Machine room rack options

From John Ward:

At any rate, I think they are both functional, well build racks.  I like
the ElectroRack models a little better.  I have found the pre-tapped screw
holes to be a great time saver.  The problem is that some equipment most
notably Dell and HP expect a rack to have the square holes like the APC
racks have.  I find the little retaining nuts that go with the square holes
that are required by most other equipment to be a big pain. I'm sure there
are other differences.  ...

John.

--On Thursday, December 02, 2004 04:39:21 PM -0800 Dan STROMBERG
<strombrg@gmail.com> wrote:

>> >> one.  The APC and ElectroRack models are the currently
acceptable
>> >> models.  Which one you choose depends on the exact
needs for the
> systems
>> >> you foresee using.
> 
> Do you folks have information about how these two racks compare?  Why
> would you chose one over another?
> 
> Thanks!

A "U" is the measured height of a server case
1U is 44.45mm (1.75inches)
19 inches is 482,6mm

Some more food for thought on risers:

The standard PCI card form factor is 107mm x 312mm [4.2" x 12.283"]. The 
low profile version of the PCI board ranges from 64.41mm x 119.91mm to 
64.41mm x 167.64mm [ 2.56" x 6.6"].
(source: http://www.interfacebus.com/Design_PCI_Card_Size.html)

A 1U rackmount case is 1.75 inches in height, and a 2U case is 3.5 
inches in height.
(source: http://en.wikipedia.org/wiki/Cabinet_%28computer%29
)

Assuming the motherboard is flat (horizontal) in the rackmount case, it 
is physically impossible to connect a PCI card perpendicularly to the 
motherboard while fitting in a 2U case, since 4.2 > 3.5 .   PCI-express 
cards have the same height specification as PCI cards, so they cannot 
fit either.  If you do not connect perpendicularly, how else would you 
connect, except using a riser card that produces slots for cards to 
mount parallel to the motherboard plane?  One alternative might be to 
connect the card to the motherboard's edge, but my gut says this is a 
shady idea, although, admittedly, I have no concrete evidence.

I can't seem to argue with 4.2" > 3.5", but we can bring it up on the phone.

Just FYI,
-Daniel Wang