4 Nov
2010
4 Nov
'10
2:07 p.m.
I guess you
know already but I keep coming across people who
think that RAID means you'll never need to backup again. Quite
how they expect to recover from accidentally deleting something
important beats me.
Or a repeating situation that eats disks. I had a hell of a time, and only partial success when
a client's Apple ][+
would not boot. So, they tried their backup copies. Then they tried
EVERY disk they could find. Unlike the SA400 (used by TRS80, etc.), the
SA390 with Apple's own logic board could write to a write-protected disk
when the controller malfunctioned.
Can it? According to the schematic in the Apple DOS manual (I've just dug
it out), the wrtite protect switch will disable the Wr Req/ line by
tri-statingB4c (a '125). The output is correcly pulled up to the inactive
state by R16 under such conditions.
Of course a problem on the analogue board can result in the thing
corrupting disks, but that would apply to any drive.
-tony