Newbie : PC-IIGS-II compatibility

[Pierre Baldensperger <balden@extreme.ece.uiuc.edu>]

Hi,

I'm an ex-Apple II user and just have the opportunity to
buy an Apple II GS. I have some very stupid questions
about it :

- Is an Apple II GS compatible with the older Apple II
  (II+, IIe, IIc) ? To what extent ?
- I know there is some kind of incompatibility between
  5.25" Apple II disks and 'current' 5.25" drives for PC.
  The Apple II GS has both a 3.5" and a 5.25" drives. Can
  the 3.5" II GS disks be read in a PC 3.5" drive ? Can
  the II GS 5.25" drive read Apple II 5.25" disks ?
- Are there PC utilities to create 3.5" II GS disks from
  disk images ?

Thanks,
Pierre.