[oclug] tape drive recommendations

[Bill Strosberg]

On Wed, 27 Mar 2002, Brad Barnett wrote:

> 7VDC if you take the reading across those two connectors.  However Bill,
> I've yet to see a hard drive that doesn't have a diode after the +5 and
> +12 inputs.
> 
> In short, how is the power going to flow?  Until you can respond to this
> point, it doesn't make much sense for me to continue to respond to the
> rest.  Even if it is well laid out it is, and politely put. ;)

Brad:

Unless the drive is floating (gravity-free) in the air, it is usually
touching a computer chassis, your hands, a stack of (conductive) papers
etc.  All (even partially) conductive surfaces will form a ground
reference point for the DC voltage.  Even air can be somewhat conductive,
depending on the relative humidity.

My point was simple - if you are depending on the power connector ground
reference to be the single point of circuit engagement/disengagement, like
home wiring a light switch, you are taking risks with your equipment.

Also, in today's commodity morketplace for low-end hardware, depending on
the production facility and hardware designer to opt-in circuit protection
devices is risky.

-- 
Bill Strosberg
-----------------------------------------
bill -at- strosberg -dot- com
bill -dot- strosberg -at- rcpsc -dot- edu