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Multitasking Illusion

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What is multitasking? it is the practice or capability of handling more than one task at the same time ..

It is said that our brain is capable of performing certain dual multiple tasks at the same time, for example, listening to the radio while writing an email, increasing the amount of tasks was one of the very basic reasons for inventing the CPU from the first place ..

Well, I completely disagree, actually there is no such thing as multitasking, only context switching which simulates multitasking, even for the CPU!
Let me explain ..

Human brain and CPU are quite different, our brain is more complicated, so I will take the CPU for an easier example ..
Consider that you need to perform 2 tasks on your PC, each requires exactly 10 seconds ..
The total time required will be 20 seconds for both tasks if running sequentially, first task will be completed after 10 sec and second task after 20 sec ..
But if you run both tasks simultaneously with the use of what called CPU multitasking, the CPU will do a context switch between both tasks, in other words, breaking down each task to segments and switch back and forth between them, assuming that each task will have 10 segments, each segment requires one second, then first task will be processed at odd seconds (1, 3, 5, ..) and second task at even seconds (2, 4, 6, ..), in that case we will have first task completed after 19 sec and second task after 20 sec, considering that the switch takes no time at all !!

Imagine the above procedure in our brain with the unexpected time required for the context switching, there is no accurate numbers but obviously the sequential approach will take much less processing than the simultaneous one, using only one switch between tasks !

On the other hand, human context switching (what I call distraction) means spreading attention among tasks, like talking on the phone while driving a car, since 2003 car accidents increased about 40% because of cell phones!


  • CPU can not actually perform simultaneous tasks, it uses context switching to simulate multitasking, even with mutli-core processors, yet each core still performs exactly the same.
  • Context switching will not reduce the total time required for all tasks, it just adds an extra time for the switching operation.
  • Multitasking more accurately refers to Managed Tasking!
  • Human context switching consumes much more time than the CPU, in addition to the continuous partial attention.


Never think or act simultaneously!


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