> Before there where capsulated 'Winchester'
type drives
> mainframes relied on removable disk stacks wit technology
> #1. Of course these had air filtration etc., but the stacks
Are you sure? On _all_ the demountable drives I have
here (DEC and CDC),
the heads fly over the disk surface. They are not at a mechanically fixed
height, like on a drum. In other words, they are like #2, not #1.
I would be _very_ suprised if you could make a
demountable drive where
you could remove the platter and put it back and get the position right
to 100 microns or so. That's why the head position has to be set by the
platter - i.e. the heads fly.
I cant speak for any drive, but some 19 years back (1979)
I've been working as a field technican for SIEMENS mainframe
computers and head adjustment has been one of the most complex
issues. Althrough air flow had influence, the main adjustment
was done by *hard*ware. No way a fixed mounted head on a
thight fited mounting could move seperatly ... and the fingers
and mountings had a weight of several kilogramms :)
Servus
Hans
--
Ich denke, also bin ich, also gut
HRK