Digital Forensics - Fall 2014

continued to decrease from about 1 mm in diameter to an average size of around .000001 mm today. As transistor size continues to shrink, it may eventually approach the atomic level. With such extremely small transistors, millions more of them can be densely packed within a given area, providing greater storage capacity in a smaller space. However, as engineers continue to miniaturize storage devices, they are going to encounter some practical problems that involve Quantum Physics. For instance, as magnetic memory bits are miniaturized, their magnetic fields begin to affect each other, thereby reducing their ability to maintain a 1 or a 0.

• Several years ago, scientists at IBM Research created the smallest magnetic memory bit at the atomic level. They were able to reliably store one bit of data using just 12 atoms. However, there are critical technical issues that have to be solved to make this process practical for everyday storage devices. The 12 atoms must be assembled using a scanning tunneling microscope (STM) at temperatures approaching absolute zero and the bits can only hold data for several hours at a time. As scientists continue with development, it may eventually lead to devices with densities 100–150 times greater than typical HDDs or SSDs.

• In a process similar to how a CD-RW is created, a small amount of gold can be added to the surface of a silicon disk. The gold then essentially forms self-assembled tracks 5 atoms wide with the extra silicon atoms sitting on top of the gold tracks. This can provide a means of data storage if each of the extra silicon atoms is arbitrarily assigned a value of 1 and the spaces between them a value of 0. However, the scale is at the nanometer level instead of the micrometer level. Atomic memory can thus provide at least a million-fold increase in storage density. Again, there are practical issues in reading and writing that involve using an STM operating at temperatures approaching absolute zero. Due to the exotic technology, it may be quite a while before Nanoscale memory devices become available for routine information storage.

This discussion will continue in a future column.

John J. Barbara owns Digital Forensics Consulting, LLC, providing consulting services for companies and laboratories seeking digital forensics accreditation. An ASCLD/LAB inspector since 1993, John has conducted inspections in several forensic disciplines including Digital Evidence. jjb@digforcon.com