Explain why legacy systems may be critical to the operation of a business?

Answer 1

Many companies still use legacy systems. Examples of legacy systems include programs like accounting programs that still run under DOS or custom-written software that has not been updated to support later operating systems.

Additionally, many companies don't upgrade as soon as new technology is available, either due to budget restraints or a (justified) fear that new operating systems would be "buggy".

Additionally, upgrading say from Microsoft Windows XP to Microsoft Vista prove cost prohibitive because of the additional processing power that Vista requires when compared to XP. So a company would not only have to absorb the cost of new OS licenses, but new hardware as well when their older systems wouldn't run the new OS.

Then, of course, will the software that they are running (for example their accounting software) run on Vista? When Vista was first released, there was a serious lack of drivers for hardware.

So legacy systems are out there, and are necessary for businesses who are running legacy software, older hardware, or simply don't have the budget to replace equipment and operating systems all at once.

Answer 2

Legacy systems often run on obsolete (and usually slow) hardware, and sometimes spare parts for such computers become increasingly difficult to obtain. These systems are often hard to maintain, improve, and expand because there is a general lack of understanding of the system (as the staff who were experts on it have retired or forgotten what they knew about it, and staff who entered the field after it became "legacy" never learned about it in the first place), which can be worsened by lack or loss of documentation. Integration with newer systems may also be difficult because new software may use completely different technologies. The kind of bridge hardware and software that becomes widely available for different technologies that are widely popular at the same time does usually not get developed for differing technologies in different times, because of the lack of a large demand for it and the lack of associated reward of a large market economies of scale, though some of this "glue" does get developed by nice vendors and enthusiasts of particular legacy technologies (often called "retrocomputing" communities