Finishing section 3

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15 Αυγ 2012 (πριν από 8 χρόνια και 11 μήνες)

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Section 3

last bits

These are the last notes for Section 3. Some interesting stuff here.

s always, use a variety of sources
and make good uses of multimedia where possible:




YouTube videos

Why not write a lit
tle song about data
integrity? O
r explore encryption algorithms through the medium
of dance?

Write your notes under my blue text.


Define syntax and semantics.

These are words that are used in linguistics. What do they mean with respect to computer
programming languages
? Gi
ve an example of a syntax error (in Java if you can).


Describe the function of high
level language translators. The translators should
be limited to interpreters and compilers.

How does the computer program that a human writes get converted into
the language of binary
that the computer can understand? What is the difference between compiling and interpreting?
What are the advantages and disadvantages

of each
? You should make reference to

speed of execution


the use of software development tools. Examples include: database
management systems, macros, CASE tools and simple language translators (interpreters
and compilers are not suitable examples in this context), HTML editor, web page editor,
code editor, visu
al IDE.

Write a short paragraph defining each of these and giving an example where possible. Look up

you are going to be using it a lot!


Outline the characteristics of secondary memory and define sequential and direct
access. Secondary m
emory should refer to flash memory, disks, CDs and DVDs and
tape. Students must know the type of access of the above secondary memory media.
They should also be able to give an application of each type and justify its use for this

You need to
make reference to sequential access and direct access. You are probably too
young to remember video or audio cassettes, but think about what you had to do if you wanted
just to listen to track 6. Compare this with a CD or DVD.


Outline recent
developments in computer system architecture including
processor architecture, primary memory technologies and secondary memory devices.
Technical details are not required unless introduced in the case study.

In truth I don’t really know what this is refer
ring to. There are some notes in the IB Java
textbook. I’ll see what else I can dig out.


Describe suitable methods to ensure data integrity in the transmission of data.
checking codes such as check sums (block character checks) and parity check
must be understood. The reasons for retransmission should be understood. The quality
of communication lines should be considered.

What is data integrity and how is it different from data security? How does the need for data
integrity checks and correctio
n arise (links with physics)? You should look at measures to
prevent data transmission errors as well as measures to detect and correct them. Be careful
how you do your research. If you just stick “data integrity” into Google you will get a lot of
nt stuff about referential integrity in relational database systems. Use “data transmission
errors” instead.


Describe suitable methods to ensure data security. Students should understand
the concept of data encryption but do not need to give algorith
mic details. They must
understand the need for, and use of, passwords, physical security and different levels of
access (permissions) for different users.

This is a huge and fascinating area. For encryption, you should be using terms like plaintext,
rtext, cipher, key, encrypt, decrypt, symmetric, asymmetric. Find out a little of how internet
encryption works (using terms like https, SSL, public key encryption, RSA). Think about the role
of each of username, password, access control (also known as pri
vileges or permissions), and
don’t forget things like walls and doors, which play a big part in data security. Talk a little about
up too (terms:
full vs incremental,
disaster recover, failover, redundancy).


Discuss the need for speed in data
transmission, and how speed can be

Students must know that documents and graphics files can be sent in different formats
and the format affects the speed of transmission. Common formats such as JPEG and
BMP should be known. The principles of data

compression should be considered but
details of methods are not required.

Explain what bandwidth is and provide some examples of current typical bandwidths of, say, an
Ethernet network, wireless network, Bluetooth, broadband internet connection. Compare v
vs raster graphics and give examples of each. Make connections to your work on analog vs
digital. Give one example of data compression and outline how it works.