11 Jun
2013
11 Jun
'13
3:05 a.m.
----- Original Message -----
From: "Philipp Hachtmann" <hachti at hachti.de>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Tuesday, June 11, 2013 1:10 AM
Subject: Re: RK05 pack (not drive!) conversion
Hi Guy,
Been on my "to do sometime" list for ages, efectivly converting
the drive
This has been discussed at length among us DEC
folks here in the SF Bay
area.
And with which conclusion?
One idea that's kind of neat
(I think it was Eric Smith who first mentioned it) was use insert a PLL
between the optical sensor circuit and the
controller that would allow you to specify the number of sector pulses
that gets sent to the controller.
I once thought about that, too. Don't
remember if I was inspired by some
posting somewhere. It would be quite easy. A $2 AVR with a crystal
oscillator would to the job as well. Then you would only need a switch for
the number of sectors. One prerequesite for this "virtual sectoring" would
be a good stability of the disk rotation speed.
With a microcontroller you could also resynchronize the software PLL with
the original index slots. That would make the thing even more accurate!
So, new question: Would there be any interest in a little circuit that can
be added to any RK05 drive?
As an aside, I'm in about the same boat. I
have 4 16-sector packs and
200-300 12 sector packs.
Hundreds and only four? I have about 15 16-sector packs.
And less 12
sector packs. But as I wrote - there's 12-sector pack supply...
Kind regards
Philipp from hard to soft sectored, should be fairly easy, i
would probably use one
of the PIC chips. Would be a lot cheeper than making new
hubs and you dont
have the problem of changing the platter and getting it true.
Dave