Ally Web Directory: Free Articles » Computers » Securely Wipe Your Old Disks or You could Face Thieves or Even Worse!

Computer users fall in varied categories. Some just rent a personal computer for use and return it after a certain period. Some people buy, use and resell or donate their old computers while purchasing newer versions. Almost all users leave potentially important information on the computers. A knowledgeable thief has to just attempt simple data recovery and gain access to the sensitive information that remains stored. Passwords, credit card details and other vital information are accessed and misused. Necessity of Wiping the Hard Disk Clean The user is often not aware that deleting information is not the same as erasing it. Operating Systems (OS) allocates files to sectors. And deletion of the file simply releases the sectors for fresh data to be rewritten on it. However, rewriting does not ensure that the unallocated clusters will be written over. Information presumed to be deleted might actually exist for years. So it is vital that computer users wipe their old disks before giving them to someone else. Preparation for Data Wiping

• Before wiping the hard disk, it is important to create a backup for all important data. This backup should be created in a removable media or an external hard drive.
• The computers should then be sent to an authorised refurbisher. They clean the hard drive and reinstall the operating system.
• The entire process takes plenty of time. The size of the hard disk drive determines the time taken for disk wiping.

Appropriate Method for Disk Wiping The process of disk wiping involves deletion or wiping out data from the hard disk by creating a very large file. The text for the file can be downloaded. Though it takes some time to run, it uses all the unused space available on the drive. The new data might get rewritten all over the deleted information. This method is simple and user-friendly. No complicated technology is necessary for this. There are varied methods of disk wiping and the level of the sensitive data determines what method has to be used.

• The simplest option is wiping out all data using 0s. This method is applicable for the least sensitive data as it is also the least secure of all methods of data wiping.
• The entire drive is filled with binary digits of 0 and 1. Repeating this entire process a number of times makes the data inaccessible. But, when the hard disk is filled with fixed data, it is possible to read the original data using specialised equipment.
• Multiple rewriting over data using a combination of different characters is more effective.
• Finally, extremely sensitive data is rewritten over 35 times using a random selection of characters.

Data Retrieval even after Disk Cleaning Most disk wiping utilities leave lots of information. The disk wiping pattern creates a file that contains all 0’s, all 1’s or a random selection of 0’s and 1’s. The entire free space is occupied and individual sectors or clusters are not dealt with. After wiping out the entire free space the disk wiping utilities check the directory also. But analysis reveals that considerable residual data remains. However, disk wiping utilities mitigate chances of recovery and recovering such data is difficult. Technological advancement in magnetic disk technology has enabled data retrieval even when it has been rewritten over. This is possible for the read write head is slightly unsteady while it flies at high speeds over the magnetic platters. But retrieval of such data is expensive. The ordinary hacker cannot get access to such rewritten data bits. Wiping the hard disk drive clean is necessary not only for personal computers but even for cell phones. For, a lot of addresses, phone numbers, text messages and other sensitive data are stored in them. Similarly, a lot of sensitive information is stored on the computers and it is necessary to erase it completely. Mere deletion is not sufficient. Disk-cleaning utilities are either commercially available or come free. Sometimes, disk-wiping does not allow the personal computer to be recycled. For, it occupies so much space that the OS often hangs up.