HP 3000 III Series Manual page 21

INTRODUCTION
I~
The HP 3000 Series III Computer Systems are general purpose com-
puters with true multiprogramming and mUltilingual capabilities.
They can simultaneously handle many interactive and batch opera-
tions; each in any of several programming languages. The HP 3000
Ser ies III Computer Sys terns feature hardware stack architecture,
variable-length code segmentation in a hardware-assisted virtual
memory scheme, user protection, dynamic storage allocation, and
integrated hardware/software design. The hardware and software
work together in an interrelated manner with the hardware per-
forming many operations conventionally performed by software.
The HP 3000 Series III Computer Systems have a single, comprehen-
sive operating system, the Multiprogramming Executive (MPE). MPE
is a general-purpose, disc-based software sys tern that supervises
the processing of user programs. MPE relieves the user of many
program control, input/output, and other housekeeping responsi-
bilities by monitoring and controlling the compilation, run prep-
aration, loading, execution, and output of user programs. MPE
also controls the order in which programs are executed and allo-
cates the hardware and software resources they require.
1-1. SYSTEM FEATURES
The HP 3000 Series III Computer Systems incorporate many features
usually found only on very large computer systems. These fea-
tures are summarized in paragraphs 1-2 through 1-10.
1-2. Stack Architecture
The system's stack architecture provides private, hardware-
protected data storage for each user as well as an automatic
method for moving this data to and from the central processor
registers. The major operating features derived from this design
are:
a. Fast execution
b. Code compression
c. Hardware-protected execution
d. Dynamic allocation of sUbprogram data space
e. Ease of parameter passing
f. Efficient sUbprogram linkage
g. Rapid interruption and restoration of user environments
h. Subprograms being able to call themselves (recursion)
1-1