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Data recovery and disk repair questions and discussions related to old-fashioned SATA, SAS, SCSI, IDE, MFM hard drives - any type of storage device that has moving parts
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How does a HDD write data on multiple platters?

July 16th, 2015, 9:03

Ok here is the next question for the pros.
A hard drive with multiple platters I wonder how the data gets distributed among them. Will the drive fill up platter 1 first then 2, 3 etc. Or do all heads write simultaneously. Can they move and write independent from each other or do all heads always move together at the same time?
Last edited by tompson on July 16th, 2015, 9:18, edited 1 time in total.

Re: How does a HDD write data?

July 16th, 2015, 9:07

1) please don't open a drive outside of a clean environment.
2) please don't practice on a client's drive

Re: How does a HDD write data?

July 16th, 2015, 9:17

jermy wrote:1) please don't open a drive outside of a clean environment.
2) please don't practice on a client's drive


This is just a general question. I have no plans to open a drive on my own. :lol:

How an HDD stores data on multiple magnetic platters?

July 16th, 2015, 9:41

Check the head stack photo here and decide for yourself whether heads can move independently:

http://hddscan.com/doc/HDD_from_inside.html

Re: How does a HDD write data on multiple platters?

July 16th, 2015, 9:59

Heads are all connected to a single arm and move at the same time. How the data is distributed throughout the platters depends on the brand and model of the drive. I've never encountered a drive that works with one full platter at a time, but have seen Samsung use very large portions (10-20GB) on a single platter before switching to an alternate surface. Most tend to use fairly small chunks.

Re: How does a HDD write data on multiple platters?

July 16th, 2015, 10:38

@tompson, have a read of this article by HDDScan: http://hddscan.com/doc/HDD_Tracks_and_Zones.html

Re: How does a HDD write data on multiple platters?

July 16th, 2015, 14:34

You can see the serpentine nature of platter traversal in HD Tune, at least for those drives which implement Variable Bits Per Inch.

How to determine number of heads using HD Tune:
http://www.hddoracle.com/viewtopic.php? ... 650&p=1796
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