Users continue to invoke the legacy IT systems using the original application means, typically through a user interface (such as a mainframe dumb terminal or a packaged application's UI).

用户将继续使用原始应用程序方法调用遗留it系统，通常通过用户界面(如大型机哑终端或已打包应用程序的UI)。

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Typically every time we look at a complete mainframe portfolio, about 30% of code is never used, and will never be executed.

FORBES: Is Your Firm Running An IT Deficit