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Found some stuff out about the Brother 120kB file system format.

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David Given
2019-02-14 22:00:52 +01:00
parent 21df54d8d8
commit 43066ddf45
1 changed files with 15 additions and 5 deletions
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@@ -87,11 +87,21 @@ record.) The sector order is 05a3816b4927, which gives a sector skew of 5.
High level format
-----------------
Once decoded, you end up with a 234kB file system image. Luckily, this turns
out to be a completely normal FAT file system with a media type of 0x58 --- did
you know that FAT supports 256 byte sectors? I didn't --- of the MSX-DOS
variety. There's a faint possibility that the word processor is based on
MSX-DOS, but I haven't reverse engineered it to find out.
Once decoded, you end up with a file system image.
### 120kB disks
These disks use a proprietary and very simple file system which I haven't
reverse engineered yet. It's FAT-like with an obvious directory and
allocation table. It'll need custom tools to access files.
### 240kB disks
Conversely, the 240kB disks turns out to be a completely normal Microsoft FAT
file system with a media type of 0x58 --- did you know that FAT supports 256
byte sectors? I didn't --- of the MSX-DOS variety. There's a faint
possibility that the word processor is based on MSX-DOS, but I haven't
reverse engineered it to find out.
Standard Linux mtools will access the filesystem image and allow you to move
files in and out. However, you'll need to change the media type bytes at