MS-DOS is now open-sourced

• MS-DOS

  59 15,623 0.0 Assembly

  Discontinued The original sources of MS-DOS 1.25 and 2.0, for reference purposes

  

Asynchronous I/O figures in prominently in Windows NT. I was really surprised to see[0]:

Each driver in the chain defines two entry points; the strategy routine and the interrupt routine. The 2.0 DOS does not really make use of two entry points (it simply calls strategy, then immediately calls interrupt). This dual entry point scheme is designed to facilitate future multi-tasking versions of MS-DOS. In multi-tasking environments I/O must be asynchronous, to accomplish this the strategy routine will be called to queue (internally) a request and return quickly. It is then the responsibility of the interrupt routine to perform the actual I/O at interrupt time by picking requests off the internal queue (set up by the strategy routine), and process them. When a request is complete, it is flagged as "done" by the interrupt routine. The DOS periodically scans the list of requests looking for ones flagged as done, and "wakes up" the process waiting for the completion of the request.

I didn't realize that kind of forwarding-looking perspective was going into the design of MS-DOS.

[0] https://github.com/microsoft/MS-DOS/blob/master/v2.0/source/...

• SpaceCadetPinball

  76 3,172 5.4 C++

  Decompilation of 3D Pinball for Windows – Space Cadet

Well, not exactly that, but check out https://github.com/k4zmu2a/SpaceCadetPinball .

• WorkOS

  workos.com sponsored

  The modern identity platform for B2B SaaS. The APIs are flexible and easy-to-use, supporting authentication, user identity, and complex enterprise features like SSO and SCIM provisioning.

  

Suggest a related project