Hewlett Packard 9100B
The HP 9100B was the second calculator made for sale by Hewlett Packard. HP's first electronic calculator, the revolutionary 9100A was introduced in the fall of 1968, with the 9100B introduced in fall of 1969. The machines were still being actively advertised as late as mid-1970, however, their marketability was rather shortened due to the arrival of reasonably-priced large-scale integrated circuitry, which could replace the complex and costly discrete transistor circuitry of the 9100A & B. HP's follow-on 9800-series calculators utilized integrated circuit technology to increase capabilities, and reduce cost.
The 9100A and 9100 B were most amazing because they managed to combine speed, features, and reliability that at the time were simply unheard of in the electronic calculator industry, and they did it all with no digital integrated circuits (though four linear integrated circuits are useed in the magnetic card reader as amplifiers). HP used all diode-transistor logic, core memory storage, wire-rope low-level microcode ROM, and innovative circuit board technology for the high-level microcode ROM. All of these technologies came together to form machines which at the time were engineering triumphs, and still today garner admiration from electronic engineers for the sheer elegance of their design. [source]