Computer Networks - An Introductory Overview

What is a computer network?

To a user - something that allows applications to talk to each other. They have an idea as to what the infrastructure should allow them to do. Email and web browsing should be reliable. Internet banking should also be secure. Internet radio, voice over IP and video streaming should have quality. With VoIP however you also want low latency (delay) too, as opposed to internet radio. The demands of the network depend on what type of application you want to run.

Cocoa Framework Summary

A summary by James Bedford.

Cocoa is a framework of tools used for software development written in Objective-C, featuring modular, object-oriented and visual design. It was originally called NextSTEP and was developed by the company NeXT. When NeXT merged with Apple in 1996, the framework NextSTEP was renamed Cocoa. However, it still remains that all objects within this framework begin with the prefix "NS", which helps to distinguished them and prevent accident errors.

This summary is work-in-progress (which will be periodically updated) and may contain mistakes. Please let me know if there are any issues, or if anything needs clarifying.

Year 2010 – Happy New Year

Now for something completely different :)

Computer Networks - Applications

Network Applications

Computer networking? There's an app for that.

A network applications is a program that communicates over a network but runs on end systems, not core network devices. You can't install skype on a router!

There are 4 distinct architectures for network apps:

Logic and Modelling – Propositional Logic

OK, first things first. I am only doing these LaM notes because i’ve been begged to do them :P

Since a lot of Propositional Logic is extremely basic, then I am going to be quick a brief on these notes. However, do note that they are slightly more advanced than what you learnt in previous years, like here: Year 1 PL

So, with this, lets get down to the nitty gritty :D

Computer Networks - Switching, Delays and Performance

Switching, Delays and Performance

Switching

A network is a mesh of routers connected, There are 2 basic ways of transferring packets through a network:

• Circuit switching:

Objective-C Programming Language Summary

A summary by James Bedford.

Objective-C is an extension to the C programming language developed in the early 1980s. It is used in all Apple products including Mac and iPhone software development. Originally referred to as "C with messaging", the primary aim of Objective-C is to introduce object oriented programming to C, and achieves this using a different approach to C++ or C#.

I’ve got no time for messing about, so here’s s summary of the entire language, assuming you already understand object oriented programming (OOP) concepts and a thorough understanding of C (because I’m not going to explain anything that’s the same as C). Example code (as infrequent as it may be) is written between quotation marks. This may get a little confusing at times, so try and stick with it (maybe copying and pasting the inside of quotes may help). The example code will always be a single line of the program.

This page is also going to be updated as I continue to summarize the language. Please let me know if anything needs clarifying, or if there are any problems with the notes.