Format fix 2004/gavin/README.md

Also renamed gavin_install.txt to gavin.md and updated formatting.

chmod +x prim (even though it won't work in some modern platforms - at
least if it wasn't corrupted at some point it might in some; it's a
32-bit ELF LSB).

2004/gavin/gavin.md

@@ -0,0 +1,44 @@
+# Usage
+
+1. First, build the kernel and filesystem (just `make`).  In short, you need to
+build this on an x86 Linux machine.  If you wish to try to compile on an OS
+other than Linux you may need modify the [Makefile](Makefile) to compile `sh`
+using a cross-compiler that produces ELF binaries - i.e. a cross-compiler
+targeting x86 Linux.  In short, you need to build this on an x86 Linux machine.
+
+2) Next, find a suitable machine to run the OS on.  It should be perfectly safe,
+and since it does not directly attempt to access any hard disk drives (only a
+ramdisk loaded by the bootloader) it should do no damage to your existing setup,
+BUT I ACCEPT NO LIABILITY FOR ANY DAMAGE DONE BY THIS PROGRAM.  Run it at your
+own risk.  The OS has been tested on half a dozen machines or so, and worked on
+all but one.  The failure came in the form of the machine rebooting itself
+midway through loading the OS, with no nasty side-effects.
+
+    Hardware requirements - i386 or better processor, but the GUI is
+    surprisingly power-hungry, so I would recommend a fast P3 or P4 processor
+    (has been tested on P3/P4/Athlon machines).  Minimum RAM is something like
+    32MB.  PS/2 mouse & keyboard required - no USB I'm afraid, and the keyboard
+    map is for a UK keyboard.  Uses Vesa VBE 3.0, so should work on any modern
+    graphics card (has been tested on NVIDIA, Matrox, and SiS cards).
+
+3. Now you need to setup a bootloader to load the OS.  If you have a system
+using a lilo bootloader you can simply add the OS to your boot menu.  Just add
+appropriate `image=` and `initrd=` lines to your `/etc/lilo.conf`, pointing at
+`kernel` and `fs.tar` respectively (as built by make earlier), then run `lilo`.
+If you do not wish modify your lilo setup, one easy option is to get yourself a
+grub boot disk image, and follow the instructions for grub below - Debian users
+can simply run`apt-get install grub-disk` to get themselves a grub boot disk.
+
+    If you run grub, then at the boot menu simply hit `c` to get a console, then
+    type `kernel=(hd0,0)/<PATH>/kernel` (substituting appropriate hard
+    drive/partition numbers & path, or using `(fd0)` to load a kernel on the
+    floppy), then `initrd=(hd0,0)/<PATH>/fs.tar`, and finally `boot`.
+
+4. Assuming the OS has booted, what can you do now?  Well, start by trying `sh`,
+to open another shell.  Then, try `vi gavin.c` to open up the OS source in a
+text file viewer (up/down or PgUp/PgDn to scroll). Note that the provided
+applications, `sh` and `vi` both have windows of the same size, and that open in
+the top left corner of the screen, so you may need drag the windows around a bit
+to tell them apart.
+
+5. To shut down - just hit the power button. :-)