Logical Log Dilemma

The company that I am working for has an off-again, on-again type of problem with logical logs. We are using Informix-OnLine 5.00 in combination with 4GL 4.10. Here's the situation: We currently continuously back up our logical logs to a Maynard (now Conner) Python DAT drive. We also have an internal 1/4" drive that we use for system backups. Every now and then, at random intervals, there will be a write error and continuous backup grinds to a halt. This has happened less often since I've started cleaning the drive regularly (and this never happens when we archive the database), although it still happens from time to time anyway. Our database is small by comparison; in fact, we will have to upgrade to a 2 GB hard drive in order to avoid running out of space on our 520 MB drive. At an Informix class I took recently, the instructor suggested first backing up to disk and then tar'ing them to tape at night. Since heavy days can generate up to 200 half-megabyte log files, we don't have room on our hard drive now, nor do we want to risk filling up the hard drive once we upgrade. Does anybody have any suggestions?