Hi,
since two weeks, i own a Whitechapel MG-1 ...
... unfortunately, i did not succeed in starting the machine. It seems, that the
power supply is defect, as i've blown 3 fuses :-(.
Does anyone have the schematics for the power supply, or maybe know the
specs for it, so i can replace it ? Especially, i don't know, what the O2 output
means ...
Thanks alot
Bernd
Bernd Kopriva Phone: ++49-7195-179452
Weilerstr. 24 E-Mail: bernd(a)kopriva.de
D-71397 Leutenbach
Germany
errr, can some people PLEASE start trimming their replies,
particularly for one-liners???
Also, those people that post HTML; It's really nice that the list
processor strips them out, and creates a web page and inserts a link, but I
just skip by most of them.
If you want to be read, post ASCII.
Thanks, Dave (bad enough email bandwidth is wasted with spam).
On 11/22/2003 03:18 AM -0600, cctech-request(a)classiccmp.org wrote:
>Date: Fri, 21 Nov 2003 20:30:56 -0600
>From: "Jay West" <jwest(a)classiccmp.org>
>Subject: Re: Grandfather system RTE6/VM?
>To: "General Discussion: On-Topic and Off-Topic Posts"
> <cctalk(a)classiccmp.org>
>Message-ID: <001901c3b0a0$b18adeb0$6400a8c0@HPLAPTOP>
>Content-Type: text/plain; charset="iso-8859-1"
>
>it's a museum!!! Emulate hardware for display?
>
>----- Original Message -----
>From: "Bob Shannon" <bshannon(a)tiac.net>
>To: "ed sharpe" <esharpe(a)uswest.net>; "General Discussion: On-Topic and
>Off-Topic Posts" <cctalk(a)classiccmp.org>
>Sent: Friday, November 21, 2003 4:50 PM
>Subject: Re: Grandfather system RTE6/VM?
>
>
> > The 2883 would be an ideal drive to replace by hardware emulation!
> >
<several pages of snip....and this message has been going on...>
[Replying to multiple messages here.]
["William R. Buckley" <wrb(a)wrbuckley.com>]
> [me, der Mouse]
>> ["William R. Buckley" <wrb(a)wrbuckley.com>]
>>> There are several architectures for computers, with all being the
>>> equal of the Turing machine.
>> That's interesting, because not one of the devices I have called
>> computers, used as computers, or heard/seen called computers, is
>> even theoretically equivalent to a Turing machine. In particular,
>> they all have finite storage.
> Consult von Neumann. When you do, remember that he devised an
> architecture which is neither the classic von Neumann nor the classic
> Harvard. It is, however, a true data flow architecture, and highly
> parallel.
This has nothing to do with my point, which is that defining "computer"
in a way that makes all computers equal to Turing machines is not a
useful definition, since there are then no "computer"s.
>>> Nevertheless, for all systems of computation, there is the
>>> possibility of self-modification of code which is accessible
>>> through other means, typically in the form of a file.
>> So I suppose a dedicated microcontroller (eg, code in
>> mask-programmed ROM) is not a "system of computation"?
> The fact is that dedicated microcontrollers define a computing
> environment, and the location of the code is immaterial.
The location of code is not immaterial when it is in an inherently
read-only medium, since you are specifying the possibility of
self-modification of code as part of your definition.
>> Even if the application that's in ROM is, say, a pocket calculator?
>> A programmable pocket calculator?
>> The microcode-and-microcpu view of a CISC CPU chip?
>> Where do you draw the line?
> This is the value of the Turing machine. I encourage you, and like
> minded list members, to consult your local computer science faculty
> of any legitimate university you like, and ask them if the computers
> they use are equivalents of the Turing machine. I seriously doubt
> that you will find a single professor who will deny the equivalence.
Perhaps you are right; perhaps not - but any such claim of equivalence
either springs from ignorance or from linguistic shorthand; anyone,
professor or not, who persists in claiming such equivalence after
having had it pointed out that real computers have finite storage is
simply _wrong_.
And in any case, I don't see how what you wrote has anything to do with
my point, which is that what looks like a Harvard architecture when
considered from one point of view may look like a von Neumann
architecture when considered from another, and that restricting
yourself to points of view which include the possibility of
code-which-writes-code (I hesitate to call it *self*-modifying code) is
unnecessarily restrictive, not to mention contrary to the usual uses of
the words to the point of being confusing.
>>> Also, remember the features of some languages, like APL, which will
>>> operate on von Neumann and Harvard architectures, and which APL
>>> code might include the execute operator, which facilitates run-time
>>> code generation and execution.
>> In the sense of "code" for which the underlying CPU is a von Neumann
>> or Harvard machine, the execute operator does not necessarily imply
>> run-time code generation.
> It is disengenuous, and intellectually dishonest, to use a lack of
> implication to assert a lack of occurrance.
That's not what I was trying to do at all. I read your statement about
APL both (a) running on both von Neumann and Harvard architectures and
(b) including the execute operator as implying that (c) both vN and H
architectures can do run-time code generation. My point was that this
implication is false: execute does not require run-time code
generation, so (c) does not necessarily follow from (a) and (b).
> In truth, there is no logical difference between a hardware based
> mechanism of computational processing, and a software based mechanism
> of computational processing.
There is when you are drawing distinctions based on whether the
hardware can modify its own code or not. For example, it is likely
that the machine I'm typing this on is microprogrammed with
mask-programmed microcode ROM, in which case the real hardware is a
strict Harvard architecture, with no possibility whatever of
code-that-writes-code. Based on what you've written, it seems to me
that this implies you do not think it is reasonable to call it a
computer.
[more "William R. Buckley" <wrb(a)wrbuckley.com>, another message]
> Neither can you alter the microcode of the x86, yet it is the essence
> of a computer.
This makes it appear that you do _not_ think that being able to alter
code is necessary for something to be considered a computer. I'm
becoming confused about what your stance actually is here.
Perhaps your position is that it is necessary for there to exist some
level of abstraction at which code-that-writes-code is possible for
something to be considered a computer? If so, it's not at all clear
>from what you've written.
["Brian L. Stuart" <blstuart(a)bellsouth.net>]
> (Almost no authors highlight the distinction between unbounded and
> infinite. [...])
Well, not when writing about computation, at least. :-) This is
probably because it's a very subtle distinction, one which I'm not
convinced even exists for some models of infinity, and one which makes
no difference whatever for (almost?) all uses.
> Now here I do agree with the desire to define a computer in terms of
> machines that can compute functions that are computable in a
> Church-Turing sense.
Hm, so you consider "analog computer" to be an oxymoron?
> So if physical realizations of the computing ideal will always come
> up short of the models of the Turning machine or the lambda calculus,
(or most other models of computation)
> then why do we ever study these models and why do we make
> distinctions between recursive and recursivly enumerable?
(a) Because we're theoreticians.
(b) Because they're useful idealizations.
> I'd say that if you can implement a simulation of a universal Turing
> machine so that the range of it's computations is limited only by the
> amount of addressable memory, then you have a real computer.
Very nicely put - and aside from leaving analog computers out in the
cold, I think I basically agree with it.
> Notice that with the definition above, any computer can implement a
> universal Turing machine and [...] such a machine can modify it's own
> programming.
Only after you make the shift from the universal Turing machine itself
(which has fixed code) to the specific Turing machine being simulated
by the uTm - and not then, even, if the Turing machine simulator is
simulating the sort of Turing machine I studied, which has fixed code,
set when its state transition table is designed. (The simulated
machine's code (= state transition table) may change from one run of
the simulator to the next, but not during a run.)
> (Remember that a universal Turing machine interprets instructions
> read from the tape.)
Yes, and the tape may change - but that doesn't constitute changes in
the code being executed by the simulated Turing machine.
[Back to "William R. Buckley" <wrb(a)wrbuckley.com>]
> I did not contradict myself. I admit fully that the ideal TM has
> infinite memory. I also note that typical, contemporary computers
> are not exactly a TM. Yet, they are computationally equivalent,
Not if there are computations that can be performed on one but not the
other.
And there are computations that can be performed on a Turing machine
with infinite - or unbounded - tape which cannot be performed on any
existing, or foreseeable, computer. (As an example, consider computing
Ackerman's function with arguments 100,100.) Therefore they are not
computationally equivalent.
[more "William R. Buckley" <wrb(a)wrbuckley.com>]
>>> The important point for computation is closure, [...]
> In the case of Turing closure, the notion is much broader. Turing
> closure refers to the ability of a system to perform any and all
> computations that can be expressed.
This is not a prticularly interesting notion, as what computations can
be expressed depends on your expressive notation.
For example, if I choose the notation of real analysis and calculus,
there are computations that can be expressed fairly easily which cannot
be carried out by a Turing machine - because the Turing machines cannot
work with real numbers, only discrete approximations to them. (Any
numerically unstable iterated computation, applied to a transcendental
number like pi, will do fine.)
/~\ The ASCII der Mouse
\ / Ribbon Campaign
X Against HTML mouse(a)rodents.montreal.qc.ca
/ \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
I have two Xerox 1108 machines with the souped-up processor, colloquially known
as a "Dandetiger". Both were working until a few months back when I finally
moved everything I really needed onto a somewhat more modern machine. The hard
disk drives are starting to make dry bearing kind of noises and may be a little
hard to boot, but otherwise seem to work OK. I was having some problems with
the floppy drives, but maybe that's just because all my 8-inch floppies are
antiques. The monitors work well, except that I think there must be a sloppy
connector somewhere: sometimes they sit silent for several minutes after
power-on before suddenly making the flyback noises and coming to life.
In addition to the basic machines I have a couple of "busmaster" cards, which
allow the Mesa bus to be plumbed into a PC extension or multibus chassis.
I have the source code releases (on floppy) for Intermezzo, Koto, and Lyric, and
Koto Beta NoteCards. I also have copies of the LispUsers and Library files, the
Koto source files, and floppy images taken before I started having problems with
the floppy drives. In theory it is therefore possible to ftp this stuff back to
one of the machines and remake the floppies as good as new. Assuming the RIAA
doesn't sue me for copyright infringements I will be happy to supply CDs of this
stuff to anyone who needs it.
There is also a shelf full of manuals (1 set only) and assorted notes I have
acquired along the way.
Anyone interested in giving them a good home? I will give them away for the
cost of shipping. Truly I am going to miss these machines, but I can't really
afford the space to keep them, or the time to tinker with them.
I don't always keep up with this list, so if you are really interested please
e-mail me directly.
| "... both Republicans and Democrats stood
Bob Bramwell 60 Baker Cr. NW | with me in the Rose Garden to announce their
ProntoLogical Calgary, AB | support for a clear statement of purpose:
+1 403/861-8827 T2L 1R4, Canada | you disarm, or we will."
| - GW Bush re: Iraq, 5 Oct 2002
hp 75000 mainframe for sale w/ following modules:
_ e1405a command module
_ e1679a sonet/sdh timing reference (shown in photo but has been sold)
_ e1671a sonet/sdh transport oh generator
_ e1693a atm generator 155/662
_ e1694a atm receiver 155/662
_ e1672a sonet/sdh transport oh receiver
_ e1662a sonet/sdh optical i/f 155/662 mb/s
_ e1663a sonet/sdh electrical interface
guaranteed fully functional and comes w/ 7 day return policy if faulty.
contact me at browe58(a)comcast.net if interested. thanx.
bill
>From: ard(a)p850ug1.demon.co.uk
>>
>> In the case of Turing closure, the notion is much broader. Turing closure
>> refers
>> to the ability of a system to perform any and all computations that can be
>> expressed. Now, there are problems with this notion, since Godel has shown
>> that some expressible computations in fact can not be computed. Still, the
>> general notion is: all that can be computed is computable upon a TM, and a
>> TM
>> is capable of computing all computations.
>
>Care to explain this in a way which is not either self-contradictory
>('There are functions that can't be computed, but a Turing machine can
>computer all functions) or tautological ('A Turing machine can compute
>all functions that can be computed on a Turing machine')?
>
>-tony
>
Hi
I believe that Turing proved that if it can be calculated
by a computer, it can be computed on a Turning machine. It
is the reverse that may not be true since the computer may
not be flexable enough. Turing didn't make comments as to
how large a Turing machine was to do this, only that it could.
Dwight
Hi
A couple of days ago the power supply on my MZ-80K released its magic
smoke (a rather nice red colored smoke at that!) from capacitor C501. The
machine carried on working throughout, although I did power down as soon
as the smoke release was seen/smelt.
So the question is, does anybody out there got documentation or can easily
get inside their 80K PSU to find out the value of this capacitor so it can
be replaced with a new one.
Many Thanks
--
Kevan
On 11/18/2003 01:23 AM -0600, Tom Jennings <tomj(a)wps.com> wrote:
Tom wrote lots of good things...
>Some BOZO designer had, I assume arrogantly, put all the video
>interrupts (vert, horiz retrace, etc) starting at 00020h, which everyone
>knows is where MSDOS has it's software interrupts. They were in a PAL or
>something, and could not be moved.
Well, I won't defend the quirks of the Rainbow... (more later)
But you're forgetting that the Rainbow 100A design pre-dates the IBM PC, it
was first designed as a CP/M machine. MS-DOS came later.
And IBM put interrupts on the PC in places that Intel's data sheets
documented as RESERVED! IBM did not pay attention to Intel's
recommendations and violated a few of their support device allocations.
DECnet-DOS was developed in the DECnet group inspite of the Rainbow group
at first. Their marketeer felt that Corvus Omninet was going to be the big
thing. Only later did we integrate when they got into LAN Manager support.
Our first target was the IBM XT with a 3Com 3C501 Ethernet board, and the
Rainbow running DDCMP on the serial port. We weren't going to wait for
the Rainbow-150 which would be a more industry compatible system. When the
IBM AT appeared, that scotched the RB-150 and lead, eventually... to the
VAXmate. (Thank KO for the delays)
I remember the MHFU watchdog and the Vertical Retrace Interupt. The DECnet
kernel basically ran as an interrupt driven background TSR. On the IBM PC
we easily shelled off the 1C clock tick, but on the Rainbow, we had to
build "clever" reentrancy shells around several interrupts to avoid some
wierd stack overflow or reentrancy into the video BIOS.
The Rainbow at least had a decent UART with a multicharacter FIFO. I had
no problem doing 19.2kbs using C routines. That stupid XT UART could
barely do 9600 with an optimized state driven assembly routine. UART FIFOs
didn't appear until the IBM PS/2 Model 50.
Dave (has two HP16Cs and runs the wprn program)
