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50g: copy all stored objects to SD card individually
10-16-2016, 02:09 AM
Post: #11
RE: 50g: copy all stored objects to SD card individually
(10-15-2016 09:46 PM)matthiaspaul Wrote:  What codepage is displayed by CHCP under CMD?

(10-15-2016 09:46 PM)matthiaspaul Wrote:  No: While it is possible to disable SFNs in NTFS, this is impossible for FAT. Even though Microsoft calls the FAT SFNs "alias names", the SFNs are the *actual* file names, and the LFNs rather than the SFNs are optional. A LFN can be seen as some kind of "extended attribute" loosely attached to the directory entry holding the SFN (and all the other information about the file). A SFN may contain invalid characters and be distorted to the point of not resembling the corresponding LFN any more at all, but it is impossible for a SFN not to exist in the FAT filesystem.

I suppose Microsoft needs to change their help output for "dir", then. Smile It states the following for the /X switch:
  /X          This displays the short names generated for non-8dot3 file
              names.  The format is that of /N with the short name inserted
              before the long name. If no short name is present, blanks are
              displayed in its place.

(10-15-2016 09:46 PM)matthiaspaul Wrote:  Was this file displayed as "AAAAA?BBBBB" or "AAAAA탂BBB" in Explorer?

I took another look at it. Explorer shows it as "AAAAABBBBB" (no visible character between the "AAAAA" and "BBBBB"). See below for how it shows with "dir /x".

(10-15-2016 09:46 PM)matthiaspaul Wrote:  And how was this file displayed by DIR /X exactly? "AAAAAZBBBBB" and "AAAAAZ~1" or something different?
10/15/2016  07:52 PM                19 AAAAAì~1     AAAAA?BBBBB

(10-15-2016 09:46 PM)matthiaspaul Wrote:  
Quote:If the file on the SD card had no SFN AND it also contained a "?" character, the file could not be read or deleted by my Win7 system. I will attempt to try some other "high ascii" characters to see if those also cause problems.
That will be very interesting.

Just out of curiosity, I decided to try the "bad character test" using a different SD card. All attempted character tests were successful using that card, including the x8D test that failed before. This led me to believe that I had some type of file system corruption on the original SD card, so I reformatted it and tested again. Now all filename tests are working properly with Windows on that card as well. So it's apparent that some type of file system corruption was causing the original problem. I'll be on the lookout for more strange issues like that, and I'll retest if I start seeing other problems. So my concerns about inaccessible files are no longer a result of embedded characters in the names. Just lurking file system corruption!

(10-15-2016 09:46 PM)matthiaspaul Wrote:  Once we know what rules are used by the calculator, we might be able to derive an "adaptive partial renaming scheme" for your library.

As I am now also pondering the possibilities in moving files back from the card to the calculator, I'm actually more inclined to keep this as simple and straightforward as possible. I've definitely got to do some testing of file IDs written to the card by the computer and seeing how the calculator interprets them. As an example, I'm curious what will happen if the computer writes a LFN using Unicode (if that's even possible on a FAT-formatted card), and how the calculator will see that object's name using SDLIB.
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RE: 50g: copy all stored objects to SD card individually - DavidM - 10-16-2016 02:09 AM

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