Question re: 8" drive form-factor

[Eric Smith]

Steven Hirsch wrote:
> Here's a strange one:  I recently acquired two Shugart 851 drives from 
> another cctech-er.  They were in nice shape and operate fine.  The 
> weird part is their form-factor.
>
> I have 8 or 10 other 8" drives in my collection, both half-height and 
> full-height, including two other 851 Shugarts.  All of these are 8.5" 
> wide, with faceplate and frame being exactly the same size.
>
> These two "new" Shugart units are _9.5"_ wide at the faceplate and 
> require a clearance of about 9-1/8" for the frame.  Can anyone explain 
> this odd sizing?  Were they perhaps manufactured against an earlier 
> standard?

IIRC, the "R" suffix drives are intended to be rack-mounted in pairs.  I 
have no idea, though, how that could be better than using the 
standard-width drives since either way they're going to need some 
mounting hardware.

Eric