On Oct 26, 2011, at 4:48 PM, Chuck Guzis wrote:
> Absolutely agreed, I was just getting tetchy about the juxtaposition of the
> talk about little RTOSes for PICs and then Unix on the PIC32. It's a
> nervous tic I have from working with too many customers whose only
> experience with micros is the PIC (because they're too lazy to try anything
> else) and insist on upgrading to a PIC32 because they think it'll be
> compatible with their existing software base.
Though I've overcome it now (mostly), I had a very strong bias against PIC
for many years mainly because of the technologically inbred nature of many
of their fans.
A few years back I started a new job to work on a project to replace an
aging PIC-based door access control module. The new platform had already
been selected by the time I started: ColdFire running an RTOS. This was
driven mainly by the fact that the new parent company had a commercial line
of HVAC controllers based on that processor. Not a bad choice but the
dreams of code re-use were mostly unfounded.
Interestingly, it turns out one of the reasons I was hired was to backfill
the fan-boy who resigned in a huff because a PIC-32 wasn't selected.
On Tue, 25 Oct 2011 20:03:45 +0100 (BST), ard at p850ug1.demon.co.uk (Tony
>> > I was referring to holding the faceplate on the CRT, not supporting the CRT=
>> > . I plan to replace the metal band, padding with e.g. strapping tape if ne=
>> > cessary. Does that make more sense? - Ian
> It wworries me, I can tell you that. That metal band is fixed ot the
> glass, it's also deliverately very tight. Somehow it supports the screen
> glass during an implosion, protectggn the viewer. It's not just a mouting
> band for the CRT.
Do *NOT* remove the band!! It protects the CRT from implosion by putting
compressive stresses on the faceplate, thereby counteracting the tensile
stresses produced by the force of the air on it and thus allowing it to
stand more stress.
The same idea as pre-stressed concrete in other words. If you remove the
band you will seriously weaken the CRT.
I recall a while back a thread on dealing with screen rot on ADM-3a terminals - surprising to me, because I have several of them and have had no such issue. But I do have nasty looking spots on a HP 9845A screen. Does anyone have specific experience with addressing this problem on this machine? Just to be clear, it looks like round mold colonies around the edges of the screen. It's likely that there's an anti-glare coating and something colonized underneath it. Again, I'm looking for specific details regarding this machine or another machine of the era using the same screen technology, and how you eliminated the colonies. :-) Thanks -- Ian
At 3:22 -0500 10/24/11, Fred wrote:
>In many cases, "REAL" (actually "floating point") numbers are
>inappropriate. For MONEY, I tried to get my students to use ints (and
>calculate the pennies not the dollars), and then just move the PERIOD
>when they display the results.
How will they ever get rich moving the rounded-down fractional
pennies into their own accounts?
- Mark 210-379-4635
Large Asteroids headed toward planets
inhabited by beings that don't have
technology adequate to stop them:
Think of it as Evolution in Fast-Forward.
Dave McGuire said:
> Kinda like the "what constitutes a minicomputer" debate.
> Nobody disagrees that, say, PDP-11s are minis,
Sadly, I've heard many people call PDP-11s mainframes, and go as far as saying DEC was a mainframe company.
> but nobody can coherently tell
I was thinking about this recently and I can't come up with a definition either. Maybe anything smaller than the smallest mainframe and bigger than the biggest PC?
> People who know about this stuff just "know".
I aplogize for the crudity of this post's formatting (but not the content). Best I can do at the moment, posting as I am from an embedded (mobile) computer that is neither PC, mini, nor mainframe.
As an alternative to the hot wire approach, I placed my moldy PDP-12 CRT+faceplate
into a tub of PROSOCO Dicone NC9 "silicone sealand & adhesive remover."
After about a week, the silicone seal had separated and was easily removed.
I'm not sure how best to remount the CRT with the glass faceplate and metal surrounding rim
without reapplying a RTV/PVA layer and re-bonding it all with silicone again.
p.s. If you're in the Bay Area: there's a gallon jug of leftover Dicone NC9 for the asking.
On Oct 20, 2011, at 7:34 AM, cctech-request at classiccmp.org wrote:
> Message: 25
> Date: Thu, 20 Oct 2011 08:28:56 +0100
> From: "Rod Smallwood" <rodsmallwood at btconnect.com>
> To: "'General Discussion: On-Topic Posts Only'"
> <cctech at classiccmp.org>
> Subject: RE: HP screen screen rot
> Message-ID: <AA472F3C2B81454EAD4B734855D4D4EE at dorsetsweets.local>
> Content-Type: text/plain; charset="iso-8859-1"
> I have fixed a few Rainbow monitors suffering from screen mould.
> It may be crude but I just removed the outer glass by breaking it into parts
> and then peeled off the offending plastic layer.
> The tube then goes back into the case and you end up with a narrow gap
> between the bezel and the tube.
> If you are not used to working with glass and CRT's then this way is not for
> Rod Smallwood
--- On Mon, 10/17/11, Al Kossow <aek at bitsavers.org> wrote:
> From: Al Kossow <aek at bitsavers.org>
> Subject: Re: HP screen screen rot
> To: cctalk at classiccmp.org
> Date: Monday, October 17, 2011, 8:33 PM
> On 10/17/11 5:06 PM, Ian King wrote:
>> Hello all,
>> Does anyone have specific experience with addressing
>> this problem on this machine?
> The procedure is removal of the RTV between the safety
> glass and CRT separating the two by
> cutting through the RTV with a hot wire, then reattachment
> at the corners.
> There are some examples on the web.
Would anyone on this list be interested in acquiring a working XT? I picked
one up a few years back and just haven't had a whole lot of use for it, so
perhaps there's someone here who would. It's in excellent condition (both
cosmetically and functionally), and I can take pics if anyone has interest.
- 640 KB RAM
- 20 MB hard drive
- 5.25" floppy
- Currently running DOS 3.3a
- Includes IBM 5151 TTL monitor (solid picture without burn-in)
> Wasn't the 11/70 in a class of machines called "supermini"
> computers...machines that were based on the architecture of
> minicomputers, but with CPU extensions(e.g., multiple CPU modes[kernel,
> supervisor, user]), larger memory capacity(including virtual memory
> capabilities), and significantly improved I/O architectures and
> bandwidth? I wonder if the poster of the auction on eBay misread
> "supermini" and thought "supercomputer"?
A complete 11/70 installation almost certainly included line printers, many terminals on multiplexers, timesharing software, a medium to large farm of massbus disks and tapes, etc. This meant it was usually in a room with a raised floor.
Just a few years later (or even overlapping) the same departmental computer market was being sold 11/780's with very similar or identical peripheral complement.
Contrast this with the (to me) more traditional -11 market of a computer that went into a lab with some custom and simple Unibus peripherals for data acquisition.
To me at least the "supermini" concept was almost closer to a personal workstation (although e.g. Encores/SEL's are certainly superminis) but these often became departmental superminis well outfitted with high performance Japanese (Fujitsu) peripherals not the crufty old Massbus-hose type stuff.
While I have a lot of respect for a complete 11/70 installation... at the same time all that Massbus stuff was pretty crufty compared to the new much smaller peripherals coming in from the low end by the early 80's.
Classic computer collectors (including the E-bay seller) often focus too much on the CPU as defining the environment.
Steven Hirsch wrote:
> I very much need to sell off my workstation collection. There has been
> essentially zero interest in my posting from last week on the subject.
> I'm trying to figure out why. [...]
> It cannot be price, since I didn't post any and am quite flexible in terms
> of negotation.
On the issue of price... you might be surprised. If you listed it on E-bay at 10 times what the stuff cost new describing it as the biggest and most historically important mainframe ever, you'd probably stroke more egos and raise more interest than if you continue trying to honestly find a good home for it.