Sysadmin blog What is multitasking? Different people seem to mean different things when they use the word multitasking. The definition chosen has implications for accepting or rejecting the prevailing design choices of modern user interfaces.

I have been a vocal critic of Windows 8's Metro interface. My chief complaint is that it does not allow for what I consider to be multitasking. Microsoft argues that in fact it does allow multitasking. When the argument winds through its inevitable course, it turns out that we are talking about two different, but interrelated, concepts.

The Redmondian view is that Windows 8 – even in Metro mode – is a full multitasking environment. From a programming perspective, Microsoft is correct. Windows 8 is a multitasking operating system in which applications and services can run in the background to perform tasks independent of what is occurring in the foreground application.

The other context in which Microsoft claims that Windows 8 allows multitasking – even under Metro – is that Windows 8 provides methods of task switching. Even if you are using full-screened Metro applications, multiple applications can operate at the same time. To multitask the Microsoft way, you simply switch between them. For those not fully comfortable with one application at a time, Microsoft has been so kind as to grant its users the ability to run two Metro applications side by side: one occupying 34 per cent of the screen, and the other 66 per cent. Microsoft claims they thusly allow multitasking, both in a programming sense, and in a practical human sense.

The option to do more

Here, I must interject some disagreement. My first disagreement is a matter of petty semantics. As it was taught to me, "multi" generally means "more than two". I would typically call "doing two things at the same time" dualtasking, and "one thing a time" monotasking.

Some puttering around with dictionaries (both online and dead tree) has turned up meanings for multi that state "more than one" others that state "more than two". The semantic debate could have legs. For the purposes of this article, consider "multitasking" to mean "more than two things at the same time", if for no other reason than to save having to use more-than-two-tasking everywhere.

Getting past the semantics of the argument, I don't consider task-switching to be the totality of multitasking. Task switching is "doing one thing at a time, switching to another task and then switching back." In a task-switching environment, you are still devoting 100 per cent of your attention to one thing at a time, now matter how easy or difficult switching between those tasks is.

There are valid arguments (PDF) to be made that task switching in humans also bears a switch cost that other methods of cognitive processing don't necessarily incur.

The switch cost can be at least partially compensated for through training and preparation. Despite this partial compensation, there is plenty of research to state that when you do more than one thing at the same time, the cumulative time expended on both tasks is greater than if you had done one at a time, and you are more prone to errors.

Task switching is only one element of how I multitask. When I sit down at a computer and there are a dozen or more dynamic sources of information, I am legitimately tracking and parsing each and every one of them. I may be working on one primary task (or switching between a handful of them,) but I am skimming the datastream presented by the dynamic information sources looking for anything more important than I am doing at the moment.

This is a form of continuous partial attention (PDF) – a separate (but related) concept to task switching. Like task switching, continuous partial attention is considered a non-optimal method of cognition. Used wisely, either or both can prove highly useful the right circumstances.

If every task I undertook was equally vital – the information in every window equally important – then a one-primary-task-at-a-time Metro-style interface makes abundant sense. A Metro-style interface really is the best way to get a certain category of tasks done.

In reality however, I am not spending my entire day exerting myself to my maximum potential. While multitasking essentially makes it impossible to learn new things, for a significant chunk of my day I am not learning anything new. Outside of academia – and a handful of other professions – the day is taken up with implementing what we already know. Skimming Google for the syntax needed to finish some obscure script, typing up documentation or doing that post-project CYA email marathon simply do not require my full attention. Button pushing and progress bars might as well be an assembly line.

Should I get the opportunity to learn a new thing I have the option of simply maximising the current foreground window. If I encounter a task that would benefit from my undivided attention for any reason, I have the choice to remove all distractions and give that single task my all.

After nearly 30 years, multitasking is as much a part of who I am as my own hands. It is so much more than task switching, continuous partial attention or a series of predetermined workflows.

Multitasking as I define it is all of these things. It is legitimately doing more than one thing at a time when I know that engaging in such an activity won't be a detriment to my work.

Multitasking may not always a good idea, but I absolutely require the option to do so. An option that – regardless of the PR spin – Metro simply doesn't provide. ®