Mailinglist Archive: opensuse-factory (528 mails)

< Previous Next >
Re: [opensuse-factory] hdparm
  • From: Donn Washburn <n5xwb@xxxxxxxxxx>
  • Date: Mon, 07 May 2007 21:29:51 -0500
  • Message-id: <463FE09F.7000106@xxxxxxxxxx>
Rajko M. wrote:

Grounds commoned on motherboard side will show shorts on the other end too. Wires are to short to see 2 wire lengths resistance with DMV, so it will appear as short on both ends. They had to use existing ground pins on 40 pins connector and they needed 40 extra wires between existing signal wires to prevent crosstalk. More: http://en.wikipedia.org/wiki/Advanced_Technology_Attachment

I never tried to find out exact reasons for the one side grounding.
I will remind everyone that grounding in multiple places is a bad idea.
Reason is what is known as a "ground loops". It ends up as hum or a potential voltage differences - worse case heat. The idea of center point ground means only grounded at one single point or at least the additional 40 wires connected at the computer MB end and open on the IDE Drive end. It can be used as a shield from adjacent signals coming from the stray magnetic fields created around a conductor by current flowing through a wire. If connected at both ends my guess it would cause interference with the shifting of data (the reason SATA is better and faster).

If they are NOT connected at either end - bad idea! All of those wires that are floating would be about 144Mhz - 2M HAM length and with my 50 Watt Kenwood radio I could likely destroy your data day. Just think 40 antennas. Grounding them at one end is good to stop this effect.

--
73 de Donn Washburn
307 Savoy Street     Email: " n5xwb@xxxxxxxxxx "
Sugar Land, TX 77478 LL# 1.281.242.3256
Ham Callsign N5XWB   HAMs : " n5xwb@xxxxxxxx "
VoIP via Gizmo: bmw_87kbike / via Skype: n5xwbg
BMW MOA #: 4146 - Ambassador
      " http://counter.li.org " #279316

Did you know?
The transistor was invented by three white men.
---------------------------------------------------------------------
To unsubscribe, e-mail: opensuse-factory+unsubscribe@xxxxxxxxxxxx
For additional commands, e-mail: opensuse-factory+help@xxxxxxxxxxxx

< Previous Next >