> You can
>punch a hole in the other side of a DDSD 720K disk and use it as a DSHD
>1.44MB
>floppy 100% reliably *as long as you write to it once a week*.
I never found that to be true. I found that they would only last a
handful of read/writes before having errors and dying entirely (once they
had errors, they never seemed to reformat again after that). These would
be continuous use. I always had to treat them like a time bomb, I'd
format, copy files to it, and know that I have about 5 or 6 uses over the
next half over before the disk went bad. Basically, it was reliable
enough to act as an emergency disk to move files from one machine
directly to another, and then expect to throw out the disk when done.
I found the same to be true if you put tape over the HD hole and used it
as DD.
But most of my testing was on Macs so maybe they were more picky about
the integrity of the disk then PCs were (I've done it on PCs as well, and
I don't recall there being a different result, but I also never
approached it scientifically and paid enough attention to all the
variables, so maybe they worked better and I just didn't notice it).
-chris
<http://www.mythtech.net>
>
>Subject: Re: OT: EMP and Equipment
> From: "Dwight K. Elvey" <dwight.elvey at amd.com>
> My understanding is that it is most effectively caused
>by an above atmosphere explosion?
> Still, if you are on the edge of where damage is minimum,
>unpowered equipment will survive better than powered up
>equipment. Things like unplugging can help if the pulse
>source is far enough way.
>Dwight
>
Distance is everything as it's a inverse square law thing.
If it weren't the sun would have done us in already, though
it does occasionally throw a good one at us like last fall.
Allison
>From: "jim stephens" <jwstephens at msm.umr.edu>
>
>no,
>EMP as related to an atmospheric nuclear explosion is caused because
>of the release of energy from the atmosphere ionized by the radiation
>pulse
>sent by the blast.
>
Hi
My understanding is that it is most effectively caused
by an above atmosphere explosion?
Still, if you are on the edge of where damage is minimum,
unpowered equipment will survive better than powered up
equipment. Things like unplugging can help if the pulse
source is far enough way.
Dwight
Does anyone have docs for a Dilog DQ656 Qbus ESDI controller?
It's got a couple of banks of DIP switches and I'd like to know what
they do before I try to run it.
Doc
>
>Subject: OT: EMP and Equipment
> From: Al Hartman <alhartman at yahoo.com>
>Let's say that tomorrow, and EMP weapon is employed
>over a major city in this country.
>
>Is there anything an average citizen can do to protect
>their Computers (Classic or otherwise)?
Yes.
>Would having them unplugged help?
Yes.
>Or must they be shielded in some way?
It would help.
The reason for the terse questions is your asking a broad
question. Basically EMP is a sudden expansion then contraction
of a magnetic field. From basic electronics there are two ways
to generate power using magnets (or their fields) one is to move
the wire and the other is to move the magnet.
The amount of energy induced into a wire is dependent on how many
lines of force you traverse and thats related to how strong the
magnets field is (also how close).
We get EMP from two sources, one common. The nuke version can
be very strong but if your close enough for EMP then you may be
too close to worry. The other common source is lightinging, every
bolt we see represents a momentary huge current that collapses
very quckly with the attendent magnetic fields. There are two
protection methods applied for lightining. One being electrostatic
and the other recognizes the electromagnetic. Protection for the
latter is simple most of the time. Disconnect the power cord,
antennas, and any control lines. In short remove any "wires" that
can have an induced field and transfer that voltage inside to the
sensitive parts. Ideally for complete protection a iron or steel
case with no breaks is best protection against near misses. In
both cases distance fromthe event is a really good thing as
magnetic fields are squarelaw IE: at twice the distance it's
one quarter strength.
So yes you can protect your hardware, assuming your far enough
away to survive. You still ahve to worry about high energy
particles (neutrons, beta and gamma particles) and other
radiations ( Xrays and infared).
Allison
I'd be most grateful for a little advice from this list please.
I'm finally getting my shed into order with my X'teen dozen computers
etc. During the clean and tidy up process I came across a couple of old
drives I grabbed a while go.
These are both ESDI drives. For your info they re:
* a Maxtor XT-8380E
* a MiniScribe 9380E
At the size of house brick I have to admire the engineering,
particularly the Maxtor. You pick it up and you can feel the quality
metaphorically speaking.
I did some Googling on these drives last night and I found plenty about
geometry but little else. It seems ESDI fitted somewhere between MFM/RLL
and IDE all be it a very brief appearance but certainly the rationale
for introducing the ESDI drives at the time was impressive for those
times.
The connectors on the ESDI drive appear to be the same as MFM so I am
assuming that I can use MFM cables.
I want to see if these drives are still operational but at this stage I
don't have an ESDI controler. I do have a PS/2 Model 80 which I believe
uses an ESDI controller but I'm not too sure about that or if this might
even work. I could just power the drives up to see if they spin (which
doesn't necessarily mean they work but it is a start). My only concern
is that I could not ascertain if these types of drives require the heads
to be parked before spinning down so I'm reluctant to do this at this
stage.
What little info I could find apart from geometry suggested that the
only comtroller for these was an Adaptec ESDI Controller Card (possibly
the ACB-2322D or ACB-2322
http://www.adaptec.com/worldwide/support/suppdetail.jsp?sess=no&language
=English+US&prodkey=ACB-2322B )but again its not abundantly clear. I am
also assuming that if I slot an ESDI controller into a motherboard that
the motherboard will recognise it as a hard disk controller without
doing much else.
Any clues greatly appreciated!!!!
++++++++++
Kevin Parker
Web Services Consultant
WorkCover Corporation
p: 08 8233 2548
m: 0418 806 166
e: kparker at workcover.com
w: www.workcover.com
++++++++++
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> The connectors on the ESDI drive appear to be the same as MFM so I am
> assuming that I can use MFM cables.
I have always used the same cables used for MFM on ESDI drives with no
problems.
> What little info I could find apart from geometry suggested that the
> only comtroller for these was an Adaptec ESDI Controller Card (possibly
> the ACB-2322D or ACB-2322
I don't believe that is true; any ESDI controller should work. A Core
ESDI controller was what I used on some of the Maxtor ESDI drives with
no problems. I do not know if changing the controller brand would
require another low-level format for the drive to work properly. The
controller cards (at least for the ones I used) have the formatting
routines built into the BIOS and I *think* they are accessed in the same
way as XT HD controller cards, i.e. debug g=C006 (?).
> I am also assuming that if I slot an ESDI controller into a motherboard
> that the motherboard will recognise it as a hard disk controller without
> doing much else.
I don't think that will work. ISTR that the instructions for the
controller just said to set the HD Type to 1.
While cleaning up here, I am looking for an ESDI HD that contains the
BBS run by Harvey Wheeler (co-author of the book FailSafe.) Harvey ran a
multiuser BBS called the Virtual Academy running PC Board that I would
like to find again. (He died last September and a friend of mine has
been getting stuff together that Harvey was involved with.) When I find
it, I may be able to comment more about how it is set up.
>
>Subject: Re: Modern floppy disk question...
> From: Richard Schauer <rws at ripco.com>
> Date: Wed, 04 May 2005 09:07:26 -0500 (CDT)
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>To add to the problem- why are modern floppy drives such junk? I was
>recently doing a 20-disk transfer between two computers, and after the
>second pass I had one disk that developed some outrageous errors in a
>particular band of tracks. So I looked at it- the drive had scratched the
>oxide off the media in a nice circle on one side around track 50. Didn't
>do it to any other disks in the stack. This had happened to me before, on
>other drives (all modern) with very little usage, and had never happened
>to me using pre-1995-or-so hardware with tons more usage.
>
>(All the drives I'm referring to are 3-1/2" of course)
>
>Richard
I've seen this before. It's related to PCs having fans that suck dust
INTO the box usually via any opening even the floppy door. If you
had cleaned all the dust bunnies out of the drive it's less likely.
Now you will have to clean the heads of oxide and binder.
My cure, noisier fan (more volume) turn it around to blow in and
put an external easily cleaned filter. Many of the S100 systems
and other boxed and fan cooled machina also had this problem.
I've also seens plain bad media that had bad shed. Once the crud
hit the head it stays there till you clean it. Until you do it
scratches other floppies ruining them.
Allison
I heartly concur. What a wonderful site indeed! And a great find you
discovered. Kudos!
Murray
Message: 33
Date: Sat, 30 Apr 2005 20:57:01 -0700
From: Marvin Johnston <marvin at rain.org>
Subject: Vintage Computer Web Site
To: ClassicCmp <cctalk at classiccmp.org>
Message-ID: <4274538D.2A549180 at rain.org>
Content-Type: text/plain; charset=us-ascii
I just ran across this site:
http://www.1000bit.net/
It has some good information *and* photos of quite a few machines. The
concept seems to be that people register and make public information
about their machines. I had listed a bubble memory module (FBM43CA) on
VCM with no knowledge of what it went to. The information on Norm's
website at http://gallery.owt.com/~anheier/index.src told me that it
goes to Fujitsu's first micro, an M-8. I *think* we have a nice find
there!
------------------------------
