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Groups > comp.sys.apple2.programmer > #1273
| From | D Finnigan <dog_cow@macgui.com> |
|---|---|
| Newsgroups | comp.sys.apple2.programmer |
| Subject | Re: spec for file entry for ProDOS extended (forked) files? |
| Date | 2014-08-18 17:08 +0000 |
| Organization | Mac GUI |
| Message-ID | <dog_cow-1408381687@macgui.com> (permalink) |
| References | <e294b892-effa-434f-b359-12dbe51c784c@googlegroups.com> |
Look at the GS/OS source. That, and the Tech Note, were my sources for
writing the implementation that I use in Format Converter for Mac GUI Vault.
In fact, this is a large block that I have copied into the source code as a
comment:
Storage type $5 is used by the ProDOS FST in GS/OS to store extended
files.
The key block of the file points to an extended key block entry. The
extended
key block entry contains mini-directory entries for both the data fork
and
resource fork of the file. The mini-entry for the data fork is at offset
+000
of the extended key block, and the mini-entry for the resource fork is at
offset +$100 (+256 decimal).
The format for mini-entries is as follows:
storage_type (+000) Byte The standard ProDOS storage
type for this fork of the file.
Note that for regular directory
entries, the storage type is the
high nibble of a byte that contains
the length of the filename as the
low nibble. In mini-entries, the
high nibble is reserved and must be
zero, and the storage type is
contained in the low nibble.
key_block (+001) Word The block number of the key
block of this fork. This value and
the value of storage_type combine to
determine how to find the data in
the file, as documented in the
ProDOS 8 Technical Reference Manual.
blocks_used (+003) Word The number of blocks used by
this fork of the file.
EOF (+005) 3 Bytes Three-byte value (least
significant byte stored first)
representing the end-of-file value
for this fork of the file.
All remaining bytes in the extended key block are reserved and must be
zero.
--
]DF$
Apple II Book: http://macgui.com/newa2guide/
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spec for file entry for ProDOS extended (forked) files? ivan@ivanx.com - 2014-08-16 18:07 -0700
Re: spec for file entry for ProDOS extended (forked) files? dempson@actrix.gen.nz (David Empson) - 2014-08-17 13:25 +1200
Re: spec for file entry for ProDOS extended (forked) files? ivan@ivanx.com - 2014-08-16 19:38 -0700
Re: spec for file entry for ProDOS extended (forked) files? D Finnigan <dog_cow@macgui.com> - 2014-08-18 17:08 +0000
Re: spec for file entry for ProDOS extended (forked) files? ivan@ivanx.com - 2014-08-22 16:29 -0700
Re: spec for file entry for ProDOS extended (forked) files? olivier.zardini@itn-group.eu - 2014-08-25 05:31 -0700
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