Adaptec AHA-2740, 2742, 2740A, 2742A, 2740T, 2742T, 2740AT, 2742AT, 2740W, 2742W, 2840A, 2842A, 2840VL, 2842VL HBAs

Preconfiguration Information

• Don't use a version of the AHA-274x series configuration utilities before version 2.1.

• Don't use a version of the AMI ECU before version 2.01 when configuring the AHA-274x on a motherboard with an AMI BIOS.

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:

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

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

3. Turn off the computer and power down the tape.

4. Jumper the tape device to SCSI ID 6.

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

Configuration Procedure

1. Select channel A as the Primary Channel.

2. Run the BIOS configuration and verify that BIOS support for more than two drives is disabled.

3. If there are multiple AIC-7770 controllers on one system, the order of the I/O base addresses must match the order of the BIOS base addresses.

   On an EISA motherboard, the I/O base address corresponds to the EISA slot number times 0x1000 plus 0xC00 for controller boards. For example, if the first slot has an AHA-274x controller, the address is 0x1C00, and if the adjacent slot also has an AHA-274x controller, the address is 0x2C00. Motherboard manufacturers usually map the controller chip on the motherboard at the highest EISA slot plus 1. Thus in an EISA motherboard with three EISA slots, the motherboard AIC-7770 address is 0x4C00.

   The BIOS base address is selected from a range of choices on the manufacturer-supplied configuration utility. Common addresses for the AIC-7770 controller are: 0xCC00, 0xD400, 0xD800, and 0xDC00. The controller with the lowest BIOS base address will become the boot or primary controller.