HP 3000 III Series Manual page 22

In t r
cd
uc t ion
1-3. Microprogrammed Operations
Many system operations that were previously programmed in soft-
ware are now microprogrammed. These operations are requested by
machine instructions which in turn execute multiple microin-
structions built into the central processor hardware. Micropro-
gram~ing
eliminates repetitive coding otherwise required for
recurring operations.
1-4. Data Base Management Faciities
The computer systems provide software facilities that allow the
user to create, access, and maintain large data bases. The in-
formation in these bases can be acces sed both interactively from
a keyboard terminal and programmatically from user programs writ-
ten in any of the the available programming languages.
1-5. Fiw Programming languages
The computer systems provide the user with a true multilingual
programmlng environment. The six available languages are COBOL,
RPG, FORTRAN, BASIC, SPL (a language developed especially for the
HP 3000 Series Computers), and APL.
1-6. Virtual Memory
The operating system's hardware-assisted virtual memory scheme
offers each user program a memory space that exceeds the maximum
main memory size of 1024K words. Virtual memory consists of both
main memory and a flexible storage area on disc. Virtual memory
is implemented using a segment trap frequency algorithm that en-
sures the automatic presence in main memory of only those seg-
ments of code and data which are currently required by the
executing program. Main memory is thus efficiently shared by
the users in a manner that gives each programmer the impression
of working with a much larger computer system.
1-7. Fault Control Memory
The computer systems employ high-speed semiconductor memory mod-
ules that provide automatic fault detection and single-bit cor-
rection with no loss in performance.
1-8. Concurrent I/O and CPU Opemtions
Many I/O operations can be performed concurrently with Central
Processor unit (CPU) and memory operations. This is possible
because, in addition to the CPU, the computer has an Input/Output
Processor (lOP) with its own dedicated data transfer path (lOP
bus) to which are connected a Multiplexer Channel(s) and one or
more Asynchronous Terminal Controllers. All of this hardware
operates under control of the MPE operating system which handles
all queuing and device sched uling.
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