On May 14, 2:41, Tony Duell wrote:
> Subject: Re: Acorn RiscPC 600 (OT - only 5 years old)
> > The bits that people tend to regard as "undocumented" are mostly the
bits
> > avbout how the interface to a second procvessor (The Tube (TM)) work.
But
>
> The Tube hardware wasn't that well documented either. It was based round
> a ULA which wasn't covered in the Advanced User Guide...
Well, the ULA wasn't in the Beeb but in the add-on, so that's not so
surprising. Most of the other addons aren't well documented (or even
mentioned) in the AUG. Don't forget that, although the authors had a lot
of moral support from Acorn, they had no official backing.
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
On May 14, 2:36, Tony Duell wrote:
> Pete wrote:
> > The Beeb video architecture is very similar to the Atom (but more
modes,
> > more colours, more resolution), the disk system is almost identical,
the
>
> Not really. The Atom is based on a 6847 (and uses the address generator,
> display data path, character generator, etc of that chip). There is some
> memory associated with the display system only.
>
> The Beeb uses a 6845 to generate display addresses in main memory. The
> video path is mostly in a custom chip ('Video ULA'), with the character
> generator (only used in the Teletext mode, Mode 7) in an SAA5050 chip.
>
> I would not call those 'similar'...
Don't confuse the implementation with the architecture. Sure, the Beeb
uses an SAA5050 for one (of eight) modes - but the others work in a way
very similar to the Atom. Actually, very little of the video path is in
the ULA on a Beeb. It contains the DACs and the palette only.
> > The Arc (not Arch, please :-)) was certainly built from the same
philosophy
>
> The 'h' is silent, but most references to that machine call it the
Arch...
Not those I've seen. All the Acorn people I know (and I know lots, don't
forget I worked in that world for ten years) use "Arc".
> The fact that the processor runs at twice the speed (2MHz) in the Beeb
> helps as well :-)
Agreed. But it's about 4 times the speed of an Apple ][, which runs at
1MHz.
> > properly buffered and streamed. What's wrong with the 1MHz bus for
> > expansion? There were lots of devices that used that, including a
>
> Nothing at all. It's just that the Apple was easier to make cards for
> than the Beeb (where you have to provide an external PSU and case (you
> shouldn't attempt to power external devices from the BBC PSU).
The switch mode PSU (not the linear "adapter and exploder" used on the
first batch) has quite a lot of spare capacity (about 2A at 5V), and an
external output connector. It was *designed* to power external devices
(mainly disk drives, but it is perfectly capable of powering other things
too). And there are power connectons on some of the device I/O connectors
including the Tube and User Port.
> I was under the impression that the Acorn host adapter didn't support
> multiple masters, and was thus better classed as a SASI host...
Many early SCSI systems didn't. It does, however, support CCS.
> > think Torch's was SASI -- and it never worked very well, I seem to
recall.
>
> Torch did 2 versions. The common one was SASI, and wasn't that good.
> There's also a much rarer SCSI unit (the ROM for it is called SCSIfs). It
> works pretty well.
I didn't know about the later one, I admit.
> > MOS. They were issued at Acorn training courses, which were run for
> > dealers and developers. There were a range of courses, and I went to
one
> > of the MOS courses run by Paul Bond (who was the major designer of the
> > MOS). It was a fascinating course.
>
> OK, it wasa never available to %random-user.... Or to be more specific, I
> couldn't get it :-)
They did cost money (though not an awful lot), so yes, they wouldn't
attract the average enthusiast, but a lot of them were attended by teachers
and school technicians.
> Well, the original 'proton' never existed as a production machine AFAIK.
Yes, only as development prototypes, as far as I know. I never saw one,
only pictures (and I'm not sure they weren't mockups).
> But the name was certainly used - and used in Acorn documentation - as a
> code name for the BBC micro. For example the diagram 103,008 is called
> 'Circuit Diagram for the Proton Final Test Jig', and is the final test
> jig for the BBC micro (or at least a machine with identical 1MHz bus,
> printer port, user port, analogue port and cassette port).
Yes, but Acorn staff had a habit of reusing names on diagrams that were
redrawn. It doesn't mean that that board was actually a Proton board by
then, although it must at least have started life as one.
> In fact the
> 103 identifies it as being a BBC-micro related product (The BBC micro
> schematic is 103,000). 102 series schematics are for the Atom, 100 series
> for the Systems (101 is for what?)
I dunno -- 104 is teletext adapter, 108 6502 2nd processor, 109 is the Z80,
115 is Prestel, I think. 107 is the 1MHz bus backplane. 101 might be one
of the Econet products, I suppose, or the original proton number series, or
an OEM device.
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
>The battery pack has a switch on it. What is this for? Currently it is
>switched to show red.
Usually was used to indicate if it was charged. You moved switch to red
after you replaced the pack with a charged one; to indicate it needs a
recharge. Like camcorder batteries that have the same feature.
Just arrived in the mail:
C4P (in beautiful physical condition, unknown
operational condition)
In the original box! (not expected)
with (also not expected):
The full C4P/C4PMF SAMs!
If you have C4P/C4PMF questions that might be
answered by the SAMs, let me know. I'll try
to help.
Bill Sudbrink
I also picked up a Toshiba T1200 laptop yesterday.
The battery has no charge, and I couldn't find the power supply, so I
don't know if it works yet.
The battery pack has a switch on it. What is this for? Currently it is
switched to show red.
What is the polarity of the 12V DC connector on the back of the machine?
--
Doug Spence
ds_spenc(a)alcor.concordia.ca
http://alcor.concordia.ca/~ds_spenc/
--- James Willing <jimw(a)agora.rdrop.com> wrote:
> On Fri, 14 May 1999, Ethan Dicks wrote:
>
> >
> > In the past two weeks, someone posted some URLs to PDP-8/e pictures. The
> > one I'm interested in was a full-screen, high-detail front panel shot...
I got a couple of good ones, thanks. One is the one I was thinking of, the
other is a user's shot of his own machines with the lights going.
> > My -8/e is behind a wall
> > of other stuff including a couple of straight -8's (as yet unrestored).
>
> ?!?!?!? A COUPLE?!? You dog! I'd trade some SERIOUS goodies for ONE!
As I've written before, one of these is the exact one from the photo on the
back cover of the large-format "CPU Wars" comic. Both of them were originally
phototypesetters from the Columbus Dispatch. There's three racks of S and R
cards below the CPU in each rack that I'm told is probably the I/O circuitry
for the typesetting hardware.
-ethan
_________________________________________________________
Do You Yahoo!?
Free instant messaging and more at http://messenger.yahoo.com
>
> In the past two weeks, someone posted some URLs to PDP-8/e pictures. The one
> I'm interested in was a full-screen, high-detail front panel shot. I was
> thinking of snagging it and sticking it on a one-off T-shirt to wear around
> the Dayton Hamvention as a "Wanted" poster with the classiccmp address at
> the bottom. Does anyone remember this recent posting? Alternately, does
> anyone have a good front panel pic that I can use? My -8/e is behind a wall
> of other stuff including a couple of straight -8's (as yet unrestored).
>
> I suppose I could capture the output from Doug Jones' xpdp emulator, I think
> a real photo would look nicer.
>
> Thanks,
>
> -ethan
>
I switched to using a smaller scan on my web page. The image you're
referring to is still available at:
http://www-users.cs.umn.edu/~lemay/pdp8e_100.jpg
A smaller image is available, just change that 100 to a 60.
If you want a more detailed scan, or a tiff image, let me know. This
scan is from a letter sized landscape advertizement, and that PDP8/e
pretty much fills the whiole page. So, these are actually very low
resolution scans (100 and 60 dpi).
-Lawrence LeMay
lemay(a)cs.umn.edu
On Fri, 14 May 1999, Ethan Dicks wrote:
>
> In the past two weeks, someone posted some URLs to PDP-8/e pictures. The one
> I'm interested in was a full-screen, high-detail front panel shot. I was
> thinking of snagging it and sticking it on a one-off T-shirt to wear around
> the Dayton Hamvention as a "Wanted" poster with the classiccmp address at
> the bottom. Does anyone remember this recent posting? Alternately, does
> anyone have a good front panel pic that I can use?
That sounds cool. If the URL does not pop up, drop me a note and I'll set
my digital camera loose on the task...
> My -8/e is behind a wall
> of other stuff including a couple of straight -8's (as yet unrestored).
?!?!?!? A COUPLE?!? You dog! I'd trade some SERIOUS goodies for ONE!
-jim
---
jimw(a)computergarage.org
The Computer Garage - http://www.computergarage.org
Computer Garage Fax - (503) 646-0174
>>> Coming soon to www.computergarage.org - the CBBS/NW on-line archives
>>> Coming to VCF III (2-3 October 1999) - CBBS/NW live!
In the past two weeks, someone posted some URLs to PDP-8/e pictures. The one
I'm interested in was a full-screen, high-detail front panel shot. I was
thinking of snagging it and sticking it on a one-off T-shirt to wear around
the Dayton Hamvention as a "Wanted" poster with the classiccmp address at
the bottom. Does anyone remember this recent posting? Alternately, does
anyone have a good front panel pic that I can use? My -8/e is behind a wall
of other stuff including a couple of straight -8's (as yet unrestored).
I suppose I could capture the output from Doug Jones' xpdp emulator, I think
a real photo would look nicer.
Thanks,
-ethan
_________________________________________________________
Do You Yahoo!?
Free instant messaging and more at http://messenger.yahoo.com
OK, now on to my _other_, less successful GRiD find yesterday...
I picked up a GRiDCASE "1500 Series" computer. It looks very similar to
the Compass that I'm typing on, but with a larger screen, 3.5" floppy
drive on the right hand side, standard PC ports, and mushy keyboard.
Anyway, when I turn it on, the *fantastically beautiful* 10.5" (diagonal)
display reads:
Phoenix 80286 ROM BIOS Version 3.06
<blah blah blah copyright>
GRiD Systems Corporation 3/17/88
640K Base Memory, 00384K EMS Memory
Time-of-day clock stopped - please set current time
A green LED comes on, next to the label reading "Lower/External disk in
use".
It sits there for a while, then beeps with the message:
Hard Disk Diagnosic Failure
Strike the F1 key to coninue
OK, so this looks like a clock battery gone dead, making the machine
forget the setup.
I tried booting up with a 720K MS-DOS floppy, but that didn't work. There
was a slight noise, and the "Upper disk in use" light came on momentarily,
but it didn't boot. It went back to the other light and evntually
complained about the hard drive again.
Unless this thing uses some kind of Stealth Hard Drive, there doesn't seem
to be a hard drive in there at all. No HD noises.
Also, there is a lift-up trapdoor above the keyboard. Opening it reveals
two empty 32-pin sockets.
So, how the heck to I crack the case on this thing? The only screws I
could find with a cursory inspection were the four screws under the
carrying handle. How do I get to the suspected dead battery?
--
Doug Spence
ds_spenc(a)alcor.concordia.ca
http://alcor.concordia.ca/~ds_spenc/
