Main Aims of the Unit:

This unit describes the main elements in the processing of data. These include input, output and data checking. The role of the main processor (CPU) is described and different types of software are explored. Various approaches to file organisation are considered and the importance of security in the user-interface is stressed.

Main Topics of Study:

A. Introduction

1. Definitions of hardware, software, package, program, data, parameter.
2. Overview of the range of computers currently used from lap-top to supercomputer,
3. Configuration diagram showing how the components of a computer system are related. Difference between control signal and data flow.

B. Input

1. Review of methods of data capture to include OCR, OMR, MICR, barcodes, text/image scanners, magnetic stripe, voice, touch screen, keyboard, and concept keyboard.
2. Advantages and disadvantages of these methods of data capture when compared with others. In particular, a comparison of speeds, costs, user involvement, accuracy of the data received by the computer.
3. Choose the best data capture method for a given application.
4. Conditions required for each of these data capture devices to be used. A detailed explanation of the internal operation is NOT required.

C. Data checking

1. Difference between Validation and Verification.
2. Validation checks – range, data type, presence, sequence, …
3. Specifying the validation possible for a GIVEN SET OF DATA.
4. Check digit systems – normally using modulo-11 and weights 6,5,4,3,2,1 etc.
   • Specify WHICH data can/should contain check digits.
   • State the guarantees that check digit numbers provide.
   • Calculate the check digit for a given number
   • Validate a number which contains a check digit.
   • The use of “X” as a check digit.

D. Output

1. Ways in which data can be represented – tables, lists, summary statistics, charts, textual reports.
2. Name the range of printers currently available – laser, ink jet…
3. Advantages and disadvantages of different types of printers.
4. Screen output. Its limitations.
5. Identifying whether screen or printer would be more suitable for a given application.
6. Types of plotters currently available. Comparison with printers.
7. Identifying whether a printer or plotter would be more suitable for a given application.
8. Other forms of output. COM. Microfiche. Applications where these might be used.

E. Processor

1. Component parts of the CPU and their functions – ALU, Control unit.
2. MAIN memory and its various forms – RAM, ROM, cache, special purpose RAM e.g. for VDU …
3. Name registers in general use – accumulator(s), program counter (PC), Memory address (MAR), Memory data/buffer (MDR/MBR), Current instruction (CIR).
4. Fetch-execute cycle.
   • Name the steps an instruction passes through in the cycle.
   • Identify how the registers are used for basic instructions.
     e.g. LDA Price, SUB Tax. This topic MUST be covered in detail.
5. Bus structures.

F. Software

1. Distinction between system software and application software.
2. Distinction between general purpose and special purpose software. Understand that the USER dictates how general purpose software is used.
3. Outline of features of operating systems including systems with multiprogramming facilities. Name different operating systems currently in use and compare in outline.
4. System software.
   • File management software.
   • Utility software. Sort file. Merge files.
   • Language translators. Assembler, compiler, interpreter – basic differences.

G. Filing systems

1. Review of current storage devices – diskette, hard disc, Winchester, flash drive/pen stick, optical devices, digital versatile disk, tape and cassette…
2. The need for buffers and their role in data transfer.
3. Definitions of storage terms – file, record, field, cylinder, track, sector, header label, inter-block gap. Distinction between storage device and storage medium.
4. The structure of data stored on a storage medium.
5. Data transfer checks. Parity and its purpose. Describe odd/even parity with specific numeric examples illustrating acceptance/failure. Cyclic redundancy check.
6. File Organisation and File Access
   • Define organisation types – serial, sequential, indexed sequential, random.
   • Distinction between organisation and access. Examples of a file being accessed in more than oneway.
   • For indexed sequential organisations – an understanding of up to 2-levels of indexing.
   • Appreciation that not all record keys appear in the index. How ANY record can be accessed.
   • Overflow areas.
   • For random access – hashing algorithms. Develop a simple algorithm for a given situation.
   • For each of the four organisation methods, describe the PROGRAM sequence of steps to:
     • a. access a SINGLE record from the file
     • b. add a new record to the file
     • c. delete a record from the file.
7. Sequential master file update using an UNSORTED transaction file. Labelled system flow chart for this process.
8. Selecting the most appropriate file organisation for a given application.

H. Processing

1. Different types of processing – batch and real-time.
2. The role of batch processing with today’s sophisticated systems. Examples of batch processing currently in use.
3. Real-time systems – examples of current use.

I. Security and privacy

1. Security defined as the safeguard of hardware, software and data.
2. Distinction between security and privacy.
3. REALISTIC methods of data security – securing against
   • accidental damage or loss of data
   • deliberate sabotage.
4. Methods of achieving good privacy of data.
5. Determining the security/privacy required for a given situation.

Learning Outcomes for the Unit:
At the end of this Unit, students will be able to:

1. Describe the main configuration of a computer systems including input, output and processor
2. Identify different types of software including system and application software
3. Distinguish between different filing and processing systems
4. Understand the users role in data security

The numbers below show which of the above module learning outcomes are related to particular cognitive and key
skills:

Knowledge & Understanding 1-4
Analysis 4
Synthesis/Creativity -
Evaluation 3
Interactive & group Skills -
Self-appraisal/Reflection on Practice -
Planning and Management of Learning -
Problem Solving -
Communication & Presentation -
Other skills (please specify) -

Learning and teaching methods/strategies used to enable the achievement of learning outcomes:

Learning takes place on a number of levels through lectures, class discussion including problem review and analysis. Formal lectures provide a foundation of information on which the student builds through directed learning and self managed learning outside of the class. The students are actively encouraged to form study groups to discuss course material which fosters a greater depth learning experience.

Assessment methods weightings which enable students to demonstrate the learning outcomes of the Unit:
3 hour examination: 100%
(Choose any 5 questions from 8. Each question is worth 20% of the marks. )

Indicative Reading for this Unit:

Main text
Refer to the ICM website for learning material

Alternative texts & Further Reading:
Computer Science for Advanced Level by R Bradley – (Stanley Thornes)
ISBN 0 7487 4046 5 (Fourth edition).

A Level Computing by PM Heathcote & S Langfield – (Payne Galloway)
ISBN 1 904467 52 0 (Fifth edition)

Guideline for Teaching and Learning Time (10 hours per credit)
Lectures / Seminars / Tutorials / Workshops: 50 hours
Tutorial support includes feedback on assignments and may vary by college according to local needs and wishes.

Directed learning: 50 hours
Advance reading and preparation / Class preparation / Background reading / Group study / Portfolio / Diary etc

Self managed learning: 100 hours
Working through the course text and completing assignments as required will take up the bulk of the learning time. In addition students are expected to engage with the tutor and other students and to undertake further reading using the web and/or libraries.

Guidelines

• It is essential that candidates UNDERSTAND the elements of this syllabus. This syllabus has been detailed more than the previous version. This module is the least changed of the modules in the new scheme but there ARE differences. The following points are more warnings than guidelines based on past observations of candidates’ work.
• There are many examples from past submissions where candidates clearly did not understand certain topics and were merely repeating sections from books or notes. Examples of this include drawing a configuration diagram with input device connected directly to output device and arrows showing DATA flow TO an input device.
• Questions requiring the candidate to describe the processes in a fetch-execute cycle for a PARTICULAR situation (where a memory map is given in table form) frequently produced a generalised description of the cycle with no reference to the table (what was it there for?). The result was low or no marks at all.
• Validation questions nearly always produce low marks. A particular situation is stated, often in detail, in thequestion and the candidate asked to DESCRIBE the validation that could be applied to THAT data. The candidate then gives a standard list from text books such as “range, format, presence…” with no reference to the data. Furthermore, a list is not a description. As above, why is the data given in the question?
• Parity is relatively easy to understand but difficult to describe. The only reliable way is to give numeric examples showing failure and passing the parity check. Questions usually ask for numerical answers but candidates do not often give them. This area clearly needs to be checked at the centre by the setting and marking of homework.
• Definitions are poorly described. e.g. Marks will not be earned for defining SEQUENTIAL if the candidate states that “data is in sequential order”. These candidates often then go on to state that a SERIAL file is in “serial number order”. Many candidates have not understood the concepts of Field/Record/File because their examples have been confusing. Giving “student name AND student number” as AN example of A field cannot gain marks if the SAME phrase is used for record. Candidates frequently do not give examples, as required, from the application area stated in the question. The result is NO marks.
• When discussing a particular application of computers, tutors must encourage realistic responses. While it might be reasonable for a large institution to employ security guards and other elaborate security methods for a business, it is unrealistic to use them in a small business.
• There are a wide range of scanners yet candidates often do not specify which is used. A common mistake is in referring to magnetic or optical reading for a given device when the other is used.