60 Appendix A: Hardware glossary
Glossary
• Auxiliary I/O signal.
An auxiliary I/O signal is a digital (on/off ) I/O signal that can have one or more
additional functions. For example, all auxiliary input signals can be used to receive
a user-defined input signal; some auxiliary input signals can also be used to receive
a trigger signal or a rotary/linear encoder input signal.
• Bandwidth.
A term describing the capacity to transfer data. Greater bandwidth is needed to
sustain a higher transfer rate. Greater bandwidth can be achieved, for example, by
using a wider bus.
• Blocking cache.
A type of cache that allows for one information request at a time. If the cache does
not contain the information needed by the processor, it will be "blocked," or
unavailable for use until the required information is obtained from memory.
See also cache and non-blocking cache.
• Bus.
A pathway along which signals are sent, generally in two directions, for
communication of data.
• Cache.
A memory area of the processor. The processor can access data from its cache faster
than it can access data from system RAM or mass storage devices.
Many processors have a primary cache and a secondary cache. When searching for
information, the processor first refers to the primary cache. If it cannot find the
required information, it will then refer to the secondary cache.
See also blocking cache and non-blocking cache.