SDS 940 BASIC (was Re: Which Dec Emulation is the MOST useful and Versatile?)

Rich Alderson RichA at
Thu Oct 26 13:35:12 CDT 2017

From: Al Kossow
Sent: Thursday, October 26, 2017 9:04 AM

> On 10/25/17 11:55 AM, Rich Alderson via cctalk wrote:

>> Noel, do have a reference for "some commercial time-sharing system in the
>> Boston area"?  From Paul Allen's autobiography, the Harvard system was
>> followed immediately by their move to Albuquerque, where they leased time on
>> the local school board's PDP-10, and that's what my friends who worked for
>> Micro-soft back then have told me, as well.

> Harvard had an SDS 940, which shipped with a version of Berkeley's
> timesharing system. Tymshare's version of that system was significantly
> improved, and included "Super BASIC". SDS's OS was replaced with Tymshare's
> at Harvard because the original was so bad, and so they were exposed to that
> version of BASIC. PA told me that was the influence for M-S's BASIC
> extensions.

Harvard also had a KA-10, which is what PGA's 8008 -> 8080 simulator ran on,
using the User UUO capabilities of the architecture and operating system:
Microprocessor 8-bit byte in the address field, and a user-defined operation in
the opcode field to do the interpretation/call the interpreter.  (The simulator
was originally written for the Traf-O-Data device, which was 8008 based.)  I
put the code on our Tops-10 system while he was writing the book, and the
version of BASIC we run on the Altair 8800 in the Exhibit Hall was compiled on
that system; it is not a Microsoft product.

I know about the influence of SuperBASIC; I did not know about the Harvard 940.
Thanks for the note!


Rich Alderson
Vintage Computing Sr. Systems Engineer
Living Computers: Museum + Labs
2245 1st Avenue S
Seattle, WA 98134

mailto:RichA at

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