E format Disc addresses

A disc address of a file or directory is in the following form:

ddd00000 0ooooooo oooooooo ssssssss

in binary. ddd is the disc number (not useful outside FileCore),
ooooooooooooooo is the object Id and ssssssss is the sector offset within
the object. An object consists of the concatenation of all the fragments
with the object's Id. The sector offset, if 0, means the object isn't shared
between several files or directories. If the sector offset is non-zero (eg
is S), then the file or directory starts at the start of the Sth sector in
that object. So disc address

0x00000233

Means that this object (in fact the directory $) starts at the 0x33th sector
in object 2. Note that the 0x33th sector starts 0x32 sectors from the start
(also the 1st sector starts 0 sectors from the start).

