Rob RussellWhy do the disks spin in a hard drive? Don't the read/write heads have less mass than the platters?
Jeff McBride@Rob_Russell this is an interesting question. The read heads rotate too, to seek. And I think they need to be much more responsive because that's what really defines seek speed, while the disks don't really have to accelerate that fast?
@Rob_Russell also the read heads have wires, so you would need a slip ring if it spun continuously.
@mcbridejc I was thinking maybe the slip ring would have been a solid reason to spin early hard disks. These days there should be a way to build a reliable slip ring for fast data rates though?
I did ignore how much the read heads have to bop around - was just imagining the track to track motion. Hard drives probably do more than mimic the parts of a record player I guess.
Hmm... so how about a record player with a stationary record and a needle that spirals around?
@Rob_Russell hmm...whenever I've tried to use slip rings it's been a big pain point. possible, sure, but adds friction (probably a big deal for read head), mass, and cost..so begs the question, whats the benefit?
Also, I have an impression that linear rails are harder than a rotary bearing.
I'm just spitballing here. I never designed a hard drive, buts its a fun thought experiment to try to predict why it ended up the way it is.
A spinning needle record player sounds like fun to watch...
@Rob_Russell in the record needle case you dont even need a second actuator I guess...if the needle is free to slide along the arm the grooves will slide it
@mcbridejc first time I dealt with a slip ring was on a turntable at an aluminium foundry :-) They did indeed cause a lot of pain. Maybe there's a spiritual successor with some magical optical connection. Still needs to get power somewhere though.
There must be some historical oddities where people have tried these ideas out before.
@mcbridejc Okay maybe the inspiration is more washing machine and less record player. I forgot how massive these old things were.
I kind of want my desk to look like this https://patentimages.storage.googleapis.com/ce/8d/53/fd152b18dc0170/US3503060-drawings-page-1.png