Can q3map2 resume the previous compiling state?
For example, a mapper instructed q3map2 to compile his map which were supposed to take 2 hours to finish. 
1 hour later he noticed he had to reboot his computer as soon as possible. :huh:
He was at a loss. :uhoh:
He wished if only q3map2 could resume! :banghead:
Is it possible?
No. q3map2 cannot do that.
There are various generic methods of freezing/thawing processes which might work, but the simplest solution is most likely to plan your reboots better.
edit: this is sometimes called checkpointing, and is often used in clusters.
Thank you SCDS_reyalP for your quick answer.
Now I am reminded of ydnar used to say that q3map2 does not support cluster at all.
Because I don’t know how q3map2 works internally, I’ve expected mighty q3map2 to do the same thing with some of the famous softwares such as wget. 
Resuming a partial download is a lot simpler than saving the entire state of a q3map2 run. However, you could certainly code this capability if you wanted to. Expect it to take nearly as much disk space as q3map2 requires memory.
As I said, there are some systems for checkpointing any program. See this for example http://lists.osdl.org/pipermail/clusters_sig/attachments/20051025/88ed8b30/Comparison-CR-0001.pdf
You can do a similar thing with VMWare for the whole VM. I’m not sure what the performance penalty for running q3map2 under vmware would be, but given that it is mostly CPU/memory intensive, it shouldn’t be too bad if you have enough RAM.
It sounds extremely slow and far from efficient.
I don’t understand why q3map2 cannot know the state of what he is doing.
Because q3map2 author seems to go back to action recently, let’s keep tabs on the progress of q3map2. 