Date   : Tue, 07 Mar 2006 19:01:14 +0000
From   : Fragula <fragula@...>
Subject: Re: Warning: Sad case on list!

Hi Jules!

Jules Richardson wrote:

> Think we've been through the SCSI side of things on this list a few
> times in the past and I can never remember the exact ins and outs, other
> than it probably won't work without modifying ROM code, and even then
> you need a drive that'll handle 256 byte sectors - which isn't many of
> them.
There are a few, but agreed they are Not the norm, at least not these
days. Oh. Now was it CRAY that used 256 byte sectors?

> Heh heh, does your ACW have the little screwed-down metal catch covers
> on the back to stop anyone being able to open the case with zero tools? :-)
I think so. It has little metal things that were a bitch to get off,
that I do remember.

>>> dead easy to come by like beebs - hence the image wall project
>> You were serious about that? 
> Well why not... 16 Cub screens, one beeb per Cub, stick the boards in a
> rack next to it, 640x1024 res in mode 2. Funky. :-)
Should be easy enough to parallelise the Mandelbrot code, have one
master (not neccessarily a Master<tm>) feeding parameters to the array,
where each machine works independantly on its own chunk. I've done that
with OpenMosix under Linux, should be even easier on the beeb. For 16
machines I reckon you will need a buffer box for the RS423 distribution
though. Are MAX232-C level convertors cheap as chips these days?

> Not sure what to use for the controlling machine as I'd like a camera
> hooked up to it - so it needs something that'll process an image and
> spit the relevant chunks out to each beeb in a reasonable amount of
> time. Gotta be something vintage too, of course.
Whoaaa neddy. this is a job for Econet!

 > Well this was Mikes (as in profpep's) baby, not mine - he mentioned on
> here that he had 8 beebs hooked together once rendering fractals on one
> screen. Strikes me that it'd make quite a cool retro display in its own
> right, and it's not like there are a shortage of BBC micros about!
idd.

>> Its not fast though. Summit like 6 hours per screen
> Hmm... probably need something that'll run in about 2 hours or so
Would need a bit of cheat math in assembler then. precalculated tables
or summit.. it could probably be sped up by an order of magnitude or so.
I just ran it up to entertain the wife really. We saw some hippy-trippy
"popumentary" TV program on Fractals, with various halfwitted academics
spouting various wild theories regarding parallels with nature, and
other psuedo-mystical gawpings. (i'll admit they are /pretty/.) I'm not
too confident of the 6502s ability to do the straight math much quicker
than its already done in BBC Basic, so it would involve some integer
cheating I guess. Will have to think more about that.

> I
> suppose, so that it'll do several passes each day and visitors can come
> back to it and see how it's doing. Of course with several beebs it
> should go pretty well...
Hmm.. It won't go any faster than with one, and probably a lot slower!
The time is taken "iterating", i.e. digging down (like sonar) to a
certain, undefined (well, defined by the algorithm), depth, calculating
where that depth is, then bailing out and basing the pixel colour
(which, is fairly arbitrary) on that depth(nothing mystical at all!) the
"deeper" a pixel is, the longer it takes for the function to return a
colour value.

The more beebs you have, the more pixels you have to calculate, and
(more importantly) the greater the "magnification" per beeb, and the
greater the time taken by those poor unfortunate beebs that draw the
short straws of great depth. A *wild* guess says multiply the time taken
by 10 or so, as all the other elements (sorry, Beebs) will have to wait
for the slowest.

However, (here the program gets a little more complex) If the beebs all
worked together, picking the next "not being worked on" co-ordinates by
"claiming" them, from a master process, sending the results to the
appropriate output beeb (which might be itself) (or just broadcasting it
and moving the screen co-ordinates on each display), then moved on to
the next available co-ordinates... And assumming zero communicatons
latency, they should all finishe fairly closely, having worked fairly
similar problems.

 > Amigas always were pretty cool
Dunno. Cool might be a bit strong. it just played music and moveies, and
did what amigas were good at. He used a PC and a Beeb for all his
serious work.

> We've got an 8600 sitting in storage which is an interesting beastie and
> takes up about ten racks :)
Nice if you have the real estate..

> PSP user! (me too, actually :)
LOL! File info checker!

> Hmm, you need to motorise those daleks...
They are voodoo deskdaleks. They have mojo that keeps away academics and
managers. One of them has had its head replaced with a blue brain made
of "stress relief" rubber! They also have functional biological weapons
systems. (i.e.fungus growing inside!)

> Nice. No GT40 I take it? I'd love to find one for lunar lander purposes...
GT40? A Ford? I'm more a Lambourghini Miura man really, But I have a BMW
R80/7.

 > eek... non-profit organisation which means no money to actually *buy*
> stuff :) (actually, we do have some cash kicking around for emergencies,
> but generally it's a no-no)
Ohh.. Well i think we should research the history anyway. I believe it
to be British in origin. "Miles Gordon Technologies"

> No idea actually. I remember drooling over the machine in a Crash mag
> review donkeys years ago...
Its cute, its fast, its got doodads and whistles, and a general air of
niceness, but its a spectrum. I was *gobsmacked* by the price on ebay,
which i feel more reflected its rareness to a collector, than its niceness.

> I think all we have are standard mushroom-a-like Oric 1's.
Mushroom-a-like? :-O Ah, you keep 'em in the dark and feed them shit. I
have a few 1s and 3s. You should probably have a 3 for the museum. its
allegedly got the bugs fixed.
>
>> Also just remembered a few more. The
>> Torch Unicorn, Graduate, Zep-100. I have two of those 3, but I can't
>> remember which two.. Both of mine are Z80 based, one is just a board,
>> the other is an external mini-tower case with a hard disk (currently
>> not-working) and a floppy etc. as well as the 2p.
> 
> 
> D'oh, I'd missed the Graduate off my mental list in previous email, so I
> think that's 18 in total:
> 
> Acorn Z80
> Acorn 6502
> Acorn 32016 (256KB/1MB)
> Acorn 32016 ('large' - 4MB)
> Acorn 32016 (Master Scientific)
> Acorn 80186 (Master 512)
> Acorn 80286 (ABC 3xx)
> Acorn 65C102 (Master Turbo)
> Acorn ARM1 (ARM Eval kit, with or without mem expansion)
> Acorn A500 (not to be confused with A500 separate machine)
> Torch Z80
> Torch Z80 Tosca (the one with the local serial port)
> Torch 68000 Neptune
> Torch 68000 Atlas
> Torch Graduate
> Casper 68000
> Cumana 68008

You still forgot the Unicorn! (68000 in a tower case with 1MHz bus
SASI/ST506 hard disk, running some flavour of Unix. Cost about 3K in the
mid 80s.

> ... plus this Transputer board.
Yes, err.. there was a typo in that. It was 256K of RAM.

 > There are a few unofficial copros about too - I think JGH had a PDP TUBE
> link (*pokes JGH*),
A What??? (/me suspects he might be having his tail pulled!)

> and Graham Toal built a 6809 copro, 
Good plan. Nice old processor. There was one in production (not by
Acorn) running OS/9+FLEX - I remember a mate of mine salivating over it.
He used to work on "PIX" (an italian arcade game) boards, which were 2x
1MHz 6809 based. He had one which did all sorts of strang things in his
living room.

Oh.. 6809 is what my synth and sampler (Ensoniq ESQ-1 and Mirage
respectively) are based on. And the Dragon 32/64 of course. Plus
probably the Tandy COCO.

 > and then there
> was an article published way back when for using a Dragon 64 as a DIY
> 6509 copro.
Talk about sh*t and see what walks in eh? "Too Silly"

> 
>> BTW I know a chap, another FidoNutter way back when, who claims to have
>> an *386* internal co-pro in his attic. He promised it to me years ago,
>> but I don't like to nag.
> 

> Wow. Would love some details on that - wonder where it fitted into
> things date-wise? 
No idea. I've never actually seen it, but other mutual friends have. It
was inside a Master 128, He may have built it himself, used to work for
a company doing design and build of hi-spec hi-res frame grabbers and
motion sensors (way beyond broadcast res) and made a number of weird
items. I have one board he made for an ISA PC, which has a 6522 and a
couple of BBC compatible user ports.

> Curious as to what Acorn's justification was too. ARM
> CPU work must have been in full swing by then, so I wonder what the
> justification was? Deffo a 386 copro for an 8 bitter rather than some
> sort of PC copro for an ARM machine?
Thats what I hear.

I have to give him a knock fairly soon. we used to run a regular Fidonet
"comms meet" in Cardiff every month, back in the 90's. Then we (starting
with myself i guess) all deserted, until recently they are only "as
called", and have been about once every two years, when one of The
Colins organises it. But the last one went well, and I think we are
expecting another in the next few months. I've been organised to knock
on 3 "missing persons" doors, and at the top of the list is the man
concerned.

> This of course assuming that it's an official board and not just
> someone's homebrew project!
Well.. he rekconed he had DOS etc. running on it, but then it could be a
hardware project compatibleised with the 286 or even 186 copro. If it
was, it will be a proper PCB, he's that sort of bloke. Might even be
able to get a copy from it. He's been threatening to give it to me since
around 2002!

 > Ahh yes, one of them under the table in the back room downstairs.
> Ugliest machine ever made :)
You HAVE seen a VAX 6400??? A MicroVAX 3100? Been in PC-world any time
in the last 10 years? I'm not going to award it any points in a beauty
pageant though.

> I'm something of national collector of Torch stuff it seems having ended
> up with the contents of their workshop from when they went under... (I
> can hear the creaking from the loft)
Yeh.. tends to be fairly heavy.
> 
> Urgh. Still, they're not *that* special- the 7xx UNIX machines are the
> ones to look for as they have more bells and whistles.
Never seen those. Saw a demo R140 once. Brilliant machine. The
demonstrator was to pop around the house to flog it "ex demo price"
after the show had toured (some trade show thing) but never turned up.

> If you ever find a Torch QuadY btw then yell (successor to the QuadX
> which was in turn successor to the popular TripleX systems). They only
> built four of them...
Don't know any of those...

> Right in the thick of it :)
Ohhh.. I'm not sure I like you any more!!! ;->

Just be sure not to forget Tommy Flowers. While I think Alan Turing was
a brilliant man, I'm sure he wouldn't know a Tetrode from a Tetleys Teabag.

> We've got the go-ahead now to take over the whole of H Block
> (13,000sqft) and form a national computer museum there,
Right.. i'm gonna have to pop up and have a look at this!
> 

> Oooh, those things are pretty awesome, and bomb-proof.
One is from 1959, one from 1960, I've had one since 1989, and another
shortly after that. I've not done a lot of maintainance, they just work.

I have broken some modules (which were beyond repair) to use the bits
(Marconi collet knobs, induction compensating wirewound resistors,
Nuvistors etc., to build a few mic preamps, and a one-off guitar&bass
preamp for myself. They are some of the best built items, true works of
techical art, that I have ever seen. And yes, i've seen inside top Neve
and Calrec studio mixers of the late 60's to early 80s. The Tek stuff
wipes the floor. Its a little like old Quad Hi-fi, or Minox cameras..
However, I'm at serious risk of serious digression. Well, even more
serious than usual.

> We've got a
> handful of old Tek valve 'scopes knocking around. Weigh a ton but still
> pretty respectable even today.
At a radio rally I let my mate buy a Tek 50MHz valve storage scope. it
was expensive as they go, a tenner. I've regretted not buying it myself
ever since.
> 
> Can't remember exactly what we have, but there's definitely a 555 'scope
> in the pile, along with a transistor curve tracer.
Heh. I have the curve tracer. And 5 beam splitters (4 on, one in the
wash) couple of differential comparators, AF/RF power analyser, plus
more that are not springing to mind at the mo. Lovely kit. way above
U.K., even "Harry Joyce", MIL spec of the era. I guess one day the CRTs
will go, but even then what *great* recycling they are.

Cheers!

M.