Just picked up a VT103 sans keyboard (and also unfortunately, sans any
QBus hardware -- just an empty backplane.) First things first, I'd like
to find a keyboard for this thing -- anyone in the Seattle area have a
spare keyboard they'd be willing to part with? Otherwise I'll go the
eBay route...
Thanks,
Josh
--- Ray Arachelian <ray at arachelian.com> wrote:
> aliensrcooluk at yahoo.co.uk wrote:
> > Ahh, thanks. I had forgotten about Google
> > (not surprising since I have been working
> > 8.5 hour days for the past week and only
> > getting 6 hours sleep each night).
> >
> Sounds a lot like my schedule. Are you also a
> sysadmin? :-)
errr.. no. I work for a water company and am
a lab technician. Among other things we test
the water to make sure it's safe to drink.
> > I don't like to rely too heavily on Wikipedia
> > as (like alot of information online) you can't
> > be sure what's right or wrong, unless someone
> > knowledgeable in the subject can confirm it.
> >
> For things that I'm familiar with Wikipedia is
> almost always correct.
> For things that I'm not familiar with, their
> external links point to
> data that agrees with it.
> > So if I understand correctly, the outer casing
> > of a harddrive acts as a Faraday cage? My
> > (4GB) Toshiba ones I use in my Amiga 600
> > have circuitry on the underside, but I suspect
> > that may stop it being a Faraday cage, unless
> > it's stuck onto the outside of the unit.
> >
> The platters are very well protected by the metal
> case. There are holes
> for air, (hard drives don't like working in a vacu
um
> or low air
> pressure) and of course holes for the control/data
> cables, so it's not a
> perfect Faraday cage, but it's close enough.
They must be really small air holes (or well
hidden) as I never saw any when installing
the HD's
Regards,
Andrew B
aliensrcooluk at yahoo.co.uk
--- Ray Arachelian <ray at arachelian.com> wrote:
> David Griffith wrote:
> > This brings to mind a question: I have lots of
> chips packaged in
> > static-safe chip tubes which are then put in
> metalized anti-static plastic
> > bags. Is it okay to put packages like this into
> said staticy plastic
> > tubs?
> >
> Yes. But to be even safer, you could line the
> inside of those bins, and
> if you can, the sides and top with aluminum foil.
> This will build
> something like a Faraday cage which will keep the
> chip tubes nice and
> safe.
>
err... what's a Faraday cage?
Someone I know sends disks to people (including
myself) wrapped in aluminum foil. I keep them
as he sent them, so I can tell which disks he
sent me. The only problem is after getting
them out I have a tough time getting them
back in the box because of the foil.
Regards,
Andrew B
aliensrcooluk at yahoo.co.uk
I recently sold a Qumetrak 842 8-inch floppy drive to a fellow who's
restoring a CMI vintage synthesizer. He says that this particular model
is what the synth uses. Can anyone think of a reason why he couldn't use
some other model of drive as long as it's capable of reading DSDD media?
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
From: "David Griffith"
Subject: 8-inch drive substitutes
> I recently sold a Qumetrak 842 8-inch floppy drive to a fellow who's
> restoring a CMI vintage synthesizer. He says that this particular
model
> is what the synth uses. Can anyone think of a reason why he couldn't
use
> some other model of drive as long as it's capable of reading DSDD
media?
Stepping rate and head-load timings will vary between drives.
Sometimes dramatically (e.g. Persci's!)
Jumpering of drives for things such as drive ready, disk
change, etc. can get hairy unless you have documentation
for both the "original" and "target" drives. Jumpering
details can vary between different board revisions. Often
transliterating the jumpering needed is easy; other times
you think you did it right but there are gotchas you don't
see until you look at schematics or pull out your scope.
In industrial uses sometimes you see door-lock and
disk-eject solenoids - available on many models but
not commonly found in many circumstances. (These
are also options on some 5.25" and 3.5" drives...)
Some drives are capable of remotely spinning up and down.
As Nico mentions, some use 50Hz AC for the drive motor,
some use 60Hz AC for the drive motor, and others run the
drive motor from the +24VDC.
And as Nico alludes to, some need just +5/+24V and others
need some negative power supply for the electronics
and others need line AC for the motor.
Often the drive itself is behind some panel/bezel and the
holes in the panel must match the holes in the drive :-).
Some drives are distinctly non-standard in terms of
dimensions, even if they come from "standard" manufacturers
(there were some weird-ass Shugarts out there.)
Tim.
>Date: Thu, 19 Oct 2006 12:51:00 -0700
>From: "Chuck Guzis" <cclist at sydex.com>
>Subject: Re: Wow; $192 for a 5.25" floppy disk drive
>To: "General Discussion: On-Topic and Off-Topic Posts"
> <cctalk at classiccmp.org>
>Message-ID: <453774B4.25279.812F7FE at cclist.sydex.com>
>Content-Type: text/plain; charset=US-ASCII
>
>On 19 Oct 2006 at 14:16, Jules Richardson wrote:
>
>> I don't think you necessarily need anything like that much; I remember Dave
>> Dunfield and I discussing this a while back and it worked out at something
>> like a couple of hundred KB I'm sure.
>
>If you're going track-by-track, probably a couple hundred K is more
>than enough. But holding a complete 8" DSHD image runs to something
>like 6MB if you hang onto the whole histogram.
>
>I think you'd definitely want to have enough storage to hold a
>complete image--it'd make copying much simpler, no? Besides, a few
>megabytes of RAM is nothing nowadays.
>
>> I don't know, what's a couple of hundred KB of memory, a CPU (say a Z80 for
>> sake of argument), a bit of ROM, and a serial interface chip, plus a bit of
>> glue logic?
>
>Probably use something a bit more common, say an ARM? Not that I
>have anything against a Z80 (or Z180, or EZ80). Just that extra
>horsepower can be very nice, even if you don't need it right away.
They're a bit more expensive (about $5 in quantity) but the
MC9S12UF32 looks interesting. It has a built-in USB interface (in
addition to the SCI serial interface) and a built-in ATA-5 interface.
I'm not sure what one would use the latter for in this application,
but the built-in USB interface would be nice if one wanted to build a
unit with both serial and USB interfaces to the host.
It would require considerably more software development, but another
interesting possibility might be to have an ethernet interface and
build the disk drive as a network storage/reading device. The
MC9S12NE64 has an ethernet MAC and EPHY built-in as well as the more
common SCI.
And of course, they both have plenty of extra horsepower.
Jeff Walther
(For list members in the USA only)
We were talking about panel work a little while ago and use of
punches for larger holes (like the Greenlee punches).
Today I note that in my email I have a coupon from Harbor Freight
Tools for their knockout punch set:
http://www.harborfreightusa.com/usa/itemdisplay/displayItem.do?itemid=
91201
$11.99 with coupon, good at any HF retail store. If you'd like said
coupon, drop me an email off-line and I'll forward it to you.
Cheers,
Chuck
Spotted on comp.os.vms
No idea if this is for real or not.
http://atlanta.craigslist.org/sys/219423935.html
Guy wants $10,000 or "trade for working condition sanfrancisco cable car".
I'm suspicious as there doesn't appear to be any history on the system, and
the pictures appear to be dated.
I have a small handful of crystals and was wondering what the easiest
way to divine their frequencies... I can say that I'm reasonably
certain that all of them are between 32.768Khz and 50MHz, but some are
blank, and some have non-obvious cryptic markings. What I'm looking
for is some simple way to get them to oscillate and measure them with
a frequency counter (i.e. - assume one is starting with a working,
trustable frequency counter).
Is it as simple as a pair of inverters/NANDs in the classic crystal
loop, or is that circuit massively frequency dependent (i.e. - works
for 1Mhz-10Mhz, not faster or slower...)?
Thanks for any suggestions.
-ethan
On 10/20/06, woodelf <bfranchuk at jetnet.ab.ca> wrote:
> woodelf wrote:
> > Well tommorow I plan to test my SCB6120 so I hope the magic smoke stays
> > inside as I just finished soldering in the sockets. Tommorow a PDP-8
> > lives < sound effects > Evil laugher , thunder bolts < / sound effects >
> >
> A bolt of lightning strikes the 6402 ...
> Ok I installed it backwards, but I had a spare in my junk box.
Oops! At least it's a common chip.
> I pull the power switch ... A bat flies by ... It *lives* .
Nicely done.
> Now I just have to run over to the local computer store a
> IDE cable and adapter for a laptop drive and mounting hardware.
I have a Mesa-brand CF adapter on mine (and a stack of sub-32MB CF cards).
One caveat - it's been discussed on alt.sys.pdp8, but one of the
commonly-available games disk image with ADVENT on it has a corrupt
FRTS.SV. You'll need a good copy of that to get Colossal Cave
working.
(thread on alt.sys.pdp8 - http://www.gatago.com/alt/sys/pdp8/21898642.html )
Spare Time Gizmos ADVENT page
http://www.sparetimegizmos.com/Hardware/SBC6120_Adventure.htm
In any case, congrats on the new 12-bitter.
-ethan
