[chord] 【chord】questions about Chord code

[潘凯]

Dear Professors£º
	I'm very interested in your Chord implementation and recently I've started to
read the code.I begin with the basic data structures in the utils and I have Some
questions:
(1)In the class locationtable,you maintain 4 lists(locs,cachedlocs,loclist and
pinlist) to record the location and pin information.It seems that the elements in
the first three lists(locs,cachedlocs,loclist) point to the same locwraps.Why
design three different data structures to record the same information?Is it
because different data structures have different advantages in the search
operation? 
(2)When I tried to read the class location i found it's a even more
difficult.Because there are so many data members in the class and I really can not
guess what they used for?Can you give me some introduction on the function of the
following data members,can you tell me to what consideration you designed them: 
    float a_var_;
    unsigned long nrpc_;
    //is it a rpc counter?why count the  rpctimes? for replace the location?
    time_t knownup_;
    time_t age_;
    int32_t budget_;
I know my questions are so trival and hard to answer.But I really need your
help.Thanks a lot!

                                                     BEST REGARDS!