Some types of operating system

Hy friends how are you?
I hope you are fine .
In my previous post i discussed only two types of operating system ,that is software real time operating system and hard real time operating system .Today i want to share some information about Single user single tasking and single user multitasking operating system.
firstly i want to discussed

Single user single single tasking operating system:
Those operating system in which one user work at a time on one computer .
All stand alone computer comes in this category .
One user work on one computer means the processor of the computer does only one job at a time .
Example: MS DOS .

               running uni program on computer

Run Wait Run
Running uni program at a time but one program is running condition and 2nd program is waiting condition in single user single tasking operating system
This operating system work very slow.

Single user Multitasking operating system :
In this type of operating system user can perform many task at once .
these requires expensive system then normal.

All programs run one by one and each program takes few milli sec for processing
Example:
CPU
programe 1 (few milli sec) program 2(few milli sec) programe 3(few milli sec)
All programs run on cpu at a time