13.5. When my system boots, it says ``(bus speed defaulted)''.

The Adaptec 1542 SCSI host adapters allow the user to configure their bus access speed in software. Previous versions of the 1542 driver tried to determine the fastest usable speed and set the adapter to that. We found that this breaks some users' systems, so you now have to define the ``TUNE_1542'' kernel configuration option in order to have this take place. Using it on those systems where it works may make your disks run faster, but on those systems where it doesn't, your data could be corrupted.