30 Mar
2004
30 Mar
'04
5:31 p.m.
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.
FWIW, the springs on hard disk heads press the heads _towards_ the
platter too. Look at something like an RK05 sometime. The heads are
lifted by flying on the air dragged round by the platter.
-tony