Re: Copying Mac MFS disks on an Apple II

["Charlie" <charlied@NOSPAMbboard.com>]

"Greg Buchner" <apple22@mn.rr.com> wrote in message
apple22-A39589.22123102092003@apollo-ge0.rdc-kc.rr.com">news:apple22-A39589.22123102092003@apollo-ge0.rdc-kc.rr.com...
> In article <acdalv4olv4h1ajrgdhr0njafd5gv2tum6@4ax.com>,
>  Jeff Blakeney <CUTjblakeney@syndicomm.com> wrote:
>
> > On Tue, 02 Sep 2003 13:01:00 GMT, "M. Pender" <mpender@hotmail.com>
> > wrote:
> >
> > >IIRC Mac HFS disk blocks are not the same size as ProDos disk blocks;
there
> > >are a few extra bytes thrown.  I doubt that the 512 byte ProDos blocks
will
> > >be very appealing to the Mac.
> >
> > ProDOS and HFS both used fixed block sizes of 512 byte blocks.  HFS+
> > supports variable block sizes but I'm almost positive the smallest
> > size they can be is 512 bytes and they must contain a number of bytes
> > that is a power of 2 (ie. 512, 1024, 2048).
>
> (I hope I've got all of this right...)
>
> Actually it's slightly more complicated.  You have to deal with physical
> blocks (the actual blocks on the hard drive, which are almost always 512
> bytes) and logical blocks, which can vary in multiples of 512 bytes
> (unless the phsysical blocks on the HD are different).
>
> ProDOS supports only 512 byte logical blocks so they map 1:1 to the HD,
> 65536 blocks to the volume.
>

One minor quibble:

I believe ProDOS supports 65535 blocks to the volume, not 65536.

Charlie