On Jul 25, 17:29, Derek Peschel wrote:
> Oops, sorry. I knew there were two FIFOs but I didn't realize they were
on
> one chip.
>
> What exactly are the MOS routines designed to offer the second processor?
> I know they can copy software over the Tube and do some relocation (and
> that the relocation was enhanced in the Master). But what are the
> functions/memory locations/etc. avaialble to each side?
To understand that, you need to have a little information about how the MOS
(Machine OS) works normally (without the Tube). The whole thing is based
on a very structured and comprehensive set of system calls which handle
everything a user, applications programmer, or sytems programmer would want
to do. The two best known are OSByte and OSWord.
OSByte is used to make system calls which take few parameters, which are
therefore passed in the registers: A holds the call number (determines
which OSByte function you want), and X and sometimes Y pass data. The
low-numbered calls mostly read or write a value in the OS variable space
(eg to set serial port parameters) and the high-numbered ones are
read/modify ones. Typically A holds the call number, X holds a value, and
Y holds a mask. The variable is ANDed with Y and EOR'd with X (so you can
set, clear, toggle, or leave unchanged any bit) and the old value is
returned in X.
OSWord is used for calls that need larger parameter sets. Here X and Y
contain the 32-bit address of a parameter block, which may be updated by
the call.
There are several other sets of calls, such as OSWrCh (write a character to
an output stream, eg screen or printer), OSFile (assorted filehandling
functions such as open or close a file, or read a file, a byte, a
directory, or whatever), OSCli (pass text to the comand line interpreter),
OSEven (generate an event - a software interrupt), etc.
Everythng is written to use these calls, and they work over the Tube. If
the call is initiated in the 2nd Processor, its ROM knows to pass it over
to the I/O processor (the 6502 in the Beeb). If it's something that
involves transferring a memory block, such as the OSWORD that reads a raw
disk sector into a buffer, the top part of the 32-bit address determines
whether the address refers to I/O processor address space or the 2P address
space. The 2nd Processor ROM only needs to know how to pass parameters to
the I/O processor, how to use the FIFOs to transfer data, and be able to
jump to an address in its own memory space.
> And how does the
> whole thing get booted (and then stay running)?
At reset, the MOS offers a series of service calls to each sideways ROM in
turn (ie, it calls each ROM in turn, with a certain "reason code" in the A
register). These calls give each ROM the opportunity to register itself as
a language, a filing system, or a service provider. The ROM containing the
Tube code accepts some of these calls and initialies the Tube interface.
Meanwhile, if there's a second processor on the other side of the Tube,
its ROM initialises its side, and when asked by the 6502 side, tells the
6502 what processor it is. Once the rest of the 6502 initialisation is
complete, it will go into a loop waiting for system calls from the other
side. If the other side is another 6502 (there's a 3MHz 65C02 2nd
Processor), it will usually ask for a copy of the current language, which
may be relocated to the top of memory, or if it's a Z80, it will ask the
I/O processor to give it the contents of the first sector of a disk (and
boot CP/M).
> Also, ULA = Uncommitted Logic Array, a semi-custom PLA-like thing. Was
> it made by Ferranti? Acorn used a few different ULAs and so did some
other
> vendors. I think Sinclair was one.
Yes, it was Ferranti. A ULA was an array of gates with no final
metallisation layer pre-defined; the designer would specify the
interconnections between the gates (rather like drawing a PCB layout) and
that was turned into a mask which was used to lay down the metallisation in
the final stages of wafer manufacture.
> And MOS = Machine OS = the ROM routines in the BBC, including the
abstract
> filesystem interface but not any filesystems (which could be added or
> removed as desired) and an astonishing number of places for the user to
> extend the code.
--
Pete Peter Turnbull
Network Manager
University of York
>more to the point :-). I had very little feedback. One from one
There may not be many 11/78x machines in hobbyist hands.
There may not be too many corporations subscribed to
this list :-)
It took me many years (admittedly in the UK) before
I came across a uPDP-11. I've never seen a Robin (hint,hint...).
You need to be patient. In my experience, the docs and
hardware will come along at different times - never
turn down an incomplete package (I'm preaching to
the converted here since you have the innards
already !).
How many VAX-11/78x machines were produced?
These days you expect that thousands of any machine would
be sold (except maybe the specialised supercomputers).
I believe that for the VAX 9000 series, only 400-500 made
it out of the door. The same order of magnitude may well
be true for the VAX-11/78x systems.
How long have people been collecting such
large machines? I don't have the room -
I could not realistically find room for a VAX 4000
right now, never mind anything bigger!
>9 months ago :-). However, I have indication that my 11/785 boards
>won't work on the 11/780 backplane. So, I'm still desperately
>looking for a 11/785. I would be a lot more patient if I saw those
I don't know anything about the 11/780 => 11/785
upgrade but I would be surprised if the backplane
had to be replaced.
>in the first place. Where are they?
They may all be in dealers wharehouses and defence
sites and nuclear power stations. I did hear of three
being decommissioned in the UK a few years ago
but that's about it.
>get some leads to follow. The underlying assumption being that
>there is one 11/785 recycled as scrapmetal every month that I don't
>find it.
I suspect the underlying assumption is just that
there are not that many of the beasts still around.
I guess by the time I have the room for one of
these, there won't be any left!
Antonio
On July 26, gwynp(a)artware.qc.ca wrote:
> > Wacky? Umm, no. Spewing a packet onto a shared medium and then
> > detecting the presence of noise on the line to indicate a collision,
> > then retransmitting at a random interval until the packet gets through
> > is wacky. Deploying 100baseT everywhere and then putting everything
> > on a MAC-layer-bridged port (thus defeating one of the primary design
> > principles of the networking technology in use) to get anywhere near a
> > usable level of performance is wacky.
>
> But less expensive.
So are Ford Festivas...you get what you pay for. I realize that I'm a
dying breed, but I prefer using the right tool for the job.
-Dave McGuire
On July 25, Dan Wright wrote:
> OK, so I've managed to scrounge up some free FDDI hardware from various places
> around the U of Illinois (several boards and a concentrator), but I've been
Free cards and concentrator, eh? Nice deal!
> stuck at one problem point for several months: I have no cables, and new cables
> are expensive, and I can't find used cables anywhere (except ebay where I'm not
> sure I trust them). So, does anyone have FDDI cables, for sale or trade?
> I need both FDDI MIC-MIC cables and MIC-ST cables (I got a DEC DEFPA PCI card
> for my PC that uses ST connectors, I think because the MIC connectors are too
My entire network of about thirty machines is FDDI, except for a few
stragglers on ethernet. ALL of my cables, except for one or two, came
>from eBay. Speaking as both a relatively heavy buyer and seller on
eBay, the eBay trust issue is effectively addressed, in my opinion, by
the feedback mechanism.
If you go to buy some FDDI cables from some seller who has a dozen
negative feedback comments complaining about bad cables, well, don't
buy from that seller. :)
> big to fit on the back of a PCI card...) I really want to get my very own
> wacky dual-counter-rotating-ring topology network going in my apartment :)
Wacky? Umm, no. Spewing a packet onto a shared medium and then
detecting the presence of noise on the line to indicate a collision,
then retransmitting at a random interval until the packet gets through
is wacky. Deploying 100baseT everywhere and then putting everything
on a MAC-layer-bridged port (thus defeating one of the primary design
principles of the networking technology in use) to get anywhere near a
usable level of performance is wacky.
-Dave McGuire
Hi Douglas,
I was the one asking about the Cipher docs. It would be great
if you could put them up -- just let me know where to look and
I'll vacuum them up. Thanks!
Brian
On Jul 13, 13:50, Zane H. Healy wrote:
> > I do not know much about any other 13W3 monitors, except that SGI also
has
> > their own 13W3 pinout, but you can make a swabber.
>
> I thought SGI and Sun used the same pinout.
Only for the R,G,B coax connections. The rest of the pins are used for
various monitor-type-sense and sync signals, and the SGI and Sun pinouts
are quite different. To make matters worse, many SGI-badged monitors don't
have the sync pins connected on the 13W3 (though you'll find articles on
the web that explain how to get at the internal connections). And then to
add insult to injury, SGI only put as many pins in their cables as they
actually need (Sun mostly use fully-wired cables). Beige Indigo cables
have one less pin than grey Indy cables!
Lawrence is broadly correct about SGI/Sun and sync-on-green/composite sync.
Indys and Indigos can generate separate sync, but the contemporary
monitors mostly don't use it. The later ones do; the lack of sync is used
to put the monitor into power-save, and Indys and O2s running IRIX 6.5 have
*two* screensaver delays: the first for the saver to kick in, the second
for the sync to be shut off to cause the monitor to power-save.
In my experience, like Lawrence's, most badged monitors can handle all
types of sync if you can get at it. The GDM-17E11 (SGI-badged Sony) for
example has the sync connections inside, just not on the 13W3, and works
fine with PCs and Suns if you add two wires. My HP-badged and DEC-badged
GDM-1961HA, with 5 BNC and 3 BNC respectively, both support sync-on-green,
and the DEC one has places to fit the extra 2 BNCs inside (IIRC you need to
add resistors as well, and obviously you need to knock out two holes in the
case).
--
Pete Peter Turnbull
Network Manager
University of York
Hi Ethan,
--- Paul Braun <nerdware(a)laidbak.com> wrote:
> Hey, group.
>
> A friend of mine just acquired one of those big programmable
> highway emergency signs (the one with the little flourescent flip
> segments).
Does the Highway Department know? ;-)
I've always wanted to play with that sort of thing. The flippy
segments
are cool, but several square feet of LEDs is cool, too. I wouldn't
do it
with a mechanical display, but an electronic one would make a cool
binary
clock.
If you want lots of lights get an old electronic fruit machine (bandit).
I was given one as scrap and it has over 400 12v bulbs (standard
car instrument lights) in a matrix with the driver cards. Very pretty
Xmas lights.
Cheers,
Lee.
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Hi, over the last weeks or so I dropped inquiries about 11/785s at
various places. Some of them not asking if I could have one, others
more to the point :-). I had very little feedback. One from one
of our friends, who had the leftovers of a 11/780 to share
(irony of that story is he got the 11/780 from Indiana to Denver
9 months ago :-). However, I have indication that my 11/785 boards
won't work on the 11/780 backplane. So, I'm still desperately
looking for a 11/785. I would be a lot more patient if I saw those
popping up as abundantly as the 6000s pop up recently. What makes
me really concerned is that few of you fellow VAX nerds have 11/78x
in the first place. Where are they?
BTW: does anyone know where Brian Chase is? Vacation? I need an
information from him related to this matter.
Sorry for being pushy with this, I'm just not as well connected
as Chuck McManis, where people seem to be dropping off truckloads
of VAX stuff at his house every other week :-). So I have to ask to
get some leads to follow. The underlying assumption being that
there is one 11/785 recycled as scrapmetal every month that I don't
find it.
So I appreciate any hints, even the slightest ones, like if you
know of a place that might still be using an 11/785 or where I
would be most likely able to detect one ...
On the other hand, it might be that you guys are all looking for
the same thing and so we may be competitors of sorts (albeit
competing friends I'd hope :-). Like you wouldn't tell me if you
saw an abandoned PDP-8 somewhere in a corner, would you? ;-)
thanks,
-Gunther
--
Gunther Schadow, M.D., Ph.D. gschadow(a)regenstrief.org
Medical Information Scientist Regenstrief Institute for Health Care
Adjunct Assistant Professor Indiana University School of Medicine
tel:1(317)630-7960 http://aurora.regenstrief.org
OK, so I've managed to scrounge up some free FDDI hardware from various places
around the U of Illinois (several boards and a concentrator), but I've been
stuck at one problem point for several months: I have no cables, and new cables
are expensive, and I can't find used cables anywhere (except ebay where I'm not
sure I trust them). So, does anyone have FDDI cables, for sale or trade?
I need both FDDI MIC-MIC cables and MIC-ST cables (I got a DEC DEFPA PCI card
for my PC that uses ST connectors, I think because the MIC connectors are too
big to fit on the back of a PCI card...) I really want to get my very own
wacky dual-counter-rotating-ring topology network going in my apartment :)
Thanks,
- Dan Wright
(dtwright(a)uiuc.edu)
(http://www.uiuc.edu/~dtwright)
-] ------------------------------ [-] -------------------------------- [-
``Weave a circle round him thrice, / And close your eyes with holy dread,
For he on honeydew hath fed, / and drunk the milk of Paradise.''
Samuel Taylor Coleridge, Kubla Khan
