Windows on Windows: Difference between revisions

Revision as of 12:09, 6 October 2024

Revision as of 13:04, 12 January 2025

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==Background==

Many 16-bit Windows legacy programs can run without changes on newer [[32-bit]] editions of Windows. The reason designers made this possible was to allow software developers time to remedy their software during the industry transition from [[Windows 3.1x1]] to [[Windows 95]] and later, without restricting the ability for the operating system to be upgraded to a current version before ''all'' programs used by a customer had been taken care of.

The [[Windows 9x]] series of operating systems, reflecting their roots in [[DOS]], functioned as hybrid 16- and 32-bit systems in the sense that the underlying operating system was not truly 32-bit,{{citation needed |reason=What is the source of this assertion? The fact that you could boot to DOS? |date=January 2017}} and therefore could run 16-bit software natively without requiring any special emulation; [[Windows NT]] operating systems differ significantly from Windows 9x in their architecture, and therefore require a more complex solution. Two separate strategies are used in order to let 16-bit programs run on 32-bit versions of Windows (with some [[Execution_(computing)#Runtime|runtime]] limitations). They are called [[thunk]]ing and [[Shim (computing)|shimming]].