Digital Evolution Report

Growth that are used The success of our Interdata 8/32 portability experiment soon led to another Tom London and John Reiser on the DEC VAX 11/780. This machine became much more popular than Interdata, and Unix and C began to spread quickly, both inside and outside AT&T. Although by the mid-1970s Unix had used a variety of projects within the Bell System as well as a small group of research-oriented industrial, academic, and government organizations outside our company, its real growth only began after portability had been achieved. Of particular note were the System III and System V versions of the system from the emerging Computer Systems division of AT&T, based on the work of the development and research groups of the company, and the BSD series of publications by the University of California at Berkeley derived from Bell Laboratories research organizations. In the 1980s, the use of the C-language spread widely, and compilers became available on almost every machine arch...

The Problems With B Language The machines on which we first used BCPL and then B were word-addressed, and the single data type of these languages, the 'cell,' was comfortably matched to the hardware machine word. The advent of the PDP-11 exposed several inadequacies of the B semantic model. First, its character-handling mechanisms, inherited with few changes from BCPL, were clumsy: using library procedures to spread packed strings to individual cells and then repack them, or to access and replace individual characters, began to feel awkward, even stupid, on a byte-oriented machine. Second, although the original PDP-11 did not provide for floating-point arithmetic, the manufacturer promised that it would soon be available. Floating-point operations were added to BCPL in our Multics and GCOS compilers by defining special operators, but this mechanism was possible only because, on the machines concerned, a single word was large enough to contain a floating-point number; this w...

Origins of C languages BCPL was designed by Martin Richards in the mid-1960s while visiting MIT and was used in the early 1970s for several interesting projects, including the Oxford [Stoy 72] OS6 operating system, and parts of the Alto seminal work at Xerox PARC [Thacker 79]. We became acquainted with this because the MIT CTSS system [Corbato 62] on which Richards worked was used for the development of Multics. The original BCPL compiler was transported to both the Multics system and the GE-635 GECOS system by Rum Canaday and others at Bell Labs [Canada 69]; During the final throes of Multics' life at Bell Labs, and immediately thereafter, it was the language of choice among the group of people who would later become involved with Unix.   BCPL, B, and C all fit firmly into the traditional procedural family of Fortran and Algol 60. They are particularly oriented towards system programming, are small and compactly described, and can be translated by simple compilers. They are ...

Where's the success C?   C has been successful to a far greater extent than any early expectations. What qualities have contributed to its widespread use?   Undoubtedly, the success of Unix itself was the most important factor; it made the language available to hundreds of thousands of people. Conversely, of course, the use of C by Unix and its consequent portability to a wide range of machines was important to the success of the system. But the language invasion of other environments suggests more fundamental merits.   Despite some aspects that are mysterious to the beginner and sometimes even to the adept, C remains a simple and small language that can be translated with simple and small compilers. Its types and operations are well-grounded in those provided by real machines, and it is not difficult for people who are used to the way computers work, to learn languages for generating time-and space-efficient programs. At the same time, the language is sufficientl...

  Two ideas are the most characteristic of C between the languages of its class: the relationship between arrays and pointers, and how the declaration syntax mimics the expression syntax. They are also among its most frequently criticized features, and often serve as stumbling blocks to beginners. In both cases, historical accidents or errors have exacerbated their difficulties. The most important of these was the tolerance of C compilers to type errors. As should be clear from the above history, C has evolved from a variety of languages. It did not suddenly appear to its early users and developers as a completely new language with its own rules; Instead, we had to continuously adapt the existing programs as the language was developed and make provision for an existing body of code. (Later, the ANSI X3J11 C standardization committee would have the same problem.) Compilers in 1977, and even after that, did not complain about ...

Short History of C Programming There are a lot of programming languages in use today, one of which is C. There are many C programming languages, including Objective-C, C++, and C #. None of these are in the same language. So, how did C get started?

DESCRIBE ABOUT HISTORY OF C PROGRAMMING LANGUAGE •        C programming language is a structured programming language, developed by Dennis Ritchie at Bell Laboratories in 1972. •        C language features have been derived from an earlier language called "B" (Basic Combined Programming Language – BCPL). •        In earlier days, the programs were written in assembly level languages. So, it happened that very large programs were written to perform specific tasks using assembly code. •        But the 'B' language could perform the same task in a few program lines, and it was faster than the assembly of the language code. •        However, the B language did not support certain features such as data types and structures, etc. So, this was a drawback to the B language. Dennis Ritchie developed C by keeping most of the B-language and adding ma...