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0 pointsdzavalishin6y ago0 comments

Word->Open file->Error reading file: LIST INDEX OUT OF RANGE

Does this?

Your point is obvious, but not specific to persistent environment. Things are getting broken sometimes.

Actually, back in 2009 when first message about Phantom appeared, I've got a message from team in Stanford. THey did an experiment about things we discuss.

Relatively big Java program was stopped in the middle of work, serialized to (I believe) XML and some objects were removed from that XML. After that program state was de-serialized and program continued to run.

Experiments shown that modern code degrades quite gracefully in such cases. Most of time problems were not global and affected just parts of program's abilities.

But again, it is not a persistent world specific problem.

If your code is wrong, no matter where index lies - in persistent memory object or in file. Index will be wrong.

The question is how system must be built, what kinds of services it must provide to limit app ability to shoot itself in a foot. That is one of the goals of this project.

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theamk6y ago

In Word (especially when save-in-place disabled), old file disappears only when the new file is complete. And since file writing naturally walks over all the structures, any exceptions usually happen during save and display time. If the file ended up on disk, it is usually OK.

And even if you are unlucky, you can still restore it from your backup (time machine, dropbox folder, restore point, etc..)

If you have explicit "save" action, all of those things happen automatically -- there is no need for programmer to do any sort of action here, other than to make sure saves are atomic.

Only persistent environments have this problem, because once your persistent-word crashes, you cannot do anything to roll back the change -- other than revert entire OS to previous snapshot, but this will roll back all other apps, too.

(Practically, I've had MS Word crash on me hundreds of times. I've only got corrupted save file once or twice. So at least from my anecdotal evidence switching to "persistent world" would make data loss much more frequent.)