>Can someone explain to me why there are 50 pin, 68 pin and 80 pin SCUSI
>controllers. Is it to do with evolved versions?

They're all different SCSI _connectors_.

Generally, the size of the connector relates to the size of the data
path. Larger connector -- as in increased number of pins -- generally
allows for a larger data path.

50-pin transfers 8 bits (1 byte) at a time.

68-pin transfers 16 bits (2 bytes) or 32 bits (4 bytes) at a time.
(To do 32 bits, a second 50-pin cable is utilized.)

80-pin transfers 16 bits (2 bytes) at a time. Connector also
transfers power to device.


There are also:

110-pin transfers up to 32 bits (4 bytes) at a time.

Firewire is also a SCSI-bus connection.



There are many good sites about SCSI. <http://www.scsita.org>


Someone correct me if I've mistaken anything.

Cheers,

Mike Whalen


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