FAT Disk is kaput

If you're having problems with the hardware of a DM41X or DM42, post about them here.
HPMike
Posts: 319
Joined: Fri Jul 21, 2017 11:01 pm
Location: DFW, Texas

FAT Disk is kaput

Post by HPMike »

Today, I turned on my DM42, and when I attempted to back up my state file before replacing the battery, I got an error that the /State directory could not be found. I then attempted to load a program and got an error that the /Programs directory could not be found. I then attempted to connect to my PC with the USB disk, and my PC reported that it could not connect because the disk was unformatted and had to be formatted first. I then attempted to view the disk info and got the error message that "Disk State NOT READY, ERROR: Missing disk info, Please report to SwissMicros". I then attempted to do a surface check and format the FAT disk, where it passed the surface check but then repeated the same error. So, is there some way to fix this or do I need SM to replace my calculator ?
Last edited by HPMike on Sat Jan 15, 2022 4:30 am, edited 1 time in total.
DM15L, S/N 00548. DM42, SN: 00159. DM41X, SN: 00973.
Michael
Site Admin
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Re: FAT Disk is kaput

Post by Michael »

Please get in touch with me by email. Thanks.
HPMike
Posts: 319
Joined: Fri Jul 21, 2017 11:01 pm
Location: DFW, Texas

Re: FAT Disk is kaput

Post by HPMike »

Email sent.
DM15L, S/N 00548. DM42, SN: 00159. DM41X, SN: 00973.
rprosperi
Posts: 1237
Joined: Mon Apr 24, 2017 7:48 pm
Location: New York

Re: FAT Disk is kaput

Post by rprosperi »

Did you format the FAT disk from the PC or using the system menu on the DM42? If not the latter, please try that as formatting results are not exactly the same; the device has knowledge of the h/w underlying the emulated disk, whereas a PC will treat it as simple media. It MAY make a difference.

Please report the results here.

Also, was the FAT disk being used in any special or non-standard way? It would be interesting and useful to know if there is some kind if use or behavior that can lead to this kind of problem.

Thanks
--bob p

DM42: β00071 & 00282, DM41X: β00071 & 00656, DM10L: 071/100
HPMike
Posts: 319
Joined: Fri Jul 21, 2017 11:01 pm
Location: DFW, Texas

Re: FAT Disk is kaput

Post by HPMike »

rprosperi wrote:
Sat Jan 15, 2022 4:34 am
Did you format the FAT disk from the PC or using the system menu on the DM42? If not the latter, please try that as formatting results are not exactly the same; the device has knowledge of the h/w underlying the emulated disk, whereas a PC will treat it as simple media. It MAY make a difference.

Please report the results here.

Also, was the FAT disk being used in any special or non-standard way? It would be interesting and useful to know if there is some kind if use or behavior that can lead to this kind of problem.

Thanks
I attempted to format the FAT drive from the system menu in the DM42, NOT the PC. Specifically, Setup > 5. System > 2. Enter System Menu > 5. Format FAT Disk 2. Format FAT Disk. The system message now is as follows:

Disk State: NOT Ready
Storage: HW-FAIL
Required action: Replace flash
Please, contact SwissMicros

Storage info:
Disk block count: 0
Bad block count: 1536
1st good block: 1536

And, no, the FAT was not being used in any special or non-standard way. And I have NEVER tried to format or repair the FAT drive from the PC. Also, as far as I can remember, I have never re-formatted the FAT drive in this calculator.

So, it seems to be a simple hardware failure.

Also, I did all this while the DM42 was connected to my PC to provide power, because the battery is low.
DM15L, S/N 00548. DM42, SN: 00159. DM41X, SN: 00973.
HPMike
Posts: 319
Joined: Fri Jul 21, 2017 11:01 pm
Location: DFW, Texas

Re: FAT Disk is kaput

Post by HPMike »

Well, what do you know ! I tried running the FAT Disk Media Test again, and this time it worked reporting no bad blocks and successfully reformatted the drive. I then connected successfully to my PC with no errors, and recopied all the data back to the FAT disk. Any programs in memory that had not been saved to the FAT disk were saved and then copied to my PC to prevent them from being lost in the future if I have any further problems with the FAT disk. Finally, I saved the State file, replaced the battery and reloaded the State file, and all appears normal.

One thing I noticed is that my PC used to give a warning when I connected the DM42 that there was a problem with my drive and would ask if I wanted to repair it, which I would dismiss, and continue with the transfer of data. Now, it no longer does this, so maybe there was something wrong that led up to this failure. So, now it appears that this was some sort of media corruption rather than actual physical media failure.
DM15L, S/N 00548. DM42, SN: 00159. DM41X, SN: 00973.
rprosperi
Posts: 1237
Joined: Mon Apr 24, 2017 7:48 pm
Location: New York

Re: FAT Disk is kaput

Post by rprosperi »

Good news, thanks for this update Mike!

When the PC warns of errors, it definitely needs to be corrected, as it is detecting the 'dirty bit' on the drive has been set and needs correction via chkdsk (logical) repairs. If logical damage is ignored, the corruption is exacerbated and can damage all your data.

It is still quite strange that the on-device format did not resolve this on the initial try, I've never heard of this happening; perhaps it's related to the low battery, or more likely somehow driven by the logical corruption (which should not matter).

In any case, thanks for the report and follow-up effort.
--bob p

DM42: β00071 & 00282, DM41X: β00071 & 00656, DM10L: 071/100
HPMike
Posts: 319
Joined: Fri Jul 21, 2017 11:01 pm
Location: DFW, Texas

Re: FAT Disk is kaput

Post by HPMike »

rprosperi wrote:
Sat Jan 15, 2022 2:59 pm
When the PC warns of errors, it definitely needs to be corrected, as it is detecting the 'dirty bit' on the drive has been set and needs correction via chkdsk (logical) repairs. If logical damage is ignored, the corruption is exacerbated and can damage all your data.

It is still quite strange that the on-device format did not resolve this on the initial try, I've never heard of this happening; perhaps it's related to the low battery, or more likely somehow driven by the logical corruption (which should not matter).
Yes, but should I use the PC's Chkdsk utility to correct errors on the FAT disk ? As far as the low battery is concerned, I don't see how this could have affected the formatting, since I had the DM42 powered off the USB cable the entire time. I guess in hindsight, I probably should have re-formatted the FAT disk a long time ago when I first noticed the problem when connecting to my PC. This problem has never occurred with my DM41X.
DM15L, S/N 00548. DM42, SN: 00159. DM41X, SN: 00973.
rprosperi
Posts: 1237
Joined: Mon Apr 24, 2017 7:48 pm
Location: New York

Re: FAT Disk is kaput

Post by rprosperi »

There is no (permanent) harm in letting the PC attempt to repair the corruption when it detects and reports it, but most often, some files are lost (the ones that are damaged, even if you don't know they are). On the other hand, ignoring the warning will just to lead to more corruption, possibly affecting more data and future data.

So, here's what I recommend:

1. The first time you see the message about corrupted data when connecting to your PC, decline the offer to repair the damage.
2. Connect and make backup copies of all your files on the FAT
3. Disconnect from the PC
4. Connect again - you will see the same warning message
5. This time, say YES/OK/Proceed, etc. to tell the PC (or Mac, etc.) to repair the damage
6. Check the status of your files

The unpredictable results depend on the original cause and scope of the logical damage, ranging from all errors being fixed w/no data loss all the way to loss of all data. But at least you will now have a good backup of your data to restore if you lose data.

In almost all cases, these problems are caused by either poor USB connection on the DM42 (due to the geometry of the case design sometimes preventing proper seating of the connector into the calculator body) or by disconnecting the USB cable prematurely (described in the DM42 manual in section 6.11.3).
--bob p

DM42: β00071 & 00282, DM41X: β00071 & 00656, DM10L: 071/100
HPMike
Posts: 319
Joined: Fri Jul 21, 2017 11:01 pm
Location: DFW, Texas

Re: FAT Disk is kaput

Post by HPMike »

rprosperi wrote:
Sun Jan 16, 2022 4:11 am
There is no (permanent) harm in letting the PC attempt to repair the corruption when it detects and reports it, but most often, some files are lost (the ones that are damaged, even if you don't know they are). On the other hand, ignoring the warning will just to lead to more corruption, possibly affecting more data and future data.

So, here's what I recommend:

1. The first time you see the message about corrupted data when connecting to your PC, decline the offer to repair the damage.
2. Connect and make backup copies of all your files on the FAT
3. Disconnect from the PC
4. Connect again - you will see the same warning message
5. This time, say YES/OK/Proceed, etc. to tell the PC (or Mac, etc.) to repair the damage
6. Check the status of your files

The unpredictable results depend on the original cause and scope of the logical damage, ranging from all errors being fixed w/no data loss all the way to loss of all data. But at least you will now have a good backup of your data to restore if you lose data.

In almost all cases, these problems are caused by either poor USB connection on the DM42 (due to the geometry of the case design sometimes preventing proper seating of the connector into the calculator body) or by disconnecting the USB cable prematurely (described in the DM42 manual in section 6.11.3).
This problem has existed from the very beginning when I received the calculator, and up to this time has not resulted in any loss of data. I have never improperly disconnected from the PC (always wait for the safe to remove notification), and now have a new USB cable with a longer connector that never causes any connection problems. This failure was catastrophic to the point of the entire flash drive being inaccessible and the surface test reporting that the entire drive was bad. Even if the entire file allocation table (FAT) were corrupted, the drive media itself should not become damaged. What I find so mysterious is how it went from being completely bad to completely good. If this were a hard disk drive, once a portion of the surface goes bad, it remains bad forever and cannot be resurrected. It will be interesting to see if this problem occurs again, at which time I'll probably need to return the calculator to SM to have the flash drive replaced.
DM15L, S/N 00548. DM42, SN: 00159. DM41X, SN: 00973.
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