IBM PC diagnostics disks
Jay Jaeger
cube1 at charter.net
Mon Aug 16 16:57:15 CDT 2021
On 8/10/2021 10:30 PM, Jay Jaeger via cctech wrote:
> On 7/29/2021 1:22 PM, Mark Huffstutter via cctech wrote:
>> Yes, I sadly, learned that important lesson years ago, after finding My
>> "Original" Original PC DOS diskette set pretty much destroyed, left in
>> The folders in storage for too long.....
>>
>> -----Original Message-----
>> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Al
>> Kossow via cctalk
>> Sent: Thursday, July 29, 2021 10:15 AM
>> To: cctalk at classiccmp.org
>> Subject: Re: IBM PC diagnostics disks
>>
>> On 7/29/21 10:08 AM, Mark Huffstutter via cctalk wrote:
>>> Hi Richard,
>>> I could use them if they are still available, I
>>> have the very nice binder manual for them, minus the disks!
>>>
>>
>> Don't store diskettes in vinyl sleeves.
>> The plasticiser leaches out of the vinyl onto the surface of the
>> diskettes.
>>
>>
>
> Interesting. The IBM ones that I have had in the clear 5 x 8.5 vinyl
> sleeves were in their paper-like material sleeves inside the vinyl. They
> have been mostly just fine - just read them in this past week.
>
> On the other hand maybe 10% or so of my 3B2 floppies that were similarly
> stored, but in a somewhat different form of vinyl had more sector
> errors. Fortunately I copied some of them (the most critical ones) some
> time ago, and those were stored separately, so I expect those will be
> fine, but I haven't yet read them in.
>
> JRJ
Correction: Out of 49 AT&T floppies that were in their paper envelopes
inside vinyl exactly ONE turned out to actually be bad - and it had been
bad many years ago (1997) when I got them. So, to date I have not
experienced any issues with vinyl holders - so long as the floppy is in
its paper sleeve, at least.
The problem I actually discovered this week that I was not reading the
3B2 floppies on a 96 TPI drive (they are 512 byte sectors, 80 tracks,
two sides, 9 sectors "quad" density.) Once I figured that out, all but
the one read just fine. On the other hand, several copies I made on a
PC floppy drive (I think) back when were mostly bad (either that, or I
made them on the 3B2, but used HD media, perhaps).
One final note: why do I re-image stuff using different techniques?
Well, here is a case in point. The images that (I believe) I had made
of these floppies in 1997 - I think using dd on the 3b2 itself to files
on the hard disk, and then transferred using zmodem to my PC - were all
ONE TRACK SHORT. Now, there is a pretty good chance that that last
track on most of those floppies didn't have any real data - but one
never knows. I did verify that the first 79 tracks of those images, and
those I made the past couple of days were the same.
Using my new greaseweazle I have verified that images I made of PC
floppies of various sorts (160, 360, 720, 1.2M (including RT/PC),
1.44M), RX50 were all just fine. Only the 3B2 images were off.
JRJ
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