Darik's Boot and Nuke (DBAN)

Deleting a file removes a pointer. Formatting a drive removes a table. Neither touches the data, which is why a disposed machine can hand a stranger everything on it. Darik’s Boot and Nuke, known to everyone as DBAN, solves that by writing over every sector on the disk, including the boot record and the partition table, until there is nothing left to recover.

It works from its own boot media rather than from inside an installed system, which is the entire reason it can do the job. Nothing is running, nothing is locked, no file is in use, and no filesystem sits between the program and the platter. Boot from a stick, pick your drives, start the wipe, walk away.

The reputation is deserved and also out of date in one important respect, which this review will get to before recommending anything.

Getting it onto something bootable

The image boots from a USB stick, from optical media, or over a network using the preboot execution environment, which is how anyone decommissioning a room full of machines actually uses it.

Writing the image to a stick is the only preparation involved, and Rufus handles that in about a minute. From there it is a matter of persuading the machine to boot from the stick rather than its own drive, which on older hardware is a key press at startup and on newer hardware is a settings trip covered further down.

Six methods, and the case for using the simplest

The method list runs from Quick Erase, a single pass of zeros, up through an eight-pass government standard, a three-pass short military pattern, a seven-pass version of the same, a thirty-five pass option, and a pseudorandom stream where you choose how many rounds to run. Random data comes from one of two selectable generators, and verification can be applied to the last pass or to all of them.

Here is the part nobody selling erasure software wants to say. On any drive of recent manufacture, one pass of random data is enough. The thirty-five pass method was designed for magnetic encodings that have not shipped in a very long time, and the multi-pass military pattern everyone cites has been formally retired by the body that wrote it. DBAN keeps them because internal policies still name them, not because they achieve anything the single pass does not.

The arithmetic makes the point. A single pass across a terabyte of spinning disk runs to a few hours, three passes take the better part of a day, and thirty-five passes become a multi-day commitment.

Pick the simple option unless a compliance document forces your hand, and the drive will be exactly as unrecoverable.

Autonuke, and why the room should be empty

Type a single word at the boot prompt instead of pressing enter, and DBAN wipes every drive it can find using the default method, with no selection screen and no confirmation. For a batch of identical machines being decommissioned, that is exactly right.

For everybody else it is the single most dangerous thing in the program. It does not distinguish between the drive you meant to wipe and the external backup you forgot was plugged in, and it never asks. Unplug everything you are not destroying before you boot, including the drive holding the only copy of something.

Even in interactive mode the parallel wiping deserves respect. Selecting several drives runs them all at once, which is efficient and also means a mis-tick affects more than one disk before you notice.

Where it will not work at all

The most important limitation first. DBAN does not properly erase solid state drives. Overwriting the sectors a drive presents does not reach the blocks its controller has remapped, the spare area held back for wear levelling, or anything sitting in over-provisioned space. Data survives in places a sector-level overwrite cannot address, and running thirty-five passes changes none of that while wearing the flash for no reason. Checking what you actually have with CrystalDiskInfo before you start takes ten seconds.

For flash storage the correct approach is a firmware-level secure erase issued to the drive itself, which the controller executes internally. A utility from the drive maker that sends that command does in seconds what no amount of overwriting achieves.

Three more walls. Drives on the newer high-speed interface are not detected at all, so a current laptop will boot the program and show nothing to wipe. Booting requires legacy compatibility mode on machines that ship with the modern firmware standard.

And RAID arrays are not disassembled automatically, so each disk has to be taken out of the array and presented individually before it becomes visible.

No paperwork, which matters more than it sounds

The wipe happens and the screen says so. Nothing is written down, nothing is signed, and no report leaves the machine.

If you are erasing your own laptop before selling it, that is fine. If you are disposing of equipment that held other people’s data under any kind of obligation, an undocumented wipe is not evidence that a wipe occurred. Active KillDisk and its commercial peers exist largely because auditors want a certificate with a serial number on it.

And if the whole disk does not need destroying, taking the machine offline to wipe it is overkill. A shredder that overwrites individual files from inside a running system covers the case where only certain things must go.

Conclusion

DBAN still does exactly what it always did, and for a spinning disk coming out of an old machine there is nothing simpler. Boot it, pick the single-pass option, walk away, and the drive comes back actually blank rather than apparently blank.

The trouble is how much of the world it no longer covers. Solid state storage is the norm now and it cannot handle it, current interfaces are invisible to it, modern firmware needs coaxing before it will even boot, and nothing here produces the paperwork that professional disposal requires.

Keep it for older hardware, know what kind of drive you are pointing it at, and unplug everything else in the room first.