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alnite

anybody here familiar with FAT?

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Anyone here familiar with FAT (File Allocation Table) used by early Operating System, and some devices today? I am trying to figure out how do you find files. Of all articles I ran into on the Internet, none of them speak about how FAT finds its files. Say, I am trying to open C:\foo\zzzzz.txt And say I have 20000 files in my C:\foo\ directory, and zzzzz.txt is the last file. Now it looks like you have to do a linear search because everything is represented in linked list. "Go to directory C:\" -> "sequentally finds foo\" -> "sequentially find files that has name zzzzz.txt" But that doesn't seem to make sense because it'd be terribly inefficient. Do they have a name mapping technique that's not described, or perhaps part of the patented FAT technology?

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Quote:
anybody here familiar with FAT?

Yes I'd used to have a lot, before I stopped eating fastfood! ;)

Sry couldn't resist.
It's a long time since I fiddled around with FAT, but I once wrote this nifty tool that changed the name entry to some special characters so that DOS couldn't recognize the entry as a valid file.
I.e, I could hide directories from all programs etc.

Quote:
Now it looks like you have to do a linear search because everything is represented in linked list. "Go to directory C:\" -> "sequentally finds foo\" -> "sequentially find files that has name zzzzz.txt"


I think you are correct here, but I also vaguely recall that there was some component that cached the LRU entries (maybe a 64K cache).
But my memory might be off.

Quote:
But that doesn't seem to make sense because it'd be terribly inefficient.

FAT wasn't efficient at all, so that's correct.

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