how to check how long the process has been running

I have a requirement to check how long a process is running on unix system.If i use ps -ef i am getting the following message

guest 2453638 1998920 0 16:16:05 – 0:00 dsapi_slave 9 8 0

but this is showing only time not the date.Can any one please advice me any script to find out how long this process is running.

Example:

Code:
Tsunami comparing # ls -ld /proc/1
dr-xr-xr-x 5 root root 0 2008-08-17 22:21 /proc/1
Tsunami comparing # uptime
01:11:18 up  2:50,  5 users,  load average: 0.05, 0.06, 0.02
Tsunami comparing # date
Mon Aug 18 01:11:24 WEST 2008
Tsunami comparing #

The creation of init process (PID 1) is more or less when the system started.