Known Problems and Limitations

• The AHA-274x is not compatible with the Wyse MP system.

• Motherboards that support level-triggered interrupts, such as an EISA motherboard, will support multiple AHA-274x adapters sharing the same IRQ (although there may be minor performance degradation).

• The AHA-2840VL adapter cannot share IRQ vectors because it supports only edge-triggered interrupts.

• When the AHA-274x host bus adapter runs under heavy load, the tape device loses arbitration contests to faster devices with higher priorities and produces "Media Error" messages. To avoid this problem, change the SCSI ID of the adapter so that it is lower than the tape device setting.

• For example, set the tape drive's SCSI ID to 7 using jumpers or an external switch. Then set the AHA-274x SCSI ID to 6 using the ECU. (Use the configuration BIOS accessed by Ctrl-A at boot to change the setting on the AHA-284x.)

• A large disk used with the Solaris operating environment on an AIC-7770 controller cannot be mounted on a controller with a different geometry; the DPT PM-2022 controller, for example.

• Some VESA local bus motherboards do not support more than one bus master controller, like the AHA-2840VL host bus adapter.

• When using AHA-2742T and AHA-2842VL adapters with slow tape devices, under heavy loads error messages like this are displayed:

  Warning: /eisa/esa@2c00/cmtp@4,0 (Tape4): 0.25 inch cartridge Tape 11: Fixed record length (512 byte blocks) I/O

Set the SCSI ID of the tape drive higher than the host bus adapter.

For example, set the tape SCSI ID to 6 and the host bus adapter SCSI ID to 5 or less by doing the following:

• Log in as root and shut down the Solaris operating environment.

• Boot DOS and change the target ID of the host bus adapter to 5 using the ECU supplied by the motherboard manufacturer.

• Turn off the computer and power down the tape.

• Jumper the tape device to SCSI ID 6.

• Boot the Solaris operating environment and run the drvconfig and tapes utilities.