Hard Drives leave factory with bad sectors?

[ontariotech]

Hard Drives leave factory with bad sectors?

Is this true? which brand leaves the factory with most bad sectors?

Was it always this way?

[Vulcan]

Hard Drives leave factory with bad sectors?

That depends on what you mean by "bad sectors". If you mean what is called (on SCSI/SAS/FC drives) sectors in the P-list - then yes.

I can think of another possible meaning to your question, so it was slightly ambiguous.

Is this true? which brand leaves the factory with most bad sectors?

Why do you care? If you mean what I explain above, then they are hidden from customer use.

Was it always this way?

Yes (at least from when I started working on disk drives in the 1980s) - look at any of the old MFM drives from that time period, for example. What is stuck to the top of those drives? A label with the defect list Only allowing perfect platters would make the manufacturing of disk drives uneconomic.

[ontariotech]

Thanks for your informative answer Vulcan.

[craig6928]

they all do leave the factory with errors

that why your suppose to do a full format of the hard drive before use

that why they map them to the defect list

anyone saying that there hard drive does not have any errors from new
is wrong

[seed.helper]

if we are lucky the hard drive will mantain only that bad sectors discovered in the factory lol

[guru]

All disk drive magnetic media has flaws (I would not call them BAD sectors) when it is first merged with the HDA/DE. Calibrations/Self Test remap these flaws to defect list/s. BAD sectors are sectors which appear after the drive has left the factory. BAD sectors AKA grown defects are warning signs because some degradation has caused the sector to become unreliable (Thermal Asperity, head crash etc)


Fresh from the factory with original mapped defects is not a problem

[Vulcan]

@guru - That was exactly why I said the initial description was ambiguous; it could be taken to mean original defects and/or grown defects. The OP did not define what they meant by "bad sectors"

[craig6928]

has anyone notice the worse drive for bad sectors seagate crap

brand new failed with in a month

hard drive going strong to this date western digital

[guru]

Between us we have made it more logical Vulcan

@guru - That was exactly why I said the initial description was ambiguous; it could be taken to mean original defects and/or grown defects. The OP did not define what they meant by "bad sectors"

[guru]

If you had lots of time you could review original factory defect flaws and come to a decent conclusion on who has problematic media :O)

[Vulcan]

If you had lots of time you could review original factory defect flaws and come to a decent conclusion on who has problematic media :O)

Very true!

My experience is that it would also vary with drive family, and perhaps even get better with time (as the initial issues in the manufacturing of a new drive family get sorted out), but you're right that it would be interesting data. I bet the various manufacturers wouldn't be too keen on that data becoming public

[guru]

I agree. Most manufacturers consider defect lists to be proprietary/confidential.

I can post some pics when I have time of real radial defect locations

[granaryloaf]

You may be surprised to find out that different manufacturers often use the exact same platter media and that this is not developed by themselves.

[guru]

Fujitsu, Samsung and Toshiba are the only non vertical manufacturers. However, I have seen SDK, SAE media used on the latest HGST 15k Viper C drives.