Reorganise disk format documentation.

doc/disk-ampro.md

@@ -0,0 +1,47 @@
+Disk: Ampro Little Board
+========================
+
+The Ampro Little Board was a very simple and cheap Z80-based computer from
+1984, which ran CP/M. It was, in fact, a single PCB which you could mount
+on the bottom of a 5.25" drive.
+
+[All about the Ampro Little Board](http://oldcomputers.net/ampro-little-board.html)
+
+It stored either 400kB on a double-sided 40-track drive or 800kB on a
+double-sided 80 track drive. The disk format it used was a slightly quirky
+variation of the standard MFM IBM scheme --- sector numbering starts at 17
+rather than 1 (or Acorn's 0). FluxEngine supports this.
+
+
+Reading discs
+-------------
+
+Just do:
+
+```
+.obj/fe-readampro
+```
+
+You should end up with an `ampro.img` which is 409600 or 819200 bytes long.
+You can pass this straight into [cpmtools](http://www.moria.de/~michael/cpmtools/):
+
+```
+$ cpmls -f ampdsdd ampro.img
+0:
+-a60014.e
+amprodsk.com
+bitchk.doc
+bitchk.mac
+cpmmac.mac
+dir.com
+himem.doc
+himem.mac
+kaydiag.lbr
+kayinfo.lbr
+...etc...
+```
+
+Useful references
+-----------------
+
+  - [The Ampro Little Board](http://oldcomputers.net/ampro-little-board.html)