[E3-hacking] Config / content filesystem

[Jonathan McDowell]

On Mon, Apr 22, 2019 at 03:24:41PM +0100, Ralph Corderoy wrote:
> Hi Jonathan,
> 
> > So, the MTD partitions do not directly map to a kernel or a Linux
> > filesystem. The "Q;Q;" blocks are an Amstrad specific way of putting
> > data into those partitions, with a type + description associated with
> > each one. For example the kernel lives in a Q;Q; block in mtd3 called
> > "LINUX". mtd3 also has Q;Q; blocks for LDR (the second stage boot
> > loader), and PARMS (the kernel boot parameters).
> 
> Agreed.  I guessed a 32-byte struct based on various `Q;Q;'s seen.

It's a 124 byte struct from my notes;

 0:   0x3B513B51      # Q;Q;
 4:
 6:   2 byte checksum
 8:   Length if uncompressed?
 C:
10:
14:   # Block name, 16 chars
24:   # Block description, 48 chars
64:   Entry vector?
68:   0xB513B513      # Note, inverted Q;Q
6c:   Load address?
70:   Compression flag, 0 == plain, 2 == compressed
74:   Compressed length
78:
7C:   END

Compression is LZRW1 without the leading 4 flag bytes.

J.

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