>There's a factor of 2^9 in there because the SCSI address counts
512-byte blocks and the character >pointer counts single bytes.

I cannot locate my copy of the draft SCSI standard, but the
book I have before me states "Logical Block" for that field
(not characters) and the text explicitly states "2 terabytes".

Now that I look more closely, the only difference between the
10 and 12 byte commands seems to be the "transfer length" field:
16 bits for 10 byte and 32 bits for 12 byte. I *think* the
upgraded uVAX 3100-10e console code uses the 12 byte set.

Antonio