Each file has one or more time stamps. They are used by the operating system to record when the file was created, last modified, or last accessed. Most TCC file processing commands allow you to select files for processing based on their time stamps.

 

1.Write time is the date and time the file was last written, i.e., when its content was last modified, On FAT volumes this is the only timestamp. In all commands and functions this is the timestamp used unless you specify another. On FAT and VFAT volumes, the resolution is 2 seconds. NTFS volumes have a 100 nanosecond resolution for the file creation and last write. (UNIX and Linux systems use 1 second resolution.) When a file is copied using the COPY command, even across a network, its write time is not changed. However, different file systems record time with different resolution, so minor changes may occur.

 

2.Creation time is the date and time  the current instance  of the file was created.

 

3.Access time is the date, and on NTFS volumes, the time, when the file was last accessed for either reading or writing.

 

Several TCC commands and functions let you specify which set of time and date stamps you want to view or work with on LFN volumes. These commands and functions use the letter

 

ccreation time stamp,
wlast write time stamp, and
alast access time stamp.

 

Note that FAT32 and VFAT volumes store the date but not the time of the last access. On these drives the time of last access will always be 00:00.

 

Time Stamp Resolution

 

The resolution of time stamps as well as the range of time instances representable vary with file systems.

 

file system

resolution

earliest time stamp

latest time stamp

FAT/VFAT

2 s

1980-01-01 00:00:00 local

2107-12-31 23:59:58 local

NTFS

100 ns

1601-01-01 00:00:00 UTC

60056-05-28 UTC

 

NTFS Timestamp Reports

 

These operating systems report timestamps in local time. However, conversion between UTC and local time is based on the difference between UTC and local time at the time of conversion, instead of that in effect when the file event occurred. Consequently, if daylight saving time is currently in effect, all file events around the year will be reported in DST. conversely, when DST is not in effect, all file events around the year will be reported in standard time. This method has the advantage that differences in event times can be calculated easily. However, the times reported will not be those when the event took place if the state DST at time of event is not the same as at the time of reporting.

 

The TOUCH command can be used to modify the timestamps of files and directories.

 

Additional information about disk files and file systems is available under Drives and Volumes, File Systems, Directories and Subdirectories, and File Names.