Looking at a "random sampling" of 3.25" CD-ROM drives, it looks like they all conform (more or less) to some kind of mechanical standard, de-facto or otherwise. Is there an actual specification for this -- outer dimensions, hole locations, connector locations, etc -- or did everybody in this business "just know" what to do? Any information would be greatly appreciated, ESPECIALLY URL's for drawings of any kind.
I assume 3.25 is a mistype, and you meant 5.25, as in the subject.
I bet they're the same mounting screw locations as on 5 1/4-inch "half-height" format hard and floppy disk drives (who remembers "full-height" 5 1/4" floppy and hard drives, as used on the Apple ][ and IBM PC and XT?). The half-height "standard" probably goes back well over 20 years, and "full-height" even further.
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It's actually a superset of the old standards for 5.25" floppy and hard drives. The outline is the same as for a hard drive, but the screw holes are more numerous. If you want to be as safe as possible, you should use the side-entry holes, and make sure you have screw holes for both sets (upper and lower).
Connector position is not fully standardized, but any drive you buy today is 95% likely to have the power connector on the RH side (looking at the drive from behind) and pin 1 of the IDE connector next to the power connector. This de facto standard seems to have arisen from the people who make the all-in-one connector+jumper assemblies, rather than the other way round.
The reason I stipulated 5.25" CD-ROMs is that although they are not
100% identical in size, they are DARN close to it. Laptop CD-ROMs, though much sexier, are (a) more expensive, and (b) considerably less standardized. (Bitter experience speaking there).
There's a spec from the SFF (Small Form Factor) committe. I don't have more info at hand.
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