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Dave Britten · 01-02-2017, 04:36 AM

(01-01-2017 11:58 PM)matthiaspaul Wrote: There are several DOS task switchers. Alan has already mentioned Software Carousel. It had a very good reputation. Another program I remember was Back&Forth. IIRC, Central Point had a task switcher named CPTASK as part of their PC Tools suite.

DR DOS 6.0 and higher came with TaskMAX, a task switcher with less overhead and more flexibility (swapping to XMS, EMS or disk) than DOSSHELL. It did not come with a file manager by itself, though - but if a user really needed a graphical file manager, s/he could use ViewMAX (a derivative of GEM).
TaskMAX came with a text mode interface by default, but it provided an API allowing other software to register as alternative interfaces. For example, if ViewMAX/2 (or 3) is loaded, it takes over the task switcher interface. Using the same API, PC/GEOS (and Windows) can do so as well. Technically, TaskMAX would also run on MS-DOS, but unfortunately this is prevented by a DOS version check, hence it could be used by you only if your Omnibook can be set up to boot alternative operating systems (or if you load a TSR to fake DOS versions).

If so, you might benefit more from switching to DR-DOS 7.03. The task manager is now called TASKMGR. If KRNL386, the 32-bit core of the operating system, is loaded (by EMM386 /MULTI), DR-DOS can provide not only task switching but multithreading as well as preemptive multitasking of applications in virtual DOS machines, so that applications can continue to run in the background, and switching the foreground task works in an instant, instead of taking up to several seconds as for a task switcher swapping to disk. This works for standard DOS as well as DPMI extended DOS applications. Other extended DOS applications will be suspended in background, the same happens with applications in unsupported graphics modes. In this mode TASKMGR no longer works as a stand-alone switcher application (unless option /S is provided) but as a frontend module to the underlying multitasking OS, so the look-and-feel remains similar.
ViewMAX and PC/GEOS can still be used as alternative graphical frontends. Under the multitasker, Windows 3.x only works in Standard mode, while it also works in 386 Enhanced mode under the task switcher. Tasks started before Windows show up seamlessly in the task list under Windows as well.

Another highly capable multitasking environment for DOS is DESQview. It even has text mode windowing capabilities.

Greetings,

Matthias

Thanks, I'll check some of those out. Sounds like DESQView would be easy enough to get running on an OB 300. Once I've got a 2.0 card to experiment with, I might try some of the other DOS alternatives too.

(01-02-2017 01:58 AM)Bill (Smithville NJ) Wrote: Dave,

What maximum memory available did you achieve. Which memory manager did you use? And could you make the config.sys and autoexec files available.

I've only been able to achieve 589kb - that's using the msdos 6.22 emm386 and himem. This is for a dos based OB-430 system - no windows loaded.

I tried using QEMM but always ran into problems using the Optimize tool - it would never complete without some warning errors.

Thanks,

Bill
Smithville, NJ

I've attached my current startup files. With these (and running OBBOOT 3 to disable DoubleSpace and Flash File System), I get this from mem immediately after boot:

636,928 bytes available to MS-DOS
592,144 largest executable program size
7,274,496 bytes available XMS memory

If you un-rem EMM386.EXE, you get a 60 KB UMB to work with, at the expense of ~3 KB conventional memory (and Windows will no longer run in standard mode with EMM386 loaded).

.zip

OB300Startup.zip (Size: 2.02 KB / Downloads: 11)