Such sensitive storage devices contain data worth thousands or millions of pounds. Any problem of the computer hardware or software necessitates the opening of the hard disk for data retrieval. Opening of the hard disk in a normal room would mean exposing it to 300,000 micron particles in one cubic foot of air. And, this would immediately lead to a permanent loss of data well beyond the point of retrieval.

To overcome such problems data recovery specialists operate in class 100 clean rooms.

Clean rooms are contamination-free zones. Here are some features of Clean Rooms:

Such standards ensure that the atmosphere in a class 100 clean room has 100 submicron particles the size of 0.5 micron in one cubic foot of air. The cleanest a room can be is class 10.

Data retrieval from a hard disk necessitates its opening in a clean room. This invasive procedure requires a totally dust free environment.

However, building and maintaining a clean room is extremely expensive. The cost of construction of a clean room varies according to the level of cleanliness maintained. The clean rooms for recovering data from a hard drive cost ? 750,000 and above for their construction and maintenance. Yet, they are necessary for, opening a hard drive in atmosphere other than the one in a clean room damages data permanently and its retrieval becomes impossibility.