Biomedical Engineering Reference
In-Depth Information
Although digital computers have evolved considerably since Turing's day, the basic elements are the
same. Memory, in the form of RAM, ROM, or hard-disk storage, together with the digital
microprocessor, forms the basic building blocks for a digital computer, as illustrated in Figure 1-13 .
As the brains of a microcomputer, the microprocessor directs the flow of data within the computer
and performs mathematical operations on the data. Within the microprocessor, the Arithmetic Logic
Unit (ALU) performs mathematics and Boolean logic operations according to the truth tables in Figure
1-12 . Registers provide temporary storage, a clock provides for the timing of events, and a common
bus supports communications among the components. The most important component, from a
process control perspective, is the input/output unit that communicates data to and from external
devices, such as the instructions to the stepper motors that control the positioning of samples in a
gene sequencing machine and accept the output of optical scanners.
Figure 1-13. Digital Computer Physical Architecture (left) versus
Abstraction (right). Process control applications emphasize input/output
hardware (left), which corresponds to the peripherals abstraction (right).
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