Reimaginings

It's easy to look back with nostalgia on the computers that were commonplace a decade or more ago; the machines on which we wrote our first program or played our first game. Moore's law has been shrinking transistors and increasing performance. Machines as powerful as what was once a home computer or even a workstation have been in our cell phones for years. Once in a while I stop and ask myself, "What would machines with the capabilities of a famous computer from ten, twenty, or even thirty, years ago look like if they were implemented with today's technology? How efficient would they be? How cheap?"

It is with this in mind that I write Reimaginings: an engineering exercise that looks back and forward at the same time, using current techniques to fit past needs, and by doing so hopefully finding new ways to look at the design of different kinds of personal computers as minimalistic tools with a minimal environmental footprint instead of engergy hungry devices of an often too large one-size-fits-all nature.

"This is idealistic nonsense," you say, "the tastes of the typical user have changed." I couldn't agree more, and I know none of the designs covered here can browse YouTube or play Bioshock. It's true that the market for devices like the ones I describe doesn't exist anymore, and probably never will again. I believe that engineering should be constrained by what is possible, not what is marketable. By exploring this design space I will answer my own personal questions about the capabilities of current computing technology and hopefully the questions of others as well.

The machines I have chosen to reimagine were each significant in their time, and have each played their part in the evolution of personal computing. They are also, except for the PDP-11, personal computers with which I have had experience.

DEC PDP-11

Perhaps the most popular minicomputer of all time, the PDP-11 is widely known as the machine on which UNIX came into its own and the C programming language was first developed. While cramped even at the time, with each process getting only 64K of virtual address space, this 16-bit computer is an icon of elegance.

Commodore 64

The most popular home computer until it was usurped in a big way by PC clones, the Commodore 64 has a very large library of software still in existence, from Zork to a working TCP/IP stack. The sound and graphics capabilities of the 64 in its heyday were superior to more expensive computers like the TRS-80 Color Computer.

TRS-80 Model 100

Originally sold in Japan as the Kyocera Kyotronic 85, the TRS-80 Model 100 was the first successful portable computer. Possible reasons for its success are the fact that it is lightweight, runs for hours off of four AA batteries, retains its state when power cycled, and boots instantly to the state it was previously in. With 24K of internal memory and a full-size keyboard, it could be used to pound out about five pages worth of text. The Intel 80C85 processor used was a low power CMOS version of the faster depletion load NMOS 8085.

IBM AT

The AT, or more accurately the AT's clones, were the standard business computer of the late 80's and early 90's. Many of the descendants of applications that ran on these machines continue to be popular today, though vastly different, from Microsoft Windows, Word, and Excel, to games like Prince of Persia and Duke Nukem.

Apple Macintosh Plus

Users of a Mac Plus with Aldus Pagemaker and a laser printer could, for the first time, create professional-looking documents themselves, from their desk. The original Macintosh, to which the Plus was the first sequel introuced the world at large to the graphical user interface, and to many concepts that are still universally embraced, or at least tolerated.