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It was expensive because minimized discrete hardware (not soon enough for any kind of real integration) was still expensive. Even the successor 2901-based D-ma
by pinewurst 10y ago
It was expensive because minimized discrete hardware (not soon enough for any kind of real integration) was still expensive. Even the successor 2901-based D-machines were expensive in absolute terms. By the time Alto-level functionality was relatively cheap to implement, the software requirements had grown well beyond. Hence PARC moving eventually to the likes of ECL for research platform development.
- kens 10y agoTo expand on what pinewurst said, the Alto was built minicomputer-style out of TTL chips, so even with minimized hardware the CPU took three large boards of chips. Within a few years, microprocessors took over and Moore's law crushed computers built from discrete chips. Here are some bonus pictures of boards from the Xerox Dorado, which used ECL chips for higher speed. First is the ALU board; the large chips are ECL versions of the 74181 ALU. Second is a detail of chips from the 10K family, as well as unusual square memory chips. https://lh3.googleusercontent.com/--KYoSBUuOhg/V4Rxs7tLB-I/AAAAAAAA4vM/_HY8Xvkg0DgRjl36M4ZyjY5PYXrvlWh2gCCo/s800/alu.jpg https://lh3.googleusercontent.com/--KYoSBUuOhg/V4Rxs7tLB-I/A... https://lh3.googleusercontent.com/-MWYhn7enXdA/V4RxsQ8YHRI/AAAAAAAA4vI/5hAeS8i7ZX8M3DNANpXNrcXStB3_0qZmACCo/s800/square.jpg https://lh3.googleusercontent.com/-MWYhn7enXdA/V4RxsQ8YHRI/A...