18 Apr
2003
18 Apr
'03
10:23 a.m.
I remember back in my early BBC days, when the floppy
drives were often
single-sided, being able to buy "flippable discs" - they had extra holes in
them so you could insert the disc into the drive either way up, and use
both sides!
I've seen a 5.25" signle-head drive that had the option of 2 index
sensors and 2 write-protect switches so that any normal disk could be
flipped over.
3" single-head drives normally allowed you to insert the disk both ways
up too, so as to use both sides. Double head drives had an extra bracket
so that the disk would only fit the right way up. Which meant that
double-head drives could not normally read disks written on single-head
drives (since the 'flup side' was recorded backwards...)
-tony