Hamburg - 28. 4 2022 - DI (FH) Markus Häfele
The structure of a clean room is designed so that the occurrence of airborne particles - which are transported into the room or have their origin there - is kept as small as possible. Clean room and clean room technology is essential for specialized manufacturing processes in which particles in regular air could cause structural errors in the circuit integration. This also results in the unconditional need for clean air in semiconductor production. But other high-tech companies also rely on clean room technology: professional data recovery.
In data recovery, such clean rooms are used for opening, evaluating damage and temporarily repairing hard drives. The "Cleanbench" in the data recovery laboratory forms one of the foundations for the risk-free opening of mechanical hard drives. The clean working environment of clean room class 5 used in the "Cleanbench" according to clean room standard EN ISO 14644-1 (clean room class 100 according to US FED STD 209E) classifies the purity of the air based on the particle concentration contained therein.
The high-performance air filter systems of the clean room unit create a barrier of air through the laminar (low-turbulence) displacement flow (vertical), which absolutely minimizes contamination of the work area and open hard drives. This prevents the deposition of particles on the sensitive ferromagnetic data carrier disks, which can cause fatal damages when powered on. The read/write heads of a hard disk hover on a wafer-thin air cushion in the micrometer/nanometer range above the data layer of the magnetic disks. The rotational speeds vary between 5,400 rpm and 15,000 rpm depending on the type, model and area of application. Since a speck of dust is many times larger, one can imagine the effects it would have if the filigree read/write heads collided with it.
It persisted until a few years ago: the myth of a complete clean room for data recovery. All employees are equipped with face masks and full body protective suits. A clean room, as is known for example from the manufacture of conductors or hard drives. A highly romanticized and in that form often in demand data recovery environment, which was partially met with appropriate websites. The reality behind it has always been different. Demystification takes place very quickly if you break down the clean room laboratory into a room with data recovery tools and a clean room component, the so-called "Cleanbench".
Even today, one of the most frequently asked questions is aimed at the existence of a clean room. The disillusionment becomes noticeable very quickly if one clears the imaginative expectations with the actual events. In addition to the “Cleanbench”, work gowns, gloves and work shoes that discharge electrical charges are just as necessary as antistatic flooring, antistatic work pads and antistatic wrist cuffs. Whole body suits or locks for atmospheric separation will be sought in vain, these are at most showmanship and are intended to suggest professionalism.
Based on the description of the failure or error process, the hard drive should, as a precaution, no longer be connected in the normal way. For example, if a hard drive has dropped, you have to assume a physical impairment. The careless commissioning, on the premise that read/write units or data carrier surfaces are mechanically damaged, could result in unpredictable damage. For this reason, the affected hard drive should be subjected to a diagnosis in the laboratory in order to be able to evaluate the degree of damage (defective components) and the possibilities of temporarily repairing the data storage device.
Temporary repairs include all work that is related to data carrier preparation and is used for the last commissioning: exchange of identical mechanical and/or electronic components, manipulations/modifications to control software and adaptive parameters, leveling processes for straightening damaged data carrier surfaces, soldering work or extensive cleaning. Attempts are made to prevent consequential damage and to maintain the operability of the hard drive for as long as is technically feasible in order to read out as much data as possible before the defects become fatal and the data carrier finally fails.
In the course of the last possible commisioning, the stored data (raw data) is carefully extracted. The data is copied onto several data carriers, with which all further processing steps follow. On the one hand to prevent the content of the original data carriers from being impaired if the logical reconstruction of the system and file structures takes place during subsequent processing; on the other hand, physical copies are independent of the network and, in the event of a risk of external attacks, are protected as best as possible against unauthorized access and data theft.
Due to the extensive diversity of hardware and software, depending on the manufacturer and model series of the respective storage medium, each case requires an individual and specialized approach. Another factor for this is the causal error. Depending on the reason for the failure and the measures taken afterwards, the approach differs considerably; there is no typical approach or patent solution. In some cases, completely new solutions have to be researched, developed and produced. In any case, the concentrated knowledge and many years of experience of the engineers is required in order to be able to develop timely individual solutions for data recovery.