1. From the NETWARE area on Adaptec's BBS download NW31X.EXE or NW40X.EXE to use the latest applicable driver.
AIC7770.DSK AHA-274x (EISA HBA), AHA-284x (VL HBA) series
and AIC7770 embedded chip set
AIC7870.DSK AHA-2940 (PCI HBA)
2. Use the "tag_disable=ffffffff" switch for the AHA274x, AHA284x, and AHA294x, AHA274x T (T is for twin channel) or any "WIDE" channel HBA. The surest way to disable tagged queuing is to use "ffffffff" (8 f's) for all drivers except the AHA1740.DSK which would require "tag_disable=ff". Novell Labs has noted that some SCSI drives report to the host adapter that they support tagged queuing, however they fail to operate properly. While the fault is not with the HBA and driver, it requires disabling tagged queuing. (Example "load aic7870.dsk tag_disable=ffffffff").
3. Set the Maximum Sync Transfer Rate to 8.0 MB/sec for the AHA-2940.
The AHA-2940 operates at greater than 10.0 MB/sec when configured at 10.0 MB/sec. Since the SCSI spec only requires devices to operate at 10MB/sec, problems may arise. With its BIOS enabled, the AHA-2940 will present a banner at system boot up time:
<<<Press <Ctrl> <A> for SCSISelect (TM) Utility!>>>
Start the SCSISelect utility, choose Configure/View Host Adapter Settings then under Additional Options, choose SCSI Device Configuration. From the SCSI Device Configuration menu change the Maximum Sync Transfer Rate from 10.0 to 8.0 for devices #0 through #7.
4. From the HARDWARE area on Adaptec's BBS download ASWC274.EXE. This file contains the latest EISA configuration files for the AHA274x series HBA. There are two EISA configuration issues which should be addressed.
4.1 These configuration files will set the BCLKS=44 as the default. Use the BCLKS=44 rather than BCLKS=60. This is particularly important if the host machine is supporting multiple adapters.
4.2 These configuration files support EDGE triggered interrupts. Run the EISA config utility and set the AHA274x HBA interrupts to EDGE triggered.
5. Avoid INT 15. Both Novell and Adaptec have recommended avoiding INT 15 when problems arise. Some users have successfully used INT 15, however, others have had problems. Any time a user is having problems with an adapter using INT 15, AHA2740 or otherwise, recommend that the adapter be used at another interrupt.
6. Do not share interrupts. The AHA-174X and AHA-274X may have difficulty when multiple adapters are installed in the computer and they are EISA configured to share interrupts. If two adapters are installed they will be sharing interrupts by default. The user must run the EISA configuration utility to change the interrupt on one of the adapters.