In the mid 1980's, I was a specialist on a machine that the architecture was spawned from the computer used in Apollo 11 - the Series/1. The Series/1 was used in a wide variety of applications in Australia. For example I worked on machines that:
- Monitored the conductivity of flesh of sheep used in experiments (the place stunk)
- Counting soiled laundry from hospitals (the place stunk worse than the sheep)
- Interfaced an array of 3101 VDU's to the System/7 for Telecom's Directory Assistance
- Interfacing the major banks to the overnight money market (Tandem operation for ultra reliability)
As for DTL, my first job out of uni was working on a machine that used DTL boards at IBM. They were used in the IBM 129 Card Punch. The cards were very similar to that Dave has been testing, but by 1971 the IC's were encapsulated in aluminium covers. It was amazing the low level logic used in that machine. As I recall, the 129 had no microprocessor, but had 80 columns of memory for verifying punch cards and a digital display - it was electronic poetry in motion. Here is a peek as to the innards of the 129 (check out the DTL board and the ratsnest of wirewraps):
http://sturgeon.css.psu.edu/~mloewen/Oldtech/Keypunch/IBM129.htmlI was very lucky to have been trained at IBM to debug much older equipment than what was used in Apollo, like the IBM 557 Alphabetic Interpreter - an immensely complex electro-mechanical programmable machine that was full of relays, commutators, motors, cams and selenium rectifiers. Quite challenging to debug. On such equipment, memory was achieved with valves (vacuum tubes) that had on-board resistors and capacitors INSIDE the valve. These were integrated circuits long before the semiconductor IC was invented.
http://www.columbia.edu/cu/computinghistory/557.htmlThe oldest machine I ever had to fix was made in 1922 called the 011 electric hand punch made by the Computing-Tabulating-Recording Company (CTR) which became IBM in 1924. I only saw on once but it was a privilege to fix that for a customers.
http://www.columbia.edu/cu/computinghistory/011.htmlFor newbies who don't know about what these machines were used for, check this out...