Debate over having USB over SD on motherboard V1.2 July 25, 2009 12:30AM |
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Re: Debate over having USB over SD on motherboard V1.2 July 25, 2009 12:52AM |
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Re: Debate over having USB over SD on motherboard V1.2 July 25, 2009 01:37AM |
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Re: Debate over having USB over SD on motherboard V1.2 July 25, 2009 10:18PM |
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Re: Debate over having USB over SD on motherboard V1.2 July 25, 2009 11:29PM |
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Re: Debate over having USB over SD on motherboard V1.2 July 26, 2009 02:50AM |
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Re: Debate over having USB over SD on motherboard V1.2 July 26, 2009 06:13AM |
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Re: Debate over having USB over SD on motherboard V1.2 July 28, 2009 08:07AM |
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Re: Debate over having USB over SD on motherboard V1.2 July 29, 2009 03:01AM |
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Re: Debate over having USB over SD on motherboard V1.2 July 29, 2009 07:05AM |
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Re: Debate over having USB over SD on motherboard V1.2 July 31, 2009 03:45PM |
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Re: Debate over having USB over SD on motherboard V1.2 August 01, 2009 03:10PM |
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Re: Debate over having USB over SD on motherboard V1.2 August 01, 2009 07:03PM |
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Re: Debate over having USB over SD on motherboard V1.2 August 02, 2009 01:08PM |
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Re: Debate over having USB over SD on motherboard V1.2 August 02, 2009 08:29PM |
Quote
Initially I tought of a bug in the code, so I checked stack sizes, removed unnecessary interrupt code, and placed error traps on the AVR-DOS calls. The traps intercepted an error 23 and "file not found" errors, so I inspected the card with the FS-Interpreter tool. What I found was an apparently-good subdirectory, except it missed the links to the parent directory. This drives the file deletion system crazy.
Thinking of a bug in the AVR-DOS library, I contacted its Author, Franz Joseph Voegel, and he was so kind to try a debug version of the code on his system (using both compactflash and hard disk drives). The code worked for days of continuous recording, writing many GB of flawless data.
Joseph suggested that this could be a card wearout problem, as the AVR continually rewrites the FAT (file allocation table) and the directories as it is writing a new file. If the number of writes of a logic sector is limited, then the sectors assigned to the FAT and DIR could exceed the maximum numbers of rewrites quite rapidly. However, creating a flash file system almost invaribly requires you to separate logic sectors from phisical sectors (the ones that actually wear out), so I'm not incline to think SD-card designers overlooked the problem.
Re: Debate over having USB over SD on motherboard V1.2 August 02, 2009 08:51PM |
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Re: Debate over having USB over SD on motherboard V1.2 August 02, 2009 09:06PM |
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Quote
.... I got a broken card (the 1 GB Kingston, but I know of a 512MB Peak with similar issues). Before its final breathe, I noticed sporadic directory corruptions. This usually happened after writing about 500MB...2GB of data, but the card was still functional after reformatting. Then things got worse, and now I'm unable to reformat or use it anymore.
To date, the cause of this problem is not clear.
.....
Thinking of a bug in the AVR-DOS library (Franz Joseph Voegel) ...
The code worked for days of continuous recording, writing many GB of flawless data.
....
this could be a card wearout problem, as the AVR continually rewrites the FAT (file allocation table) and the directories as it is writing a new file. If the number of writes of a logic sector is limited, then the sectors assigned to the FAT and DIR could exceed the maximum numbers of rewrites quite rapidly.
Re: Debate over having USB over SD on motherboard V1.2 August 03, 2009 05:47AM |
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