How It Works

Deleting files on computers is an easy task and is actually really quick. Even the deletion of huge files apparently only takes a few milliseconds. However, if you expect that your data is gone you are completely wrong.

Read further to understand how data erasure does work and how to wipe disks safely with Wipezero.

Usually files or data of entire disks are being removed by the following two procedures. Let us explain how those work.

Most Operating Systems provide a standard way for users to delete files easily and quickly. In Windows, Mac OS and some Linux Distributions users move their files into a trash and once the trash is being emptied the files are gone.  Similar to this by using Command Line Interfaces files are being deleted directly without being moved to trash first.

However you do delete files, the data of the files actually remains in place and only the links to the files are removed. Therefore, the disks File System just intentionally forgets where the data of the file is located. The Operating System knows that it can write to this now unused space and might overwrite it later. This, however, depends solely on the write activity of the disk.

Occassionally users format their disks. May it be to prepare USB flash drives or with the intention to install a new Operating System.

During formatting the partition may change and a new file system is being implemented. Once the disk has been formatted it seems that the data is entirely gone as all space is freed and could be reused. However, only the partitioning and the file system has changed. Similar to File Deletion almost all, if not any data is still in place but the file system does not know where to find it. All remaining data can be recovered easily with widely available data recovery tools.

Several data erasure options are available to wipe disks in order to make data unrecoverable. Wipezero uses those techniques to wipe disks safely so data cannot be recovered.

Zero Filling overwrites every bit of every accessible sector on a disk with zeros. All data and meta data is overwritten and therefore cannot be recovered. The speed of this data erasure method highly depends on the write speed of the disk and can even take days for large drives.

Zero Filling is the recommend way to wipe disks that do not support Secure Erase, e. g. SAS disks and USB flash drives. 

Random Filling overwrites every bit of every accessible sector on a disk with random data. All data and meta data is overwritten and therefore cannot be recovered. Generating a stream of random data is more expensive compared to zeros and is therefore slower. 

Most modern SATA drives support a so called Secure Erase, an internal mechanism to wipe disks. This is the recommended way to erase data as it is considerably faster than zero filling because it is does not depend on the physical write speed.

Secure Erase can also increase performance of SSDs. More information about Write Amplification performance drain for SSDs.