Michael Black wrote:
On Thu, 10 Jul 2008, mdj wrote:On Jul 10, 11:15 pm, pau...@saaf.se (Paul Schlyter) wrote:But really, the Disk ][ was fast, simple, and therefore cheap. The controller was not only industry changing, but a work of art.That's ambiguous. If it was so "industry changing" then everyone else would have leapedto the design. And nobody did. A handful of companies did use GCR formatting, Commodore comes immediately to mind, but they sure didn't usesuch a simple controller. And of course to balance the controller design, Apple had to have special drives manufactured, because a standard drivehad "too much circuitry". That's a liability, and even into the age of the Mac the non-standard drives were a negative thing for Apple, sinceit kept the cost high.
Well, actually, Apple had a deal with Shugart to buy drives *very* cheaply without the "analog card" and the head load solenoid (which was optional anyway). The volumes Apple ordered made the partial drives a very good deal for both Apple and Shugart. The drive sold to Apple was simply an "incomplete" or "stripped" drive that was considerably cheaper than the "loaded" drive, and, controlled by RWTS, faster, too! Since Shugart set the standard for drives and heads, as other drive manufacturers entered the 5.25" arena, most could easily be bought in the stripped configuration to work with Apple analog boards--or, as the market grew, even ordered with Apple-compatible analog boards. In the 3.5" era, Apple's use of non-standard speed controls did limit their choice of suppliers, but that's a different matter. -michael AppleCrate: An Apple II "blade server"! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it's seriously underused."