitor was in the back of my head when I was
writing before, but I didn't trust my memory enough to mention it.

One thing about your patch: You didn't need to use the patching mechanism
($</$>), since you were already writing into the running monitor. You could
simply have put the JRST RSKP into location CHKPSW.

Glad everything worked out for you!

Dan Cross

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Aug 6, 2021, 11:24:56 AM8/6/21

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In article <mdd8s1g...@panix5.panix.com>,
Rich Alderson <ne...@alderson.users.panix.com> wrote:
>cr...@spitfire.i.gajendra.net (Dan Cross) writes:
>>[snip]

>
>Good catch, Dan! Swappable monitor was in the back of my head when I was
>writing before, but I didn't trust my memory enough to mention it.
>
>One thing about your patch: You didn't need to use the patching mechanism
>($</$>), since you were already writing into the running monitor. You could
>simply have put the JRST RSKP into location CHKPSW.

Ah, very cool: I'll file that away for the next time I forget my
password. :-)

>Glad everything worked out for you!