I'd be really interested in how you'd make your own alignment diskette.
Could you shed some light here? If this were in any sense straightforward,
I'd have made my own long ago. I suppose I could fiddle with one of my
PerSci drives, causing the head positioner to move as it would have to in
order to produce the famous "cat's-eye" pattern on track 38, but I believe
one would have to build special electronics to generate the sync reference
burst or pulse (depending on whether you prefer DYSAN or SHUGART alignment
diskettes) on tracks 1 and 76. Now, I've got no idea how to make the
azimuthal adjustments precisely enough that I'd trust the results.
Dick
-----Original Message-----
From: John B <dylanb_at_sympatico.ca>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Monday, November 29, 1999 6:46 PM
Subject: Re: Needed: 1 IBM 8" alignment disk.
>
>
>
>-----Original Message-----
>From: Richard Erlacher <edick_at_idcomm.com>
>To: Discussion re-collecting of classic computers
><classiccmp_at_u.washington.edu>
>Date: Monday, November 29, 1999 8:31 PM
>Subject: Re: Needed: 1 IBM 8" alignment disk.
>
>
>>Having aligned about 25 8" drives over the last 6 months, I can tell you
>>that if your drive is "eating" your diskettes, the problem isn't with
>>alignment. If it's damaging your diskette emulsion, it's likely that it's
>
>
>No.. My "eating" implies I am sticking in original IBM software disks to
old
>IBM minis and writing over the data on them. :-(
>
>>either missing the headload pad, or the head penetration is misadjusted.
I
>>don't know what the procedure for head penetration adjustment on your
>>particular drive is, but most drives seem to require a couple of feeler
>>guages and some glyptol to make sure it doesn't move when you're done.
>>
>>Before I'll consider LENDING anyone one of my no longer readily available
>>alignment diskettes, I want to be dead certain it won't be chewed up as
>>might happen with the misadjusted head penetration or missing headload
pad,
>>or written on as might happen with an inappropriately set-up drive or
>>controller. Even a $1k deposit won't ensure I get back a thoroughly
>useable
>>diskette, and I've not seen one for sale in over 15 years.
>
>The *moment* I get this drive up I'll be making IBM alignment disks for the
>planet!
>
>>
>>Dick
>>
>>-----Original Message-----
>>From: John B <dylanb_at_sympatico.ca>
>>To: Discussion re-collecting of classic computers
>><classiccmp_at_u.washington.edu>
>>Date: Monday, November 29, 1999 5:38 PM
>>Subject: Needed: 1 IBM 8" alignment disk.
>>
>>
>>>Before I find the highest building to jump off of, I though I might ask
>>here
>>>first....
>>>
>>>I have a Sykes 7150 8" floppy drive (negibus PDP-8I) that I have invested
>a
>>>half and hour in and have solved *most* of it's problems... It finally
>>talks
>>>to the PDP and I can select tracks, reset, read status, etc... once in a
>>>while read a sector.
>>>
>>>I need a single sided 128 byte record alignment floppy.
>>>
>>>When I do a read now, the drive stays busy forever looking for the sector
>I
>>>asked it for. (even if the head is on top of it). Since it was made in
>1974
>>>with TTL chips it is only bright enough to sit there and *wait* for the
>>>correct data to come by. An alignment disk would make life a lot easier.
>>>
>>>Anyone have one available? Please e-mail.
>>>
>>>P.S. The sooner the better.. this thing is eating original IBM software
>>>diskettes from the early '70s
>>>
>>>
>>>PDP-8 and other rare mini computers
>>>
>>>http://www.pdp8.com
>>>
>>>
>>>
>>
>>
>
Received on Mon Nov 29 1999 - 19:59:14 GMT