[TUHS] Date madness

Doug McIlroy doug at cs.dartmouth.edu
Sat Dec 16 20:50:45 AEST 2017


>>>  Flipping it to unsigned int was the quickest way out to kick the can until Sun Feb 6 06:28:15 2106.  If you have source it’s incredibly trivial to change, and nothing changes size wise.
>>
>> Easy, but perhaps unwise. The sign bit is a potential escape hatch for
>> times, just as it is for characters in UTF-8.
> 
> I'm not sure what you're suggesting - UTF-8 works because it's a
variable length encoding - a variable length timestamp might be
interesting as an academic exercise, but there's no way for time() to
specify how much space is needed, or be informed of how much space is
allocated

Like UTF-8, a variable-length time would be something normal
programs aren't supposed to see--it would be a format for
external media (i.e. file systems). Times in inodes would be
variable-length. Times returned by stat() and time() would
be full length. Only the kernel needs to know the encoding.

One may note that inodes already use a variable-length
encoding for the list of physical block addresses, so there 
is nothing radical here.

I admit, though, that if the kernel can tell "old" from "new"
inodes, then they could have different time encodings rather
than one variable-length encoding.

Doug


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