RESEND: Re: Feb '95 FC-AL Direct Attach Disk Adhoc minutes

Bob Snively Bob.Snively at Eng.Sun.COM
Thu Feb 23 20:06:23 PST 1995

The minutes say:

   - Consider having a 3-bay design vs a unitized connector (one for
     basic functions, one for power, and one for options) if this is
     less costly.

I would like to strongly discourage a unitized connector.  Instead,
I would like to suggest an optional pair of auxiliary connectors
adjacent to the 50-pin SCA-2 connector that would not partake in any
normal backplane plugging.  The only requirement would be to keep
a space clear adjacent to the SCA-2 connector to make sure no accidental
or unintended contact was made with these connectors.  The precise
location of these optional auxiliary connectors would be flexible, but
their contact type and pin assignments would be defined in the specification.

That allows the cable plugging, but retains the far more beneficial
characteristics of SCA-2 plugging.

A typical 3.5" drive end might then look like:

     |     _______________    _________________________         _____   |
     |    |               |   \                       /        |     |  |
     |    |  Power conn  <   | \   SCA-2, 50-pin     / |       | aux |  |
     |    |_______________|     \___________________/          \_____/  |

            ^                           ^                       ^
            |                           |                       |
	   Optional power connector     |                    Optional control
           Type/pinout spec'd           |                    Type/Pinout spec'd
           Location suggested           |                    Location suggested
           Suitable for cabling         |                    Suitable for cables
                                       Mandatory SCA-2 connector
					Type/pinout spec'd
					Location spec'd
					Designed for blind mating,
					Useable for signal plugging

Bob Snively
Sun Microsystems Computer Company
Mail Stop UMPK 12-204
2550 Garcia Avenue
Mountain View
California 94043-1100

Phone:		(415) 786-6694
FAX:		(415) 786-6458
e-mail:		bob.snively at

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