SAS-1.1 PHY - Comments on 05-059r0
bill_ham at ix.netcom.com
Thu Mar 3 15:45:19 PST 2005
* From the T10 Reflector (t10 at t10.org), posted by:
* Bill Ham <bill_ham at ix.netcom.com>
Somehow, the point I made about the use of the free and fixed terminology seems to have been lost in this discussion. Let me state it one more time:
The fixed and free terminologies were adopted in SFF connector documents for the sole purpose of avoiding a terminology war with EIA. Free and fixed were originally intended by EIA to describe the application with the implicit (but somewhat flawed) assumption that the connector itself would map to the application. For example in wall power outlets the receptacle is usually fixed and the plug is usually free. This concept does not map well as a connector descriptor in several cases because the application description terminology free and fixed actually have only a coincidental relationship to the connector properties.
That notwithstanding the terminology of free and fixed was used in SFF connector documents to denote the GENDER NOT THE APPLICATION with clear illustrations in the SFF documents to illustrate the meaning. The choice of whether to use free or fixed was driven by the most common applications for the gender but the use does not depend on the application - it only depends on the gender of the connector. This scheme apparently worked because we had no comment from EIA on the point. In hindsight maybe we should have had that terminology war.
The only value of having the free and fixed terminology in the SAS documents is to match the terminology used in the connector specifications. I still think the the receptacle (fixed) and plug (free) is the best way for SAS. This is exactly what is used for example in SFF-8470.
Issues of shielding, retention mechanism, size, number of conductors etc. were never intended to be covered by the terms free and fixed. Free and fixed were only used to denote the gender of the connector.
To illustrate the point of why free and fixed do not map to the application consider the following:
I have an electric start snowblower that uses 120V to drive the starter. In this application there is a fixed receptacle in the wall outlet, a plug on the free end of the cord used to connect to the snowblower, a receptacle on the other free end of the cord, and a plug mounted firmly (fixed) on the snowblower. Hmmmm... free and fixed do not really work very well to describe the connector gender do they? Yet that is exactly how the terms free and fixed are used in SFF and EIA documents: to describe the connector gender (not the application).
Dal Allan wrote:
>* From the T10 Reflector (t10 at t10.org), posted by:
>* Dal Allan <endlcom at acm.org>
From: Bill Ham <bill_ham at ix.netcom.com>
Sent: Mar 1, 2005 9:46 AM
To: Alvin.Cox at seagate.com, t10 at t10.org
Subject: Re: SAS-1.1 PHY - Comments on 05-059r0
Actually the fixed and free terms were chosen to avoid conflict with EIA terminology and have nothing to do with political correctness or sexual inferences. The only issue that I know of on this topic is consistency with SFF and other connector documents. Personally I prefer plug and receptacle in cases where there is clearly a plug and receptacle based on the physical features of the connector. Some connectors have both plug properties (i.e., protruding contacts) and receptacle properties (i.e., features designed to accept the plug in the mated condition) so the designation as plug or receptacle may not be as clear as one might think.
Probably the best solution is to use both terms. For example plug (free) and receptacle (fixed) or whatever applies.
From: Alvin.Cox at seagate.com
Sent: Feb 28, 2005 3:41 PM
To: t10 at t10.org
Subject: SAS-1.1 PHY - Comments on 05-059r0
Item 1 of this proposal has been included in r1 of 05-023. This revision
corrects the figure reversal.
Regarding item 2, I suggest that we do not change the naming of the
clauses and figures. The recommendation is only a partial solution, as the
retention of the words plug and receptacle, per my understanding, does not
satisfy the intended political correctness that fixed and free are
supposed to bring by removing any sexual connotation. The bottom line is
that plug and receptacle are very descriptive names for the connector
physical attributes while fixed and free relate to usage (fixed location
or free to move to another location) and have no relationship to the
connector physical description.
Test from 05-059r0:
Item 2: Recommendation
Explicit and consistent titling of the clauses and figures as per the
following (or similar).
126.96.36.199 and Figure SAS Fixed Internal Plug Connector
188.8.131.52 and Figure SAS Free Internal Cable Receptacle Connector
184.108.40.206 and Figure SAS Fixed Internal Backplane Receptacle Connector
220.127.116.11 and Figure SAS Free External Cable Plug Connector
18.104.22.168 and Figure SAS Fixed External Receptacle Connector
22.214.171.124 and Figure SAS Fixed Internal Wide Plug Connector
126.96.36.199 and Figure SAS Free Internal Wide Cable Receptacle Connector
Seagate Technology, LLC
E-Mail alvin.cox at seagate.com
Phone 7x24 978 828 9102
Fax 978 470-0321
Phone 7x24 978 828 9102
Fax 978 470-0321
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