DOS ain't dead

hardly a 100% solution (Developers)

posted by ecm  , Düsseldorf, Germany, 30.05.2011, 19:33

> Not an error, but yes a failure due to a rude TSR not acting responsibly!
> Being able to preempt both the foreground task and the OS itself is a
> privilege, with privilege comes responsibility - at least I was brought up
> thinking so.

In my method, there isn't any way for the TSR to determine properly that it acts "not responsibly". In your method of protecting the section by clearing the interrupt flag, there arguably isn't either: If the protection works as intended, the TSR won't pop up. If it fails (21.48 call, running in debugger, running in V86-mode?) the TSR has no way of determining you intended to leave the interrupt flag disabled.

> "Alternate method 1" sketched in my previous post, under CLI, would
> completely prevent the potential for such nuisance.

No, because as I alluded to, resident code could allocate the memory that would be required for your optimal allocation (say, a UMB of just the right size) before you enter your protected section of code.

---
l

Complete thread:

• keyb: new! memory scheme, easy TEST - Ninho, 22.05.2011, 19:10 (Developers)
  • boring - ecm, 22.05.2011, 23:58
    • boring - Ninho, 23.05.2011, 01:20
      • not that boring after all (nt) - ecm, 23.05.2011, 13:27
  • review - ecm, 23.05.2011, 13:18
    • review - Ninho, 23.05.2011, 23:10
      • review - ecm, 24.05.2011, 00:45
        • review - Ninho, 24.05.2011, 12:50
          • review - ecm, 24.05.2011, 15:20
            • of TSR powers & limits - Ninho, 25.05.2011, 11:24
              • Swap! - ecm, 25.05.2011, 14:13
                • of TSR powers & limits - Ninho, 25.05.2011, 15:14
    • fix - Ninho, 29.05.2011, 14:36
      • opinion - ecm, 29.05.2011, 14:49
        • opinion - Ninho, 29.05.2011, 16:36
          • evaluation - ecm, 29.05.2011, 17:26
            • evaluation - Ninho, 29.05.2011, 21:00
              • hardly a 100% solution - ecm, 29.05.2011, 22:17
                • hardly a 100% solution - Ninho, 30.05.2011, 19:26
                  • hardly a 100% solution - ecm, 30.05.2011, 19:33
                    • hardly a 100% solution - Ninho, 30.05.2011, 21:14
                      • hardly a 100% solution - ecm, 30.05.2011, 21:20
                        • hardly a 100% solution - Ninho, 30.05.2011, 23:50
                          • allocation no higher than the PSP - ecm, 30.05.2011, 23:56
                            • allocation no higher than the PSP - Ninho, 01.06.2011, 18:56
                              • allocation no higher than the PSP - ecm, 01.06.2011, 19:10
          • opinion - Ninho, 30.05.2011, 19:04
            • sti - ecm, 30.05.2011, 19:26