Using Mirroring for incremental backups? We have a machine tool application that runs on a SQL server backend.  These tools run all day every day and I am looking for a way to incrementally backup the database without any machine downtime.

I've seen mirroring solutions with two servers, but these solutions would not work for us do to cost and size constraints.  Is it possible to programmatically or through some service to mirror this database to a backup hard drive on the main PC?

Some data loss is acceptable.
None of the SQL Server backups require downtime. Full, differential, log backup are all online. 

So just do a normal run-of-the-mill backup scheme (eg. full weekly, diferential daily, log hourly etc) and go with it. Is incremental and is online.