For partitioning such a big drive in one Block you should consider an alternative Filesystem. I have lately tried a 50 GB SCSI Drive on the SCSI controller of an E-Matrix 530. Under OS3.9 and FFS the largest single partition that could be formated useing quickformat was 17 GB (I found this out by try an error) Still this could be a limitation of the E-Mtrix devicedriver. On my A4000T I have an 60 GB IDE drive running on the UWSCSI of the CSPPC via an IDE-SCSI converter and I have a partiton of around 20 GB running with no Problem, but I`m useing SFS for this drive.
