[GTALUG] ancient computer history

James Knott james.knott at jknott.net
Tue Sep 18 13:21:52 EDT 2018


On 09/18/2018 12:43 PM, Stewart Russell via talk wrote:
> On Tue, Sep 18, 2018, 10:48 James Knott via talk, <talk at gtalug.org
> <mailto:talk at gtalug.org>> wrote:
>
>      I also used to maintain a PDP-8i
>     computer.  When browsing through the programming manual, I found DEC
>     actually recommending self modifying code, to get around the
>     limitations
>     of the instruction set!
>
>
> The basic PDP-8 didn't have a hardware stack, so you had to prepare
> subroutines by modifying the code's return address before you called it. 
>
> I'm building a PDP-8 compatible right now, based on the Harris HD-6120
> "PDP-8 on a chip" used in the DECMate desktops. I'd best brush up my
> octal, as it's a 12-bit machine. 

Being a hardware tech, I didn't really get into software.  However, I
found on my IMSAI, with the 8080 CPU, working in octal was better than
hex, as the digits lined up with the instruction fields.  They didn't
with hex.

I just tried to dig up an article I read in Byte magazine about that
chip, but couldn't find it.  However, I did find an article that, in
addition to mentioning the PDP-8, included this:

And Ethernet's Fate?
A report issued by Strategic Incorporated, a market-research firm in San
Jose, California, predicts Xerox Corporation's  Ethernet local-area
network will be a total failure within two years. According to
Strategic's president, Michael Killen,  "Xerox is headed for the worst
failure in the company's history." He believes that Xerox lacks
technological and price advantages, sales force, and customers
interested in buying large systems.   Further,   he contends that
Ethernet's baseband approach to local networking will prove inferior
over the long haul to the broadband approach taken by Xerox's
competitors.   He points out that broadband systems are better suited to
carry video, heavy voice and data transmissions, among other
applications. In response to the report, Xerox issued the following
statement:
" Based on the level of customer satisfaction with our existing network
installations, the backlog of orders for network products and service,
and the interest in Ethernet on the part of major accounts,  we are
confident that Xerox will be a leading vendor in office automation."


I suspect that report was a bit off the mark!  ;-)

https://tech-insider.org/personal-computers/research/acrobat/8203.pdf


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