[MITgcm-support] newbie question about mnc output

[Shafer Smith]

Hi,

Great model, super well documented for the most part, but perhaps for
ultra-newbies, a few things are hard to figure out....

I have compiled and run exp0 on an ibm  js20 cluster,  single processor,
and am trying to understand how to read the output.
Though I believe I have read the manual, I cannot seem to figure out the
following:

1.  Why are there four of every file?  e.g.

state.0000000000.t001.nc
state.0000000000.t002.nc
state.0000000000.t003.nc
state.0000000000.t004.nc

2.  How do I make the model save basic snapshots for analysis at some
interval?

pChkptFreq (permanent checkpoint - i can make multiples by setting this
less than run time)
chkptFreq (rolling checkpoints -- overwriting same files??)
dumpFreq ... I don't understand how to use this parameter.  I also
found an old post about this, but it seemed to advanced for what I'm
asking....

3.  mnc_assembly.m  seems to expect a series of files differing by
increasing integer values in its file name.  If I set pChekptFreq to
save multiple checkpoint files (which I expect is not what I want to
do), they differ by some larger factor:

pickup.0000000720.t001.nc
pickup.0000001440.t001.nc
pickup.0000002160.t001.nc
pickup.0000002880.t001.nc
pickup.0000003600.t001.nc
pickup.0000004320.t001.nc
pickup.0000005040.t001.nc
pickup.0000005760.t001.nc
pickup.0000006480.t001.nc
pickup.0000007200.t001.nc
pickup.0000007920.t001.nc

(there are also t002, t003 and t004 versions).

Thanks in advance for your help!
Shafer Smith