32 bit SCA connector

"Permanent address gardner" at acm.org "Permanent address gardner" at acm.org
Tue Sep 27 12:02:18 PDT 1994

Jim McGrath writes:

>>As a natural extension of the SCA concept, I would like to float out
>>the possibility of including a 32 bit SCSI connector as part of SPIT.
>>Note that using the existing 80 pin SCA contact spacing we can fit
>>this on a 3.5" drive (I suggest 120 pins, which is 32 of the additional
>>40 for the extra 16 bits plus 8 for fun).

For a "fun" use of the extra 8 pins, I'll suggest an extra 4 bits
of error checking.  With the incentives to push for faster
transfer rates and more devices, simply parity is becoming
inadequate for reliable error checking.  For a working suggestion
perhaps a 4-bit reed-solomon code calculated on the previous data
transfer cycle, possibly including the phase lines.  By providing
an error check on the previous transfer, we catch clocking
glitches as well as data glitches.

Ed Gardner

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