Help! Corrupted QL_BDI image on SD Card...

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martyn_hill
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Help! Corrupted QL_BDI image on SD Card...

Postby martyn_hill » Fri Sep 22, 2017 11:17 pm

Hi everyone

So, I've fallen faol of my own complacency and have experienced my first corruption on the wonderful SD Card that I use in one of my QLs.

I have some older backups of the QL_BDI.BIN image file used to hold the 8MB QL filesystem and, with a few days work could recreate 95% of the files in a fresh image.

But, I wonder, are there any options open to me to try to repair the corrupted image file - even perhaps as an exercise (i.e. that might actually take longer than recreating the 95% from backups)?

Any tools to repair QuBIDE file-systems, when hosted on an SD Card, for example?

Just to be clear, the corruption is _within_ the (QL/QuBide) image filesystem, as opposed to the SD Card FAT filesystem that hosts it, which appears intact.

Some points of note:
a) The corruption occurred when one of my QL programs tried to write to the SD Card until it completely filled the available free-space.
b) Using the lovely (thought experimental) support in QXLWinReader, I can happily read the directory structure from the QL_BDI.BIN file-image.
c) In QXLWinReader, I found the offending (massive!) file and deleted it.
d) Still in QXLWinReader, any attempt to 'Copy' files from the SD Card image report 'Disk is Read Only' (which doesn't make much sense, but nevermind.)
e) Both on the QL and from within QEmuLator+BDI_BIN extension, attempting to mount the image produces 'Invalid FAT' error (which is also a bit misleading - the FAT structure on the SD Card itself is intact - Windows happily reads/writes to the card and reported no errors at the FAT FS level.)

Thanks in advance for any ideas?


martyn_hill
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Posts: 230
Joined: Sat Oct 25, 2014 9:53 am

Re: Help! Corrupted QL_BDI image on SD Card...

Postby martyn_hill » Fri Sep 22, 2017 11:47 pm

UPDATE!!!

After trying QEmulator (with the BDI extension) unsuccessfully to mount the QL_BDI image, I tried once again QXLWinReader - just to check what I would need to re-create from backups (from the still-available directory listing).

This time, QXLWinReader allowed me to copy-off everything from the image to my QXL.win image file that I use in QPC. Don't ask what changed between attempts as I have no idea - perhaps the QEm/BDI driver touched something on the BDI file-system to allow this. Curious, QEm/BDI still can't actually mount the original image...

Anyways, I am now in the process of building a fresh QL_BDI image file and will copy-across all the folders/files saved on to QXL.win and see if I'm spared a few man-days of unexpected labour...

A cautionary tale for any other BDI/SD Card users foolish enough as I to forget to apply a suitable backup strategy to their QL work... Lesson learned, and all that.

Would still be VERY interested to know what options I would have had to attempt repair...


martyn_hill
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Posts: 230
Joined: Sat Oct 25, 2014 9:53 am

Re: Help! Corrupted QL_BDI image on SD Card...

Postby martyn_hill » Sat Sep 23, 2017 12:16 am

SAVED - thanks to QXLWinReader and whatever QEm/BDI did to allow files to be copied off!

Well, thanks are due to their incredible authors, but you knew what I meant!

Back to my real QL work now... (Still working away at the QLAN to SER/USB Bridge Adapter, really...)



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