FAQ for Wiping Mass Storage Device

  1. What should we pay attention to when we dispose of IT equipment with storage devices or external storage devices or when we transfer them for recycling use?
    It is not easy to say whether a storage device contains sensitive information or not. As a rule of thumb, when we dispose of or transfer storage device for recycling use, we should make sure that all data stored inside a device are erased in such a way that they are unrecoverable.

  2. Is it safe to delete and purge all files or reformat the whole storage device using standard means?
    Deleting files on a hard disk or reformatting the whole storage device using standard means will leave behind traces of information, and with special tools, it is possible to recover deleted information.

  3. What is the meaning of “unrecoverable”? What should I do?
    There are at least two methods that can remove data permanently and are unrecoverable - by use of a degausser or by use of a hard disk wiping tool.

  4. What services are provided by the Computing Services Centre (CSC) in data erasure?
    There are many service providers offering data erasing services, but they are both very expensive and inconvenient. The Computing Services Centre (CSC) provides a complete solution with all three choices to users with no charge and are easy to reach. The choices are wiping, degaussing, and shredding. The following is a brief description and comparison among these three methods for users to choose the one that fits them most.

    Wiping Degaussing Shredding
    Principle of the method Destroy the data by writing data patterns to the storage devices multiple times Destroying the magnetic patterns that record the data Physically destroy a device and crush it into little pieces
    Suitable for
    • Both magnetic and non-magnetic (e.g. SSD hard disks) type of data storage
    • Hard disk that is needed to be reused
    • Magnetic hard disks only
    • Removing data even if the hard disk is not functioning
    • HDD, SSD, USB thumb drive, memory card and CD/DVD, smart phones (internal battery must be removed beforehand)
    • Device that is not to be reused
    NOT suitable for
    • Connection type other than SATA and PATA, i.e., SCSI drives are not supported
    • Drives already found malfunctioning
    • Non-magnetic storage devices such as SSD hard disk and flash drives
    • Device that cannot fit the size of the insertion hole (~5¼”)
    • Device with a tendency to curl (e.g. tapes, cords)
    • Device with heavy rubber and sticky materials
    Recycling Yes. Storage devices normally can be reused as this method just overwrites the drives with randomized data pattern. No. Hard disks once erased by this method CANNOT be reused since the factory setting of the hard disk is also destroyed in the process. No. It will be all ground into pieces and cannot be reused.
    Time required Very long time required, depending on the size and speed of the storage device (e.g. 500GB magnetic drive will require more than 3 hours to complete) Very short time required and does not depend on the hard disks. Normally less than 10 seconds per disk. Only that time is required to charge up the equipment Very short time required. Normally less than 10 seconds per item
    Where is the service? There are several wiping machines installed in CSC Workshop as well as in Teaching Studio Area There is one degaussing machine installed in CSC Workshop. There is one shredder installed on ground floor of YEUNG building.

  5. What is the procedure to apply for these data removal services from the CSC?
    To use the wiper machine in the CSC Teaching Studio Area, users can reserve it through the CSC Booking System, which can be found in the Portal. To request for other services, staff can apply through their own Departmental Network Administrator (DNA) to raise a CSC Work Request.

  6. Can I get back my data from the storage device after performing data erasure?
  7. One very important reminder is that, for data removed by one of the above methods, users can no longer get them back by any means. Therefore, the CSC staff handling the request will ask users to sign a declaration form before the erasure operation to ensure users clearly understand and agree to the consequence of data removal.

    Therefore, users are reminded to back up the data required before starting the data removal process.

csc.servicedesk@cityu.edu.hk