November 23, 1999
How Computers Really Work

Review of Charles Petzold, Code: The Hidden Language of Computer Hardware and Software Have you ever wondered just how your computers really work? I mean, really, really work. Not as in "an electrical signal from memory tells the processor the number to be added," but what the electrical signal is, and how it accomplishes the magic of switching on the circuits that add while switching off the other circuits that would do other things with the number. I have. I have wondered this a lot over the past decades. Yet somehow over the past several decades my hunger for an explanation has never been properly met. I have listened to people explain how two switches wired in series are an "AND"--only if both switches are closed will the lightbulb light. I have listened to people explain how IP is a packet-based communications protocol and TCP is a connection-based protocol yet the connection-based protocal can ride on top of the packet-based protocol. Somehow these explanations did not satisfy. One seemed like answering "how does a car work?" by telling how in the presence of oxygen carbon-hydrogen bonds are broken and carbon dioxide and water are created. The other seemed like anwering...

Posted by DeLong at 04:06 PM