Wasn't there an add-on developed for the Xerox 820/ Big Board that used the 2793? As I recall it was a a simpler (and less expensive) circuit as compared to the other add-on being offered at the time. I had one and lost it (as well as my 256K memory expansion board) during the course of my moves. If anyone has the schematics for it I'd like to try and put another one together.
Lou
>I happened to be watching the Sci Fi Channel tonight and caught the re-
>broadcast of the first "Sliders" episode. Quinn has a PDP-11 in his
>basement in San Francisco.
If I had to be able to interface to computers both 30 years in the past
*and* 30 years in the future, I'd be sure to use my PDP-11 too :-).
--
Tim Shoppa Email: shoppa(a)trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927
If they aren't classic, they soon will be. I've got this ancient Cisco AGS+
router (68040-based) with Multibus and some kind of Cisco-proprietary slots
inside. I have a quad V.35 card (useless to me because of the 26-pin high-
density D-shell connectors and no cables). What I need is at least a dual
Ethernet card. Whenever I ask my friends in networking, they always tell me
the same story, "Oh, yeah. We used to have some of those, but we threw all
that stuff out X months ago."
So if all these folks have been throwing this sort of stuff out, I figure that
*someone* on this list has seen the occasional item float by. Any and all
leads are appreciated. I'm willing to pay in excess of 1.2 * shipping, but
the sky is not the limit.
Thanks,
-ethan
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--- Chuck McManis <cmcmanis(a)mcmanis.com> wrote:
> It is the LSI-11 built into a VT100 thingy (a PDT-11?) The cards are from
> left to right:
> LSI=11/03 processor, RQDXn disk controller, Memory (looks like an M8044),
> serial port, and RX01 floppy controller. A cute system and well worth the
> dollar that is currently bid :-)
> --Chuck
I see that you're the high bidder, or I'd probably bid on it myself (that,
and I already have a VT103 and boxes of Qbus cards).
What _I_ see there in the ad is an 11/23 CPU (KDF-11), some third party
(floppy) controller (white handle - the RQDX3 has a 50-pin connector in
the middle of a red handle; the RQDX1 and RQDX2 are quad-width), memory
(perhaps an M8044, as you say), an IVB11 (IEEE-488) and a DJV11-J 4-port
SIO card. Pretty standard stuff.
Good luck on the box. I hope you get it.
-ethan
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Does anyone have any information on this item, a "Prometrix Omnimap 11" in
what looks to be a VT-100 case? It's currently for sale on eBay, item
246642084. What was this used for? What OS or Application does it run? Is
software available out there from anyone on this list? Was this equipment
made entirely by DEC, or does it have modifications made by a reseller?
What is this thing really worth? I know, lots of questions! Any answers?
Bill
whdawson(a)mlynk.com
In a message dated 02/04/2000 3:34:32 PM Eastern Standard Time,
ard(a)p850ug1.demon.co.uk writes:
> The 1772 appears to be identical to the 1770 apart from the step rates it
> uses. If your drives can take said higher rates, then the 1772 will work
> in your controller.
Thanks for the information, Tony. Upgrading the drives is not a problem
since I have access to many types of drives. In fact, I recently had some
trouble finding a drive *ancient* enough to work with the 1770 i/f.
Glen
0/0
In a message dated 02/04/2000 3:02:46 PM Eastern Standard Time,
ethan_dicks(a)yahoo.com writes:
> I am looking at a WDC-1772. It has 28 pins. Doesn't the 1770 have 40 pins?
I am looking at a (dead) WD1770 and it's a 28 pin DIP.
Glen
0/0
In a message dated 02/03/2000 10:47:16 PM Eastern Standard Time,
mcquiggi(a)sfu.ca writes:
> I too vote against embedded HTML in email. Give me the content, the fancy
> formatting is superfluous.
I second the motion. Most usenet groups will savagely attack anyone posting
binaries or html, and so it should be, here.
If God had meant for us to read html, we would be born with browsers built-in.
Glen
0/0
Be careful what you assume about this chip.
As I wrote before, the external lowpass filter is different for different
data rates, so if you want to use both 5-1/4" and 8" drives, (and the 3-1/2"
ones that look like 8") then you need two lowpass filters. These can be
hooked up very simply today as there are analog multiplexors with on the
order of 1 ohm of on-resistance, though back then it was necessary to use
relatively costly low-on-resistance D-mos switches. I very much prefer the
digital approach, which, then, was the only real alternative.
Dick
-----Original Message-----
From: Dwight Elvey <elvey(a)hal.com>
To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org>
Date: Friday, February 04, 2000 6:23 PM
Subject: Re: What's a WD2793A chip?
>Allison J Parent <allisonp(a)world.std.com> wrote:
>>
>> <In going through and sorting my piles of classic ICs, I ran across this
Wes
>> <Digital WD2793A chip. What is it?
>>
>> Take a 1793 and put some of the stuff needed to make it useful on the
die,
>> call it 2793. Basically it's a 1793 with data sep and precomp logic
built
>> on.
>
>Hi
> Anyhow, if anyone wants the schematic for the iSBX card
>I have with the 2793, I can trace it out for someone.
>Just let me know. It has all of about 4 chips.
>Dwight
>
The Feruson BIg Board ( of which I have a bunch) was single-density only,
for which clock extraction was dirt simple. MFM requires a gentler hand.
It was, as you suggest, straight from the WD App Notes.
The Big Board-II used the 9216.
Back in those days, there was a big fight between the analog guys and the
digit-heads, and it didn't help a thing. It got me paid for designs that
were never implemented on more than one occasion, even though my
meticulously designed and carefully stolen and tested, then improved digital
separators worked much faster and better than the analog ones.
Dick
-----Original Message-----
From: Al Kossow <aek(a)spies.com>
To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org>
Date: Friday, February 04, 2000 6:18 PM
Subject: Re: What's a WD2793A chip?
>"I've often thought that a PAL or small CPLD would do the job. Has anyone
>written the appropriate state machine or equations?
>"
>
>From memory, didn't the Furgusson 'big board' use a digital data separator
>that was a bipolar prom state machine? I know I've seen this same design in
>several late 70's floppy controller boards (maybe it was even in the WDC
>data sheets)
