tbray@mprvaxa.UUCP (04/27/84)
x <-- USENET insecticide Ken Reek writes of machines that force operand alignment "ignore them and maybe they'll go away." His argument is that byte addressability is a win because of the greater ease in writing software and the high cost today of software vs hardware. Not so! Because... 1. All significant machine code today is generated by compilers, not by people, and the compilers do the messy work of aligning everything. 2. Removing the byte-addressability constraint allows the hardware boys to build much more cost-effective architectures, and to build them quicker. 3. Point number 2 is vital since the line about the rising cost of software with respect to hardware is so much horse puckey. All those graphs of the future that showed a graph that looked like an X, the rising line being software and the falling line hardware, never happened. The reason being that the demand grows at a phenomenal rate and every year software becomes more layered, more functional, and less hardware- efficient (*see note). Which is as it should be. So quick, cheap architectures are IMPORTANT. If somebody can build, say, a Ridge 32 and it runs a really nice UNIX (it doesn't yet) and goes like hell for < $50K (it does), I'll cheerfully grapple with nUxi and alignment problems in my existing software. As for the guy with the 10 man-year investment in carefully optimized structures, well the new architectures aren't going to go away. I'd say he has a problem. ---- *note As to the reduced machine efficiency of modern software, this was really brought home to me one time I was touring a DEC manufacturing plant, and there were these 6 huge backplane-wiring machines running flat out, all being driven by a little wee PDP-8 (!). When I expressed surprise, the manager explained that the 8 could do it with room to spare because there was no operating system to get in the way...