neese@adaptex.UUCP (06/15/90)
>/* ---------- "Adaptec 1542A tuning of 386/ix 2.2" ---------- */ >I recently upgraded from 386/ix 2.02 to 2.2 and am wondering >what I can do to get the best throughput out of my 1542/SCSI >drive/tape system.. > >The documentation mentions tuning space.c, but in /usr/include/sys/aha1540.h >are some parameters like: > >#define AHA_BUSON 5 >#define AHA_BUSOFF 9 >#define AHA_DMASPEED 1 >#define AHA_NUM_MBOX 8 >#define AHA_RES_MBOX 2 > >the only thing that I have changed is the AHA_DMASPEED from the default >of 5 MB (0) to 6.7 (1) - and was wondering if I should try changing some >of these other values and jumpering on the controller... You could add the synchronous negotiation jumper on the board. This allows the adapter to negotiate for synchronous protocol. Makes a difference. Setting the bus on time to 7 would help as well. You don't want to go any higher than that as it will cause floppy DMA problems. The busoff time should be 4. Roy Neese Adaptec Senior SCSI Applications Engineer UUCP @ uunet!swbatl!texbell! {cpe,merch,nominil}!adaptex!neese uunet!mlite!adaptex!neese