Essential Guide to Computing: The Story of Information Technology, The

Conclusion

Microcomputer operating systems are only about 25 years old, and evolution has been rapid. Within about ten years, this category of OS had transitioned from 8-bit to 16-bit code, and was on its way to being the first type of computer to employ a graphical user interface. Indeed, by the time they were only about 15 years old, microcomputer OSs had acquired most of the characteristics of their mainframe parents, including such things as virtual memory, true multitasking, and the use of 32-bit code. Of course, much of this development was made possible by the rapid improvements in hardware. The original MS-DOS had to work with a computer whose CPU ran at under 5 MHz and which had access to only 64 Kb of memory. Today's Windows 2000 can ...