diff --git a/README.md b/README.md
index 99b46a9..d35dbec 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,30 @@
 IBM2030
 =======
 
-An IBM System/360 Model 30 in VHDL
\ No newline at end of file
+An IBM System/360 Model 30 in VHDL
+
+There are two main components to this release:
+* VHDL for the CPU (with 8k storage) and Multiplexer channel
+* The microcode image (4k x 55)
+
+I am not claiming copyright to the microcode image - this is based on IBM manuals from 1964-1965 which may or may not be copyrighted themselves.
+
+The VHDL is based on the IBM Maintenance Diagram Manual (MDM), which can be found on Bitsavers.
+
+As supplied, the compiled system is suitable for a Digilent Spartan 3 board with a 1000K device, see http://www.digilentinc.com/Products/Detail.cfm?Prod=S3BOARD
+It uses the following I/O:
+* VGA output (8-colour, 3-bit)
+* Parallel I/O for switch scanning (10 out, 14 in)
+* On-board pushbutton inputs (4)
+* On-board slide switch inputs (8)
+* On-board LED outputs (8)
+If using an alternative board, it may be sufficient to modify the UCF file to reallocate inputs and outputs
+
+These files can be compiled using the Xilinx ISE Webpack (and presumably other versions of the Xilinx suite).  I have not tried compiling them with other VHDL compilers.
+
+Apologies for the varied quality of the VHDL.  This project has taken over 5 years and I have not necessarily re-visited code that was written early on.  So there is a variety of styles and conventions.  In my defence, it works (or seems to).
+
+Lawrence Wilkinson
+lawrence@ljw.me.uk
+2010/07/16
+