Biomedical Engineering Reference
In-Depth Information
The analogy depicted in
Figure 2-11
highlights the concept of working memory. Data are pulled from
archives, whether they reside in the double helix of a chromosome or on a tape cartridge, and are
put in position where they can either be acted upon or direct other activities. In the cell, the activity
is protein synthesis. In the workstation, this activity can be identifying a nucleotide sequence,
predicting the 3D structure of a protein, or modeling how multiple proteins interact at the molecular
level.
For example, as illustrated in
Figure 2-12
, a pattern-matching program that is searching for a match
in a long nucleotide sequence works on the sequence in local, high-speed, active (and volatile)
memory—the computer's RAM. As soon as the length of nucleotide sequence that can fit in RAM is
searched, it is discarded and replaced by a new sequence that is copied (akin to transcription) from
the hard disk, flash memory, or other non-volatile storage media. Just as RNA is discarded after it
has been involved in the translation process to make room for the next set of instructions from the
DNA, the data in RAM are constantly refreshed and updated under the direction of the computer's
CPU.
Figure 2-12. Working Memory. Limited working memory in volatile RAM is
