>I'm serious. I really have wanted to build something like this. In terms
>of size, the problem isn't the wiring, it's the redundant circuitry.
Most of the DEC core planes use a fair number of special-purpose
transistor arrays (often specially matched) for drivers as well as pulse
transformers and delay lines. If you look back at alt.sys.pdp8 archives
(or its mailing-list twin, PDP8-LOVERS) you'll find some suggestions
for part substitutions and/or rebuild directions.
I believe that at least one of the electronics rags in the Lasnerian mid-70's
(Radio Electronics? Popular Electronics?) published an article on using
surplus core arrays that were readily available at the time, but the
article was remarkably detail-free when it came to the actual details
of driving and sensing. There were at least a few implementations of
S-100 core memory in the mid-70's, and one of them was a S-100 to
Unibus translator of sorts. (Not to be confused with the IMSAI
S-100/Unibus shared memory module, which is in several of my IMSAI
price lists from 1977/1978 but which I believe to be vaporware.)
--
Tim Shoppa Email: shoppa(a)trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927
<Well, I don't know the Electrical Codes across the Pond exactly (I have a
<fair idea of the UK regulations...), but I think I read somewhere that
<you can't have a 220V outlet for equipment less than a certain wattage
<(1.4kW comes to mind). Seems a very silly regulation, but then a lot of
<regulations are.
Meaningless. I have a pigtail at the box with a 3terminal twist and lock
(hubble) wired for 220. It's there as general use for heating in the garage
or welding equipment if I had it. I've used it for testing motors (1/4HP)
that were clearly under 1.4kw. The codes are aimed at providing reasonable
power. Here a 15A/115v is the nominal and 115V/20A is a max but 220/208
at any current the mains can be wired for is common. It would be foolish
to sell 220V/1500W hair dryers here as the nominal mains are expected to
handle that kind of load.
Allison
Am I correct in assuming that a M9300 or a M9300-YA can not be substituted
for a M9302?
Zane
| Zane H. Healy | UNIX Systems Adminstrator |
| healyzh(a)aracnet.com (primary) | Linux Enthusiast |
| healyzh(a)holonet.net (alternate) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| and Zane's Computer Museum. |
| http://www.dragonfire.net/~healyzh/ |
Am I correct that this is used to connect the UNIBUS backplane in one
chassis to a UNIBUS backplane in another chassis?
Zane
| Zane H. Healy | UNIX Systems Adminstrator |
| healyzh(a)aracnet.com (primary) | Linux Enthusiast |
| healyzh(a)holonet.net (alternate) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| and Zane's Computer Museum. |
| http://www.dragonfire.net/~healyzh/ |
While your comments are valid observations, I submit, however, that we're
coming at this from two different viewpoints. I wish to address the
question "Which processor is faster, 6502 or Z-80?" while you want a general
comparison of processors. Unfortunately, answering one question doesn't
address the other.
Dick
-----Original Message-----
From: Bill Yakowenko <yakowenk(a)cs.unc.edu>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Wednesday, April 21, 1999 12:26 AM
Subject: Re: z80 timing... 6502 timing
>On 19 Apr 1999, Richard Erlacher <edick(a)idcomm.com> wrote:
>] It's true that may be more interesting when you have different vehicles,
but
>] if you're trying to determine which of two is faster, don't you focus on
>] those two? Having lots of variations in the hardware only tends to muddy
>] the water.
>
>Obviously, some of us care about vehicles other than those two.
>Doesn't muddy _my_ waters one bit. :-P
>
>I, for one, am interested in processor capabilities independent
>of video/disk/etc gorp. Roman numerals isn't going to be a
>thorough comparison, but it's better than nothing, and small
>enough to be fun. If this is still going on in a month or two,
>maybe I'll write an entry myself. As it is now, my schedule
>barely allows me to keep up with all the stuff you guys are
>writing!
>
>
>
>And then, later the same day, regarding my suggestion about
>noting the relative ages of processors when comparing their
>results, he wrote:
>] It's pretty hard to imagine how a limitation like your suggestion would
>] apply. Newer processors addressed weaknesses in the older ones. One of
>] those was ease of programming. In some cases, e.g. the 6809, the
processor
>] was designed with a regular instruction set and lots of addressing modes
so
>] as to make generating code easy. It didn't necessarily make it faster.
I
>] don't know how elegant such code will ultimately turn out to be.
>
>If you want to get a handle on which processors were really
>better than others performance-wise, you look at the best they
>can do on some specific problems. Granted, the results may
>not be easy to interpret because of varying environmental
>characteristics. Welcome to Earth. Nothing is simple here.
>
>Obviously, if the 6809 loses to some older processor, its
>adherents can still claim ease-of-coding as a benefit. But it
>would still be interesting to know if it could regularly get
>whomped by a measly, pathetic, sad-excuse-for-a-processor like
>the 6502. :-) :-) :-) :-)
>
>My suggestion was not meant as any sort of limitation, just my
>take on what kind of result would be interesting; one way of
>interpreting the results. If an older processor doesn't do as
>well as the newer one, well, we expected that. But if an older
>one outperforms a newer one, there is something worth exploring
>there, a lesson to be learned about an improvement really wasn't.
>
> Bill.
>
>
>> In the case of DEC parts, having a dumpster-dived copy of the "Option/Module
>> Hardware List" stamped "DEC Confidential" all over it helps a little
>> bit :-).
>The holy grail of DEC dumpster divers everywhere.
>Unfortunately, mine stayed at DEC when I left. I was a good boy when
>I left.
--- Sean 'Captain Napalm' Conner <spc(a)armigeron.com> wrote:
> > Problem: Convert a binary value to Roman, using ASCII characters (or
> > the native character set if applicable) into a string
> > with a termination character (if ASCII, use the NUL (0)
> > character).
> >
> Sorry, I goofed. The longer string is 16 characters long:
>
> 'MMMDCCCLXXXVIII' plus termination character.
In terms of how to represent numbers like 1999 (MIM or MCMXCIX), the rule
I learned as a kid was that it was not proper to subtract any numeral
>from any other numeral willy-nilly. Only certain combinations were
allowed and you had to just memorize them.
Here's some links to some pages with something to say about Roman Numerals
http://www.cod.edu/people/faculty/lawrence/romans00.htmhttp://www.col-ed.org/cur/math/math41.txthttp://www.mcn.net/~jimloy/roman0.htmlhttp://raven.bu.edu/~grozdits/student/roman_num.html
... and we now return you to your regularly scheduled Off Topic discussions...
-ethan
_________________________________________________________
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Get your free @yahoo.com address at http://mail.yahoo.com
>And again, more questions:
>If I'm right at Megans description, she just include the next lower
>digit when it comes to these subtraction rules, and your Algo seams
>to be weak at the same point. Let me give an example:
>49 would be normaly coded as IL (always remember, it was kind of a
>system to reduce writing as much as possible - there are even examples
>where the number 248 is written CIIL) while Megan seams to code it as
>XXXXIX - basicly wrong - or did I miss something ? I'm not realy
>what one can call a DEC-Geek.
My code would produce XLIX, not XXXXIX...
I guess I'm unclear as to whether any numeral can be used to reduce
the value of a higher, subsequent numeral.
Using your explanation, 1999 would be MIM, instead of the more
standard (as I have seen it) MCMXCIX. Also, what's to stop
someone from writing it in a form employing the vinculum:
__
III
>So do we only have to supporte the one-less rule, or the rule
>of one subtraction numeral - or the full possibility with the
>goal to reduce writing to a max ?
So long as someone can clearly explain the rules to what can
be subtracted from what, I'll implement it... (kind of like
requiring a spec). Without it, I can only go on what I can
find documented in the encyclopedia...
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry!zk3.dec.com |
| Unix Support Engineering Group | (home): mbg!world.std.com |
| Compaq Computer Corporation | addresses need '@' in place of '!' |
| 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ |
| Nashua, NH 03062 | "pdp-11 programmer - some assembler |
| (603) 884 1055 | required." - mbg |
+--------------------------------+-------------------------------------+
It looks like everything is coming together... We have a team
assembled (compiled?) to decommission and move a set of KS10
decsystem-10 36-bit machines and the move happens this weekend!
I was in attendance earlier today as the machines were shut
down for the final time where they have been for quite a few
years. I got a picture of the final systat screen, and they
stopped timesharing...
We then got busy unloading and shutting down all the disk drives.
I then shut down the individual boxes and power controllers for
the system cabinets and isolated the cabling (they had LOTS of
terminal cables). I then raised all the stabilizing feet and
used a tie-wrap to attach the panel keys inside the cabinet. I
then closed and latched the front doors. I also did the same
for the tape drive cabinets. They're all rolling free and ready
to go.
On friday, we'll be pre-staging all the disk drives, and on
saturday we load-out to trucks.
I'll be taking more pictures as we go along...
Megan Gentry
Former RT-11 Developer
+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL | Internet (work): gentry(a)zk3.dec.com |
| Unix Support Engineering Group | (home): mbg(a)world.std.com |
| Compaq Computer Corporation | |
| 110 Spitbrook Rd. ZK03-2/T43 | URL: http://world.std.com/~mbg/ |
| Nashua, NH 03062 | "pdp-11 programmer - some assembler |
| (603) 884 1055 | required." - mbg |
+--------------------------------+-------------------------------------+
Believe it or not, the most common use of keeping keystrokes was for employee evaluation. I remember weekly postings of graphs of "keystrokes/hour" in data entry and word processing departments, with a weekly "prize" [nominal value] for the "best" data entry operator of the week.
This and similar productivity measurement measures were not uncommon.
