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swingtan
July 2nd, 2009, 02:04 PM
Hi Guys,

I'm wondering if we can get a slight change added to the next update of the firmware?

Currently, when starting a log, the V2 will probe the SD card for...

Presence of the card.
the required folder structure


It then attempts to write a new log on the SD card. If you knocked the "write protect" tab as you inserted the card, the V2 will error and says


File or Folder not found

then cancels the log session. I think it would be a little more helpful if there was a write protect check and a message to say that the media is write protected, like when you attempt to format the SD card with the write protect tab on. there have been a few times where I thought the SD card just needed re-seating and tried 3 or 4 times before noticing the tab.

Simon.

swingtan
July 14th, 2009, 09:57 AM
I have another "issue" that I think would be good to address.

I've been doing some testing with a 32MB SD card ( because I got one with a camera and it's way to small for that ) and a major benefit. When doing multiple logs, they time delay to start logging is almost non existent no matter how many logs are on the card already. The bigger the card though, the more delay you get after the first log. ( This was discussed in another thread ). However, given the size of the SD card and the fact that I'm logging an E38, means you can only get a dozen or so logs on the card before it fills up.

The V2 does not seem to do a "free space" check at any time, so as long as it can perform the initial "open" of the log file, it'll happily log away even after the card is full. When it goes to close the file, it simply closes the file handle and you end up with a 0-byte length file with no warning that anything "bad" has happened. You can then do multiple successive logs, all resulting in 0 length files.

Is there some check that can be done to prevent this?


A check after the final write that the file size is > 0?
An initial "free block count" check that alerts if there is less than "X" Min's of log time available ( referenced to the controller type and an "expected average packet size" ).
An "Auto Log Finalisation" process if the free space is less than "x", the V2 just finalises the log and stops logging, sets a flag to not allow logging till there is free space again.


Yes, I know this is a "nice to have", but it would help prevent the loss of multiple logs if you don't check between every one.

Simon

Blacky
July 14th, 2009, 11:19 AM
The auto checks for SD card format and folder presence is in the next firmware update.

The free space issue is a real problem. The FAT file system can take multiple seconds to perform a free space check. It is not acceptable to do that prior to each log. You've proprosed some good alternatives which I will look into. I know there needs to be a better check for "no space" and a better way of handling it.

Regards
Paul

swingtan
July 14th, 2009, 02:05 PM
Sounds like you're on to it then. I'll sit back and wait.... :P