SCSI ParityCheck all SCSI devices to ensure that they generate parity. If any SCSI device doesnot generate parity, then all SCSI devices should be set to disable parity checking. Ifall SCSI devices generate parity, it is recommended that parity checking be turnedon for all devices. Please note that generating parity and checking parity are twoseparate functions. The AHA-1740A/1742A/1744 configuration overlay can be used toenable/disable parity checking for each SCSI ID.Hardware InstallationThe Adaptec AHA-1740A/1742A/1744 EISA-to-Fast SCSI host adapter has been de-signed to operate as shipped in standard EISA class computers. The board (or the sys-tem in which it is installed) is normally shipped with a configuration disk whichpermits the board to be configured to the actual slot location in which it is installed.Unlike AT/ISA boards, but like Micro Channel boards, EISA boards do not normallyrequire hardware jumpers. An exception is configuration of the floppy disk controlleron the AHA-1742A (a description follows).Ensure that you have the correct version of the AHA-1740/1744 for your system. TheAHA-1740A/1742A supports the more common single-ended SCSI interface. TheAHA-1744 supports the differential interface, more common on SCSI peripherals forminicomputers. While the two use the same signal protocol, they are not electricallycompatible.WARNINGThe AHA-1740/1740A/1742A require single-ended devices. The AHA-1744 re-quires differential devices. Failure to match drive types can result in electricaldamage to the board and the peripherals.BIOSAIC565BMICAIC575 AIC6251AIC4600ProductIdentificationLabel HereRN3RN4RN2Differential InterfaceLogic (AHA-1744 Only)EEPROMadaptec, incAHA-1740ASSY44726-00Figure 3-1. AHA-1740/1744 Board Layoutadaptec AHA-1740A/1742A/17443-4
