【正文】 . In either case, calls to other system routines are used to actually carry out the display of the results or the accessing of the file from the disk.When the application reaches pletion or is prompted to quit, it makes further system calls to make sure that all data that needs to be saved has been written back to disk. It then makes a final system call to the operating system indicating that it is finished. The operating system then frees up the RAM and any device that the application was using and awaits a mand from the user to start another program.5 HistoryPeople have been storing sequences of instructions in the form of a program for several centuries. Music boxes of the 18th century and player pianos of the late 19th and early 20th centuries played musical programs stored as series if metal pins, or holes in paper, with each line representing when a note was to be played, and the pin or hole indicating what note was to be played at that time. More elaborate control of physical devices became mon in the early 1800s with French inventor Joseph Marie Jacquard’s invention of the punchcard controlled weaving loom. In the process of weaving a particular pattern, various parts of the loom had to be mechanically positioned. To automate this process, Jacquard used a single paper card to represent each positioning of the loom, with hole in the card to indicate which loom actions should be done. An entire tapestry could be encoded onto a deck of such cards, with the same deck yielding the same tapestry design each time it was used. Programs of over 24,000 card were developed and used.The world’s first programmable machine was designedalthough never fully builtby the English mathematician and inventor, Charles Babbage. This machine, called the Analytical Engine, used punch cards similar to those used in the Jacquard loom to select the specific arithmetic operation to apply at each step. Inserting a different set of cards changed the putations the machine performed. This machine had counterparts for almost everything found in modern puters, although it was mechanical rather than electrical. Construction of the Analytical Engine was never pleted because the technology required to build it did not exist at the time.The first card deck programs for the Analytical Engine were developed by British mathematician Countess Augusta Ada Lovelace, daughter of the poet Lord Byron. For this reason she is recognized as the world’s first programmer.The modern concept of an internally stored puter program was first proposed by HungarianAmerican mathematician John von Neumann in 1945. Von Neumann’s idea was to use the puter’s memory to store the program as well as the data. In this way, programs can be viewed as data and can be processed like data by other programs. This idea greatly simplifies the role of program storage and execution in puters.6 The FutureThe field of pu