Using Fedup

[Rick Stevens]

On 06/18/2015 04:09 PM, Mickey wrote:
>
>
> On 06/18/2015 06:08 PM, Rick Stevens wrote:
>> On 06/18/2015 02:48 PM, Joe Zeff wrote:
>>> On 06/18/2015 02:32 PM, Rick Stevens wrote:
>>>> Should go fairly well if your F20 is up to date. You may have to wait
>>>> for a full moon and shave a goat under it, but you should be OK. :-)
>>>
>>> And, just as with getting SCSI to work, always use black candles!
>>
>> I was on the ANSI SCSI committee back in the day (like 30 years ago) so
>> I had "special powers" and could get by with dark blue candles and only
>> having to pluck a live chicken on alternate Tuesdays to get my drives to
>> work. I still have a bunch of the old 220/330 ohm DIP packs (the blue
>> ones) to terminate cables if you need any. :-)
>>
>> I was also incredibly stupid back then, so I mistakenly volunteered and
>> got stuffed onto the ANSI C committee as well. At least that had the
>> silliness of PJ Plaugher of Whitesmiths on the committee, too:
>>
>> Under "Bugs" on the Whitesmiths' C users' guide for "onexit() (their
>> library's version of what became "atexit()"):
>>
>>     "The type declarations defy description and are still wrong."
>>
>> And under "Bugs" for "cpystr()" (their version of "strcpy()"):
>>
>>     "Forgetting the terminating null is mildly perilous."
>>
>> PJ was nothing if not, uhm, "clever". :-p

> Rick do you remember the old S100 bus on computers, it was very
> important to have the bus terminated ?

Sure do! I had several Altair 8800s. My first one was serial number
3 that I bought directly from Ed Roberts at MITS in Albuquerque.
The motherboards came in 4-slot chunks and you had to jumper them
together with 100 2" long wires. Fully expanded, you had 18 motherboard
slots. Power supply was woefully undersized at only about 12A for the
8V bus. Not nearly enough.

Bus termination wasn't mandatory, but it sure as hell helped. Some
company (can't remember who) developed an active terminator board that
was much better than just passive resistors, but stability also
depended on how well designed the daughter cards were. Some had very
weak bus drivers that couldn't reliably drive the bus once it had a
number of cards on it.

And remember, the fastest processor you could get back then was the
Zilog Z80 at a mind-bending (wait for it......) 4MHz! The standard
Intel 8080 was 2MHz and the 8085 theoretically could run at 3MHz, but I
never saw a stable one at that speed. I did see the LSI 9080 run at 3MHz
pretty solidly, but they were pretty rare.

I also had two IMSAI 8080s (22-slot motherboards), a Polymorphic 88,
a Processor Tech Sol 20, Vector Graphic V80 and lots of others. I had
ASR and KSR 33 teletypes (the ASRs had paper tape punches and readers),
Tarbell cassette adapters, DEC VT100 terminals, ICOM floppies (later
replaced with Micropolis drives when I went to work for them) and lots
of other bits and pieces. This was back in, let's see, 1977 or 1978.

Interesting tidbit: The S100 connector was chosen by Ed Roberts at
MITS because he bought a job lot of them (about 1000) as surplus, dirt
cheap. Since MITS was the first in the industry, that standard stuck.
Weird but true!

And yes, I am that farking old. I fart dust. :-)
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- Rick Stevens, Systems Engineer, AllDigital    ricks at alldigital.com -
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