Circular?
Believe me, I gave it strong consideration.
Purely to determine the efficiency of image manipulation in Java.
Oh yes, to show off as well, I guess.
I thought better of it, and went on to write emulators of my Soviet
Calculators instead.
;)
Cheers
Andrew
-----Original Message-----
From: Joe <rigdonj(a)intellistar.net>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Thursday, February 05, 1998 6:20 AM
Subject: Re: Slipping sticks
>At 04:20 AM 2/5/98 +1100, you wrote:
>>Well, since we're on this subject... how can I resist once more
>>mentioning...
>>
>>Slide Rule Trading Post
>>http://www.comcen.com.au/~adavie/slide/
>>
>>On my site you will find a link to JavaSlide on the main menu. That's a
>>JAVA slide rule I wrote some while back, so you can reminisc even if you
>>can't find your old faithful. Its quite good, actually.
>
> Yes, but when are you going to make a circular version? :-)
>
>
>
>
In fact, there are some useful things you can do to ACTUALLY recover
on computer running a reasonable operating system. Back in the late
60s and through 1981, Oregon State University ran an operating system
(called humbly OS-3 (short for Oregon State Open Shop Operating System
or OSOSOS)) but I digress.
OS-3 ran on a Control Data 3300 which had been fixed to actually
conform to the Control Data specifications for User/Supervisor
operation. The operating system was written to be as reentrant as
possible; all OS code (but a very small part pertaining to interrupt
dispatch) was PURE (not self modifying.) This is noted, since the
standard subroutine call (as was common those days) altered the
first instruction of the subroutine to be a JUMP back to the calling
code. I.e. there was no "stack" mechanism in hardware.
Since the monitor code was not self modifying, the OS could at boot
time compute an exclusive-or checksum for itself and save it for the
occurrence of a parity error. Parity errors only reported the memory
location of the error, not the actual value read. So when a parity
error occurred and if it was in the monitor reentrant section, the OS
could recompute the value of the bad location by exclusive-oring
all the OTHER locations together and then exclusive-oring the computed
monitor checksum. This reproduced the contents of the bad location,
it was stored back at the address indicated by the parity check
hardware and the OS resumed from the parity error interrupt.
Of course, for user programs (which were seldom re-entrant) the OS
just aborted the program with an error and went on about it's business.
Consequently, the parity error interrupt was RARELY fatal (at least to
the system at large. Individual users did occasionally complain when we
had a memory stack that started to go bad, but didn't get bad enough
to find with the overnight diagnostics.)
This was all back in a day when ECC did exist, but it was Horribly Expensive
(and this was compared to memory that cost about 1 to 2 dollars per byte.)
Gary.
At 05:24 PM 2/8/98 -0500, you wrote:
>> Tis' true if you meant ECC parity but this is really OVERKILL in
>> consumer machines that we're using. My machine is happily running
>> for years on non-parity as long as the memory are top quality kind
>> and cover by life-time warrenty if possible. Mac are doing that for
>> years ever since first Apple II all the way to today's Mac PCI's.
>
>Yes, I would not think of adding full ECC to a home computer. Doing so
>would probably add $25 to the cost of producing the machine - something
>the marketing types would scream about because it really adds nothing for
>them to sell!
>
>Anyway, it would have been nice if PeeCees were made so a parity error
>would tell the BIOS (or DOS) to try to clean up and do a gracefull
>shutdown, rather than just reporting the error and halting. Many parity
>errors are soft errors, only effecting one bit of the memory, so there is
>a chance that the programs (or DOS) could react and do a little damage
>control.
>
>William Donzelli
>william(a)ans.net
>
<So, if someone has a good source for VS2000 memory, I'd love to buy
<an extra 4 to 8 MB for it.
Keep an eye open as finding another VS2k with more memory than the one
you have is more likely. VS2ks are pretty common. Besides you can then
use the short memory one for spares. They are also a fun little vax. I
have three here, one running VMS, one diskless (mopboot)
and one running ultrix.
They can hold up to 14mb, with the 4 and 8 mb cards being the most common.
FYI: VMS 5.4 will run in 2mb (slowly as it will swap it's brains out).
With 4mb and a RD54 it makes a fine single user system with DECwindows
support.
Allison
<From: "Zane H. Healy" <healyzh(a)ix.netcom.com>
<Since you can now add support for the VMS filesystem to Linux, I was hopi
<that it would be able to then share the files via NFS to a VMS machine.
First the VMS machine would have to support IP networks and VMS default
is DECnet. Now if linux would support DECnet that would be nice too.
<course I have no idea how full-featured the VMS support under Linux is.
It would have to be pretty rich as VMS is a loaded OS.
Allison
<You ought to be able to just "dd" from the raw CD to a file, which you
<can then write to a hard drive, again using the "raw" device. Then
<stick the hard drive on the VAX. (Or, alternatively, ftp the image
<of the CD to the VAX, and use one of the virtual disk drivers available
<for OpenVMS.)
there are several things on that disk including versions 5.4 through 6.1
and a bootable standalone. Most of the files are savesets.
Allison
Does anyone know what format this CD is in? Someone I know has been trying
to access his copy which he just got with no luck. I've not gotten a copy
yet, but I'd been hoping to stick it in one of my Linux machines and NFS
mount it on the VAX.
Zane
| Zane H. Healy | UNIX Systems Adminstrator |
| healyzh(a)ix.netcom.com (primary) | Linux Enthusiast |
| healyzh(a)holonet.net (alternate) | Classic Computer Collector |
+----------------------------------+----------------------------+
| For Empire of the Petal Throne and Traveller Role Playing, |
| see http://www.dragonfire.net/~healyzh/ |
| For the collecting of Classic Computers with info on them. |
| see http://www.dragonfire.net/~healyzh/museum.html |
Sorry... I don't know about such things. I knew about PS/2 parts
(keyboards, mice, etc.) then PS/2 SYSTEMS (last summer), then PS/1 systems
(about 2 months ago). So, other than the fact that they DO EXIST, I know
nothing about them. I'm guessing Microchannel, but I've never seen such as
system myself.
I don't know if he was willing to GIVE IT TO ME. Anyway, what's a
"garden variety" PS/1? What are un-garden variety PS/1's?
>If it's a garden-variety PS/1, strictly he should pay you to take it, but
>you can be a nice guy and let him give it to you. After all, that way it's
>off his hands.
>
>__________________________________________
>Kip Crosby engine(a)chac.org
> http://www.chac.org/index.html
>Computer History Association of California
>
>
<Does anyone know what format this CD is in? Someone I know has been tryi
<to access his copy which he just got with no luck. I've not gotten a cop
<yet, but I'd been hoping to stick it in one of my Linux machines and NFS
<mount it on the VAX.
It's VMS file format, files-11. I doubt it can be read as linux NFS for
the same reason though you can read individual blocks.
Allison
Hi!
Someone here has a couple of 64 GS's - I had only heard of them in
passing before, and thus don't know their interest. I looked on the web
but found almost nothing - are they worth getting hold of? Not saving as
such, as the owner isn't threating to destroy them or anything, but
simply worth owning. :)
It's been a reasonable week for me, computerwise. Other than being
offered a mainframe, which was fu, I picked up the Atari 800, 800xl,
heaps of software, and (a personal favorite) a Vectrex. Ok, so it is
only a games machine - but I have wanted one for 15 years, and I finally
have one. And for $15, too. :)
Adam.
