IPT Tools 3

Mr Zarkovic
Tools for Information
Processes - PART 3

 In this lesson we will examine the
information processes:
• Storing and retrieving
• Processing

Storing and Retrieving
 This involves saving data and information
and reloading it
 Students are required to identify the
storage and retrieval processes at work in
an existing system e.g. a trip to the school
library or the administration office enable
these features to be identified
 The administration office is also a good
venue to introduce students to data
backup and recovery, the importance of
which become evident ‘close to home’

Storing and Retrieving – Hardware
 This there is a major emphasis on hardware and
the media used to store data/information
 The syllabus suggests that students be given the
opportunity to use hardware devices (with
associated software)
 Students need to be made aware that they do
this already
• Retrieval e.g. every time they activate a piece of
software or open a document it is being retrieved from
the computer hard disk (secondary storage) and then
loaded into memory (primary storage)
• Storage e.g. saving an open document to a USB drive or
burning a music CD

 Knowledge of the method used by each
type of media to represent data is
important
 I show students a collection of old media
and storage devices, from the ‘relics’ box,
to show them how storage technology has
advanced over the years and discuss the
pros and cons of each
 Also we categorise them using terms such
as magnetic, optical, physical, primary,
secondary, volatile, non-volatile, random,
sequential, etc (see below)

 One way storage can be classified in terms
of how data is accessed
 Random (or direct) – data is able to be
accessed by read/write head moving to
the location on the medium where the
data is located e.g. this is the method
commonly used with magnetic disks
 The location of each data item on the disk
is stored in a file allocation table (FAT) in a
reserved part of the disk

 Sequential – The read/write head starts
reading data at the beginning of the
medium and keeps reading until it finds
the required piece of data
 This method is commonly used for tape
drives. These devices are still important,
because they are the most common
method used for backing up large volumes
of data
 CDs also use one continuous spiral track
but songs can be accessed randomly

Storage can also be classified in terms of its
permanence:
 Volatile storage – is non permanent. It will

only store data for as long as electricity is
supplied to the device e.g. Random Access
Memory – RAM
 Non-volatile – more permanent, will store

data for a long period of time without the
presence of electricity e.g. Hard Disk,
Diskette, USB drive, etc

Storing and Retrieving – Software
 All storage devices need driver software to
enable the device to be integrated with
the rest of the system
 Most drivers are included as a part of the
operating system
 File management software enables data
files to be organised on some of the
storage devices attached to the computer
(like a hard disk)

Storing and Retrieving – Software
 Databases are also another important
piece of software used to store data
 FTP software is used to upload web page
files to a service provider (like the DET)
 This is a good activity to do with students
as they enjoy seeing their work published
on the web but be aware of DET’s policies
on publishing material to the web

Non – Computer Tools
 Students need to be aware that a
computer is not always the best
solution to a data storage problem
e.g. An address book is an efficient
means of storing data about friends
and relatives: non-volatile, random
access (if indexed), portable, no
hackers, no viruses, etc

Processing Data
 At the macro level this process involves
the editing and updating of data
 The importance of carrying out this task
are fairly obvious
 At the micro level this process involves the
operation of the Central Processing Unit
(more later)
 Students need to be able to distinguish
between: Centralised, Distributed and
Parallel processing

Centralised Processing
Dumb Terminal
(aka thin client)
– just a
keyboard and Server
screen
Data for processing is sent to server

Results of processing sent back for
display on the dumb terminal

Distributed Processing

Network
P.C.s – data is processed
using the local CPU
Server – performs
more complex
processing tasks
such as
authentication and
file storage

Parallel Processing
Large Task for Processing

CPU breaks large task into
smaller tasks

Small task 1 Small task 2 Small task 3 Small task 4

Multiple
CPU’s
process
each task
Result task 1 Result task 2 Result task 3 Result task 4

CPU combines the small results
to get an overall result

Result

The operation of the CPU
 CPU – Central Processing Unit
 The device that does all the “thinking”
 Is made up of millions of microscopic
electrical components located on a single
silicon chip (aka microprocessor)
 On larger systems the CPU can be
composed of many silicon chips

Components of the CPU
 Control Unit – directs the flow of data
around the various components of the
computer.
 Arithmetic Logic Unit (ALU) – carries
out arithmetic and logical operations,
basically doing additions very fast
 Registers – small, temporary memory
locations used to hold the data and
instructions needed for processing

Operation of the CPU
 The CPU processes data by using the
Fetch / Execute cycle
 During i-time data/instructions are
fetched from memory and decoded
 During e-time the ALU performs
operations on the data and stores
the result

Fetch Execute Cycle
Fetch Execute
or or
i-time e-time

Control Unit decodes ALU performs
the instruction (i.e. required operation on
What it has to do) data

Control Unit fetches Control Unit sends
next instruction from result back to RAM or
RAM and loads into a a register.
register.

Fetch Execute Cycle
 Pipelining is a common method used to
speed up processors
 In the past, each instruction went through
the entire fetch execute cycle before the
next instruction
 With pipelining, when the CPU has sent
the first instruction for decoding, it also
fetches the second instruction
 When the first instruction is being
executed by the ALU, the second
instruction is being decoded and the third
instruction is being fetched, etc

IPT Tools 3

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IPT Tools 3