[File] [PATCH] of Magdir/archive for misidentified Apple DiskCopy 4.2 image; correction
Jörg Jenderek
joerg.jen.der.ek at gmx.net
Mon Apr 6 22:40:05 UTC 2020
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at 07.04.2020 00:23 wrote Jörg Jenderek:
> Hello,
> some months ago i send patch for Magdir/archive for Apple DiskCopy
> 4.2 image. In the mean time sometimes other files are misidentified
> and i get an output like
> windows7en.mbr: Apple DiskCopy 4.2 image
> uÀZм, 3024206762 bytes,
> 0x55cd135d tag size, 0xf7 encoding, 0xc1 format
>
> Unfortunately Apple DiskCopy files have no real good 4 byte magic
> pattern. But according to mentioned DiskCopy 4.2 format
> specification on wiki.68kmla.org at offset 0x52 a 2 byte magic
> value 0x0100 is found. That is used as first test by line:
> 0x52 ubeshort 0x0100
>
> Two byte magic is not so strong. So i looked for more test lines.
> According to website lowest disk size is 400K. So test for such or
> bigger disk sizes by line
> >0x40 ubelong >409599 Apple DiskCopy 4.2 image
>
> Unfortunately these 2 tests are also true for master boot record of
> English Windows 7 (See example windows7en.mbr), but for that
> misidentified example an extreme high disc size of 3024206762 is
> shown. According to documentation for such floppy disc images
> highest size is 1440k. So now i also test for disk size equal or
> below 1440k by third additional line. This now becomes like
> >0x40 ubelong >409599
> >>0x40 ubelong <1474561 Apple DiskCopy 4.2 image
>
> Additional i also display a user defined mime magic by line like
> !:mime application/x-dc42-floppy-image
>
> After applying the above mentioned modifications by patch
> file-5.38-archive-dc42.diff then misidentification vanish
> and such old Apple disc images are still identified and described l
ik
> e:
>
> Disco 12.image: Apple DiskCopy 4.2 image
> Disco 12, 1474560 bytes,
> MFM CAV dshd (1440k), 0x22 format
> Microsoft Mail.image: Apple DiskCopy 4.2 image
> Microsoft Mail, 819200 bytes,
> 0x4b00 tag size,
> GCR CLV dsdd (800k), 0x22 format
>
> I hope my diff file can be applied in future version of
> file utility.
>
> With best wishes
> Jörg Jenderek
>
>
Sorry i have appended a wrong older patch file-5.38-tplink-dbt.diff
Now comes the correct patch file-5.38-archive-dc42.diff !
Thanks
Jörg Jenderek
- --
Jörg Jenderek
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-------------- next part --------------
--- file-5.38/magic/Magdir/archive.old 2019-11-15 21:03:14 +0000
+++ file-5.38/magic/Magdir/archive 2020-04-06 17:28:21 +0000
@@ -446,4 +446,7 @@
# test for disk size equal or above 400k
->0x40 ubelong >409599 Apple DiskCopy 4.2 image
+>0x40 ubelong >409599
+# test for disk size equal or below 1440k
+>>0x40 ubelong <1474561 Apple DiskCopy 4.2 image
#!:mime application/octet-stream
+!:mime application/x-dc42-floppy-image
!:apple dCpydImg
@@ -451,20 +454,20 @@
# image pascal name padded with NULs like Microsoft Mail
->>00 pstring/B x %s
+>>>00 pstring/B x %s
# data size in bytes like 409600
->>0x40 ubelong x \b, %u bytes
+>>>0x40 ubelong x \b, %u bytes
# tag size in bytes
->>0x44 ubelong >0 \b, 0x%x tag size
+>>>0x44 ubelong >0 \b, 0x%x tag size
# data checksum
-#>>0x48 ubelong x \b, 0x%x checksum
+#>>>0x48 ubelong x \b, 0x%x checksum
# tag checksum
-#>>0x4c ubelong x \b, 0x%x tag checksum
+#>>>0x4c ubelong x \b, 0x%x tag checksum
# disk encoding
->>0x50 ubyte 0 \b, GCR CLV ssdd (400k)
->>0x50 ubyte 1 \b, GCR CLV dsdd (800k)
->>0x50 ubyte 2 \b, MFM CAV dsdd (720k)
->>0x50 ubyte 3 \b, MFM CAV dshd (1440k)
->>0x50 ubyte >3 \b, 0x%x encoding
+>>>0x50 ubyte 0 \b, GCR CLV ssdd (400k)
+>>>0x50 ubyte 1 \b, GCR CLV dsdd (800k)
+>>>0x50 ubyte 2 \b, MFM CAV dsdd (720k)
+>>>0x50 ubyte 3 \b, MFM CAV dshd (1440k)
+>>>0x50 ubyte >3 \b, 0x%x encoding
# format byte
->>0x51 ubyte x \b, 0x%x format
-#>>0x54 ubequad x \b, data 0x%16.16llx
+>>>0x51 ubyte x \b, 0x%x format
+#>>>0x54 ubequad x \b, data 0x%16.16llx
# ESP, could this conflict with Easy Software Products' (e.g.ESP ghostscript) documentation?
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