Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

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Preface
This manual documents functionality for the MPE/iX 6.0 release, as
well as later releases, for HP 3000 Series 900 systems.
This manual documents a subset of the system-supplied intrinsics
available through the native mode of operation for MPE/iX on HP 3000
Series 900 computers. The intrinsics described here are those that are
particularly useful for the programmatic control of asynchronous
devices. An asynchronous device is a device which can be configured as
a terminal or serial printer and communicates with the system in an
asynchronous, serial manner, as described in Chapter 1, “Introduction.”
NOTE MPE/iX, Multiprogramming Executive with Integrated POSIX, is the
latest in a series of forward-compatible operating systems for the
HP 3000 line of computers.
In HP documentation and in talking with HP 3000 users, you will
encounter references to MPE XL, the direct predecessor of MPE/iX.
MPE/iX is a superset of MPE XL. All programs written for MPE XL will
run without change under MPE/iX. You can continue to use MPE XL
system documentation, although it may not refer to features added to
the operating system to support POSIX (for example, hierarchical
directories).
Finally, you may encounter references to MPE V, which is the operating
system for HP 3000s, not based on the PA-RISC architecture. MPE V
software can be run on the PA-RISC HP 3000s (Series 900) in what is
known as compatibility mode.
Audience
This manual will be of greatest value to applications programmers who
need to access and manipulate asynchronous devices during execution
of a process. While some general and conceptual information is
provided in the first two chapters of the manual, the intrinsic
descriptions assume that the reader has a good basic understanding of
system intrinsics and their use.