HP BASIC for OpenVMS is the latest name for a dialect of the BASIC programming language
Programming language
A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs...
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
Itanium is a family of 64-bit Intel microprocessors that implement the Intel Itanium architecture . Intel markets the processors for enterprise servers and high-performance computing systems...
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
-like extensions, as well as supporting the original Dartmouth BASIC
Dartmouth BASIC
Dartmouth BASIC is the original version of the BASIC programming language. It is so named because it was designed and implemented at Dartmouth College...
Programming languages typically support a set of operators: operations which differ from the language's functions in calling syntax and/or argument passing mode. Common examples that differ by syntax are mathematical arithmetic operations, e.g...
In computing, a line number is a method used to specify a particular sequence of characters in a text file. The most common method of assigning numbers to lines is to assign every line a unique number, starting at 1 for the first line, and incrementing by 1 for each successive line.In the C...
s are optional, unless the "ERL" function is present. It allows you to write "WHEN ERROR" error handlers
Exception handling
Exception handling is a programming language construct or computer hardware mechanism designed to handle the occurrence of exceptions, special conditions that change the normal flow of program execution....
In computer programming a statement can be thought of as the smallest standalone element of an imperative programming language. A program written in such a language is formed by a sequence of one or more statements. A statement will have internal components .Many languages In computer programming...
. The more traditional but less elegant "ON ERROR" statement lacks such context or scope.
One of HP BASIC's more innovative features is built-in support for OpenVMS
OpenVMS
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
Record Management Services are procedures in the VMS, RSTS/E, RT-11 and high-end RSX-11 operating systems that programs may call to process files and records within files. VMS RMS is an integral part of the system software; its procedures run in executive mode...
(RMS). Before VAX BASIC (as it was then called), you would only get native RMS support in DEC's COBOL
COBOL
COBOL is one of the oldest programming languages. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments....
compiler.
History
HP BASIC for OpenVMS has gone through many name changes. It began at DEC
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
Compaq Computer Corporation is a personal computer company founded in 1982. Once the largest supplier of personal computing systems in the world, Compaq existed as an independent corporation until 2002, when it was acquired for US$25 billion by Hewlett-Packard....
, who then merged with HP. Since the company name is embedded in the product name, each new owner changed the product name. It has also been ported
Porting
In computer science, porting is the process of adapting software so that an executable program can be created for a computing environment that is different from the one for which it was originally designed...
A computing platform includes some sort of hardware architecture and a software framework , where the combination allows software, particularly application software, to run...
as they were developed by DEC/Compaq/HP, over a period of more than 30 years.
BASIC-PLUS
HP BASIC began as BASIC-PLUS, created by DEC for their RSTS-11 operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...
A minicomputer is a class of multi-user computers that lies in the middle range of the computing spectrum, in between the largest multi-user systems and the smallest single-user systems...
. Programming language statements could either be typed into the command interpreter directly, or entered into a text editor
Text editor
A text editor is a type of program used for editing plain text files.Text editors are often provided with operating systems or software development packages, and can be used to change configuration files and programming language source code....
, saved to a file, and then loaded into the command interpreter from the file. Errors in source code were reported to the user immediately after the line was entered.
In computer science, source code is text written using the format and syntax of the programming language that it is being written in. Such a language is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source...
file, using the "SAVE" command. It could be "compiled" into a non-editable binary .BAC file, using the "COMPILE" command. This command did not produce true machine language programs, but rather a byte code called "tokens". The tokens were interpreted upon execution, in a manner similar to the more modern Java
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
.
Programs were entered into the command interpreter starting with line number
Line number
In computing, a line number is a method used to specify a particular sequence of characters in a text file. The most common method of assigning numbers to lines is to assign every line a unique number, starting at 1 for the first line, and incrementing by 1 for each successive line.In the C...
s, integers from 1 to 32767. Lines could be continued onto multiple lines by using a line feed character. For ease of external editing of the source file, later versions of BASIC-PLUS also allowed the & character as a line-continuation character. Multiple statements could be placed on a single line using \ as the statement separator.
RSTS is a multi-user time-sharing operating system, developed by Digital Equipment Corporation , for the PDP-11 series of 16-bit minicomputers. The first version of RSTS was implemented in 1970 by DEC software engineers that developed the TSS-8 time-sharing operating system for the PDP-8...
), address space was limited to about 64 KB. With BASIC-PLUS, about half of this was used by the combined command interpreter and run-time library. This limited user programs to about 32 KB of memory. Older RSTS-11 systems lacked virtual memory, so the user program had to fit into whatever was left of physical memory after RSTS and BASIC-PLUS took up their share. For example, on a PDP-11/35 with 32K of physical memory, running RSTS-11 V04B-17, user programs were limited to 7 KB. Large programs could be broken up into various pieces by use of the "CHAIN" instruction. Programs could chain
Chain loading
Chain loading is a method used by computer programs to replace the currently executing program with a new program, using a common data area to pass information from the current program to the new program. It occurs in several areas of computing.Chain loading is similar to the use of overlays...
to specific line numbers in a secondary program. The use of a shared memory section called core common
Core common area
The core common area is that area of a computer program wherein data can remain between the end of execution of one program and the start of execution of a subsequent program in a pipeline....
also allowed programs to pass data among each other as needed; disk
Hard disk
A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...
files could also be used but were slower.
The interpreter included a garbage collecting memory manager, used for both string data and byte-code. A running program could be interrupted, have variables examined and modified, and then be resumed. Many of the control structures used in other high-level languages existed in BASIC-PLUS, including WHILE and UNTIL. The language also supported the use of conditional modifiers on a single line. For example, the line "PRINT I UNLESS I < 10" would print the value of "I" unless I was less than 10.
BASIC Plus 2
Basic Plus 2 (BP2 or BASIC-Plus-2) was later developed by DEC to add additional features and increase performance. It used true compilation into threaded code
Threaded code
In computer science, the term threaded code refers to a compiler implementation technique where the generated code has a form that essentially consists entirely of calls to subroutines...
, and wrote its output to machine language object files. These were compatible with other object files on the system, and could be assembled into libraries. A linker (the TKB taskbuilder) then created executable files from them. TKB also supported overlays; this allowed individual routines to be swapped into the main memory space as needed.
RSX-11 is a family of real-time operating systems mainly for PDP-11 computers created by Digital Equipment Corporation , common in the late 1970s and early 1980s. RSX-11D first appeared on the PDP-11/40 in 1972...
or RSTS/E's RSX Run Time System. This RTS only occupied 8KB (later, 2KB) of the user's address space, leaving 56KB for the user's program. These two factors allowed individual BP2 programs to be much larger than BASIC-PLUS programs, often eliminating the need for CHAINing. Unlike BASIC-PLUS (which was only available on RSTS-11), BP2 allowed use on the RSX-11 operating system as well..
VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs...
A minicomputer is a class of multi-user computers that lies in the middle range of the computing spectrum, in between the largest multi-user systems and the smallest single-user systems...
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
operating system, and called it VAX BASIC. VAX BASIC used the standard VMS calling standards, so object code produced by VAX BASIC could be linked with object code produced by any of the other VMS languages. Source code for BASIC Plus 2 would usually run without major changes on VAX BASIC.
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
. VAX BASIC was likewise ported to Alpha and renamed DEC BASIC. The BASIC interpreter
Interpreter (computing)
In computer science, an interpreter normally means a computer program that executes, i.e. performs, instructions written in a programming language...
was permanently dropped at this point, which meant that DEC BASIC programs could only be run as OpenVMS executable
Executable
In computing, an executable file causes a computer "to perform indicated tasks according to encoded instructions," as opposed to a data file that must be parsed by a program to be meaningful. These instructions are traditionally machine code instructions for a physical CPU...
Compaq Computer Corporation is a personal computer company founded in 1982. Once the largest supplier of personal computing systems in the world, Compaq existed as an independent corporation until 2002, when it was acquired for US$25 billion by Hewlett-Packard....
in 1997/98, the products were renamed Compaq BASIC for OpenVMS VAX and Compaq BASIC for OpenVMS Alpha.
Compaq Computer Corporation is a personal computer company founded in 1982. Once the largest supplier of personal computing systems in the world, Compaq existed as an independent corporation until 2002, when it was acquired for US$25 billion by Hewlett-Packard....
merged with HP in 2001/02, the products were renamed HP BASIC for OpenVMS on VAX and HP BASIC for OpenVMS on AlphaServer. HP has since built new server
Server (computing)
In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients"...
Itanium is a family of 64-bit Intel microprocessors that implement the Intel Itanium architecture . Intel markets the processors for enterprise servers and high-performance computing systems...
chip, and there is now a HP BASIC for OpenVMS on Integrity as well.
Celsius to Fahrenheit conversion
10 PRINT "Enter a temperature in Celsius "
20 INPUT C
30 PRINT "Temperature in degrees Fahrenheit is "; (C * 1.8) + 32
40 END
