Network Security is concerned with three main areas: Secrecy. Only the sender and intended receiver should understand the content of messages. Authentication. The sender and receiver need to confirm their identities. Integrity. Need to ensure the message is not altered without detection.
Read MoreCollections in Java
The Java API contains numerous classes for managing collections (or sets) of objects. A collection allows us to easily model a large number of data values or objects. There are four main types of collections which are available through various API packages; firstly lists. A list is an ordered collection of objects, we’d use this […]
Read MoreLets Talk About Sets
A set is a collection of distinct objects considered as a whole. [Wikipedia – http://en.wikipedia.org/wiki/Set ] A set can be thought of as a collection of objects – or elements – and these objects can be anything, data – numerical – or indeed other sets. Elements in a set are in no particular order, and […]
Read MorePropositional and Predicate Logic
A Proposition is a declarative sentence, which may be shown to be either true, or false, whether the statement is true or false is not – however – relevant. Both “1+2-=3” and “1+2=4” are example of propositions. Predicate logic allows us to explore the truthfulness of a statement, it has an expressive power which propositional […]
Read MoreManaging Your Memory
Another key role of the Operating System is to manage memory resources, there are two separate conceptual levels of memory. Firstly, physical memory – this is what the operating system sees, and it relates directly to your actual physical hardware. Secondly, there is virtual memory, which is what a programmer will see when developing an […]
Read MoreCombinatorics
Combinatorics is a branch of mathematics concerned with the study of finite objects, and has many applications in the field of Computer Science. Combinatorics is useful in problem solving, and is most often involves ideas such as counting elements in a set, or calculating permutations or combinations of elements in a set.
Read MoreAlgorithms & Time Complexity
Rosen describes an algorithm as: “An algorithm is a finite set of precise instructions for performing a computation or for solving a problem.” An algorithm can be expressed in a number of different ways however, it could be explained in plain English, written in a generic pseudocode (not a true programming language in itself, but […]
Read MoreComputer Architecture
The function of a computer is to carry out instructions, this occurs within the Central Processing Unit in loop known as a the Fetch-Execute Cycle.
Read MoreUsing RAID
Some notes from aaaaages ago, not necessarily part of our syllabus. RAID stands for (Redundant Array of Independent Disks) (or originally, Inexpensive disks, unfortunately that’s not the case any more!). Lets break that down into what it really means: “Array”, so we’re talking more than one disk drive here. “Independent”, these are separate disks that […]
Read MoreBinary Arithmetic
We can apply the normal rules of arithmetic to binary, just as we can to any other number system – and the only time this can get a little complicated is when considering binary subtraction – or negative binary since strictly the negative sign should not be used.
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