Re: Looking for old Delta programs

["Gary L. Luckenbaugh" <garyll@ibm.net>]

The simulator is definitely slower than the real PDP-11/45.  It is very
noticeable when compiling programs and assembling .MAC files.  The reason
the clock is running too fast has to do with the way interrupts are
simulated.  The simulator just makes a rough guess as to when to issue a
simulated clock interrupt.  It's neither based on simulated PDP-11 cycles
nor real-time from what I can tell.  The code comments talk about disk
interrupts.  Apparently the disk I/O is synchronous, but he simulates the
interrupt by triggering it some number of simulated instructions later in
time.  The simulator keeps a queue of interrupt events to trigger later in
time.

It really is a remarkable achievement on Bob Supnik's part that all of this
works.

Gary
-----Original Message-----
From: Ken Cowan <KenC@numega.com>
To: 'deltoids@mcws.net' <deltoids@mcws.net>
Date: Monday, June 08, 1998 11:21 AM
Subject: RE: Looking for old Delta programs


>
>I haven't tried it yet, but I'm really curious whether the simulator
>running on a modern PC is faster or slower than a real 11/45 or
>11/70.
>
>  KC
>
>> -----Original Message-----
>> From: Alan Flippen [SMTP:flippen@nytimes.com]
>> Sent: Monday, June 08, 1998 10:14 AM
>> To: deltoids@mcws.net
>> Subject: RE: Looking for old Delta programs
>>
>> At 12:46 AM 6/7/98 -0400, Bob Mader wrote:
>> >Gary,
>> >
>> >This is great! It's up on the web site now.
>> >http://www.eecis.udel.edu/~mader/delta/downloadrsts.html is the place
>>
>> >to go. Now everybody can relive the RSTS experience. I trust all of
>> you
>> >former Deltoids are going to want to at least take a look at this!
>> I'll
>> >be curious to hear your reaction to RSTS after 20+ years? Seems a bit
>>
>> >more primitive than I remember. Enjoy!
>>
>> Gary and Bob,
>>
>> Just got it running, and I second the cheers. But ... no wonder it
>> seems a
>> bit more primitive than Bob recalls: it's the vanilla version, before
>> all
>> the Delta enhancements that we couldn't live without! Now if only
>> there were
>> a way to scan in all the programs we've all got on hard copy in the
>> basement ...
>>
>> Great work,
>> Alan
>>
>