10 Part I . Linux First Steps The (Web and email hosting)
10 Part I . Linux First Steps The simplicity and power of the UNIX design began breaking down barriers that impeded software developers. The foundation of UNIX was set with several key elements: . The UNIX file system After creating the structure that allowed levels of subdirectories (which, for today s desktop users, looks like folders inside of folders), UNIX could be used to organize the files and directories in intuitive ways. Furthermore, complex methods of accessing disks, tapes, and other devices were greatly simplified by representing those devices as individual device files that you could also access as items in a directory. . Input/output redirection Early UNIX systems also included the concept of input redirection and pipes. From a command line, UNIX users could direct the output of a command to a file using a right arrow key (>). Later, the concepts of pipes was added (|) where the output of one command could be directed to the input of another command. For example, the command line $ cat file1 file2 | sort | pr | lpr concatenates (cat) file1 and file2, sorts (sort) the lines in those files alphabetically, paginates the sorted text for printing (pr), and directs the output to the computer s default printer (lpr). This method of directing input and output enabled developers to create their own specialized utilities that could be joined together with existing utilities. This modularity made it possible for lots of code to be developed by lots of different people. . Portability Much of the early work in simplifying the experience of using UNIX led to its also becoming extraordinarily portable to run on different computers. By having device drivers (represented by files in the file system tree), UNIX could present an interface to applications in such a way that the programs didn t have to know about the details of the underlying hardware. To later port UNIX to another system, developers only had to change the drivers. The applications program didn t have to change for different hardware! To make the concept of portability a reality, however, a high-level programming language was needed to implement the software needed. To that end, Brian Kernighan and Dennis Ritchie created the C programming language. In 1973, UNIX was rewritten in C. Today, C is still the primary language used to create the UNIX (and Linux) operating system kernels. As Ritchie went on to say in his 1980 lecture: Today, the only important UNIX program still written in assembler is the assembler itself; virtually all the utility programs are in C, and so are most of the applications programs, although there are sites with many in Fortran, Pascal, and Algol 68 as well. It seems certain that much of the success of UNIX follows from the readability, modifiability, and portability of its software that in turn follows from its expression in high-level languages.
Note: If you are looking for high quality webhost to host and run your jsp application check Vision jsp web hosting services