What is a DCO/HPA/AMAX?
HPA was initially created so that drive manufacturers could change the size of a drive that is easily accessible, therefore allowing them to sell drives as if they were a smaller size. You could run a command called 'getsectors' that would allow you to see the actual size of the drive. AMAX or Accessible Max Address is much like HPA where its functionality limits the overall size that is reported to the operating system by the drive.
DCO was later released and could do the same thing as HPA, but it included other features such as being able to turn on/off drive features (like SecureErase for example). DCO also introduced the command 'NATIVE MAX' which worked the same as 'getsectors'. However, with the DCO you can change what the ouput is of 'NATIVE MAX' to be somewhere within the range of what the drive was set to show from the manufacturer and what the drive actually is. (For example, if the drive was set to show 8000 sectors, but actually has 10000 sectors, you could set the 'NATIVE MAX' to show 9000). The command 'DCO IDENT' was also added that worked the same as 'getsectors' and shows the actual size. Finally, the BIOS was configured to be able to set a 'DCO FREEZE' which makes it so that the DCO no longer responds to DCO commands (like DCO IDENT).
How Does WipeDrive Handle a DCO?
WipeDrive first queries the drive to see if it supports DCO features. If it does, it then sends the 'DCO IDENT' command to try and see the size of the drive. If that command comes back with nothing, then WipeDrive knows that there is a DCO lock. However, it does not know if the DCO size has been altered. If a DCO lock is detected, it will show up as 'DCO-Locked: WARNING...' and 'DCO found / removed: No / No' in the log file. (See below). This is because WipeDrive knows it is locked, but does not know if there is a DCO configured.
If the 'DCO IDENT' command comes back with a sector size, then you know the DCO is not locked and WipeDrive had full access to the entire drive. This will show as 'DCO found / removed: Yes / Yes' in the log file and will not display the warning message.
How Do You Remove a DCO Lock?
The DCO becomes locked when the firmware of the machine issues the '
It is possible that the graphics card will not wake back up from sleep. However, the drive may still be wiping. If you encounter this, you may be able to check if the drive is still running by looking for a light on the drive (depending on the drive) or if the drive is still spinning. If you are unsure, or if the drive is still running, please wait a day to allow the drive to finish. Once finished, it will send the log file to the destination you pre-selected and you will then know that the drive is finished and is wiped. You may now power off the machine. If this is happening frequently, you may want to consider wiping the drives in a PXE environment, as the PXE Server will show you the activity of the drive and allows you to see if the drive is still being wiped.
The prompt will only appear if the drive has DCO features. If WipeDrive does not detect that the drive has DCO features, it will not show the prompt and you can continue on as normal.
If the drive is DCO locked (and the lock is not removed prior to wiping), WipeDrive is not able to detect how many sectors (if any) are behind the DCO lock. It is possible that WipeDrive is still wiping the entire drive, but the only way to know is to compare the sector size of the drive to the sectors WipeDrive wiped. While rare, there may be information stored on the DCO. If so, that information will persist on the drive unless the DCO is removed and WipeDrive can access the entire drive. Removing the DCO Lock is the only way of knowing what the current DCO Configurations are for the drive.
If a drive's original size has been altered by DCO features, then the drive will report having a DCO currently active. In this event, WipeDrive will report that a DCO has been detected, and if WipeDrive was successful in removing the DCO configurations that were altering the drive's size, then the software will also report 'DCO Removed: Yes'.
For any additional questions or concerns, please contact Support here or chat with us on our Live Chat during regular business hours.