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I'm just confused. I was a Windows user pretty much all my life. But now I want to switch to Linux for good. I have a 1 TB hard-drive attached to my laptop. As you know, in windows, the total hard-drive storage is divided into a couple of drives(i.e. Drive:C, Drive:D, Drive:E etc.). Usually, Windows is stored in Drive:C. My question is if I choose the Erase disk and install Ubuntu/ubuntu-derivatives option, will it erase the data on the other drives such as Drive:D/Drive:E, or will it just erase the drives where windows/any other OS is installed and keeping the data on other drives safe ?

wjandrea
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Chrollo_Rifat
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4 Answers4

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Only Windows confusingly calls partitions "drives". Everyone else calls partitions "partitions", and disks/drives "disks".

The erase disk option uses the term "disk" in the non-Windows sense. Everything on that physical storage device (disk, SSD) will be erased, including all partitions regardless of what they are called.

  • If "D:" is another partition on the same physical storage device (disk, ssd), it will be erased.
  • If "D:" is on a separate physical storage device, it won't be touched.
user535733
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    @Voo Minor edit to clarify; thanks. If the OP learned their disk/drive/partition nomenclature somewhere other than Windows, I extend a hearty apology to the hard-working folks in Redmond. – user535733 Jul 06 '21 at 17:58
  • Yeah I'm honestly not sure what exactly a "drive" is (google also seems to like the name as a metaphor for a storage unit though). Presumably it's the same as a disk, but yeah.. who knows. Luckily most of the time it's not that important. – Voo Jul 06 '21 at 18:04
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    @Voo a "disk drive" is the mechanism which drives the disk. It's very much similar to a record player: there are belt drive and direct drive turn tables. We shorten "hard disk drive" to "drive" because we're lazy and like shorthand. – RonJohn Jul 06 '21 at 19:03
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    it's not Windows who calls that but CP/M and DOS that use the term "drive" – phuclv Jul 07 '21 at 10:06
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Other people have explained 'drive' and 'partition' in the Linux context. Anyway, "Erase disk and install Ubuntu” removes the old partition table and creates a new one. This means that the opeating system sees the memory locations as empty in the whole physical device.

But the memory cells are still containing the data that were written before (in your case while it was still formatted by Windows). It is still possible (but a lot of hard work) to recover some of these data with special tools, e.g. PhotoRec.

If you want to make it impossible to recover the previous data, you can

  • overwrite the whole drive with zeros or some random data, or
  • use a built-in tool in the drive to remap the links between logical memory locations and physical locations (which works like encrypting without offering a key).

Removing the old partition table and creating a new one is usually good enough, at least for personal use.

You can find more details at this link.

sudodus
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  • Only SSDs have a mapping layer that you can logically erase. Rotational magnetic HDDs need to actually overwrite (unless their controller supports full-disk encryption so you can just generate a new key like on some SSDs); the logical -> physical mapping is trivial and linear on HDDs except for a few spare sectors it can remap to cover bad sectors as the drive starts to wear out. – Peter Cordes Jul 06 '21 at 05:01
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    @PeterCordes, We have different experiences. I will not argue with you. I agree that you are right in some cases (about wiping a HDD). Each user should use a method to protect their privacy, that they can rely on, even if many people think it is overkill. – sudodus Jul 06 '21 at 12:46
  • I didn't say you were wrong, just wanted to point out that your 2nd bullet point only applies to SSDs. Using hdparm to do an ATA SECURE ERASE command on an HDD will make its firmware write zeros over the whole thing, similar to if you'd used dd to do the same thing, at least in performance / how long it takes. – Peter Cordes Jul 06 '21 at 12:56
  • Several years ago I did that (used hdparm to do an ATA SECURE ERASE command on an HDD) and it took 2 hours. Overwriting with dd (or corresponding took more than 10 hours if I remember correctly), so yes, in that case hdparm was overwriting, but in a much more efficient way compared to dd (or shred or some gui tool using dd under the hood). I think DBAN was also efficient (and fast), similar to hdparm on that old SATA HDD. However, it was a long time ago, I am not quite sure that I remember correctly. – sudodus Jul 06 '21 at 13:10
  • Interesting. I wonder if it could get all heads to write zeros in parallel. Unlikely it was bottlenecked by the CPU, even with the default bs setting, not bs=64k or whatever to get dd to make fewer system calls. Anyway, it's still not just replacing a mapping table. – Peter Cordes Jul 06 '21 at 13:15
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    @PeterCordes Well since we're in nitpicking corner ;-) That understanding is correct for traditional CMR drives, but not so much for SMR drives. At least device managed drives will do something very similar to flash memory controllers in their firmware and there isn't a simple mapping from LBA to on-disk structure. – Voo Jul 06 '21 at 17:54
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You can boot into a "live" environment from an Ubuntu USB/DVD and use GParted to resize your hard drive and make room for your Ubuntu installation. It can get messy for those new to doing this so ensure you have a backup of what you want to keep. There is plenty of instruction on the net as to how to go about this.

Coconutdog
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If your storage device that you want to install linux on does in fact have more than one partition i.e. Drive D: and possibly Drive E: In Windows ,transfer all your personal data that you want to save that is on the Drive C: to one of these other drives. If you are installing Ubuntu or an Ubuntu flavour,choose "something else" in the installer, a partition manager will open and you can install to the partition you wish. N.B. the partitions in the linux partition manager will not be named in the windows fashion,so you will have to carefully identify which one is C: You can usually do this by noting the sizes of the "drives" and the free space in them ,in Windows, and then comparing these values in the linux partition manager (Gparted) If you do this carefully ,the two other partitions will remain untouched. Backups are always advisable.

Paul Girardin
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