Making Utilities for MS-DOS :: Microsoft Computers System Software Essays

Making Utilities for MS-DOSThese days, when computers play an important role in virtually all aspects ofour life, the issue of concern to many programmers is Microsofts hiding of technical reenforcement. Microsoft is by far the most important constitution softw ardeveloper. thither can be no argument about that. Microsofts MS-DOS operating(a) arranging has become a de facto standard (IBMs PC-DOS is actually a licensed rendition of MS-DOS). And this should be so, because these agreement of ruless are very wellwritten. The people who designed them are perhaps the best parcel engineers inthe world.But making a computer platform that is a de facto standard should imply a goodnessdeal of responsibility before the developers who make applications for thatplatform. In particular, proper documentation is essential for such a platform.Not providing enough documentation for a system that everyone uses can standdisastrous results. Think of it, an operating system is useless by itself, its sole purpose is to provide services to applications. And who would be able todevelop applications for an operating system if the documentation for thatsystem is undercover and available only to the company that create it?Obviously, only the company that has developed that operating system will beable to develop software for it. And this is a violation of the Antitrust Law.And now I start having a suspicion that this is happening with Microsoftsoperating systems. It should be no secret to anyone that MS-DOS contains a lotof undocumented system calls, data structures and other features. Numerous bookshave been written on this subject (see bibliography). Many of them are vital tosystem programming. There is no way to write a piece of system software, such asa multitasker, a local area network, or another operating system extension,without knowing this undocumented functionality in MS-DOS. And, accepted enough,Microsoft is using this functionality extensively when developing operatin gsystem extensions. For example, Microsoft Windows, Microsoft Network, andMicrosoft CD-ROM Extensions (MSCDEX) desire heavily on the undocumented internalsof MS-DOS.The reader can ask, Why do they leave functionality undocumented? To answerthat question, we should look at what this functionality actually is. In MS-DOS, the undocumented functionality is actually the internal structures thatMS-DOS uses to implement its documented INT 21h API. Any operating system musthave some internal structures in which it keeps development about disk drives,open files, network connections, alien file systems, data track tasks, etc. And MS-DOS (later Ill call it simply DOS) has internal structures too. Thesestructures form the amount of undocumented functionality in MS-DOS. Thisoperating system also has some undocumented INT 21h API functions, but they