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Re: 2 GB netCDF limit

> From: address@hidden (John Sheldon)
> Subject: Re: 2 GB netCDF limit
> To: address@hidden (Russ Rew)

Hi again John,

> I just took 3 "real" data files, each 1.2 GB, and concatenated them,
> then used ncrcat to pick off the last 20 timesteps (about 20% of the
> 3.6GB file). I was able to ncview the result on my SGI and everything
> looked OK! (?)
> 
> Any idea how this is possible?  How does that "32-bit slot for a
> variable offset" work?  Is it actually a byte count, or a record count,
> from which a byte count can be computed knowing the record size?  It
> still would bomb on a 32-bit system, but be OK on a 64-bit system.
> 
> As you might surmise, I'm still hopeful....

I guess if the length is all in record variables, the offsets can be
computed in 64-bit ints from the 32-bit starting point in the 0th
record, and everything just works, because the large integers are
computed, not stored.  If this works for you, you're in luck.

I'm forwarding this to Glenn for an authoritative answer.

--Russ