Question re sata cables

[gene heskett]

On Wednesday, October 06, 2010 01:45:49 am Basil Chupin did opine:

> On 06/10/2010 15:23, gene heskett wrote:
> 
> [pruned]
> \
> 
> > Cables generally come with drives, so I do have some spares.  I'll see
> > how my knee feels about crawling under the desk tomorrow.  I have one
> > that isn't too enthusiastic about such activities
> 
> Know how you feel. Which is why I have the computer sitting on a Laminex
> covered board which makes it very easy to slide the computer from under
> the desk (the floor is carpeted) or, as I did for a friend, whose floor
> is simply polished, I put the computer on an old towel. The only
> crawling I need to do is to disconnect/reconnect the cables but all the
> work is done with the computer sitting on the breakfast bench in the
> kitchen.
> 
> [pruned]
> 
> > Looking at the new ones I just pulled out of the plastic bag, I am not
> > convinced the gold flashing on the contact wires is good for more than
> > a couple of plug/unplug cycles, no color to speak of.  What a cheap
> > connector those things are.
> 
> I have never been impressed with this "gold" plated stuff. What's UNDER
> the "gold" plate?
> 
> The following comment probably does not apply nowadays but years ago a
> brand of 80-wire cables went on sale - and people started to experience
> strange problems with their HDs and data.....
> 
> Reason? The cables were too long (they were marketed as providing you
> with more cable length to make it easier to connect the bits to the
> mobo). At that length the cables caused what I think was called "bounce"
> or "echo" or some such. Normal cables were designed to be only so long
> as to not cause distortion to the signal to/from the HD but these cables
> were too long (only by about 25mm I think).
> 
> BC

Chuckle, yep.  As a broadcast engineer, I've been dealing with VSWR for 
about 50 years & every twice in a while, specially when scsi was _the_ only 
way, I'd publish about a 3 page tome on the proper care and feeding of the 
transmission line known as SCSI.  One little known fact is that its cable, 
if properly terminated, can be run as far as 39 meters!  Unforch, the 
darned bean counters between the engineers and the production floor never 
understood that it needed those high priced active terminations to make 
anything more than 6" long work truly correct.  So they used the passive 
resistor packs, which are typically +-20%.  The results were 100% 
predictable, and not even sacrificing virgins would make them work until 
someone who understood transmission lines fixed it.  Actually, there are two 
problems there, the second one being the the cheap SI diode used for power 
buss isolation, should have been either a germanium, or better yet a 
schotky(sp?) because the SI's .7 volts loss kills any logic one noise 
margin it ever had.  Gah, got me started, sorry.  I'll shut up.

Thanks Basil.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
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