LBA Question

[keelen]

I am performing some vibration tests on different HDD's and I have a question concerning logical block addressing. I know that the LBA is the physical blocks that data is being stored on but where are they physically located on the platter? Does the LBA start from the OD or the ID? . As well, does most HDD's start writing data from the OD to the ID?

[Vulcan]

See:

viewtopic.php?f=1&t=25600

There are some exceptions (e.g. for reallocated blocks, and "mini-wraps") but without going into those details, the above link answers your basic question.

[keelen]

Thanks for the help

[HaQue]

I know that the LBA is the physical blocks that data is being stored on but where are they physically located on the platter? Does the LBA start from the OD or the ID? . As well, does most HDD's start writing data from the OD to the ID?

Hi,
This document states that the first track is on the outer edge. It may help in your study.
http://pages.cs.wisc.edu/~remzi/OSFEP/file-disks.pdf

This document supprts this:

The table below (Figure 2) shows the zones used by a 3.8 GB Quantum FireballTM hard disk having a total of 6,810 usable data tracks on each platter. Also included is the raw data transfer rates for each zone. Notice how the transfer rate decreases as you move from the outer edge of the disk (zone 0) to the center of the disk (zone 14). The data transfer rate at the edge of the disk is almost double that of the center.

http://www.dewassoc.com/kbase/hard_drives/hard_disk_sector_structures.htm

Some nice slides here:
http://media.uri.edu/cs/csc485/Disks/hard_disk_geometry_TOC.pdf

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BTW, the google search that produced this info in 5 minutes was:

hard disk sector 0 is of the drive platter

cheers

[keelen]

Thanks HaQue for your help.