Process Explorer : few network/io questions

I have a couple questions... this is for Windows XP but probably applies elsewhere.

1. Most process statistics, like CPU time and I/O Reads and Writes are counted regardless of whether Process Explorer is open, I assume because the kernel keeps track. However, Network Receive Bytes and Network Send Bytes are lost whenever PE is closed. Is that because PE has to keep track itself? Any way to make this tracking always-on?

2. I've read that I/O Other is often associated with backup and network activities. What sort of I/O commands would a backup utility be running that didn't involve reading or writing? 

3. Related to #1, is there a way to save a history of all processes that have launched since a point in time, even if they're no longer running? Would be a great way to audit usage.

Thanks for any tips!