The files in "trace" contain the traces
The traces are split into multiple hourly-traces. 

The format is best described by the code that generates it: ftrace.c
The salient points are 
field	    what
1	    time (seconds past start of trace)
2	    pid of process generating that request
3	    output status 
4	    output error
rest	    call specific information

The files in  "ps-output" contain the output of a "ps" at the end of each hour.

The files in the "ls-output" contain the output of a "ls" on the entire
filesystem (done a couple of months later)