Re: ProDOS misc. questions

[wbaguhn@nyx10.cs.du.edu (Will Baguhn)]

In article <31FE0E42.4CB6@cardshow.com>,
Michael Guitton  <webmaster@cardshow.com> wrote:
>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

I think that a far more likely way of doing it under ProDOS 8 would be
the way P8 handles AppleShare volumes... can only handle transactions
dealing with FILES, not blocks.  In this way, a "hacked" P8 could access
HFS, as well as a "Super ProDOS" filesystem.

All existing software would work, so long as it only did read/write calls
on Files, not blocks.

-- 
                                      --- Rev. SPQR (wbaguhn@nyx.net)