Archive for May, 2010

Bits and bytes and broadband: Part One

May 26, 2010

Ever been confused by broadband speeds? In this two part blog I’m going to try and explain all.

Bits and Pieces

First let’s go over a few terms you’ve probably read or heard about:

  • Kilobits
  • Megabits
  • Gigabits
  • Kilobytes
  • Megabytes
  • Gigabytes
  • Megablobs (OK I made that one up….)

The first thing to say is don’t feel bad about not understanding these unit!

They are confusing, used only for historical reasons and are not even consistently used. Computer scientists, physicists, network & hard drive manufacturers might give you a different definition of some of these units.

This is not your fault, and in fact some companies will actively use this confusion against you.

So let’s try to unravel these units.

The basic units are reasonably easy:

  • A bit is a zero or one

A “bit” is the smallest unit of information in computing. It’s basically a “0” or a “1”, or if you like a “yes” or a “no”. It might sound strange that the whole basis of modern technology is built on so humble a thing, but the reason is because of  the way electronic hardware (i.e . your computer) works. The point is that if you string together enough “yes” and “no’s” you can represent anything (imagine a game of 20 questions, only you have a million goes!).

  • A byte is 8 bits

A “byte” is 8 lots of bits in a row. A byte is roughly enough information to represent a single character of the English language. So “hello” would be 5 bytes (which is 40 bits (5 x 8)).

(I’m glossing over two issues: firstly older computer systems might use different numbers of bits to refer to a “byte” e.g. 6, 7, 8 or 9 bits. Nowadays, it’s almost universally 8 bits. Secondly, characters in other languages might require 2 or more bytes to store).

  • A kilobit is 1000 bits.
  • A kilobyte  is 1000 bytes.

So those are easy. Maths nerds reading this will realise  that a kilobyte is 8 times larger than a kilobit. That’s a commonly repeated pattern you’ll see between “bits” and “bytes”.

(So actually I’m lying here, again. SOME people (Computer Scientists in particular)  actually call a kilobyte 1024 bytes. The reasons for this are highly technical and really just to make life easier for Computer Scientists – thanks guys!

Recently there was a move to try to standardise the “kilobyte” to be 1000 bytes, but the problem is that lots of people still use the old size. You’ll see this issue repeated for Megabytes and Gigabytes – some people say a Megabyte is 1000 kilobytes, others say it is 1024 kilobytes. Read more about it here.

For most cases, the difference is quite small, so don’t worry about it too much.)

For those of you who remember studying the solar system at school, here is a familiar to-scale representation of the sizes of these units:

Relatively speaking, these units (up to the Kilobyte) are still very small. By comparison, a typical JPEG photo would be at least 200 kilobytes.

The next step up is the Megabit and Megabyte.

  • A megabit is 1000 kilobits
  • A megabyte is 1000 kilobytes

And here they are in comparison:

And finally we get to Gigabit and Gigabyte.

  • A Gigabit is 1000 Megabits
  • A Gigabyte is 1000 Megabytes

You can also see the relative size of a typical MP3 and a moderately high quality photo (JPEG).

Note how “kilobits” and “kilobytes” are so small, they don’t even appear on this chart. For modern day computing, the only unit of any useful size is Megabits/Megabytes, and Gigabits/Gigabytes.

That massive orange Jupiter-like blob in the corner is a Gigabyte. A modern decent sized hard drive would be at least 200 Gigabytes so you can imagine how big that would be.

Shortened Names

You’ll often see these units shortened like this:

  • kbps
  • mbps

The first two letters “kb” refer to the unit (kilobits, kilobytes, megabits, megabytes). “ps” stands for “per second”. So, it’s a measurement of how much data can be transferred in 1 second.

Unfortunately, these abbreviations are often used inconsistently, and not clearly.

One issue is how to distinguish between “kilobits” and “bytes”.

Often the convention is to use UPPERCASE “B” to refer to bytes and lowercase “b” to mean bits.

So:

  • KBps means kilobytes per second
  • kbps means kilobits per second
  • MBps means megabytes per second
  • mbps means megabits per second

BUT this  is often not consistently used, particularly in some companies’ marketing material. The rule of thumb is this: if it’s a broadband company talking about internet speeds, they will be referring to megabits and kilobits regardless of whether they use upper or lowercase letters for “mbps”.

Conclusion

  • A bit is the smallest unit of information: a zero or a 1
  • There are 8 bits in a byte
  • Common pattern of each unit is that it’s 1000 times larger than the previous unit (kilo –> mega –> giga)
  • Kilobits/Megabits are 8 times smaller than kilobytes/megabytes
  • Beware of abbreviations: kbps, mbps

In part two I’ll be talking about some of the pitfalls in the way broadband companies report speeds.

Broadband speed is relevant to our product, BuddyBackup, as it determines how quickly you can backup and restore files over the internet.

John Wood

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Online and Off-site

May 7, 2010

Data backup is all about making sure you don’t lose stuff if you have a disaster.

The question is, what kind of disaster?

Sure, your computer might just go “pop” and smoke a little, but it might also go “ka-boom” and smoke a LOT. Like this one:

A computer highly damaged and melted by fire

Oops! Good job I had off-site backups...

When it comes to backup, you have to ask yourself exactly what you’re trying to achieve. If you just want to handle to occasional lost file, or Windows crash then actually maybe you don’t need to do anything.

Modern operating systems and applications are much better at dealing with this sort of stuff. For example, you’ve probably noticed that newer versions of Microsoft Word can restore “lost” files, so if your computer crashes and you forgot to save, you might be OK.

Similarly, most modern operating systems use a Recycle Bin, so when you delete files, they’re not immediately gone.

Geeks can even sometimes restore “really” deleted files using special software, and if you’re really serious you can send corrupted hard drives to companies who will try and read the data from them (it’s expensive, mind).

So why bother backing up?

Unfortunately, it’s very much like home insurance. You might go through a lifetime without having a major fire or flood, but that doesn’t mean you won’t buy house insurance (right?). So to me, data backup is the same: it’s the 1 in 100 event; the small percentage of us that have a major disaster such as fire, flood or theft. If your backup strategy doesn’t account for this, then what’s the point?

In the business we talk about “off-site” backups. What this means is making sure that a copy of your data exists away from the place of business. The same principle should apply to home users as well.

In the past (and still present in some cases!), the solution to this was to physically move your backups (which might be on magnetic tape or removable hard drives) to a second location. For example, you’d have someone responsible for taking home the backup tapes at the end of the week.

Of course this requires a lot of diligence, and also, well, a guy to carry tapes around, so is completely inappropriate for use in the home or small businesses.

A more recent solution to this has been “online backup”. With this, your files are delivered over the internet to a third party company, who looks after them for you. You rely on the company to store the files for you, and let you download them when you need them.

Usually you run some software on your PC to manage the backups (BuddyBackup fits into this category), but sometimes it might be a done via a website.

The nice thing about online backup is that it’s much less effort: you’re using the internet for delivery so there is no messing about physically moving stuff. Also, (depending on the quality of the software running on your PC), it can be easier to setup and run.

It’s also often the only viable “online”/”off-site” option home or small office users.

So, when you think about backup, think about what exactly you’re trying to protect against. In this internet age, there are plenty of options for off-site backup that is actually going to survive a real disaster.

BuddyBackup gives you off-site backups for free by saving your files encrypted onto your buddies’ computers.

John Wood