Backing up an external portable HDD efficiently

[bluenitepk]

I have an external USB HDD all data to be used on multiple PCs. These data backs up for security reason. Now I do it manually, the other usb disk, in a way which is quite useful, but quite inefficient and laborious.
Mainly because data size of about 400GB. These are photos, xls files, documents, drawings. Simply files that I am continuously working on them.
I tried more online or other backup solutions, not suit me. After some time they wasn't updated and controllable as multiple versions of the same file.
It can be done differently? Is there any sw which when run can compare two different usb hdds on the base of existing database and update the second hdd by the first one?
This means only the changed files updated by more recent data (differential or incremental backup).
Parameters: no resident program, ease of use. What is your experience of this kind?
thanks for the tip
Peter

 

[ronintexas]

Synchback free: http/www.2brightsparks.com/freeware/freeware-hub.html

This allows you to automate backups from multiple PCs on a network. I utilize this at home and work (you have to pay for the commercial version - but the home version is free). I have a large internal drive on my PC that backs up data from the other 5 PC's in the house. I only copy changed files on a daily basis. It usually takes about 5 minutes per PC (initial backs were 30-45 minutes per PC).

About once a month, I backup the backup drive from the internal drive on my PC to my external HDD (I keep this in a fireproof safe outside the home). If I do something important on the PC, I may back it up sooner.