Optimizing write performance

Further to the recent discussion about the relative merits of mirroring, RAID etc., what if I had a database which is updated in bulk and queried in a really trivial, computationally cheap way and therefore for which I wanted to maximize insert, update and delete speed but really wasn't bothered about select speed? It's SCO 3.2.4.2 / Online 4.10.UC2 so fragmenting is not an option. Several tables are huge (i.e. of the order of 4G "data bytes" and 1.3 million rows). Short of upgrading, what's the best thing to do? I thought of using plain old raw partition allocation and arranging for the chunk allocation to happen in such a way that each of the big tables reside on seperate disks and then do the batch inserts, deletes and updates across multiple tables simultaneously. Would this give me a speed increase commensurate with keeping two or three disks busy instead of just one? I suspect RAID and Mirroring are out because of their degraded write performance. Any ideas anyone? S