3 ms·
One thing I've always wondered, and somebody on here must know the answer :) When a HDD is manufactured, how are the disk platters initially seeded? Are they ju
by trollied 6y ago
One thing I've always wondered, and somebody on here must know the answer :) When a HDD is manufactured, how are the disk platters initially seeded? Are they just liberally splattered with material & the tracks are created on first write, or are the tracks pre-created? If so, is it a stamping method, akin to making a vinyl record or CD?
- matesi 6y agoThe servo signals are written using special equipment (a precise head/servo mechanism, not the regular HDD heads). You can see them in this magnetic image - the whole 25% to 75% of the image is the servo signal area. The tracks are seen on the bottom 20%, top 80%: https://commons.wikimedia.org/wiki/File:Aufnahme_einzelner_Magnetisierungen_gespeicherter_Bits_auf_einem_Festplatten-Platter..jpg https://commons.wikimedia.org/wiki/File:Aufnahme_einzelner_M... Bottom to top: - sync (the regular lines) - positional track number, gray encoding (irregular lines) - track fine tune (the block trio) - fine track ID After fine track ID is read correctly, the position is deemed correct, the RX head is turned off, and the TX head is turned on. This is the rx-tx gap. Then track data starts.
- effie 6y agoWow, thanks for this. It seems insanely complicated. Why not just use single fat track that announces the ID number of the corresponding data track?