[Simh] Problem with reading tape with PDP-11 SIMH

[Armistead, Jason BIS]

So now that Alan has TPC working, where and how do we document all this, i.e. the symptoms, the underlying SIMH design & behavior vs the expected RSX behavior that cause it to manifest itself as a problem, and the DEP TS TIME solution, in an easy-to-find way so the next person doesn't have to go through this pain ?

There is an awful lot of collective wisdom from the contributors to this e-mail list, but unless someone diligently searches the mailing list archives and gets lucky, it's not easy for a user to solve their own problem, even if it's been seen several times previously.

The SIMH FAQ on the trailing edge web site (in PDF) has not been updated in 3 years, and the DOC version on GitHub was last updated a little over 2 years ago, and I wonder whether a better "living" form of documentation like a Wiki would be a more useful solution. i.e. when a system-specific usage-related problem is discovered (and hopefully fixed), the cause, effect and solution is distilled into an appropriate new or existing Wiki page.

As I read the e-mails on this list, I am in constant awe at the depth of knowledge that many contributors have - in this particular case Mark and Timothe did the heavy lifting to help Alan, but there are many others whose first-hand experience "back in the day" drives SIMH user problems to a solution.  How do we preserve everyone's legacy of product knowledge for future generations who will use SIMH long after they are gone ?  To me it's as important as preserving the knowledge of the hardware SIMH simulates.

Jason

-----Original Message-----
From: Simh [mailto:simh-bounces at trailing-edge.com] On Behalf Of Alan Frisbie
Sent: Thursday, 21 May 2015 8:16 PM
To: Mark at infocomm.com
Cc: SIMH at trailing-edge.com
Subject:  Re: [Simh] Problem with reading tape with PDP-11 SIMH

Mark,

> Please follow Timothe Litt's suggestion and get back to me with the 
> minimal value of DEP TS TIME which produces reasonable results for the 
> original TPC problem you saw.

Here are the results:

5000 - TPC works fine
2500 - TPC works fine
1800 - TPC works fine
1500 - TPC works fine, RSX reported tape drive errors
1350 - TPC works fine, RSX reported tape drive errors
1200 - TPC hangs
0    - TPC hangs

To be safe, I think I'll use 2000 from now on when using TPC.

Thanks a lot for all the help.   It saved me a lot of
debugging and head scratching.

Alan Frisbie
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