{"id":963,"date":"2025-07-28T21:55:17","date_gmt":"2025-07-28T19:55:17","guid":{"rendered":"https:\/\/blog.udisks.ovh\/?p=963"},"modified":"2026-03-07T16:33:51","modified_gmt":"2026-03-07T15:33:51","slug":"apple-ii-dos-2","status":"publish","type":"post","link":"https:\/\/www.mundocaos.com\/?p=963","title":{"rendered":"Apple DOS"},"content":{"rendered":"\n

En 1977 el ejecutivo e inversor de Apple, Mike Markkula<\/strong> escribi\u00f3 un programa de balance de cuentas. Pero su programa tardaba demasiado tiempo en cargarse desde la unidad de cinta del Apple II, por lo que le pidi\u00f3 al cofundador Steve Wozniak<\/strong> que dise\u00f1ara un sistema de unidad de disco.<\/p>\n\n\n\n

El dise\u00f1o de un sistema de unidad de discos implicaba dos problemas para Wozniak. Por un lado el dise\u00f1o del hardware y por otro el software de control, o sistema operativo.<\/p>\n\n\n\n

Durante las vacaciones de Navidad de 1977, Steve Wozniak resolvi\u00f3 el primer problema. Dise\u00f1\u00f3 un controlador de disquete “inteligente<\/em>” que utilizaba \u00fanicamente 8 circuitos integrados, haciendo mediante l\u00f3gica programada lo que el resto de controladores de discos consegu\u00edan con hardware.<\/p>\n\n\n\n

Seg\u00fan el propio Wozniak:<\/p>\n\n\n\n

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I have no idea how I came up with that incredible disk controller. I was good at creating anything in electronics, analog or digital. I had no prior experience of any kind, not even in classes, regarding disk hardware or software. So my thinking had to be from the ground up. I had to sense data coming from the disk and make decisions about 0\u2019s and 1\u2019s based on timing.<\/p>\n\n\n\n

I had taken a graduate level course at Berkeley (although an undergrad, I only took grad courses in anything having to do with computers in any university) on state machines and thought of how I could use 2 simple low cost chips as a state machine to do this, sort of a minimal microprocessor hand-built. At the time I just knew that it would read and write data but I assumed that I was leaving out many ingredients of a disk controller due to not knowing what they did. I assumed this because my design took so few parts. But in the end, mine did more in some good ways, especially since it was in the computer and tied to software that could alter how it worked, which eventually led to greater storage and faster speed that would not have been possible using the normal disk. Plus, I took about 20 chips off the drive itself and bypassed them from my own controller, because they were just middlemen that got in the way of things.<\/p>\n\n\n\n

The best work I did, over and over, was partly due to not having money and having to learn how to use the fewest parts of anyone, and also due to the fact that everything great I created I had never done before.<\/p>\nhttps:\/\/www.bigmessowires.com\/2021\/11\/12\/the-amazing-disk-ii-controller-card\/<\/a><\/cite><\/blockquote>\n\n\n\n