Understanding Wiping (Not Related To Potty Training)

It’s hard to keep a straight face after this title but I’ve decide to write a short piece on the topic to help readers understand how things work with a server.

A computer, or server, is a group of electronic assemblies operating under the direct control of the operating system. Operating systems include Windows, Linux, iOS, Android etc. A large part of the operating systems’ role is organizing data on a hard drive or other form of mass storage like and SD card. A hard drive which is customarily used on servers, laptops and desktop computers is very much like a record player. The platter spins at a high r.p.m. and the drive heads float over the platter’s surface. Those heads move through an actuating arm so the heads can be positioned to write to or read data from the rotating platter. All of that occurs under the operating system’s control.

When you write a letter or an e-mail message the operating system saves the data to the hard drive. Part of the process entails the creation of an index that points to where on the platter’s surface the file is stored. A file is not stored contiguously on the platter surface, it’s actually stored across a number of physical locations. Using those pointers, the operating system is able to then locate the data for later use. The same is true when you receive and e-mail or save any data to the hard drive, a pointer is created that identifies the physical location(s) on the platter where the data is stored. Once a location is used, it is no longer available for other files.

When you delete a file, you’re not erasing its actual data; you are erasing the pointers to that file. With the pointers gone, the operating system sees that physical location as being available for data storage. So, when you highlight an e-mail message and click on “Delete” you are simply removing the pointer to that e-mail. However, its text remains on the drive until it’s overwritten by the operating system.

Over time and with continuous use, a drive can become fragmented. This means that pieces of a file are scattered all over the surface of the platter. Imagine a vinyl LP where you have to continuously move the record player’s arm to listen to a single track. Fragmentation reduces the computer’s efficiency and speed. Operating systems include a utility, which when executed gathers up all of a file’s fragments and attempts to store them closer together or contiguously on the platter surface. This is a routine maintenance function that should be scheduled at standard intervals.

Wiping a drive is a process requiring dedicated software; separate from the operating system. When you wipe a drive, the software overwrites all parts of a drive for where there are no pointers. With the pointers missing, the wipe software sees a space not occupied by a live file and overwrites that space with things like ASCI Null characters, zeros, exclamation points or any other character. The objective is to overwrite whatever was originally in that space so that any old data is indiscernible. Wiping a drive is a tedious process and in order for it to be effective the software needs to run a minimum of 7 passes. Wiping a large capacity drive can take days, depending on the system. Wiping a drive does nothing to improve system performance. When properly performed it simply ensures that data previously stored on the target drive is indiscernible.

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