Re: ProDOS misc. questions

[Michael Guitton <webmaster@cardshow.com>]

Henrik 'Ratte' Gudat wrote:
> =

> In <31FDD36C.B59@cardshow.com> Michael writes:
> =

> > o Why the root directory of a ProDOS volume is limited to 51 files?
> There's limited space for the root structure.
> =

Why this root structure has to fit entirely into Block 2?

> > o Would it be possible to overcome the 32MB partition size limit of > >=
 ProDOS?  [...]
> =

> Theoretically yes, practically no.
> Prodos does not support logical blocks. All block references are
> associated with physical block numbers.
> Unfortunately, ProDos uses 16-bit values for blocks, limiting volumes
> to 32Mb.
>
Yes... Up to 65536 blocks of 512 bytes.

> To overcome this limitation,you'd have to rewrite about everything.
>
I don't have time nor knowledge to do that.

> Strangely enough, the SmartPort can deal with volumes as large as 8Gb bec=
ause
> the extended SmartPort protocol supports 32-bit block numbers.
>
If I'm good at computing, 8GB (GygaBytes) maximum volume size is =

attained with a 24-bit addressing mode, isn't it?

2 ** 24 =3D 16777216
16777216 * 512 =3D 8589934592
8589934592 / (1024 ** 3) =3D=3D 8GB.

While a 32-bit addressing mode would allow:

2 ** 32 =3D 4294967296
4294967296 * 512 =3D 2,19902325555 E12
2,19902325555 E12 / (1024 ** 4) =3D 2 TB !!! (Did I miss something?:)

An Apple II expert could then hack a new 24-bit addressing version of =

ProDOS, couldn't he? Is there a need for this?

> I hope the Mac will once get rid of this logical block business. With 64-=
bit
> architecture, there's really no need for that.
> =

Wait and see. MacOS 8 should get rid of the logical block business, =

which makes small files bigger than they really are. =


-- =


Micha=EBl Guitton
webmaster@cardshow.com