The definition of a legacy system

[suchona.kani.z]

In total, there are certainly almost 10,000 installations. The majority are in the USA, and we have around 150 installations in German-speaking countries. However, the trend is decreasing (around three to five percent per year), which means that mainframe development costs are being spread across fewer and fewer shoulders. The reasons for the decline are varied: for example, data centers have been consolidated or outsourced as part of corporate mergers, or companies are opting for standard software. But one thing is the same for all of them: the baby boomer generation, which has played a key role in shaping this technology,


will retire in the next few years. This means that, demographically speaking, 75 percent of mainframe skills will leave the job market in the next few years and probably only half will be able to be usa consumer email list replaced (Forrester Research in 2021). For young people, Cobol is "old school" and only Java is really sexy. This is very dramatic, because many of today's core applications are still based on code from the 1970s. This is no wonder, as IBM has ensured that upward compatibility is always available with each new generation of computers and software. Today, we still find many assembler and immensely large Cobol programs (more than 100,000 lines of code) that have been hardened over the years and certainly do their job very efficiently and reliably. We are talking about so-called legacy systems here.


In computer science, the term legacy system or legacy system, and in a narrower sense legacy code, refers to an established, historically grown application in the area of ​​business software. The English word "legacy" is a largely value-free technical term in this context. However, it can also be used colloquially in a negative sense in the sense of an annoying "legacy" or "legacy burden" in a figurative sense.