Speedcoding, Speedcode or SpeedCo was the first

high-level programming language A high-level programming language is a programming language with strong Abstraction (computer science), abstraction from the details of the computer. In contrast to low-level programming languages, it may use natural language ''elements'', be ea ...

created for an

IBM International Business Machines Corporation (using the trademark IBM), nicknamed Big Blue, is an American Multinational corporation, multinational technology company headquartered in Armonk, New York, and present in over 175 countries. It is ...

computer. The language was developed by John W. Backus in 1953 for the

IBM 701 The IBM 701 Electronic Data Processing Machine, known as the Defense Calculator while in development, was IBM’s first commercial scientific computer and its first series production mainframe computer, which was announced to the public on May 2 ...

to support computation with floating point numbers. The idea arose from the difficulty of programming the IBM SSEC machine when Backus was hired to calculate astronomical positions in early 1950. The speedcoding system was an

interpreter Interpreting is translation from a spoken or signed language into another language, usually in real time to facilitate live communication. It is distinguished from the translation of a written text, which can be more deliberative and make use o ...

and focused on ease of use at the expense of system resources. It provided pseudo-instructions for common mathematical functions: logarithms, exponentiation, and trigonometric operations. The resident software analyzed pseudo-instructions one by one and called the appropriate subroutine. Speedcoding was also the first implementation of decimal input/output operations. Although it substantially reduced the effort of writing many jobs, the running time of a program that was written with the help of Speedcoding was usually ten to twenty times that of machine code. The interpreter took 310 memory words, about 30% of the memory available on a 701.

History and development

In August 1952, several dozen IBM engineers and

customers met in

Poughkeepsie, New York Poughkeepsie ( ) is a city within the Poughkeepsie (town), New York, Town of Poughkeepsie, New York (state), New York. It is the county seat of Dutchess County, New York, Dutchess County, with a 2020 census population of 31,577. Poughkeepsie i ...

to exchange ideas and best practices on programming the new machines in assembly. Several attendees expressed frustration with the slow nature of assembly programming and debugging, and questioned the utility of the 701 in applications where solutions to problems were needed quickly, or when the value of a solution justified the expense of computation time but not the cost of programming and debugging. Attendees likewise complained with issues with "scaling", or the need to religiously track the decimal point in arithmetic operations. John W. Sheldon, a supervisor of IBM's Technical Computing Bureau attending the meeting, and others felt that an "interpretive" programming system that utilized floating point operations was the best solution to this problem. Sheldon asked John Backus, who had previously worked on a CPC to SSEC code translator, to supervise the creation of a new floating-point interpretive programming language for use internal to IBM. Backus himself had previously expressed interest in improving programming methods, and observed that computing costs were roughly equally split between the cost of computation and cost of programming personnel, and that the additional expense of testing made labor the considerably larger expense. Starting in 1953, Backus and five colleagues designed this new language and named it "Speedcoding", where its use soon spread outside of IBM to customer installations of the 701 system.

Syntax and semantics

Speedcoding programs are organized as a series of instructions, each of which are stored in memory as a single 72-bit data word. An instruction generally consists of two operations (OP₁ and OP₂) and 4 memory addresses. The first operation (OP₁) is a mathematical or input/output operation that has 3 associated memory addresses, one or more of which can be modified depending on the nature of the operation. Mathematical operations include basic arithmetic, square root, and trigonometry functions. The logical operations include functionality for reading, writing, skipping, and rewinding

magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use magnetic ...

, as well as operations for interacting with data stored in

drum memory Drum memory was a magnetic data storage device invented by Gustav Tauschek in 1932 in Austria. Drums were widely used in the 1950s and into the 1960s as computer memory. Many early computers, called drum computers or drum machines, used drum ...

. The second operation (OP₂) is a logical operation that has the remaining 1 associated memory address. Logical operations allow instructions to be carried out in a different order from which they are written allowing for implementations of gotos, conditionals, loops, and other advanced behavior. Reserved Arithmetic and Input/Output Operation Keywords Reserved Logical Keywords

History and development

Syntax and semantics

See also

Notes

References

Further reading