Scsi Parity; Hardware Installation - Adaptec AHA-1740A Technical Reference Manual

adaptec

SCSI Parity

Check all SCSI devices to ensure that they generate parity. If any SCSI device does
not generate parity, then all SCSI devices should be set to disable parity checking. If
all SCSI devices generate parity, it is recommended that parity checking be turned
on for all devices. Please note that generating parity and checking parity are two
separate functions. The AHA-1740A/1742A/1744 configuration overlay can be used to
enable/disable parity checking for each SCSI ID.

Hardware Installation

The 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 which
permits 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 normally
require hardware jumpers. An exception is configuration of the floppy disk controller
on the AHA-1742A (a description follows).
Ensure that you have the correct version of the AHA-1740/1744 for your system. The
AHA-1740A/1742A supports the more common single-ended SCSI interface. The
AHA-1744 supports the differential interface, more common on SCSI peripherals for
minicomputers. While the two use the same signal protocol, they are not electrically
compatible.
The AHA-1740/1740A/1742A require single-ended devices. The AHA-1744 re-
quires differential devices. Failure to match drive types can result in electrical
damage to the board and the peripherals.
adaptec, inc
AHA-1740
AIC
4600
3-4
WARNING
Product
Identification
Label Here
RN2
EEPROM
AIC
AIC
575
6251
BMIC
Figure 3-1. AHA-1740/1744 Board Layout
AHA-1740A/1742A/1744
RN3
RN4
Differential Interface
Logic (AHA-1744 Only)
AIC
565
BIOS