Birds Eye View of HTTP

Written by Chris Inga


If you have been usingrepparttar internet for a while, you have probably typed into your browser something that starts with "http:" and ends with ".html", hit "Go", watched your modem lights flicker on and off, and a couple of seconds later you are magically looking at page of todays news or a page of pictures. Let's try and take some ofrepparttar 118795 magic away ...

I thought about calling this article a "Geeks view of HTTP"; I am not going intorepparttar 118796 nitty gritty, but rather present a sketch of how a geek might see something like HTTP, how they can think something like HTTP is simple, and why they are not trying to make things complicated just forrepparttar 118797 sake of it!

--* Layers *--

The background torepparttar 118798 sketch is that computers are full of layers. Programmers and designers think in layers, because organizing in layers makes it easier to build things.

You don't need to know what or whererepparttar 118799 layers are in your computer, or where one starts and another stops, but it is helpful to remember that they are everywhere because that is how geeks organize things.

--* Specifications and Protocols *--

Specifications and Protocols arerepparttar 118800 things that arerepparttar 118801 mostly likely cause of all your computer frustrations ... but they are a necessary evil. A wise man once said that any specification longer than one line will have ambiguities and be a source of problems.

There are lots of specifications and protocols in everyday life. An example of a protocol is when you are driving and see a red light you slow down and stop until it turns green. The specification of this protocol isrepparttar 118802 rule that is (probably) written down inrepparttar 118803 road-rule book. But we don't need to readrepparttar 118804 road rules, it is just common sense to know to stop for a red light. Of course we all knowrepparttar 118805 words computers and common sense don't belong inrepparttar 118806 same sentence, and that is why there are so many computer specifications and they are generally so long and detailed.

A common sentiment is "you really need to spell things out for a computer". I think this is a bit misleading. It isn'trepparttar 118807 computer that needs things spelt out, it isrepparttar 118808 programmers and designers who buildrepparttar 118809 higher layers who need to spell things out for other programmers creating other higher layers.

If one programmer ignoresrepparttar 118810 rules of a specification, or doesn't know there is a rule to follow,repparttar 118811 result can berepparttar 118812 same as if a driver runs a red light ... a crash.

--* Connection *--

I have finished withrepparttar 118813 background ofrepparttar 118814 sketch, and now I am going to draw a picture of a couple of boats in a bay, each with a two-way radio. I grew up around boats and always liked listening intorepparttar 118815 chatter onrepparttar 118816 two-way radios. The following conversations are from my memories of growing up, butrepparttar 118817 ideas are probablyrepparttar 118818 same for cb and other forms of radio.

The first boat we will call "Rock n Roll"repparttar 118819 second "Jazz". There was only one channel, and I noticed that there was a protocol that everyone seemed to follow (except on Sunday afternoons) to keep things orderly. I don't know if this protocol was written down anywhere as a set of specification rules or was just common sense. If Jazz wanted to call Rock n Roll they would wait until they heardrepparttar 118820 current conversation end with an "Over and Out". They would wait a couple of seconds and then say something like "Rock n Roll, Rock n Roll, this is Jazz, do you read me, over". If someone on Jazz was listening, they would say "Rock n Roll, this is Jazz, go ahead, over". Bingo!, they have a connection.

The same kind of thing happens when you type an address into your web browser and hit "Go". Your computer is just moving a bunch of numbers torepparttar 118821 modem. To keep things simple, lets ignore thatrepparttar 118822 modem is converting those numbers into sounds, and pretend that it is those numbers that are traveling out along your phone line. The reason sending numbers out along your phone can work, is that atrepparttar 118823 other end ofrepparttar 118824 line is your ISP's computer. This computer, and allrepparttar 118825 other computers onrepparttar 118826 internet, have layers written by programmers and designed by computer architects, that follow strict and detailed specifications of what to do withrepparttar 118827 numbers coming out of your computer.

Digital Rights Management

Written by Thom Leggett


Asrepparttar internet progresses in both popularity and structure, DRM is going to become very important in moving away fromrepparttar 118794 early free-for-all towards a more paid-for model. However, there is an argument overrepparttar 118795 degree of restriction of freedom that DRM appears to lead toward.

Copyright has always included an element of ‘fair use’, which givesrepparttar 118796 consumer a certain degree of freedom. For example, you are allowed to quote or criticise another person’s work or, in certain countries (not inrepparttar 118797 UK despite what many seem to believe), copy works for personal use. Many people fear that these arerepparttar 118798 sort of rights that would be trampled by pervasive DRM.

Onrepparttar 118799 other hand, many of those same people agree that some form of DRM is undoubtedly required ifrepparttar 118800 commerce of ideas, concepts and abstract works is to progress.

This much-discussed problem is at least partly due torepparttar 118801 digital age we live in: it is now perfectly possible to make fully functional copies of work, at a fraction ofrepparttar 118802 cost of developing it yourself.

You only have to look atrepparttar 118803 phenomenal number of illegal music files and software packages available onrepparttar 118804 internet to realise what an issue this is for people who make a living from something that can be distributed digitally.

Some people get a bit hysterical when they hearrepparttar 118805 term DRM, as they tend to assume that it means ‘big brother’ style controls on what we can see and hear onrepparttar 118806 net. Butrepparttar 118807 concept of protecting digital content andrepparttar 118808 intellectual property and/or copyright contained within, has been around for a while. Copy protection of CDs, software (e.g. activation on windows XP) and computer games are all examples of primitive DRM systems.

DRM can be taken much further than this though and be used to control content on a more fine-grained level. For example, DRM applied to music files could allow you to play them onrepparttar 118809 computer you downloaded them on, and make one copy to play inrepparttar 118810 car, but then deny further copying or playing on other devices. Alternatively, it could allow you to hearrepparttar 118811 song once before self-destructing. In effect, any method of distribution and licensing thatrepparttar 118812 copyright owner can conceive can in theory be enforced.

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