Atari 520 ST and the Decimal Expansion of Fermat 9.
In 1990 Dr. Arjen Lenstra published the factorization of Fermat's 9th number. At the time, the commercially available Arbitrary Integer Arithmetic was Mathematica, with a decimal expansion limit of 99 digits. He published the factors of the 155 digit number, having 7 digits, 49 digits and 99 digits respectively. I had an Atari 520ST with 4MB of RAM, screaming along at 8 MHz, when IBM compatibles were limited to 6 MHz. The Atari, with its Motorola 68030 processor had a true 32 bit bus, while IBM compatibles were making a 16 bit bus do double duty for long ints. I wrote a small program named "Muncher," in (compiled) GFA Basic to multiply the factors, and expand Fermat's 9th number in decimal. To do so, I employed the Trachtenburg algorithm, taking each digit as a tuple, multiplying two numbers together at a time. The principle was to multiply the connected set of digits together, keeping track of the power of ten, and then add the columns vertically, in an array. In th