Wednesday, April 6, 2011

Osborne I...

I owned one of these back in the early '80s, along with the (not pictured) optional Fresnel lens magnifier for the tiny little CRT.  I also wrote software for it – a little utility that automatically “tuned” the stepper motor head drive on the floppy disk drives. 

Ordinarily the stepper motors were driven at a constant step rate, controlled by a Western Digital floppy controller chip that was a nearly universal standard in computers of the day.  This constant step rate was the simplest approach, but it wasn't the only one possible.  My utility accelerated the head motion for the first half of its travel, and decelerated it for the second half.  The result was considerably improved head positioning performance.  On such a slow system, this was no small matter.  I had no trouble demonstrating significant performance improvement on such common tasks as starting up an application.

However, that performance improvement is not why most people bought my little application.  There was, briefly, a little buzz about my “FastTrak” utility – because it made the Osborne I much quieter.  This was an unintended, but happy, side-effect of the performance improvement.  It turns out that a smoothly-accelerating head positioner doesn't “grind” the way a linearly-stepping head positioner does.

There's a lesson in there somewhere, but I'm not entirely sure what it is...

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