27 Oct
2007
27 Oct
'07
11:30 p.m.
Date: Sat, 27 Oct 2007 20:37:35 -0700 (PDT)
From: David Griffith <dgriffi at cs.csubak.edu>
Subject: dsdd floppies
To: cctalk at classiccmp.org
Message-ID: <Pine.GSO.4.55.0710272034030.10982 at helios.cs.csubak.edu>
Content-Type: TEXT/PLAIN; charset=US-ASCII
Someone here posted about a friend in Canada who has
boxes upon boxes of
unopened blank DSDD 5.25" floppies. Who was that? I think I deleted the
relevant emails (or at least grep is failing me).
--
David Griffith
dgriffi at cs.csubak.edu
------------------
That might have been me, but he's also on this list; Golan, are you listening?
m
28 Oct
28 Oct
8:13 p.m.
New subject: 10 Sector Hard sectored disks.
HI,
Does anyone have a source for hard sector (10 sector) 5.25" floppy
disks? I have a Northstar double density disk controller in an old
IMSAI that I would like to get running. I also have single density
NorthStar Disk controller at my parents home in a Netronics Explorer-85
(8085) S-100 bus system I built in the 80s. I'm afraid to use it too
much before I have some backups of the precious code I have on the old
disks.
Atsushi
On Sun, 2007-10-28 at 02:30 -0400, M H Stein wrote:
Date: Sat, 27 Oct 2007 20:37:35 -0700 (PDT)
From: David Griffith <dgriffi at cs.csubak.edu>
Subject: dsdd floppies
To: cctalk at classiccmp.org
Message-ID: <Pine.GSO.4.55.0710272034030.10982 at helios.cs.csubak.edu>
Content-Type: TEXT/PLAIN; charset=US-ASCII
Someone here posted about a friend in Canada who
has boxes upon boxes of
unopened blank DSDD 5.25" floppies. Who was that? I think I deleted the
relevant emails (or at least grep is failing me).
--
David Griffith
dgriffi at cs.csubak.edu
------------------
That might have been me, but he's also on this list; Golan, are you listening?
m
29 Oct
29 Oct
11:20 a.m.
New subject: 10 Sector Hard sectored disks.
On 28 Oct 2007 at 20:13, Atsushi Takahashi wrote:
Does anyone have a source for hard sector (10
sector) 5.25" floppy
disks? I have a Northstar double density disk controller in an old
IMSAI that I would like to get running. I also have single density
NorthStar Disk controller at my parents home in a Netronics Explorer-85
(8085) S-100 bus system I built in the 80s. I'm afraid to use it too
much before I have some backups of the precious code I have on the old
disks.
You could always make your own, by punching or drilling additional
index holes in soft-sector media. Or you could use soft-sector media
and employ something like a PIC microcontroller to simulate the
additional sector holes via software. With a bit of programming,
said PIC could determine if HS or SS media was present in the drive
and generate sector signals only if required.
In any case, I'd strongly advise you to back what you have up to
other media--old disks won't last forever.
Cheers,
Chuck
1:59 p.m.
New subject: 10 Sector Hard sectored disks.
On 29/10/2007 18:20, Chuck Guzis wrote:
On 28 Oct 2007 at 20:13, Atsushi Takahashi wrote:
> Does anyone have a source for hard sector (10 sector) 5.25" floppy
> disks?
You could always make your own, by punching or
drilling additional
index holes in soft-sector media.
Having relatively recently acquired disk drives for my Exidy Sorcerer,
which also wants 10-sector hard-sector 5.25" disks, I was wondering
about that too. The PIC solution isn't so attractive for that, partly
because I've only just bought my first PIC and partly because of the
dedicated interface on the drive board for the Sorcerer.
Anyone in the UK got a few spare 10-sector floppy disks?
--
Pete Peter Turnbull
Network Manager
University of York
2:42 p.m.
New subject: 10 Sector Hard sectored disks.
Hi,
When reading, you could sense where the data starts and ends but to
write to a new disk you'd have to make sure the motor speed was constant
before trying to generate fake sector hole signals. Maybe some kind of
PLL circuit. Any idea what jitter is allowed?
Has anyone made any kind of jig to physically punch holes? I am
thinking about destroying a somewhat damaged disk drive to get enough
parts to build a jig but wasn't sure what kind of mechanical accuracy I
need to get the hole position jitter within spec. I saw, somewhere out
on the web, a persons description of hand punching the holes so I can't
imagine the tolerance is too tight.
I have been worried about my old disks but haven't archived them
yet. Last time I visited my folks, one on my 5.25 floppy drives on the
NorthStar controller stopped working. I swapped drives but next visit,
I have to try to revive or replace that!
Atsushi
On Mon, 2007-10-29 at 11:20 -0700, Chuck Guzis wrote:
On 28 Oct 2007 at 20:13, Atsushi Takahashi wrote:
Does anyone have a source for hard sector
(10 sector) 5.25" floppy
disks? I have a Northstar double density disk controller in an old
IMSAI that I would like to get running. I also have single density
NorthStar Disk controller at my parents home in a Netronics Explorer-85
(8085) S-100 bus system I built in the 80s. I'm afraid to use it too
much before I have some backups of the precious code I have on the old
disks.
You could always make your own, by punching or drilling additional
index holes in soft-sector media. Or you could use soft-sector media
and employ something like a PIC microcontroller to simulate the
additional sector holes via software. With a bit of programming,
said PIC could determine if HS or SS media was present in the drive
and generate sector signals only if required.
In any case, I'd strongly advise you to back what you have up to
other media--old disks won't last forever.
Cheers,
Chuck
28 Oct
28 Oct
4:43 p.m.
New subject: 10 Sector Hard sectored disks.
Has anyone made any kind of jig to physically
punch holes? I am
thinking about destroying a somewhat damaged disk drive to get enough
parts to build a jig but wasn't sure what kind of mechanical accuracy I
need to get the hole position jitter within spec. I saw, somewhere out
on the web, a persons description of hand punching the holes so I can't
imagine the tolerance is too tight.
I'd thought of doing much the same thing. Probably raid an ex-PC 1/2
height drive. Remove just about everything. put a punch and die in place
of the index sensor, and a disk with 11 notches suitably-spaced in place
of the pulley/rotor on the bottom of the spidnle. THen provide some kind
of detent for that.
It would then just be a matter of putting a disk in, aligning the
existing index hole with the punch, locking it to the spindle in the
normal way and then engaging the detent in the other 10 notches, punching
a hole each time.
As regards accuracty, you want them fairly evenly spaced becuase if 2
holes are 2 close together they won't be enough space to find the data in
that sector. But apart from that, it shouldn't be that critical. The same
hole is used to synchronise the controller for both reading and writing,
so there's no intercahnaility adjustment type of problems.
-tony
29 Oct
29 Oct
3:30 p.m.
New subject: 10 Sector Hard sectored disks.
On 29 Oct 2007 at 14:42, Atsushi Takahashi wrote:
When reading, you could sense where the data starts
and ends but to
write to a new disk you'd have to make sure the motor speed was
constant before trying to generate fake sector hole signals. Maybe
some kind of PLL circuit. Any idea what jitter is allowed?
It would depend on the format, but there's always a run-in (sync) gap
on these things.
Here's what I've been thinking.
Time two or three revolutions of a disk after motor on and select
before generating the index pulse. If it's a soft-sector disk,
you'll see a real index pulse every 200 msec. or so and you can
subdivide the rotation accordingly and update your rotational rate
metric every revolution. If you see many index pulses, just pass them
through as you're handling a hard-sector diskette. You'd need to
look at drive select, index and perhaps ready as inputs and ready and
index as outputs.
At first blush, it appears as if a PIC 12F629 8-pin DIP might just be
able to do the job.
Cheers,
Chuck
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