Why did microcomputers die off?

On Mon, Dec 23, 2013 at 2:16 PM, ben <bfranchuk at jetnet.ab.ca> wrote: The H-11 price was far cheaper than a 100% DEC PDP-11 (the H-11 has a real DEC CPU, but lots of Heath I/O and a 100% Heath backplane), but yeah, compared to contemporary micros, the H-11 was still expensive. The "problem" with PDP-11s is and has always been peripheral, especially mass storage, support. You can invent any kind of register model you want when you make your own device (we did for the COMBOARD), but it's then on you to write a driver for your OS of choice that lets you use your device. The alternative is to completely emulate an existing device down to the register level including odd behavior and side-effects (odd things like writing to a read-only register on an RP-11C generating an interrupt is required to successfully boot 2BSD). It's a big reason MSCP controllers got popular later - every OS supported them and you didn't have to fiddle rl vs rk vs hk vs rx vs xp... I'm not saying don't try, but you might want to start small like providing a multi-serial interface to your PDP-11 and hang a virtual (or externally emulated) TU58 off of that. The register footprint and implementation is trivial because you already have to have a console SLU, and this is the same thing at a different I/O address as far as the CPU is concerned. RT-11, at least, can boot off of TU58. UNIX not so much, so it's still OS-dependent, but it gets you started. -ethan