Let's go through the log messages for a test Squid run and see what each line means:
2010/09/10 23:31:10| Starting Squid Cache version 3.1.10 for i686-pc-linux-gnu... 2010/09/10 23:31:10| Process ID 14892
Looking at the preceding example, the first line represents the version of Squid we are currently running and provides some information about the platform. The next line contains the process ID for this instance of Squid.
2010/09/10 23:31:10| With 1024 file descriptors available
This line shows the number of file descriptors available for Squid in this run. We can check back similar lines in our cache log, if we increase or decrease the available number of file descriptors and restart the Squid process. ...