I have stripped down the machine, disconnected and reconnected the hard drives. I have re-installed LINUX (though not yet allowed YOU to get any updates) using the same LVM disk partition arrangement, but re-formatted all the partitions. I am presently restoring the data to the LVM. I will let you know if the problem recurs.
If this still fails then I will switch to an alternative mobo ie change the ide controller chip.. before finally sending the Primary Slave disk back to the supplier (it is only 10 months old).
I have now filled the disk with data, and it is performing without problem. I will keep an eye on it for a while. Maybe the re-format helped ? One other thought, am I correct in thinking that having used an LVM I am forced to use LILO rather than GRUB. There are usually special instructions on a Kernel update that require manual intervention when using LILO. Could YOU have installed a new kernel, without the special handling for LILO ? I have previously left YOU to operate as a CRON job and auto-update each night. So far I have not allowed any ONLINE UPDATES to the system as I test it. My system is now a basic SUSE Prof 9.1 straight from the CDs, with no updates. Any thoughts? Philip