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Try to recover memory?
03-25-2019, 03:28 PM
Post: #2
RE: Try to recover memory?
Yes it does work, but it seems you haven't encountered any situations yet where it has a chance to recover something. A total power loss causes the RAM chip to wipe its contents, so there's nothing left to recover (flash memory is resistant to this, so port 2 and the SD card both are suitable places for backups). Memory corruption can leave parts of the RAM intact, so that's when recovery becomes useful.
While writing and testing SysRPL programs I've had quite a few instances of memory corruption (due to bugs in my programs, of course). In that case, if the memory area known as USEROB (all global variables, i.e. the home directory and all of its subdirectories) was affected, the home directory's checksum is wrong - that's what causes the message in the first place. However, each subdirectory has its own checksum which lets the calculator check the integrity of that separately, and trying to recover memory means scanning for intact subdirectories. Their names will be lost as those were part of the parent directory's structure, and any variables of other types in HOME will be lost as well, but the recovered directories will be put into the new HOME with names such as 'D.01', 'D.02', etc. Inspecting their contents should tell you what they are, since all variables inside are preserved, including their names.
Most of the time you'll even find one directory you don't recognize: the hidden directory. In one case that came in handy for me because I had substantially modified my user key definitions recently and hadn't saved them onto the SD card yet when I caused a TTRM crash. One of the variables in the hidden directory contains the user key definitions, so I was able to get them back by pulling them out of the recovered hidden directory and undoing the format changes they undergo in STOKEYS.
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Messages In This Thread
Try to recover memory? - franz.b - 03-25-2019, 09:05 AM
RE: Try to recover memory? - 3298 - 03-25-2019 03:28 PM
RE: Try to recover memory? - franz.b - 03-26-2019, 07:09 AM
RE: Try to recover memory? - John Keith - 03-26-2019, 07:32 PM
RE: Try to recover memory? - TravisE - 03-28-2019, 01:34 AM
RE: Try to recover memory? - franz.b - 03-28-2019, 07:42 AM
RE: Try to recover memory? - 3298 - 03-28-2019, 09:28 AM
RE: Try to recover memory? - John Keith - 03-28-2019, 02:43 PM
RE: Try to recover memory? - 3298 - 03-28-2019, 10:13 PM
RE: Try to recover memory? - ijabbott - 03-30-2019, 05:07 PM
RE: Try to recover memory? - franz.b - 03-28-2019, 02:48 PM
RE: Try to recover memory? - John Keith - 03-30-2019, 01:07 PM



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