Point by point:
“If you had a spiral architecture, the calculations would be more complicated.”
Yep.
“To start with, how would you detect the sync point unless the disk had a special kink in it to tell the head where it was.”
Did you see in the original post where I mentioned “a sensor to...
OK. My takeaway (so far) is maybe HDD sectors could and should be organized in a spiral.
Could – MikeHalloran sees possible problems, but is talking possible implementation methods.
Should – I don't think anyone has shot a hole in the time savings, though IRstuff might still disagree.
MikeHalloran, I followed paragraph 1 fine. I think I might have gotten lost in the 2nd, because it seemed to be talking about delays in all drive technologies. For example, I assumed ALL drives went open loop in the gross movement from initial track to destination track and closed loop aligning...
IRstuff, I am not ignoring you.
How is additional slowness produced seeking to a spiral sector vs a conventional sector?
You move the head(s) to the sector. Period. What am I missing?
Addressing the last three posts...
IRstuff - “It takes 8ms to complete 1 track, so the incremental change is less than 12% improvement in performance.”
True. We are talking about a maximum of 12.5% (or 16% at 10,000rpm) HDD read/write improvement. I'm calling that “significant”.
MikeHalloran...
Hi. Thanks for replying!
"...what difference does it make ... given that an HDD is a random access device?"
Because a large percentage of head movement requests are single track step.
So, like I said, by eliminating these single track steps (track-to-track), it looks like HDD performance would...
(Out of my field, so I apologize if I'm presenting this poorly, or if it is noobish.)
Why are hard disk drives not made with user data and the servo information in a single spiral a la DVD?
I ask because track-to-track seeking is so common, and reducing it from 1ms to 0 would be a big deal...
