• Q - "I've seen other 2U cases that take six removable HDDs. Why don't yours?"
• A - Cooling!!! We planned for 10,000- and 15,000-RPM SCSI drives. These drives dissipate a lot of heat. Any drive, of any speed, will overheat
if insufficient cooling is provided, but 10,000- and 15,000-RPM drives require extra consideration.
Drives allowed to operate continuously at elevated temperature will have shortened life and higher failure rates.
If three 1" drives are mounted in a vertical stack in a 2U
case, the gap between drives will be very small, 0.100" or less. It will be very difficult or impossible
to move enough air thru such a small gap. Case designs of this sort will have trouble cooling Dual "Nocona" Xeon CPUs and high-performance SCSI hard-drives. If you use a case with a stack of three removable
hard-drives and you measure the temperature of the drives in actual operation, you may be in
for a rude surprize.
This said, we do use three-drive stacks in our D20 cases, but these are fixed drives, not removable.
Each stack has it's own, ducted, high-velocity 80mm fan to guarantee adequate air through the stack. Plus, there are additional vents elsewhere in the front-panel. Any
other approach can let the drive and CPU temperatures get too high.
• Q - "I've seen 1U cases take three removable HDDs and CD and floppy. Why don't yours?"
• A - It's because of cooling. There's no way of getting enough air through the front panel if it is filled with
so many drives. We've seen manufacturers cheat, by adding air inlets behind the left and right rack-mounting points, but this is not safe. Many rack
enclosures are sealed and all the available cooling air must go through the front panel. Moreover, if you use slide
rails to mount the 1U devices, the rails will cover the sides and prevent any air from going thru side air holes. If you try this in a dual-Xeon system
with 10,000rpm SCSI drives you're inviting problems.
• Q - "Why can't I use a normal CDROM drive in your 1U cases? I've seen others do it!"
• A - It's because we adhere to the standard 1U EIA height and the others don't. The nominal
height of a 5¼" CDROM drive is 1.625" but it is common to see 1.640 and the plastic
face can be as big as 1.700. If you take the 1.64" drive, and put a chassis bottom under it and
a lid over it, now your at 1.740 total height. But the EIA spec is 1.731! And you still
haven't provided for paint layers which are at least .003" each, top and bottom, inside and outside. If you load a rack
with 10 or 20 such chassis, all just a little too big, the excess will accumulate. The last
few chassis won't fit - - the mounting holes won't line up properly - - and they will scratch themselves
and their neighbors when being slid in and out.
Also, when you design a hole in the front panel big enought for the large CDROM drive you
have weakened the front panel so it no longer provides any structural support. If the front panel can't provide support, mechanical support
stresses can get transferred into the CDROM. Now the CDROM is supporting
the chassis instead of the other way around! We saw this design as fundamentally
flawed and we avoided it, although we still see our competition sell this poor design
to customers who don't know better.
• Q - "Your 4U case has space for 9 drives. When I put in 9 devices, why do I still see more space?"
• A - This guarantees air for each drive. It also guarantees another path for cooling air to enter
the case. In our own production we spread the extra space out among all the devices,
equally, so no one device has a large gap next to it, and each gap is small enough to
We found out (the hard way) that some 5¼" products are bigger than they're supposed to be.
Another situation is where you use a removable drive-bay and put a 1.625" high drive
into it.....when it's fully assembled it is bigger than it's supposed to be and the drive's top
is right against the inside of the lid. Then, when you put the neighboring drive in it's
in contact too, and there is no air flow and no way to cool the drives. We made our
drive-bay field slightly larger than necessary so there can be a slight gap between each device.
This eliminates rubbing and scratching and any possibility of one device interfering with
its neighbor, even if it's out-of-spec.
• Q - "Why don't you sell . . . . . "
• A - We select products, in part, as a function of the manufacturers' ability and willingness
to provide adequate support as well as good products. Over the years we've accumulated many
war-stories of manufacturers who wasted our time, and our VARs' time, with inadequate
tech-support, essentially supplying 'tech-unsupport'. If we aren't selling a certain product that you're expecting to find, it may be
because we've already determined that there is a problem with the manufacturer and/or the product.