Traditional procedural-oriented languages (such as C and Pascal) suffer some notable drawbacks in creating reusable software components: Why re-invent the wheels? Traditional Procedural-Oriented languagesĬan we do this in traditional procedural-oriented programming language such as C, Fortran, Cobol, or Pascal? However, for each new application, we have to re-invent the wheels and write the program from scratch. Since the advent of computer 60 years ago, we have written tons and tons of programs. How about software? Can you "assemble" a software application by picking a routine here, a routine there, and expect the program to run? The answer is obviously no! Unlike hardware, it is very difficult to "assemble" an application from software components. Hardware, such as computers and cars, are assembled from parts, which are reusable components. The components are reusable, e.g., a wheel can be used in many cars (of the same specifications). Similarly, a car is assembled from parts and components, such as chassis, doors, engine, wheels, brake, and transmission. Nevertheless, it is not difficult to set up a machine from hardware components. Of course, you have to make sure that you have the correct interfaces, i.e., you pick an IDE hard disk rather than a SCSI hard disk, if your motherboard supports only IDE you have to select RAMs with the correct speed rating, and so on.
You simply put the hardware components together and expect the machine to run. You need not worry whether the motherboard is a 4-layer or 6-layer board, whether the hard disk has 4 or 6 plates 3 inches or 5 inches in diameter, whether the RAM is made in Japan or Korea, and so on. Suppose that you want to assemble your own PC, you go to a hardware store and pick up a motherboard, a processor, some RAMs, a hard disk, a casing, a power supply, and put them together.
0 kommentar(er)
