In their comment on the issue of `checkpoints' in GAP Frank Celler and
Prof. Neubueser don't mention a point that I find very important.
If one runs a calculation that might take several weeks (or even months)
of CPU time, it is crucial to have the possibility to save the current
status of a computation at a given time. The reasons why it is so crucial
is simple: During the calculation the system might crash, be taken down
for maintenance or GAP might run out of memory and one would like to
continue the computation at a time when the system is less busy. Checkpoints
would simply be a safeguard against the various uncertainties that might
occur during a long calculation. For this purpose it is not necessary to
have a very flexible way of saving the GAP workspace; I don't think that
portability across different computer architectures is really an issue.

I am aware of the fact that it is not trivial to implement a checkpoint
facility, but I think a very simple one, that supports people in doing
extensive calculations, is better than none.

I am very interested to hear other people's opinion on this matter.

Regards, Werner Nickel.