Today, the reality of research teaches me a lesson...
Few weeks ago, I began to split the data into a number of fragments, and distributed them on different machines. Yesterday, I finished the code which could combine the separated data into one and perform the final step. It seems pretty good, but it is not... As it has been so long since the date I setup the first step, some critical configurations I made has became blurred. I suppose to remember those simple numbers which parsed into my programs, but it has been to late to correct me.
I lost about 20% of the data, which may need another few weeks to recover.
So, I suggest that, every one should keep a simple log, to record some crucial information you may need in the future, such as what/when/how you have done. Even it is not exact you need, it could help you to remember at least.