Thompson, Steve wrote:
I don't remember what vacuum tube logic circuits looked like. Are you sure they were much noisier than the transisterized circuits that replaced them?
I never saw the tubes in the earlier machines, except in pictures, but the last tube generation used any of a family of dual triodes: 12AU7, 12AW7, and 12AX7, also used back then in better radios and Hi-Fi equipment. Each pair was mounted in an open frame, approximately the size of a 200-300 page hardcover book, with discrete components (mostly resistors) aligned vertically. Additionally each module had two vertical shafts, one at each end, containing a cam that locked the module in place.
Gerhard Postpischil Bradford, VT ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
