KindleLink (via Digg)The latest result of my design activities is the Apple-II which is the main subject of this system description article. The Apple-II builds upon this idea by providing a computer with more memory capability, a read only memory (ROM) BASIC interpreter, color video graphics as well as point graphics and character graphics, and extended systems software.
A key part of the Apple-II design is an integral video display generator which directly accesses the system's programmable memory. Screen formatting and cursor controls are realized in my design in the form of about 200 bytes of read only memory which are built into the Apple-II's mask programmed 8 K bytes of read only memory. A 1 K byte segment of the processor's main memory is dedicated to the display generator, although it is also accessible to programs. The display transfer rate is the time it takes to fully define the contents of this segment of memory, and averages about 1000 characters per second, limited primarily by the software scrolling routines in the system read only memory. Since the Apple-II incorporates this display generator as a part of its design, its text mode becomes the terminal for the system. The display has 24 rows of 40 characters displayed on an ordinary black and white or color television screen. Each character in the Apple-I I design is a 5 by 7 dot matrix, so the present version of the system only implements upper case characters of the 6 bit ASCII subset, as well as the usual numbers and graphics available in standard character generator read only memory parts.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.