14 Jan
2011
14 Jan
'11
2:28 p.m.
seems that instead of requiring a particular time
between step pulses,
these drives allow the controller to step as fast as it likes and they
What happens with one of these drives is you slow the steppign rate (at
the cotnroller) right down, say to 20ms steps? Does it still sometimes
kil the index pulse?
Is this behavious properly documented anywhere? I guess that the days of
getting OEM and service manuals for such drives are long gone :-(
Pete Turnbull tells me that the TEAC data sheet for the FD-235HF series
mentions it. He also has a write-up on the issue here:
http://www.dunnington.u-net.com/public/BBC/index_and_READY.html
Regards,
Peter Coghlan.
15 Jan
15 Jan
3:10 a.m.
On 14/01/2011 22:28, Peter Coghlan wrote:
Peter has a better memory than I; I'd forgotten about that!
The TEAC data sheets used to be on TEAC's Data Storage Products Division
web pages and available from their fax-back service. Trying to find the
index page might be interesting, but AFAICS the docs are still there.
They're also on www.devicemanuals.com.
The ones I referred to are documents called:
3fd0020a.pdf -- this is mainly a description of the jumpers to select
various functions on a TEAC FD235F/FD235HF 3.5" drive, and amongst other
things describes the jumper settings for gating the /INDEX and /RD DATA
lines. Choices are "full mask" (index valid only when coincident with
pulse detection and drive-select and ready (up to speed) and seek
complete); "half mask" (pulse and drive select and ready); "no mask"
(pulse and drive select and motor on). However, not all FD235 drives
have all the jumpers.
http://www.teac.com/DSPD/pdf/3fd0020a.pdf
http://www.devicemanuals.com/guide/Floppy%20Drives/TEAC/TEAC-3FD0020A-3.5-D…
5fd0010a.pdf -- a similar document but for the FD5050 combo drive (a
3.5"and 5.25" in the same half-height chassis), though it contains more
information about installing the drive.
http://www.teac.com/DSPD/pdf/5fd0010a.pdf
5fd0020a.pdf -- description of FD55-BR 5.25" drive; describes jumper
settings but doesn't mention any gating of /INDEX.
5fd0050a.pdf -- similar document for the FD55-GFR-3/4/5/7xx drive
ranges; also doesn't mention gating /INDEX.
Incidentally, all describe how to set the speed select and/or density
select according to pin 2 input, and where appropriate, how to make that
pin an output; also how to select pin 34 as /READY or /DSK-CHG.
--
Pete Peter Turnbull
Network Manager
University of York
Is this
behavious properly documented anywhere? I guess that the days of
getting OEM and service manuals for such drives are long gone :-(
Pete Turnbull tells me that the TEAC data sheet for the FD-235HF series
mentions it. He also has a write-up on the issue here:
http://www.dunnington.u-net.com/public/BBC/index_and_READY.html
3:20 a.m.
On 15/01/2011 11:10, Pete Turnbull wrote:
The TEAC data sheets used to be on TEAC's Data
Storage Products Division
web pages and available from their fax-back service. Trying to find the
index page might be interesting, but AFAICS the docs are still there.
A bit of digging did eventually find me the support pages at
http://www.teac.com/DSPD/support/floppy_drives/floppy_drives.htm
which is useful, but the links to what should be the index
(http://www.teac.com/DSPD/catalog.htm) to the PDF docs are broken. The
files are there, but not (apparently) the index.
--
Pete Peter Turnbull
Network Manager
University of York
11:12 a.m.
On 15 Jan 2011 at 11:10, Pete Turnbull wrote:
The TEAC data sheets used to be on TEAC's Data
Storage Products
Division web pages and available from their fax-back service. Trying
to find the index page might be interesting, but AFAICS the docs are
still there. They're also on www.devicemanuals.com.
Fine, but what does this have to do with the operation of the 3.0"
drives that Philip was asking about? AFAIK, the custom ICs used on
Teac drives are sui generis and not shared with other manufacturers.
It'd be a little difficult to generalize universal operation from
Teac specs, I'd think.
At any rate, on many Teac 3.5" drives, there are many undocumented
jumpers (look for the pads marked "Sx"), so behavior is a lot more
flexible than the OEM documentation would imply for that model.
For example, one can convert several models of the FD235HF to operate
as FD235HG by changing the setting of the pads at S4.
--Chuck
1:45 p.m.
On 15 Jan 2011 at 11:10, Pete Turnbull wrote:
Absolutely. The point is that different manufacturers did things in
different ways (in this case a drive not being 'ready' could bne
indicated by inhibiting the index signal).
The TEAC data sheets used to be on TEAC's
Data Storage Products
Division web pages and available from their fax-back service. Trying
to find the index page might be interesting, but AFAICS the docs are
still there. They're also on www.devicemanuals.com.
Fine, but what does this have to do with the operation of the 3.0"
drives that Philip was asking about? AFAIK, the custom ICs used on
Teac drives are sui generis and not shared with other manufacturers. It'd be a little difficult to generalize universal
operation from
Teac specs, I'd think.
True. The problem seems to be (and it's come out in this thread) that
different manufactuers did their own thing. There is nu universal
specification. TYhe best you can do is read as many of the disk drive
manuals and specs as you can and work out how to be compatible with all
of them.
At any rate, on many Teac 3.5" drives, there are many undocumented
jumpers (look for the pads marked "Sx"), so behavior is a lot more
flexible than the OEM documentation would imply for that model.
Annoyling the jumpers -- even the standard ones -- are not documented in
the service manuals at all. They're shown on the schemaitcs, but they
just connect to pins on the ASIC.
-tony
16 Jan
16 Jan
5:38 a.m.
On 15/01/2011 19:12, Chuck Guzis wrote:
On 15 Jan 2011 at 11:10, Pete Turnbull wrote:
> The TEAC data sheets used to be on TEAC's Data Storage Products
> Division web pages
Fine, but what does this have to do with the operation
of the 3.0"
drives that Philip was asking about?
We've been discussing the general case of index pulses being masked, in
relation to the /READY signal. This thread wasn't specifically about 3"
drives, it was about the interface, even though Philip asked in relation
to a particular drive. You yourself made comments referring to 8"drives ;-)
It'd be a little difficult to generalize universal
operation from
Teac specs, I'd think.
True. But in response to uncertainty about whether the phenomenon was
real I gave an example of a case where the drive design actually does
mask index pulses. Surely that's useful/relevant? No-one else has come
up with a documented example or evidence.
For example, one can convert several models of the
FD235HF to operate
as FD235HG by changing the setting of the pads at S4.
As noted in the docs :-)
--
Pete Peter Turnbull
Network Manager
University of York
10:36 a.m.
On 16 Jan 2011 at 13:38, Pete Turnbull wrote:
I'm sitting here with a brand-new FD235HF-A240 drive. Please point
me to the documentation for this model that notes the HF-to-HG jumper-
-or for that matter, what any of the option pads S1-S6 do.
All the best,
Chuck
We've been discussing the general case of index
pulses being masked,
in relation to the /READY signal. This thread wasn't specifically
about 3" drives, it was about the interface, even though Philip asked
in relation to a particular drive. You yourself made comments
referring to 8"drives ;-)
To quote Phil's original message.
"I'm (slowly!) working through the rebuild of one of the Amstrad
drives (an EME231 I know to have working mechanical components,
potentially good heads, and a fried control board), and I'm stuck on
deciding how to deal with the READY output."
My comment on 8" was to the effect of saying that (1) 8" drive
schematics are available online (2) that all 8" drives to my
knowledge have READY outputs and (3) few 8" drives use undocumented
custom ICs to derive this ready signal. Therefore, it would seem to
be a good resource for inspecting the legacy way of getting a READY
signal.
For example,
one can convert several models of the FD235HF to
operate as FD235HG by changing the setting of the pads at S4.
As noted in the docs :-)
5:14 p.m.
Hi, Chuck.
This pointless argument (if argument it is) doesn't need to be on the
list.
On 16/01/2011 18:36, Chuck Guzis wrote:
To quote Phil's original message.
Yes, I did go back and read Phil's original message. My messages about
3.5" drives and how INDEX and READY are sometimes manipulated followed
directly from subsequent messages about INDEX in general. If you'd been
following the various splits of the threads in order, I expect you'd
have noticed that.
OK, so I don't have the docs for an HG drive. It's hardly relevant.
--
Pete Peter Turnbull
Network Manager
University of York
5:47 p.m.
On 17 Jan 2011 at 1:14, Pete Turnbull wrote:
This pointless argument (if argument it is)
doesn't need to be on the
list.
Hi Pete,
My point was that using a Teac 3.5" floppy drive probably would not
duplicate the behavior of the original 3" drive that Phil is trying
to rebuild.
I'm very familiar with the behavior of various drives, including
Teac. Some late-model 5.25" drives, for example, won't come ready if
a hard-sectored floppy is used. You get no index output at all.
Some drives send the index pulse through even if READY hasn't been
asserted by the drive.
I suppose that I ought to settle this by hauling out one of my 3"
drives and document the READY signal behavior.
OK, so I don't have the docs for an HG drive.
It's hardly relevant.
I suspect that you also don't have detailed documentation on option
pads for the FD-235HF-A240 either--neither do I. While I do have
some schematics from the Teac FAX-back service, at some point Teac
quit honoring requests for low-level technical information on their
floppies.
I've had to use mostly trial and error to do things, such as find out
how to make the 5.25" part of an FD505 operate in 2-speed mode (it
can be done).
But I'm with you in one respect--further discussion of this topic is
less than satisfying.
Best regards,
Chuck
17 Jan
17 Jan
11:17 a.m.
Hi, Chuck.
This pointless argument (if argument it is) doesn't need to be on the
list.
I would agree... I see nothing at all wrong with the origianl thread.
This isa discussion list. If you want a consultancy service where you ask
a question and get an answer back, then I, and I assume many other list
memebrs, will be happy to provide one -- for a fee. As it is, we all get
something out of the list by the discussion. I have certainly learnt
things from this thread. On a discussion list, topics aree goingto drift.
It's almost in the nature of a discussion.
The term 'clasisc computer' has never been defined, but we all have an
idea what it means. Now I think it's fair to say that floppy disks were
used with many classic computers. In which case the drives themselves
bevome on-topic for this list both as a part of the classic computer
(this list is not, and should not be, about processors only) and as a way
to preserve the software used on said classic comptuers.
So what's happend is that an origianl on-topic question has generated an
on-topic discussion. On a discussion list. What on earth is the problem
with that?
-tony
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