Connor 1060S & Corruption

Hi Folks, We are concerned about some "strange" things that have occured with data on Connor 1060S SCSI drives on 2 different Systems. Hardware wise, about the only things common between the two systems are the Connor drives, the SMC 8013 network cards, and 1540 SCSI adapters (genuine adaptec though one is somehat older than the other but unfortunately, I don't have exact model details with me). One machine is an AcerMate 800 75Mhz Pentium and the other is a "bits and pieces" 486 clone which apart from this problem has run faultlessly in a development environment for more than 2 years. Software wise, one system is runnnig SCO ODT 3 .0 and INFORMIX SE 5.03 and the other is running SCO Open Server Enterprise 5.0 and INFORMIX SE 7.10. On both systems, there are IDE root filesystem drives and the SCSI's are secondary drives. From time to time Informix Data Files (usually .idx files but not always) get slightly corrupted. They are nearly always fixable with bcheck/secheck. We also get a "No such device or address" error during queries occasionally. Both problems ocur on both systems and usually occur at least once or twice a week. These problems never occur on the IDE drives in these systems, nor have we ever had any problems with non Informix files. We have other systems using 1540 controllers but not the Connor Drives that are also running Informix etc flawlessly. These two systems are the only ones with these connor drives. Has anyone ever seen such problems and better still khow to reslove them (apart from the obvious "go out and buy a new system" approach)? TIA Scott.