Re: [ferret_users] Reading NetCDF files while they are being written to

[Ryo Furue <furue@xxxxxxxxxx>]

Roman,

I don't know internal workings of Ferret and I speak only from
my experience.

| I have a question about NetCDF files and I apologize if this is
| tangential to the theme of the list.
| 
| I was wondering if reading data by Ferret from NetCDF files while
| they are being written to by another program (i.e. Fortran) is safe?
| I was told that it should be OK as long as the reading program
| (Ferret in this case) does not lock the file. Do you know if it
| locks the files?

Probably Ferret doesn't lock files on Linux/Unix.
I'm not sure about Windows or Mac.  (On Windows,
you often find applications lock the files they open.)

I often overwrite an existing netCDF file while it's being opened
by Ferret.  Nothing bad happens.  In that sense, it's "safe".

But, probably you have to close the file and open it again
in Ferret after it is modified.  I don't exactly know
what happens if you try to continue to use it without first
closing it.

If I hazard a guess . . . If you add a time slice at the end
of the existing time series, Ferret may not see the new time
slice.

Regards,
Ryo