Checksum Question

In php cr32 will create a checksum number, 10 digits, in linux cksum will create one of 9 digits and sum linux will generate a 5 digit number. We use these numbers in a db field to determine if a file has changed and needs to be reviewed, redone, whatever...rather than keep the orginal file on hand. Given the task at hand and given I'm confused about why there are different length numbers, is there one particular option that allows for better change checking..or is it simply a matter of longer is better...I mean the longer the checksum number the better. rm __________________________________________________ Do You Yahoo!? Get email alerts & NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com