For DOS taskswitching/multitasking I always used PC-MIX by Proware. It's able to run on a 286 or an 8088, only requires 256K to run and can use EEMS. It can be configured to run three programs simultaneously. Once I discovered it I never ran my 286 without it (for obvious reasons).
Here's the blurb. Pay close attention to the 'PC-MIX is Small:' paragraph as this little program manages to do something WinBlows never could master.
And it's only a 34K ZIP file!
Easy to Use:
With PC-MIX we went to great lengths to bury the complexity of the
system deep in the software. We don't burden you with all kinds of
complex set-up and control. We made Multitasking easy to use. In fact,
it is so easy to use you almost don't even need to read the User's
manual!
It's Simple to Learn:
We put a lot of effort into making PC-MIX simple to learn. We don't
overwhelm you with a lot of complex command sequences and useless
information. With PC-MIX you'll be up to speed in no time at all!
It's Quick to Set-Up:
PC-MIX is quick and easy to set up. In addition to our clear and
concise User's Manual, you'll get a specially designed configuration
editor. The Editor gives you all the configuration parameters on just
one screen along with a graphical display of your computers memory.
It won't take you any time at all to be up and running with a
customized multitasking system.
PC-MIX is Small:
Have you ever loaded a utility into your computer and found, to your
dismay, that it consumed half of your memory? Somebody must have
thought it was the only thing you wanted to run. PC-MIX will not hog
your computer's memory like other Multitasking programs. PC-MIX uses
only 30K Bytes. That's Small!
PC-MIX Features:
True Pre-Emptive Scheduling; PC-MIX allows your program to share your
computer. PC-MIX switches back and forth between your programs many
times a second. It's automatic. You won't know it's Happening.
Three Programs Running Concurrently; PC-MIX allows you to have three
application programs, such as spreadsheets, data bases, and word
processors, running concurrently.
Fast and Efficient Program Execution; PC-MIX does not swap your
programs out to disk. They always remain in memory. This makes your
programs run fast and efficiently.
Rapid Switching Between Programs; It only takes Two Key strokes to
switch from one task to another.
Full-Screen Program Displays; PC-MIX allows your programs to use the
entire screen just like they are designed to. Each program has it's
own dedicated screen.
System Status Display; PC-MIX gives you a composite view of your
computer system with the system status display. Information is concise
and well organized. You can quickly see the status of all your programs.
Configurable Memory Partitions; Your computer's memory is divided
into three partitions; one for each task. You can easily customize
the size of each partition to suit your needs.
Selectable Task Priorities; Task priorities determine the execution
sequence of your programs. PC-MIX gives you the flexibility to set
each task's priority to one of three levels.
Operation Beyond 640K; With EEMS memory, PC-MIX can dramatically
increase the size of your task's memory partitions. With some
computers you can have 640K bytes of memory for each task.
Dedicated Graphics Screen; Scheduling graphics programs can be a
terrible burden on a multitasking system. Huge Video buffers must
be continously swapped in and out of video ram. The performance of
the system drops dramatically. PC-MIX has solved this problem by
dedicating the computer to the Graphics programs. All other programs
are put on hold until the graphics program is finished. You won't
have to work with a slugish computer. It will be as fast as it
normally is.