The SMALL and the BIG. Looking at the ICT 1301 around here. http://www.shedlandz.co.uk/ Last years open house video was what caught my eye. http://oldwuzzark.co.uk/exprtvid/od11_big.wmv --Chuck Ben.

On 29 Apr 2012 at 18:46, Richard Smith wrote: Sounds like plain old RTL--which was certainly available in 1969. --Chuck

On 04/30/2012 05:35 AM, Dave Rowland wrote: I started buying RTL (uL9xx series) in '68. I got my first parts from a "engineers junkbox" back around 1966. uL914 was dual two input nor uL923 was a single JK FF The basic inverter was transistor with resistor in the base and collector load, a NOR was two transistors each with resistor on the base and a common collector load. The package was TO5 8 lead. Motorola the 7xx series was 14 pin DIP and had more of the same in the package like two FF, hex inverter, quad two input NOR, three input NOR and others. RTL was slow, FFs could clock to maybe a bit more than 10mhz. They sucked current and had poor fanout/fan-in with high susceptibility to noise. Hobbyists used them as analog functions as well (the dual 2 input nor made a dandy differential amps) . I still have an assortment of those parts including uL913 full adders. In the later 60s Motorola offered ECL 1000 series which were far faster but even less dense. They were popular with hobbyists for analog uses as the devices could offer 100mhz gain as differential pairs. DTL was also around then, added series diodes on the base to make the thresholds higher. it was more noise immune and faster. The first 4000 series parts were late 68-69. By 1971 it was fairly common and inexpensive. Though slow it was very low power, good noise immunity, and faster than RTL though not by much. TTL was common by 1970, I built a state machine controller using about 200 pieces for a work project in 1972. The 95H90 was the first 300Mhz ECL /10 counter and was available by 1972 at hobbyist prices. In 1973 I used the 1101 256bit by one Pmos static ram. The fast parts were 1us and the slow ere 1.6uS. The 8008 was a PMOS chip. The concept of a transistor computer was fairly dead but 1966-7. As ICs had started to displace raw transistors most everywhere save for high power needs like core drivers and analog functions. Allison