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In one rotation, how many sectors are passed over and how many tracks are passed over?
If you know the average value of sectors per track for a hard drive, how do you use this to estimate the number of cylinders?
Do all modern hard drives have 63 sectors per track? Are there any hard drives that have more than this?
Phenom
Posted 2010-02-11T21:23:17.510
Reputation: 6 119
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No easy way to say - every hard drive is different and has different density, on top of this, there are obviously more the further away from the centre you are as the circles become wider.
Pick a model, and give a bit more information (such as the outer most circle) and I will try to help you further.
William Hilsum
Posted 2010-02-11T21:23:17.510
Reputation: 111 572
I'm trying to figure out the maximum sectors per track of this hard drive:
http://www.scsi4me.com/hitachi-deskstar-e7k1000-hde721050sla330-500gb-7200rpm-sata-hard-drive.html
Sorry - found the datasheet here - http://www.hitachigst.com/tech/techlib.nsf/techdocs/2232622C3696936F8625747B0082266E/%24file/Deskstar_E7K1000_DS.pdf, however, (could be wrong here) I don't think there is a hardware maximum, but controlled by the filing system you use.
– William Hilsum – 2010-02-11T21:52:11.2806
Almost all modern hard drives report 63 sectors per track, because that's the maximum allowed by the BIOS specs.
This number (along with heads and cylinders) is of course fake and used only for compatibility addressing with very old programs. Internally they use a simple sector number starting from 0 (called LBA mode).
The real sector per track number is not only much larger, but it also varies depending on the distance from the spindle. See, for example, this page from the makers of HDDScan.
efotinis
Posted 2010-02-11T21:23:17.510
Reputation: 3 524
This is correct. – Alex – 2010-03-13T09:18:57.200
Ah the days of CHS; how I do not miss them. Even with a formula, it was still difficult to get the numbers to work.
– Synetech – 2011-09-13T06:28:22.7832
As the disk spins, sectors travel under the read head at a rate that depends on the RPM of the disk. So the transfer rate is the rotation rate times the number of sectors in a track times the number of bytes in a sector.
(RPM / 60) * Sectors-per-track * bytes-per-sector = bytes-per-second
Where do I plug in the media transfer rate into this equation? – Phenom – 2010-02-11T20:27:48.617
bytes-per-second is the transfer rate. – None – 2010-02-11T20:55:19.873
Please refrain from asking the same question in 3 different ways. Especially when a perfectly legitimate answer was given already http://superuser.com/questions/107704/hard-drive-bytes-per-sector/107714#107714 (see page 9) If you do not get an acceptable answer consider editing your original question with more details or adding a bounty(http://superuser.com/faq).
– heavyd – 2010-02-11T21:44:13.5301@heavyd: actually his 3 questions are all related, but separate, questions. they're all closely related enough that they could have been posted as one question, though, so perhaps the best thing to do is close 2 and edit the last to include the others. – quack quixote – 2010-02-11T22:41:31.847
See this set of 6 closely related questions: http://superuser.com/questions/119446/sectors-and-clusters http://superuser.com/questions/119051/transfer-time-for-a-file http://superuser.com/questions/107723/hard-drive-sectors-vs-tracks http://superuser.com/questions/119048/number-of-tracks http://superuser.com/questions/119026/rotational-latency http://superuser.com/questions/119030/bytes-per-track
– Jonathan Leffler – 2010-03-16T11:07:55.383And http://superuser.com/questions/120461/transfer-time-of-a-cylinder
– Jonathan Leffler – 2010-03-16T11:13:18.257and http://superuser.com/questions/120489/sectors-per-track
– quack quixote – 2010-05-06T07:22:35.723