[Ham-Computers] RE: SATA
Loren Moline WA7SKT
lmoline at hotmail.com
Wed Dec 31 00:32:37 EST 2008
Thanks for the additional info Robert! Loren WA7SKT Member: ARRL and Pacific Northwest VHF SocietyMember: Hearsat Satellite Monitoring GroupLocation: CN86cx
From: WA5CAB at cs.comDate: Wed, 31 Dec 2008 00:30:44 -0500Subject: Re: [Ham-Computers] RE: SATATo: ham-computers at mailman.qth.netLoren,To add one further point to what Aaron wrote, consider the physical layout of the commonly used parallel cables versus the serial ones. Laid out flat in a straight line, the parallel ribbon cable is pretty predictable, although specs on the outer wires will be slightly different from the inner ones. But you can fold, bend and otherwise mutilate the ribbon as it is stuffed into the box. If you Z-fold a ribbon to shorten it you add feed-forward capacitance between those wires lying closest together. If you fold it the long way to get it through a hole, you add a small shunt capacitance between wires. Etc. So in the practical case, the actual parameters of the cable are much more variable from installation to installation than with a small diameter round serial cable. And at a gigahertz this becomes significant in terms of the bit timing problems Aaron mentioned. Among other things, it varies the velocity factor of each wire in a totally unpredictable manner.Robert Downs - Houstonwa5cab dot com (Web Store)MVPA 9480
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