3 Aug
2009
3 Aug
'09
8:59 p.m.
---------- Forwarded message ----------
From: Justin Eastham <jceastham(a)googlemail.com>
Date: Mon, Aug 3, 2009 at 9:44 PM
Subject: Re: [Fdutils] Second FDC not recognised.
To: David C Niemi <niemi(a)tuxers.net>
I'm beginning to think it's the PC.
The distro I'm using (System Rescue CD) seems to have all the necessary
floppy support.
I'm sure the AHA-1542b is okay, because when it's set to be the primary FDC
(mobo's FDC disabled), then I can boot from the FDD connected to the
AHA-1542b.
Did PCs from a certain point in time stop supporting a second FDC ? But even
then; I'm not convinced as the kernel is just talking to an IO port (in this
case 0x370) and using standard stuff like IRQs and DMA channels.
If the AHA-1542b will play ball on 0x3F0, then why not 0x370 ?
I'm satisfied I'm using the correct modprobe floppy command (unless I'm told
different)
I'm going to try with an older PC, but I'm running out of ideas :-(
It's frustrating, as I know this should work. I can't use a pre-PCI machine,
because I've got a Catweasel PCI card to go in.
The plan was to have a "floppy" PC, with :
2.88Mb 3.5" as fd0
360K 5.25" as fd1
....both connected to the primary FDC via the Catweasel. This means I can
read all the DOS formats (apart from 1200K 5.25"), plus Amiga and C64 disk
formats.
The secondary FDC was to connect the 1200K 5.25" FDD as fd4
Then I could have a single PC that would handle all the different disk
formats and filesystems (FAT, Amiga, C64 etc)
Just tried an ISA I/O card, but it looks like the FDC is broken on it, as it
won't even function when configured to be the primary FDC (with the mobo's
FDC disabled)
Any help is much appreciated - like what era of PC have people had success
with ?
TIA
Justin
On Mon, Aug 3, 2009 at 8:26 PM, David C Niemi <niemi(a)tuxers.net> wrote:
Hello Justin,
It's probably been 15 years since I last did this sort of work. I think
you're on the right track -- if it found FDC 1 it would have said so, so
something must be blocking or disabling it.
DCN
3 Aug
3 Aug
9:23 p.m.
New subject: Fwd: Second FDC not recognised.
Hi Justin,
These are just guesses, and not very educated ones at that.
Did PCs from a certain point in time stop supporting a
second FDC ?
But even then; I'm not convinced as the kernel is just talking to an
IO port (in this case 0x370) and using standard stuff like IRQs and
DMA channels.
If the AHA-1542b will play ball on 0x3F0, then why not 0x370 ?
Have you gone through every BIOS setting to see if there's anything
configured there that may be blocking access?
Does dmesg(1) give any more information after you've attempted to access
the 1524b?
Cheers,
Ralph.
9:50 p.m.
New subject: Fwd: Second FDC not recognised.
On Mon, Aug 3, 2009 at 10:23 PM, Ralph Corderoy <ralph(a)inputplus.co.uk>wrote;wrote:
>Have you gone through every BIOS setting to see if there's anything
configured there that may be blocking access?
I've not, to be fair. But the only difference between the AHA-1542b working
as the primary FDC and the secondary FDC is the IO port. My understanding is
that the two FDCs share the same IRQ and DMA. It works on 0x3F0; it doesn't
on 0x370. And cat /proc/ioports doesn't convince me that something else is
hogging 0x370. I've tried 2 different PCs (both Athlon T-bird based), 2
different distros. All I can think of, is the PCs are too new, or there's
some obscure fault with the AHA-1542b. Unfortunately; I don't think I have
any more ISA cards with a FDC on.
>Does dmesg(1) give any more information after you've attempted to access
the 1524b?
dmesg (and /var/log/messages) yield nothing about the second FDC, not even
when I load the driver with debugging enabled. It's as though it's
invisible. If I knew enough about DOS, I'd try and get it working under
that.
Is this supposed to work - pure and simply (given good hardware), or is it a
bit of a black art ?
Thanks for the response
Justin
9:24 p.m.
Justin Eastham wrote:
Did PCs from a certain point in time stop supporting a
second FDC ? But even
then; I'm not convinced as the kernel is just talking to an IO port (in this
case 0x370) and using standard stuff like IRQs and DMA channels.
Are you using a different IRQ and DMA channel for each controller? I've seen
at least one machine that stubbornly refused to let two controllers use the
same IRQ and DMA, and the secondary card I had couldn't be jumpered for
anything different (in the end I hacked the board and re-routed some of the pins)
I'm going to try with an older PC, but I'm
running out of ideas :-(
If you've got other hardware, try it. I had a huge amount of trouble finding a
machine that'd both read and write FM-density, allow more than one drive on
the primary controller (I've seen HP machines with broken FDC implementations
that won't recognise a second drive) and be happy with a second controller.
....both connected to the primary FDC via the
Catweasel. This means I can
read all the DOS formats (apart from 1200K 5.25"), plus Amiga and C64 disk
formats.
What's the CW support like under Linux? I've been put off buying a CW many a
time because it wasn't obvious what the support/resources/community was like
under different OSes.
cheers
Jules
10:20 p.m.
New subject: Fwd: Second FDC not recognised.
On Mon, Aug 3, 2009 at 10:24 PM, Jules Richardson <
julesrichardsonuk(a)yahoo.co.uk> wrote
I chose these particular mobos, as they both have just the one ISA slot;
which is all I need. I'll try a Pentium 233 (socket 7) PC on the weekend. I
do have a VIP board (Vesa, ISA and PCI), but I think that's inviting trouble
;-). Need to have PCI for the catweasel. From what you're saying, getting
the two FDCs to play nicely under Linux isn't a walk in the park
Are you using a different IRQ and DMA channel for
each controller? I've
seen at least one machine that stubbornly refused to let two
controllers use the
The secondary FDC is on an Adaptec 1542b card, and the only thing I can
change is the IO-port. IRQ6 and DMA2 has to be shared between the 2 FDCs
same IRQ and DMA, and the secondary card I had
couldn't be jumpered for
anything different (in the end I hacked the board and re-routed some of
the pins)
If you've got other hardware, try it. I had a
huge amount of trouble
finding a
machine that'd both read and write FM-density,
allow more than one drive
on
the primary controller (I've seen HP machines
with broken FDC
implementations
that won't recognise a second drive) and be
happy with a second
controller.
What's the CW support like under Linux? I've
been put off buying a CW many
a
There's two Linux drivers for the catweasel under Linux : cwfloppy and
cwtool
Check out : http://unusedino.de/cw
cwtool seems the better bet, as cwfloppy doesn't have write support under
kernel 2.6
I can't speak from experience, as I've not had it working yet.
So from the responses I've had so far, it seems my problem is hardware
related; at least no one has suggested an alternative way to load the floppy
kernel module
Justin
time because it wasn't obvious what the
support/resources/community was
like
under different OSes.
11:02 p.m.
New subject: Fwd: Second FDC not recognised.
What-Ho Justin!
So from the responses I've had so far, it seems my
problem is hardware
related; at least no one has suggested an alternative way to load the
floppy kernel module
Having taken a peak at
http://lxr.linux.no/linux+v2.6.30/drivers/block/floppy.c#L4058 can I
suggest you tinker around with some of the options listed there and look
into what they do? E.g.
sudo modprobe floppy 'floppy=debug two_fdc'
and then inspect dmesg for enlightenment. I don't know that will help,
but it would be my next move.
Cheers,
Ralph.
11:33 p.m.
New subject: Fwd: Second FDC not recognised.
I've tried (as root) :
modprobe floppy "floppy=4,4,cmos"
modprobe floppy "floppy=two_fdc 4,4,cmos"
....both with and without debug. Dmesg and /var/log/messages yield nothing
I'd do a jig if I could see "FDC 1 is a...." mentioned ;-)
So far, I've only heard from one person who got two FDCs working under
Linux, and that involved hacking the card the secondary FDC was on :-(
On Tue, Aug 4, 2009 at 12:02 AM, Ralph Corderoy <ralph(a)inputplus.co.uk>wrote;wrote:
What-Ho Justin!
So from the responses I've had so far, it
seems my problem is hardware
related; at least no one has suggested an alternative way to load the
floppy kernel module
Having taken a peak at
http://lxr.linux.no/linux+v2.6.30/drivers/block/floppy.c#L4058 can I
suggest you tinker around with some of the options listed there and look
into what they do? E.g.
sudo modprobe floppy 'floppy=debug two_fdc'
and then inspect dmesg for enlightenment. I don't know that will help,
but it would be my next move.
Cheers,
Ralph.
4 Aug
4 Aug
12:34 a.m.
New subject: Fwd: Second FDC not recognised.
On Tue, 4 Aug 2009, Justin Eastham wrote:
I'd do a jig if I could see "FDC 1 is
a...." mentioned ;-)
So far, I've only heard from one person who got two FDCs working under
Linux, and that involved hacking the card the secondary FDC was on :-(
Well, I have definitely done it, but it was back in 1993-1994. Even very
slow-moving parts of the kernel like the floppy driver have changed a lot
since then.
+-----------------------------------------------------------+
| David C Niemi (Reston, VA, USA) niemi at tuxers dot net |
+-----------------------------------------------------------+
12:29 a.m.
New subject: Fwd: Second FDC not recognised.
On Mon, 3 Aug 2009, Justin Eastham wrote:
The secondary FDC is on an Adaptec 1542b card, and the
only thing I can
change is the IO-port. IRQ6 and DMA2 has to be shared between the 2 FDCs
I don't think that'll work, I'm pretty sure in conventional ISA you need
separate IRQs and DMA channels for each device that needs them (as well as
IO ports).
However, if you had an IRQ or DMA conflict I think the FDC would still be
recognized, as long as nothing else was sittig on its I/O address. Can
you turn off serial and parallel ports?
+-----------------------------------------------------------+
| David C Niemi (Reston, VA, USA) niemi at tuxers dot net |
+-----------------------------------------------------------+
1 a.m.
New subject: Fwd: Second FDC not recognised.
I've double checked the AHA-1542b documentation, and I can set the FDC to be
IRQ10. So I was wrong; I can directly set the IO-port and the IRQ.
On the subject of DMA; would DACK and DREQ correspond to a DMA channel ? If
so, I can set DACK and DREQ to 3 (instead of 2). Also, I'm pretty sure I can
disable DMA when I load the floppy kernel module.
The only other thing is the "base address", and I must confess; I'm not
even
sure what that is. I'm not even sure I can tweek it.
But I was sure that the secondary FDC could share the same IRQ and DMA as
the primary FDC. After all; four com ports can share 2 IRQs and 2 IO ports.
Thanks for the response though - it's given me some hope
And yes; I don't need the serial or parallel ports, so I can disable them -
which frees 3 IRQs
(3,4 and 7), but I don't think there's any interference with the IO-ports.
Thanks again
On Tue, Aug 4, 2009 at 1:29 AM, David C Niemi <niemi(a)tuxers.net> wrote:
On Mon, 3 Aug 2009, Justin Eastham wrote:
The secondary FDC is on an Adaptec 1542b card,
and the only thing I can
change is the IO-port. IRQ6 and DMA2 has to be shared between the 2 FDCs
I don't think that'll work, I'm pretty sure in conventional ISA you need
separate IRQs and DMA channels for each device that needs them (as well as
IO ports).
However, if you had an IRQ or DMA conflict I think the FDC would still be
recognized, as long as nothing else was sittig on its I/O address. Can
you turn off serial and parallel ports?
+-----------------------------------------------------------+
| David C Niemi (Reston, VA, USA) niemi at tuxers dot net |
+-----------------------------------------------------------+
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2:24 a.m.
New subject: Fwd: Fwd: Second FDC not recognised.
On Tue, 4 Aug 2009, Justin Eastham wrote:
I don't think two COM ports can really reliably share even an IRQ, if
they're both truly active. I've heard of several cases where that causes
hangs or data drops. And they definitely cannot share I/O ports.
+-----------------------------------------------------------+
| David C Niemi (Reston, VA, USA) niemi at tuxers dot net |
+-----------------------------------------------------------+
After all;
four com ports can share 2 IRQs and 2 IO ports.
Actually; that's wrong isn't it. Four com ports need 4 IO ports; but
only 2 IRQs
11:57 a.m.
New subject: Fwd: Fwd: Second FDC not recognised.
David C Niemi wrote:
On Tue, 4 Aug 2009, Justin Eastham wrote:
I don't think two COM ports can really reliably share even an IRQ, if
they're both truly active. I've heard of several cases where that causes
hangs or data drops.
I can't remember for sure, either. But it's one single chip handling two
ports, so if there's interrupt sharing going on between the ports then it's
under control of the chip designer as to how they implement it.
Any IRQ-sharing issues in the FDC world (and it's not certain that's Justin's
problem) arise because there are two FDCs (the Adaptec and the on-board) from
different vendors trying to share an IRQ line, and that could easily cause
conflicts.
I think the off-the-shelf FDC chips - which the Adaptec probably uses - should
work together, so long as they're not being accessed at the same time. The
problem's likely with the on-board FDC, which is doubtless integrated into
other stuff on the motherboard and designed by folk who never anticipated
someone wanting to share it.
Justin, if you come across any more hardware, one test might be to disable the
on-board FDC completely and try to get the Adaptec to work alongside another
FDC-on-a-card. I suspect that might work (but finding cards with on-board FDCs
is tricky these days)
cheers
Jules
After
all; four com ports can share 2 IRQs and 2 IO ports.
Actually; that's wrong
isn't it. Four com ports need 4 IO ports; but
only 2 IRQs
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12 comments
4 participants
participants (4)
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David C Niemi -
Jules Richardson -
Justin Eastham -
Ralph Corderoy