Hypothetically I have a 200GB hard drive. But I want it to appear as a 100GB hard drive. How would this be accomplished?

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    I don't think its possible to make it appear to be less without actually making it less. Can you provide a bit more background information as to why you want this? Perhaps there are other methods we can tell you that will work in your case. For example, you could shrink your partition to 100 GB, create a 2nd partition of 100 GB and instead of assigning a drive letter to it, assign a path that is nested somewhere on your harddrive. Of course, the rest of the harddrive is still only 100 GB big. – LPChip Dec 15 '15 at 18:20

Russel, this is completely achievable on a low level. Most hard drives are actually larger then what is displayed to the end user even on a whole disk view, not just a partition view.

These settings are managed in the Host Protected Area (HPA) or it is sometimes called the Disk Configuration Overlay (DCO)

https://en.wikipedia.org/wiki/Host_protected_area https://en.wikipedia.org/wiki/Device_configuration_overlay

In fact, most spinning platter hard drives actually come with a number of bad sectors from the manufacturer, and these sectors are already marked "bad" in the HPA, and as such do not show up as part of the drive size and cannot be written to. It is completely possible to "mark" half of the sectors on a drive as "bad" with a low level HPA tool. It's also a way to hide data from prying eyes.

One tool that can be used to modify the HPA of a hard drive is hdparm. http://linux.die.net/man/8/hdparm

Here's more info on how to set the number of addressable and visible sectors:


Source, 4 years of Digital Forensics college.


You will need to create a single partition sized to 100gb and ignore the other free space.

There is a basic guide titled "How to Manage Partitions on Windows without downloading other software" if you would like to learn how this is done on windows.

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