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From: Luther Johnson <>
Subject: [TUHS] Re: Burroughs funded $30,000 for a port to E-mode stack machine in 1983!
Date: Sun, 15 Jan 2023 12:19:19 -0700	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Well, FPGAs use SRAM-based look-up tables to do their combinational 
logic functions - so not that crazy - if it works and gives good enough 
results for the task at hand, people will find ways of using the 
technique. But I imagine there were a host of other things that weren't 
done as well as possible that added up to 8 hours vs. 3 minutes.

On 01/15/2023 12:09 PM, ron minnich wrote:
> I just stumbled across an old letter, from a VP of Burroughs to me and 
> Steve Bartels, authorizing $30,000 for a port of Unix to the E-mode 
> stack machine. I had forgotten getting it.
> Burroughs was famed for its stack machines. E-mode was a kind of last 
> gasp attempt to save the stack architecture, which failed as far as I 
> know, see this table:
> I worked as a hardware engineer on the A15. I also had been a Unix 
> user for 7 years at that point and kept pointing out how awful the 
> Burroughs CANDE time-sharing system was, and how much better Unix was. 
> At some point I guess they asked me to put up or shut up. I got that 
> money, and left Burroughs a week later for grad school.
> Funny note: A15 was Motorola ECL (MECL), and ran at 16 Mhz., 
> considered fast at that time.  We used a technique called "stored 
> logic" which was, believe it or not, using MECL RAM to map logic 
> inputs to outputs, i.e. implement combinational logic with SRAM. Kind 
> of nuts, but it worked at the time. We also used a precursor of JTAG 
> to scan it in. Those of you who know JTAG have some idea of how fun 
> this had to be.
> One side effect of working with MECL is you realized just how well 
> designed the TI 7400 SSI/MSI parts were ... MECL always just felt like 
> an awkward family to design with.
> Another funny story, pointing to what was about to happen to 
> Burroughs. We had an app that ran for hours on the stack machine. We 
> quick ported it to a VAX, started it up, and headed out to lunch -- 
> "this will take a while, let's go eat." We got to the front door and: 
> "Oh, wait, let me hop back into the office,I  forgot my jacket". And, 
> noticed, the program was done in ... about 3 minutes. Not 8 hours.
> That's when we knew it was game over for Burroughs.
> If a picture of this letter would be useful in some archive somewhere, 
> let me know, I can send it.

  reply	other threads:[~2023-01-15 19:19 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-15 19:09 [TUHS] " ron minnich
2023-01-15 19:19 ` Luther Johnson [this message]
2023-01-16  0:51 ` [TUHS] " ron minnich
2023-01-16  1:59   ` Lawrence Stewart

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