Mounting HP7970e 9-Trk 1/2" Tape Drive

[Jay West]

Chuck wrote...
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The HP disk array rack is a pretty standard 19" EIA rack, with some extra slots for mounting the disk drive slides.

Looking at the 7970, without the mounting kit, it's a standard 19" wide.
 The right side flange has holes for mounting; the left side (the side with the support hinges for the works) has a similar flange, but without holes.  Since mounting holes on an 19" rack are 18" apart, I could see where just boring a couple of holes in the hinge-side flange and countersinking them for flathead bolts would work to secure the drive.
On the DA cabinet, however, the side "skins" project about an inch forward of the mounting rails, so you'd probably have to remove one to
get clearance to open the drive up for servicing.   On the other hand, a
"naked" rack would probably work just fine.
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Yes, it's all "standard 19 inch" but..... the HP gear and mounting kits of that time expected certain things to be present in the rack design/construction well beyond just the space between the vertical posts.

As I recall, on the left, the flange (where mounting holes are - on the right) does not have mounting holes. And drilling and tapping would be difficult because a 2 inch thick piece of solid metal from the side of the casting covers those. You would only be able to screw them in from the back, and in many racks that wouldn't be possible. Not to mention that part of that solid metal casting cantilevers when the unit is in the service position, so drilling all the way through (or anchoring the casting) is going to disallow getting to stuff you want to get to. And if you can't use the internal access door as-mounted, I'd bet the chance of injury or damage goes up exponentially every time you need to pull it out of the rack so you can get to stuff. There ARE bolt holes for attaching on the left, but they are not on the flange as they are on the right side. They are on the left side of the aluminum housing, about 7 inches back from the front, in a vertical line. You're not going to find a rack that has attach points there, and those are the PRIMARY attach points for the entire left hand side (and they are in aluminum housing, so absolutely depend on the steel bracket on the left for weight support).

I'm wondering if connecting the tape unit by using bolts along the outer flanges (assuming they were present on left and right - which they weren't) may not be sufficient given the weight of the unit. That is why the special HP mounting bracket has an L-angle on the bottom, to take much of the weight of the unit. Without it (ie. in a non-(hp-period)standard rack) I wonder if the flanges really aren't designed to hold that kind of weight.

So... I'm curious how they were actually mounted on the left in that particular rack. The only method I've ever seen that mostly works is using L-brackets under the unit. But that still doesn't attach the left side. Some may be ok with that I'm sure. I myself have visions of 150# of mostly cast aluminum and steel coming off those L brackets and they would bend the right racksupport severely (or the tape unit) for sure. 

I'm not at all saying it can't be done and done sufficiently. I'm just curious how :) I've been blessed with the right brackets and racks, so never had to mess with it. And like I said, haven't laid eyes on my 7970s in over a year, so my memory is prolly foggy :)

J