31 Mar
2004
31 Mar
'04
8:32 a.m.
>>>> "Tony" == Tony Duell
<ard(a)p850ug1.demon.co.uk> writes:
> LGP-21 fixed-head-platter mechanical memory (main
store, not
> "disk") the heads sit crashed (sic) and lift when up to speed. The
> platter surface has fine scoring -- it's normal. It's only 80 bits
> per inch. Nickel plated steel. In fact, there's little springs
> that press the heads DOWNWARD.
Tony> FWIW, the springs on hard disk heads press the heads _towards_
Tony> the platter too. Look at something like an RK05 sometime. The
Tony> heads are lifted by flying on the air dragged round by the
Tony> platter.
Drives like the RK05 retract the heads as part of spindown, so the
heads never land on the platter. They only load when the disk is up
to speed.
Gravity is a component of the head loading force, which is why the
"up" and "down" heads are different -- different springs.
paul