Re: Why isn't the "last access time" part of the filesystem library?

From: Ken Hagan (yg-boost-users_at_[hidden])
Date: 2003-05-08 04:18:06

> "Ben Hutchings" wrote:
>>
>> What does that figure refer to, if anything?

richard_fanta wrote:
>
> Typical application usage.  Yes, mileage can vary.
>
> Out of the last 50 apps you wrote that did file access, how many
> involved CD-ROMS/DVDs that were ISO 9660 filesystems?

I don't understand the question. The topic under consideration is
"last access time", so I take your expression "did file access"
to mean "used the last access time". Since the latter isn't
available for read-only or write-once media, the only possible
answer is "none".

Looking beyond CD-ROMs, I don't think I've ever written an
application that needed the last access time, and given the
variation in support, accuracy and precision that Beman mentions,
I'm not sure I could come up with one if I tried.

Since Windows has been mentioned as an OS that supports them,
let me quote from Q245214...

  "Windows NT and Windows 2000 only updates the Last Access Time
   every hour for performance reasons."

...although it is stored in the usual very high precision.
Actually, that's only true on NTFS. On a FAT file system,
the resolution is "one day".

Worse, however, is the last access time on my pagefile, which
is "06 May 2003, 17:15:04" (the last time I rebooted) because
the OS hasn't closed the file yet, so it sees no need to update
any of the file times.