On Ubuntu 12.04 I did the following
- stat a file
- cat the same file
- stat the file again
- cat the file again after 5 min
- stat the file
The access time reported at 3. reflects the point at which 2. was run. However, the access time reported at 5. coincides with 2. and not 4. Is this because Linux serves the file out of cache and avoids disk access in the second instance? Also is there a way to retrieve a list of files that are currently resident in disk cache?