At 03:14 PM 5/30/2010, William Donzelli wrote:
>The Roman merchants and engineers had a fairly standard abacus thing,
>so math for them was not as bad as one might think.
http://en.wikipedia.org/wiki/Roman_abacus
Similar to the Japanese soroban, it says... and "undeniable proof that Romans
were using a device that exhibited a decimal, place value system, and the
inferred knowledge of a zero value as represented by a column with no beads
in a counted position. Furthermore, the bi-quinary nature of the integer
portion allowed for direct transcription from and to the written Roman
numerals. No matter what the true usage was, what cannot be denied is that
these instruments provide very strong arguments in favour of far greater
facility with practical mathematics known and practised by the Romans."
- John
Does anyone know a reason why I can't remove the G8018's and G8019 and
replace them with newer OEM power supplies? I know that one G8018 supplies
5V @ 25a, +15V @ 2a, -15V @ 2a and +20V @ 4a. I believe the 20V is only used
for core memory. So.a 5v supply @ 50a should be sufficient, and a 2 dual
output +/- 15v supply @ 2@ each should be a reasonable substitute. I am
aware of the functions of the G8019 and that I would be defeating the "dead
fan shutdown" and battery backup feature.
OR.
Does anyone have a written procedure for troubleshooting the backplane,
specifically the SC260m triac, the opto isolator, the 2n6531 transistor and
what causes the 47 ohm resistor to burn. With all boards removed I know how
to defeat the removal of the two G8018's and on a good backplane by adding a
jumper between two pins on the G8018 connectors. I can apply 3v to a pin on
the G8019 connector to get the triac to fire. But this is not enough for
troubleshooting a bad backplane.
All help will be greatly appreciated.
Thom
Melbourne Florida
> Josh wrote:
> I was working on software to dump 4051 tapes over a serial port or the
> GPIB bus, as well as an emulator. Both are still works in progress
> (progress being very slow at the moment) based on disassembling the
> system ROMs and going through the service manuals. I recently came
into
> possession of the actual source code for the 4051's ROMs on
microfiche,
> which I've passed on to Al for archiving. Looking forward to reading
> through those once he's done!
>
> I'm hoping that once I work out enough to write a basic emulation,
I'll
> know enough about the hardware to write some assembly code for the
real
> 4051 to allow raw dumps of 4051 tapes (and hopefully writing them
> back!). But I have a few other things stealing time from me at the
> moment, so it won't be in the near future...
I found some of my notes to "un-secret" the programs on the 4051. You
need to load a string variable with 6800 program code and execute it to
clear the secret flag. This is what I found:
You can execute at the command line:
L$="7?008039"
CALL "exec",L$
The string is code for the hexadecimal equivalent, where A through F is
replaced with a=":", b=";" c="<", d="=", e=">", f="?"
Or the real hex codes are: 7F,00,80,39
Which represent the 6800 instructions:
CLR 00 80 ; clear memory at 0x8000
RTS ; return from subroutine
I have one tape that came with the 4051 I recently acquired. After
replacing the broken band I borrowed from another cartridge I have been
able to read parts of it. It gets a read error part way through the
first file. My question is, how long will old tapes and disk media
remain readable? This tape was written about 20 years ago, and I have
tapes & disks for other systems that are much older. Other than
keeping media in a cool, dry climate away from magnetic fields, what is
the best way to preserve them? How long can the magnetic encoding
survive?
> As to the 8 egg holders in the fridge, perhaps it is
> related to why hot dogs are sold 10 to a pack, and hot
> dog buns are sold 8 to a pack.? One cynical answer to
> that would be a deliberate attempt to force you to buy
> 40 at a time.? Or maybe it is due to the same cause
> for number of appetizers tending to be realively prime
> with the number of diners?
This is an critical, longstanding problem that needs to be addressed. Here is an attempt to do so:
http://www.youtube.com/watch?v=YhXzM70CNrw
This is a longshot but I know this list reaches far and wide, so I'll
give it a try. I am looking for a Bulgarian Apple ][ clone known as
the Pravetz (or Pravets) 82:
http://www.old-computers.com/museum/computer.asp?c=956&st=1
They were sold (or attempted to be sold) outside of the Eastern Bloc,
I believe in the UK and mainly. Maybe one of them defected during
this time or remained hiding in an attic somewhere in the Motherland.
If you know of one already in the US, that would be great. Otherwise
leads on one (working, preferred!) to be shipping stateside are
appreciated as well.
(And to those with experience with Eastern Euro machines, what is
needed to run them on US power? Just a 220v->110v converter, or does
the video have to be processed from PAL->NTSC as well?)
-j
--
silent700.blogspot.com
Retrocomputing and collecting in the Chicago area:
http://chiclassiccomp.org
I just found an interesting sales pamphlet in some of the stuff from
the January Commodore delivery. It was mixed in with a bunch of
non-Computer books that I also got, so I hadn't noticed it when I
went through the Commodore stuff from that load.
Has anyone heard of, or seen, a series of sensors, electrodes and
cartridges from an outfit called "Bodylog, Inc."? It looks like you
plugged the "Bodylink" into the cartridge slot, which had its own
cartridge slot, microprocessor, and I/O channels for various sensors
and electrodes. Pretty wild, I've never seen anything like this for
a Commodore Computer.
One of the most interesting things is a "Micromem Cartridge", a solid
state storage device for storing Bodylink BASIC programs.
Zane
--
| Zane H. Healy | UNIX Systems Administrator |
| healyzh at aracnet.com | OpenVMS Enthusiast |
| | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| PDP-10 Emulation and Zane's Computer Museum. |
| http://www.aracnet.com/~healyzh/ |
Hi at all,
in the newsgroup comp.os.cpm, more than 10 years ago, there has been a
little discussion about the varying of SBC Ferguson BigBoard 1.
Below i indicate where to find all topics availabe also at this address:
http://elazzerini.interfree.it/FERGUSON BIGBOARD's Daughters.doc
The folks were: Alastair S. Preston, bill_h, David Tweed, Don Maslin, Holger
Petersen, Max, O. Alan Jones, Paul Lenz, and Scott Marti.
I'm interested to know better those SBC varying: schematics, layout,
pictures, EPROM listing, experiences, and so on to try to assemble those
info in my website: http://elazzerini.interfree.it even with link to other
materials across internet. Here you can find the entire discussion in word
format in my website.
Those SBC were:
- JLS Computers (aka Vidtek). produced in Toronto similar to SBC BB1
supported through the Micro/Access online BBS system;
- California something or other name: Bill Sigmund and another
fellow who got Ferguson to 'fix' most of the shortcomings of the original BB
and the Xerox 820 from the SBC BB1;
I'm interested also to get contact with who have or had BBII came with
VARBIOS and ZCPR3... Twente Digitaal in the
Netherlands.
Some info seems to be on a magazine called Computing Now!, the Canadian
computing magazine.
Is anybody who could help to find some issues (already scan on internet)??
At this moment I prefer to leave out from my searches the Kaypro and the
Xerox 820 already WELL documented on Internet.
Bigboard motherboard
1 O. Alan Jones 8 Feb 1998
2 David Tweed 9 Feb 1998
3 timolmst 9 Feb 1998
4 Don Maslin 9 Feb 1998
5 Alastair S. Preston 9 Feb 1998
6 bill_h 9 Feb 1998
7 Paul Lenz 11 Feb 1998
8 bill_h 12 Feb 1998
9 Max 13 Feb 1998
10 bill_h 13 Feb 1998
11 Don Maslin 13 Feb 1998
12 Paul Lenz 14 Feb 1998
13 Alastair S. Preston 12 Feb 1998
14 Max 13 Feb 1998
15 Max 13 Feb 1998
16 Holger Petersen 10 Feb 1998
Thanks for any kind of support.
Regards
Enrico - Pisa - Italy
On Fri, 28 May 2010 21:02:27 -0400, Patrick Finnegan <pat at computer-refuge.org
> wrote:
> km signs indeed do exist. I-19 from Tuscon, AZ south to the Mexico
> border is an example.. distances and exit numbers are given in km. I
> can't remember for sure if speed limits are give in km/h at all, but I
> think they aren't.
>
> Pat
> --
They were for a while (mph and kph) until someone beat a speeding
ticket claiming that he mistook the kph posting to be mph...
CRC
Hi at all,
in the newsgroup comp.os.cpm, more than 10 years ago, there has been a
little discussion about the varying of SBC Ferguson BigBoard 1.
Below i indicate where to find all topics availabe also at this address:
http://elazzerini.interfree.it/FERGUSON BIGBOARD's Daughters.doc
The folks were: Alastair S. Preston, bill_h, David Tweed, Don Maslin, Holger
Petersen, Max, O. Alan Jones, Paul Lenz, and Scott Marti.
I'm interested to know better those SBC varying: schematics, layout,
pictures, EPROM listing, experiences, and so on to try to assemble those
info in my website: http://elazzerini.interfree.it even with link to other
materials across internet. Here you can find the entire discussion in word
format in my website.
Those SBC were:
- JLS Computers (aka Vidtek). produced in Toronto similar to SBC BB1
supported through the Micro/Access online BBS system;
- California something or other name: Bill Sigmund and another
fellow who got Ferguson to 'fix' most of the shortcomings of the original BB
and the Xerox 820 from the SBC BB1;
I'm interested also to get contact with who have or had BBII came with
VARBIOS and ZCPR3... Twente Digitaal in the
Netherlands.
Some info seems to be on a magazine called Computing Now!, the Canadian
computing magazine.
Is anybody who could help to find some issues (already scan on internet)??
At this moment I prefer to leave out from my searches the Kaypro and the
Xerox 820 already WELL documented on Internet.
Bigboard motherboard
1 O. Alan Jones 8 Feb 1998
2 David Tweed 9 Feb 1998
3 timolmst 9 Feb 1998
4 Don Maslin 9 Feb 1998
5 Alastair S. Preston 9 Feb 1998
6 bill_h 9 Feb 1998
7 Paul Lenz 11 Feb 1998
8 bill_h 12 Feb 1998
9 Max 13 Feb 1998
10 bill_h 13 Feb 1998
11 Don Maslin 13 Feb 1998
12 Paul Lenz 14 Feb 1998
13 Alastair S. Preston 12 Feb 1998
14 Max 13 Feb 1998
15 Max 13 Feb 1998
16 Holger Petersen 10 Feb 1998
Thanks for any kind of support.
Regards
Enrico - Pisa - Italy
