I suspect the key good task switching is some of it falling on the OS and some of it on writing apps that "behave" properly or are adapted to the limits of the system. The right architecture might be something like Windows does. All the apps call for and use system resources through calls to a common API not the firmware or BIOS routine. That way the OS can track what calls the apps were making when they got switched out.
Yeah I think thats the whole reason 386 architecture developed the way it did. Its really just a two page processor. Switch the page to the clone before swap, freeze the stack and all there when you hand over to the next session. While the next session is executing copy the page out to RAM or disk to prepare for the next swap. Of course now they do fancier things with multi-core but I think thats how it started. Windows had potential but swapping just didn't work very well on the single page 286. I can't remember can the RAM disk driver access RAM outside the range of the CPU in standard mode? You can still use a RAM drive judiciously and copy the most used binaries and data files to it on boot to improve performance. Yeah DOSHELL was just a menu system. Came way too late since they were many freeware versions years earlier that worked well. But had an overdue file manager that worked well. The last DOS task switcher I remember that worked reasonably well was something called DOORS. It was all over the BBS system in the early 1990s. The best DOS file manager before DOSHELL. was one called FM by Bill Neidert. Always had a suspicion Bill was an alias for a woman who wote it. On 6/1/13, dos386 <[email protected]> wrote: >> Now the second point is if I remember the "stuff" correctly the >> problem with DOS task switching is having the CPU start again in the >> right place when a session was switched back into the DOS space > > The primary problem with multitasking is that you must care about clean > rock-solid sharing of ALL resources (CPU, memory, screen, keyboard, sound > card, disks, ...). DOS is not designed for that. > >> Or boot Windows and start multiple DOSBOX windows :-) > > :-( > >> modern Intel boxes have way more RAM >> than does DOS can use or needs > > You can use it as RAMDISK or for image or video editing :-) > > But > 2 GiB seems to be a problem (MMIO space steals physical RAM). > >> But do they still support PAE? Did they ever? (Win2k3 perhaps? > > I don't know and don't care. The mainstream future is 64-bit. Be happy as > long as new PC's can run DOS natively. If not, there is BOCHS :-) > > ------------------------------------------------------------------------------ > Get 100% visibility into Java/.NET code with AppDynamics Lite > It's a free troubleshooting tool designed for production > Get down to code-level detail for bottlenecks, with <2% overhead. > Download for free and get started troubleshooting in minutes. > http://p.sf.net/sfu/appdyn_d2d_ap2 > _______________________________________________ > Freedos-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freedos-devel > ------------------------------------------------------------------------------ Get 100% visibility into Java/.NET code with AppDynamics Lite It's a free troubleshooting tool designed for production Get down to code-level detail for bottlenecks, with <2% overhead. Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap2 _______________________________________________ Freedos-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freedos-devel
