2. Переведите на русский язык термин “Shadow Data”.

3. Прочтите текст и переведите его на русский язык.

Shadow Data (Part 1)

Have you every thought about why some government agencies require computer data to be erased by overwriting it at least seven times or even more? Have you ever thought why classified (or secret) government agencies prefer to destroy computer hard disk drives rather than surplus them? The reasons for these levels of paranoia are valid and they are connected with the potentials of security breaches tied to I shadow data.

When computer data is written to a floppy disk, zip disk, hard disk or tape, a mechanical device called a head is used to write the data. The information is stored electronically in magnetic patterns of binary ones and zeros. The patterns are j in the form of sectors which are written consistently in concentric rings called tracks. The process is fast and efficient. I However, it also involves the use of a mechanical device I which operates with less than exact tolerance levels. Horizontal < head straightening and vertical head placement is just a bit j different every time the information is written and rewritten to the same track. This situation limits the effectiveness of software data scrubbers and it creates the potential for government security breaches on well used storage devices. Thus, government agencies require multiple writes when data is destroyed with data scrubbers. However, even multiple writes can not guarantee complete removal of legacy data. The last data that remains on the track is called shadow data, j However, NTI’s М-Sweep Pro Software removes almost all I potentials for the forensic recovery of shadow data.

Shadow data contains the leftovers of computer data that was written previously to a track and it is located slightly j outside the track’s last recording path. It gets a bit moro complicated though. There are actually two reasons which cause shadow data to come about: mechanical issues and

magnetic issues. To illustrate the mechanical issues, imagine a long, straight road of a consistent width. A car traveling along that road has a paint sprayer attached to its bumper, and paints a line as it goes. Mechanical shadow data manifests itself due to imperfections in the drive’s servomechanism which causes the write arm, which holds the write head over the drive’s surface, to shake horizontally to the left and right to a certain extent. This would be analogous to our vehicle weaving back and front on the road as the paint sprayer continues doing its job. The resulting painted line would not Im- in a straight line, but something like elongated “s” pattern. Mach pass of the write head varies slightly creating new elongated “s” patterns within the bounds of the storage space unsigned to the track.

The source of magnetic shadow data is analogous to the paint sprayer’s nozzle being moved up and down vertically мм the line is painted. If it is high, the paint spray pattern will be wide. If it is low, the paint pattern will be narrow and

1. hr painted line will be thin. With this analogy the paint over pray would be shadow data which would not be completely

covered if a new line were to be painted on the road. This

2. ilatter effect is actually caused by variances in signal strength an the head moves up and down vertically as the data is written to the track.