If you doubt BillG's technical acumen:

A Joel Spolsky classic story, "My First BillG Review"

"Bill came in...

He had my spec in his hand.

He had my spec in his hand!"

http://www.joelonsoftware.com/items/2006/06/16.html

Thanks. That was a good read I hadn't read before. It's so very true. Non-software people shouldn't run software shops unless they can delegate to someone who is.

Late 1980s. In a speech from September 1997, BillG says:

"I wish I got a chance to write more code. I do mess around. They don't let my code go in shipping products. They haven't done that for about eight years now."

http://www.microsoft.com/presspass/exec/billg/speeches/1997/...

I've heard that Gates last wrote production code sometime in the mid-eighties, though he wrote gradually less and less before then.

He claims to have written much of the firmware in the TRS-80 Model 100, released in 1983: http://americanhistory.si.edu/collections/comphist/gates.htm...