2 ms·
Instead of having some kind of switch or sensor to know when the read head was at track 0, the stepper motor just banged the head repeatedly against the metal s
by joezydeco 8y ago
Instead of having some kind of switch or sensor to know when the read head was at track 0, the stepper motor just banged the head repeatedly against the metal stop until it was sure things were in alignment. This was that "chukchukchukchuk" sound you heard.
I remember playing around with the delays in that routine to make the head move at different frequencies. With a little bit of playing around you could make the drive play music.
- scarface74 8y agoThat scared the hell out of me when I was in 6th grade and first tried to format a disk. I thought I broke my computer.
- scarface74 8y agoWith a little bit of playing around you could make the drive play music. That's basically the same thing you had to do to make the Apple play music anyway -- do a LDA to a certain address with various timings to toggle the 1 bit speaker. Amazingly enough, you could do legible text to speech with it -- https://en.wikipedia.org/wiki/Software_Automatic_Mouth https://en.wikipedia.org/wiki/Software_Automatic_Mouth
- joezydeco 8y agoAbsolutely true....although I'm not sure the Disk ][ head was meant to be vibrated at 400 Hz like a paper cone speaker was. =)
- oh5nxo 8y agoAlso, you could find the sweet spot in step interval, making seeking super smooth and quiet. Oh, this was with a PC, Apple drives must have been optimally adjusted by default ;)
- joezydeco 8y agoThis was more about homing the head, not the stepper motor noise between tracks.