hot backup mode?

I'm in the process of setting up a centralized backup facility for a network of hp 9000's and some other machines. Unfortunatley most of these machines are running either informix 5.x or sybase 4.9x with applications that MUST be up 24 hours a day, 7 days a week. I have been told by a VAR that his product can handle this by putting the database in what he called a "hot backup mode". Supposedly this will cause all transactions to be written out to a log file that can later be rolled into the database. The plan is that while the transactions are going to the log we can backup the database itself. This sounds nice, however neither I, my DBA nor my network guru has ever heard of this. Obviously we are just a tad suspiscious. Does this sound even vaguely familiar to anyone? Thanks in advance, Chuck