Too many mega-XXX

There is a word that has crept into [slang] English, which is used to denote something that is very good indeed. Young people may be heard to say “That’s mega!” As the word does not really exist, I guess it is an abbreviation for a word that has the prefix “mega-“. Whatever it means, I find it rather annoying.

However, hearing it recently did get me thinking about the different ways that the prefix is used and abused and how it is applied as a marketing tool to sell intelligent people things that they do not need …

The meaning of the mega- prefix is clear enough: it refers to a million of something. So, the SI unit of frequency is hertz – Hz. A thousand hertz is a kilohertz – KHz. A million hertz is a megahertz – MHz. So, of course 1000KHz = 1MHz. This is all quite straightforward and consistent with other physical units, like metre, gram etc. It can also be used as a simple count of objects. So, “megadeath” is the killing of a million people [in nuclear warfare, for example]. We are all familiar [or think we are] with the megapixel term that suggests that there are a million pixels in a digital camera, but I will come back to that.

There is some confusion in the computer world. A megabyte should mean a million bytes, but it normally refers to 1,048,576 bytes, as this is 2 raised to the power of 20 and computers like to work in terms of powers of 2. Although this logic is sound, I do find it ironic that, in a world which is normally steeped in precision, there is this odd fuzziness.

In some contexts, I am sure that people allow errors to slip by, as the confusion helps sell stuff. A good example is broadband Internet connections. I have heard people refer to 10 megabytes per second. That would actually be very fast, but what that actually mean is 10 megabits per second, which is around 10X slower.

It is so common for customers to select technical products using the “mega-numbers” game. There is a perception that the bigger the number, the better the product. I can think of two examples where this fails the unwary buyer:

One parameter that describes a PC is the CPU frequency. This used to be MHz, but nowadays is normally shown as GHz. These high frequencies push the electronics very hard and consume lots of power [and, thus, generate lots of heat]. You should really be offered a PC that is powerful enough for your needs. Instead, “big numbers are better” applies. The result is that people commonly buy a PC, which runs hot enough to fry eggs and consumes battery charges in no time, that could happily model the world climate like a supercomputer, when all they want is a bit of Internet browsing and word processing. Even 1GHz is overkill for such tasks.

Digital photography is a minefield. Firstly, 1 megapixel [mpx] is not a million pixels really. The pixels come in threes – one red, one green and one blue. A 3mpx camera has a million of each color, which effectively produce a one megapixel colored image. But the software in the camera creates extra pixels, which use up memory card space and transfer time, just to make the camera look better than it is. I think I might start the Campaign for Real Pixels to get this fixed. But it gets worse.

Obviously a 10mpx camera is going to make pictures that are twice as good as a 5mpx one. This is not true. There are more pixels, but, because they are packed onto the sensor chip so tightly, there is more electronic “noise”, which adds fuzziness to the image. Almost nobody needs 10mpx anyway. If you are only going to look at pictures on the screen, 1mpx is more than enough. If you want to make prints, 2mpx is OK for snaps – 4-6mpx will make nice large prints. So why are so many cameras sporting bigger mpx numbers? Because big numbers sell.

While we are on digitral photography, do not get me on why SLRs are quite pointless …

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This article first appeared on the Siemens Digital Industries Software blog at https://blogs.sw.siemens.com/embedded-software/2011/04/21/too-many-mega-xxx/