Hello: I was lucky enough to be able to switch to a new SSD - the Crucial M500/960GB, this on an 2011 15 Early Macbook Pro. As this is my first SSD, it looked up all the needed tweaks for SSD, implemented the ones that makes sense ( TRIM, SmartSleep, no access time flag, etc... ) In the process I noticed that there is a steady stream of write I/O to the SSD. After some 30 hours, Activity monitor shows 15GB read, and 32GB written. That seems to be strange. I used iotop to see some of the writes - but this gives a snapshot, while I'd like a summary after some longer period of time. For this, Google says uses rwbypid.d or bitesize.d. The problem is that these do not seem to work. When I terminate them via CTRL-C, they just exit, but do not print any collected stats. Am I wrong in expecting them to print the stats on exit ? In addition - are there any other tools to get per/process disk I/O statistics ? Thanks for any info. Paul.