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From: Gordon Weast on 13 Apr 2010 13:21
Kate,

From your description, I'm fairly sure this is a hardware issue, but
exactly which hardware is faulty isn't quite certain.

I've had floppy disks fail even though I've been booting on them
regularly and the disk hasn't left the drive on the target.
Since none of the machines can read your first disk now, that
says that the disk itself has failed. However, what if you try
to format the disk in PC3? Will it format or error out?

With the second floppy, what happens if you try to read it on
PC3 after you try to boot the target? Can you still read it on
the host machine? I'm wondering if the target drive has scratched
it. If so, then trying to boot from it would damage it. That
shouldn't happen since you said you replaced the target drive.

If a drive can't read all of a disk, then I would say that either
the drive or the disk is bad.

I'm guessing here, but some possibilities come to mind:

1. The host drive is bad. You're able to read the disk immediately after
writing to it, but not after you remove and reinsert it. This needs to be
tested. Exchange disks between your host and PC3 and see if either can
read one formatted on the other. So far, you've only shown that the
host can read the directory after writing to it.

2. The replacement target drive is also damaging the disks (unlikely, but
that might explain it).

It might be time to get tech support involved instead of continuing
here. It's easier to bring other people here into it that way.

Gordon Weast
xPC Target Development
The MathWorks



Kate J. wrote:
> Hi, Gordon,
>
> I replaced my Target PC's floppy drive, but unfortunately, the behavior
> hasn't changed or improved:
>
> One question I have: in your advice above, you give me 2
> recommendations, depending on whether Windows can or can't read the
> floppy disk on my Target PC; below, I describe the behavior of the 3 PCs
> I'm working with (my Host, my Target, and a third PC that isn't used at
> all for xPC Target, but which is the newest of the 3, and theoretically
> has a newer, functional floppy drive).
> Based on the descriptions below, would you say that my Target PC *can*
> or *can't* read the floppy disk (i.e., if it *begins* to read at least
> one of the disks, but then gets stuck)?
> -------
> When I try to open/view the contents of the floppy disk that was created
> using xPC Target and previously worked perfectly (a couple of weeks ago)
> to boot up my Target PC, I get the following behavior on the 3 PCs:
>
> Host PC: Error message: The disk in drive A:\ is not formatted.
> Do you want to format it now? Y\N
>
> Target PC: Error message: The disk in drive A:\ is not formatted.
> Do you want to format it now? Y\N
>
> 3rd PC: Error message: A:\ is not accessible The wrong diskette is in
> the drive. Insert (Volume Serial Number: ) into drive A:\
> _____________________________
>
> If I create a new boot floppy on the Host PC, with a brand-new disk of
> the same brand that had previously worked for me, the behavior is:
>
> a) Host PC: The 3 files that the floppy contains are displayed
> (BOOTSECT.RTT (1 kB), checksum.dat (1 kB), xpctgb1.RTA (796 kB))
>
> b) Target PC: Error message: The disk in drive A:\ is not formatted.
> Do you want to format it now? Y\N
>
> --> When I attempt to restart the PC to boot from the floppy, it begins
> to load (says “Loading….”) but then just gets stuck,
> and doesn’t complete the load.
> c) 3rd PC: Error message: The disk in drive A:\ is not formatted.
> Do you want to format it now? Y\N
>
> --> When I attempt to restart the PC to boot from the floppy, it begins
> to load (says “Loading….”) but then just gets stuck,
> and doesn’t complete the load.
> ____________________________
> One possible solution I can think of to explain the above behavior is
> that maybe my entire boxes of blank floppy disks, as well as my
> previously-working formatted boot disk, all somehow got corrupted (even
> though the formatted disk had been kept in my Target's floppy drive for
> weeks on end, while the boxes of blank disks had been in a cabinet,
> stored separately).
> Another potential source of the problem is if the Host's floppy drive
> isn't correctly generating the boot disks; is there any way for me to
> test/confirm that the disks it creates are correct and not corrupted?
> Are the 3 files I listed above on my newly-generated boot disk
> (BOOTSECT.RTT (1 kB), checksum.dat (1 kB), xpctgb1.RTA (796 kB)) the
> correct contents of this disk?
> Thanks for your input.
From: Kate J. on 13 Apr 2010 14:01
>> From your description, I'm fairly sure this is a hardware issue, but exactly which hardware is faulty isn't quite certain.
I believe you’re correct.


>> With the second floppy, what happens if you try to read it on PC3 after you try to boot the target?
Error: The disk in drive A is not formatted.
Do you want to format it now? Y/N


>> Can you still read it on the host machine?
Hmm, no, I can’t, now. It now gives the error message:
A:\ is not accessible.
No ID address mark was found on the floppy disk.


>> I'm guessing here, but some possibilities come to mind:
>> 1. The host drive is bad. You're able to read the disk immediately after
writing to it, but not after you remove and reinsert it. This needs to be
tested.

When I use a brand-new disk again and create a formatted disk via xPC Explorer on the Host PC,
-- the first disk I attempted to format was not successful, and appeared to go into an infinite loop of attempting to write to the disk. I had to discard the disk.
-- the second disk completed formatting successfully, and I was able to view the 3 files on the A: drive. After I ejected the disk and reinserted it into the Host (I tried it several times in a row, to be sure), I continue to be able to view all 3 files on the A: drive.


>> Exchange disks between your host and PC3 and see if either can
read one formatted on the other.

-- When I insert this newly-created disk into PC 3, I get the error message
The disk in drive A is not formatted.
Do you want to format it now? Y/N
-- If I attempt to boot up the Target PC with the disk, it doesn’t recognize the disk, and just boots up into Windows.
-- When I attempt to view the disk contents on the Target PC, it “thinks” for a long time, and then gives the error message:
The disk in drive A is not formatted.
Do you want to format it now? Y/N
-- If I reinsert the disk in the Host PC, I can still successfully view the 3 files on the disk.


>> However, what if you try to format the disk in PC3? Will it format or error out?
If I reinsert the newly-created disk into PC3 again, and I attempt to format it after receiving the error message that it’s not correctly formatted, it quickly errors out, and then I get the error message,
“The disk in drive A:\ is not able to be formatted.”

__________________________________

>> 2. The replacement target drive is also damaging the disks (unlikely, but that might explain it).
Not as likely, since PC3 doesn’t even correctly read the newly-created disk, before it’s ever inserted into the Target’s floppy drive.


>> It might be time to get tech support involved instead of continuing here. It's easier to bring other people here into it that way.
I might create a new Mathworks service request, although if you don’t mind responding to the updates above, I’ve been finding your input very valuable; my previous support request on this topic, last week, didn’t end up helping too much, unfortunately.
From: Gordon Weast on 13 Apr 2010 14:26
Kate,

From what you've gone through, it's starting to sound like the host
floppy drive is misaligned or somehow damaging the disks.

You said the host can still see the files, but you didn't try to
read the files. Can you copy the files from the floppy to some
temp directory on the host?

If you format a new floppy on PC3 and try to read it on the host,
can it? Make sure you copy some files to the floppy. If it's
not able to read it, that really sounds like an alignment problem.

I find it really strange that you can't format one of the bad
floppies on PC3 after being formatted on the host. Very strange.

Getting a Q-tip into the head with head cleaner on it might be tricky,
but perhaps the host drive is dirty? These drives don't seem to be
made such that the head can be cleaned very easily.

I believe you have the drive you took out of the target. Can you try
that in the host? You might be able to just connect the cables and
let it hang out to the side before doing all the mechanical replacement.
That's just for a trial.

Of course, the whole box of disks could have gone bad on the shelf.
It's possible for age to cause the oxide to go bad, although I'm really
reaching for something now...

Gordon Weast
xPC Target Development
The MathWorks

Kate J. wrote:
>>> From your description, I'm fairly sure this is a hardware issue, but
>>> exactly which hardware is faulty isn't quite certain.
> I believe you’re correct.
>
>>> With the second floppy, what happens if you try to read it on PC3
>>> after you try to boot the target?
> Error: The disk in drive A is not formatted.
> Do you want to format it now? Y/N
>
>
>>> Can you still read it on the host machine?
> Hmm, no, I can’t, now. It now gives the error message:
> A:\ is not accessible.
> No ID address mark was found on the floppy disk.
>
>>> I'm guessing here, but some possibilities come to mind:
>>> 1. The host drive is bad. You're able to read the disk immediately after
> writing to it, but not after you remove and reinsert it. This needs to be
> tested.
> When I use a brand-new disk again and create a formatted disk via xPC
> Explorer on the Host PC,
> -- the first disk I attempted to format was not successful, and appeared
> to go into an infinite loop of attempting to write to the disk. I had to
> discard the disk. -- the second disk completed formatting successfully,
> and I was able to view the 3 files on the A: drive. After I ejected the
> disk and reinserted it into the Host (I tried it several times in a row,
> to be sure), I continue to be able to view all 3 files on the A: drive.
>
>>> Exchange disks between your host and PC3 and see if either can
> read one formatted on the other.
> -- When I insert this newly-created disk into PC 3, I get the error message
> The disk in drive A is not formatted.
> Do you want to format it now? Y/N
> -- If I attempt to boot up the Target PC with the disk, it doesn’t
> recognize the disk, and just boots up into Windows. -- When I attempt to
> view the disk contents on the Target PC, it “thinks” for a
> long time, and then gives the error message:
> The disk in drive A is not formatted.
> Do you want to format it now? Y/N
> -- If I reinsert the disk in the Host PC, I can still successfully view
> the 3 files on the disk.
>
>>> However, what if you try to format the disk in PC3? Will it format or
>>> error out?
> If I reinsert the newly-created disk into PC3 again, and I attempt to
> format it after receiving the error message that it’s not
> correctly formatted, it quickly errors out, and then I get the error
> message,
> “The disk in drive A:\ is not able to be formatted.”
> __________________________________
>
>>> 2. The replacement target drive is also damaging the disks (unlikely,
>>> but that might explain it).
> Not as likely, since PC3 doesn’t even correctly read the
> newly-created disk, before it’s ever inserted into the
> Target’s floppy drive.
>
>>> It might be time to get tech support involved instead of continuing
>>> here. It's easier to bring other people here into it that way.
> I might create a new Mathworks service request, although if you
> don’t mind responding to the updates above, I’ve been
> finding your input very valuable; my previous support request on this
> topic, last week, didn’t end up helping too much, unfortunately.
From: Kate J. on 13 Apr 2010 16:16
>> You said the host can still see the files, but you didn't try to read the files. Can you copy the files from the floppy to some temp directory on the host?
I was able to copy and paste the 2 1-kB files into a new directory on my Host PC’s C: drive. However, when I attempted to paste the third, larger file, it copies for a few minutes, but then terminates with the error message:
Cannot copy xpctgb1: Data error (cyclic redundancy check).

Just to see if I could repeat this behavior, I started with a new disk, formatted it in xPC Target Explorer, and then tried again to copy the files to my Host’s C: drive; this second time, all 3 files copied successfully.


>> If you format a new floppy on PC3 and try to read it on the host, can it? Make sure you copy some files to the floppy. If it's not able to read it, that really sounds like an alignment problem.
When I insert a new, blank disk into PC3’s floppy drive and attempt to access it, I get the error message that it’s not formatted. When I click Yes to reformat it, I almost immediately get the error message:
Windows was not able to complete the format. The disk in drive A: can not be formatted.


>> I find it really strange that you can't format one of the bad floppies on PC3 after being formatted on the host. Very strange.
I agree, particularly because, as I mentioned, PC3 is by far the newest and most reliable PC of the three, otherwise…

>> Getting a Q-tip into the head with head cleaner on it might be tricky,
but perhaps the host drive is dirty? These drives don't seem to be
made such that the head can be cleaned very easily.

>> I believe you have the drive you took out of the target. Can you try
that in the host? You might be able to just connect the cables and
let it hang out to the side before doing all the mechanical replacement.
That's just for a trial.
I will try both of your suggestions above; hopefully, one of them will work. If the entire problem is just that the Host’s drive needs to be cleaned or replaced, I will be very happy.

I’m still not clear about why my PC3’s drive appears to be acting so poorly, and doesn't seem to be able to read or access *any* disk, even if it's brand-new; fortunately, I don’t need that drive to work in order to use my Host-Target system.
From: Kate J. on 14 Apr 2010 12:26
Update: to make a long story short, I ended up shutting down my Host PC, and I received a strange "cannot access memory" error message. I started it back up, and to my surprise, the Host booted up as an xPC Target! (I had accidentally left a boot floppy in the drive.) I switched the boot disk to the Target PC, and magically, it recognized the disk, and correctly booted up.

Given that I didn't create a new boot disk since I shut down and restarted the Host, I'm at a loss to explain why the Target would suddenly start recognizing the floppy that, yesterday, it was ignoring. But I'm not complaining... for the moment, both my Host and Target PCs are now working as expected, and I can only keep my fingers crossed that I don't encounter any more inexplicable problems in the future.

Thanks again for your assistance, Gordon... it was very useful.
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