Cie AS Computing
Syllabus code 9691 Syllabus code 9691 June and November 2012
Syllabus
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
11
5. Syllabus content
Section 1: Computer systems, communications and software
This section provides candidates with an understanding of the following core aspects of computer systems:
• components of a computer system and modes of use
• system software
• data: their representation, structure and management
• hardware
• data transmission and networking.
The systems development life cycle is studied with reference to particular applications, so candidates are
expected to look at a range of different types of application areas. Although candidates are not expected to
have specific knowledge of every one of these, they should be able to make use of relevant examples for the purpose of illustration.
This section also provides candidates with understanding of the following aspects of computer systems:
• systems development life cycle
• choosing applications software for application areas
• handling of data in information systems
• implications of computer use.
1.1 Components of a computer system and modes of use
Content
1.1.1 Types of hardware
1.1.2 Types of software
Learning outcomes
Candidates should be able to:
(a) define the terms hardware, software, input device, storage device and output device
(b) describe the purpose of input devices, storage devices and output devices
(c) define the different types of software: operating system and generic/common applications software
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
12
5. Syllabus content
1.2 System software
Content
1.2.1 Operating systems
1.2.2 User interfaces 1.2.3 Utility software
Learning outcomes
Candidates should be able to:
(a) describe the purpose of operating systems
(b) describe the characteristics of different types of operating systems and their uses: batch, real-time,
single-user, multi-user, multi-tasking and network systems
(c) identify a range of applications requiring batch processing and a range of applications in which a real
time response is required
(d) describe different types of user interface: forms, menus, GUI, natural language and command line,
suggesting the characteristics of user interfaces which make them appropriate for use by different
types of user
(e) describe the purpose of a range of utility software e.g. disk formatting, file handling, hardware drivers,
file compression and virus checkers
1.3 Data: its representation, structure and management
Content
1.3.1 Data types
1.3.2 Data structures
1.3.3 Data management
Learning outcomes
Candidates should be able to:
(a) explain the use of codes to represent a character set (e.g. ASCII and Unicode)
(b) explain the representation of different data types: integer, Boolean, date/time, currency and character
(c) express positive integers in binary form
(d) understand the structure of arrays (one and two dimensional), including initialising arrays, reading data
into arrays and performing a simple serial search on an array
(e) describe the LIFO and FIFO features of stacks and queues
(f) explain how data is stored in files in the form of fixed length records comprising items in fields
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
13
5. Syllabus content
(g) define and explain the difference between serial, sequential, indexed sequential and random access
to data, using examples and stating their comparative advantages and disadvantages
(h) describe how serial, sequential and random organisation of files may be implemented using indexes
and hashing as appropriate
(i) select appropriate data types/data structures for a given problem and explain the advantages and
disadvantages of alternative choices
(j) explain the procedures involved in backing up data and archiving, including the difference between
data that is backed up and data that is archived
1.4 Hardware
Content
1.4.1 Processor components
1.4.2 Primary and secondary storage
1.4.3 Peripheral devices
Learning outcomes
Candidates should be able to:
(a) describe the function and purpose of the control unit, memory unit and arithmetic logic unit (ALU) as
individual parts of a processor
(b) explain the difference between types of primary memory and their uses (RAM, ROM)
(c) describe the basic features, advantages, disadvantages and use of secondary storage media
e.g. magnetic, optical and solid state
(d) describe use of buffers and interrupts in the transfer of data between peripheral devices and primary
memory
(e) describe a range of common peripheral devices in terms of their features, advantages, disadvantages
and uses
(f) relate the choice of peripheral device to a given application, justifying the choices made (g) understand the potential problem of speed mismatch between peripheral and processor
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
14
5. Syllabus content
1.5 Data transmission and networking
Content
1.5.1 Data transmission
1.5.2 Circuit switching and packet switching
1.5.3 Protocols
1.5.4 Networking
Learning outcomes
Candidates should be able to:
(a) describe the characteristics of a local area network (LAN) and a wide area network (WAN)
(b) show an understanding of the hardware and software needed for a local area network (LAN) and for
accessing a wide area network (WAN)
(c) describe the different types of data transmission: serial and parallel; simplex, half duplex and full
duplex modes
(d) explain the relationship between bit rates and the time sensitivity of the data
(e) recognise that errors can occur in data transmission; explain the use of parity checks, echoing and
check sums in detecting and correcting these errors, and the use of parity blocks to aid self checking
(f) explain the difference between packet switching and circuit switching
(g) define the term protocol
(h) describe the need for communication between devices, and between computers, and explain the
need for protocols to establish communication links (candidates will not be expected to have detailed
knowledge of specific protocols)
(i) explain the need for both physical and logical protocols and the need for layering in an interface (detail
regarding layers is not required)
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
15
5. Syllabus content
1.6 Systems development life cycle
Content
1.6.1 Identification of problem
1.6.2 Feasibility study
1.6.3 Information collection
1.6.4 Analysis of a problem, based upon information collected, including producing a requirements
specification
1.6.5 Design of system to fit requirements 1.6.6 Development and testing of system
1.6.7 Installation of system
1.6.8 Maintenance of system
1.6.9 Obsolescence
Learning outcomes
Candidates should, with reference to particular applications, be able to:
(a) explain the importance of defining a problem accurately
(b) describe the function and purpose of a feasibility study
(c) explain the importance of determining the information requirements of a system and describe
different methods of fact finding, highlighting the advantages and disadvantages of each method
(d) describe what is involved when analysing the requirements of a system, explaining the nature of the
requirements specification and its content, identifying inefficiencies/problems, user requirements and
hardware and software requirements
(e) design the data structures, inputs, outputs and processing using diagrammatic representations where
appropriate (including the use of dataflow diagrams (DFDs) and system flowcharts)
(f) explain the importance of evaluating the system against initial specifications
(g) explain the content and importance of documentation in the system life cycle, including the
requirements specification, design specification, program specification and documentation
(h) explain the importance of testing and installation planning, including the method of installation
(i) explain the reasons for maintaining the system
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
16
5. Syllabus content
1.7 Choosing appropriate applications software
Content
1.7.1 Custom written software versus off-the-shelf software packages
1.7.2 Applications software
Learning outcomes
Candidates should, within context, be able to:
(a) distinguish between custom-written software and off-the-shelf software packages, and discuss the
advantages and disadvantages of each in given situations
(b) identify the features of common applications found in business, commercial and industrial
applications, e.g. stock control, payroll, process control, point of sale systems
(c) identify suitable common generic applications software for particular application areas, e.g. word
processors, spreadsheets, desktop publishers (DTP), presentation software, drawing packages, and
justify the choices
(d) identify application areas for which generic applications software is not appropriate
(e) describe the purpose and impact of different types of generic applications software, e.g. word
processors, spreadsheets, desktop publishers (DTP), presentation software, drawing packages
1.8 Handling of data in information systems
Content
1.8.1 Data capture, preparation and data input
1.8.2 Validation and verification of data
1.8.3 Outputs from a system
1.8.4 Knowledge based systems
Learning outcomes
Candidates should, within a context, be able to:
(a) describe manual and automatic methods of capturing and inputting data into a system, including form
design, keyboard entry, barcodes, Optical Mark Recognition (OMR), magnetic stripe cards, Optical
Character Recognition (OCR), sensors and data logging, touch screens, chip and pin
(b) describe image capture by use of a scanner, video capture card and digital camera/camcorder
(c) explain the techniques of validation and verification, and describe validation tests which can be carried
out on data
(d) describe possible output formats such as graphs, reports, interactive presentations, sound, video,
images and animations stating the advantages and disadvantages of each format
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
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5. Syllabus content
(e) discuss the need for a variety of output formats according to the target audience
(f) describe knowledge based (expert) systems, how they are created and how they function
(g) explain the use of knowledge based (expert) systems as a diagnostic tool
1.9 Designing the user interface
Content
1.9.1 Interface design
Learning outcomes
Candidates should be able to:
(a) discuss the importance of good interface design
(b) discuss human computer interaction (HCI) design issues such as the use of colour, layout, and
content
(c) identify the required characteristics of a user interface with respect to information, type of user,
physical location and current technology
1.10 Logic gates
Content
1.10.1 Uses of logic gates to translate Boolean concepts into physical uses
Learning outcomes
Candidates should, within a context, be able to:
(a) understand the effects of logic gates AND, OR, NOT, NAND and NOR on binary signals in a processor
(b) calculate the outcome from a set of logic gates given the input
(c) understand how logic gates can be used within the processor as a form of refreshable memory and
as an accumulator
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
18
5. Syllabus content
Section 2: Practical programming techniques
This section provides candidates with an understanding of the techniques required for programming through
a study of the following topics:
• designing solutions to problems
• the structure of procedural programs
• data types and data structures
• common facilities of procedural programs
• writing maintainable programs
• testing and running a solution.
2.1 Designing solutions to problems
Content
2.1.1 Design of the input, output and interface
2.1.2 Use of structure diagrams to describe the modular nature of a solution
2.1.3 Use of program flowcharts and pseudocode to describe the steps of an algorithm
Learning outcomes
Candidates should be able to:
(a) discuss the importance of good interface design
(b) design and document data capture forms, screen layouts, report layouts or other forms of input and
output (e.g. sound) for a given problem
(c) explain the advantages of designing a solution to a problem by splitting it up into smaller problems
(top-down/modular design)
(d) produce and describe top-down/modular designs using appropriate techniques, including structure
diagrams, showing stepwise refinement
(e) produce algorithms to solve problems using both a program flowchart and pseudocode
(f) understand algorithms presented in the form of program flowcharts and pseudocode
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
19
5. Syllabus content
2.2 The structure of procedural programs
Content
2.2.1 Basic programming constructs/control structures
2.2.2 Use of subprograms/subroutines, including procedures and functions
2.2.3 Recursion
Learning outcomes
Candidates should be able to:
(a) define and correctly use the following terms as they apply to procedural programming: statement,
subroutine, procedure, function, parameter, loop
(b) identify the three basic programming constructs used to control the flow of execution: sequence,
selection and iteration
(c) understand and use selection in pseudocode and a procedural programming language, including the
use of IF statements and CASE/SELECT statements
(d) understand and use iteration in pseudocode and a procedural programming language, including the
use of count-controlled loops (FOR-NEXT loops) and condition-controlled loops (WHILE-ENDWHILE
and REPEAT-UNTIL loops)
(e) understand and use nested selection and nested iteration statements
(f) understand, create and use subroutines (procedures and functions), including the passing of
parameters and the appropriate use of the return value of functions
(g) use subroutines to modularise the solution to a problem
(h) identify and use recursion to solve problems; show an understanding of the structure of a recursive
subroutine, including the necessity of a stopping condition
(i) trace the execution of a recursive subroutine
(j) discuss the relative merits of iterative and recursive solutions to the same problem
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
20
5. Syllabus content
2.3 Data types and data structures
Content
2.3.1 Data types: integer, real, Boolean, character, string
2.3.2 Data structures: arrays (one and two dimensional), records
2.3.3 Storing, retrieving and searching for data in files
Learning outcomes
Candidates should, when writing a program in a procedural language, be able to:
(a) define and use different data types e.g. integer, real, Boolean, character and string
(b) define and use arrays (one- and two-dimensional) for solving simple problems (this should include
initialising arrays, reading data into arrays and performing a simple serial search on a one-dimensional
array)
(c) design and implement a record format
(d) estimate the size of a file from its structure and the number of records
(e) store, retrieve and search for data in files
(f) use the facilities of a procedural language to perform file operations (opening, reading, writing,
updating, inserting, appending and closing) on sequential files
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
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5. Syllabus content
2.4 Common facilities of procedural languages
Content
2.4.1 Assignment statements
2.4.2 Arithmetic, relational and Boolean operations
2.4.3 String manipulation
2.4.4 Input and output facilities
Learning outcomes
Using an appropriate procedural programming language, candidates should be able to:
(a) understand and use assignment statements
(b) understand arithmetic operators including operators for integer division (+, -, *, /, MOD and DIV) and
use these to construct expressions
(c) understand a range of relational operators, e.g. =, <, <=, >, >= and <> and use these to construct
expressions
(d) understand the Boolean operators AND, OR, and NOT and use these to construct expressions
(e) understand the effects of the precedence of standard operators and the use of parentheses to alter
the order of evaluation
(f) evaluate expressions containing arithmetic, relational and Boolean operators and parentheses
(g) understand and use a range of operators and built-in functions for string manipulation, including
location (LOCATE), extraction (LEFT, MID, RIGHT), comparison, concatenation, determining the length
of a string (LENGTH) and converting between characters and their ASCII code (ASCII and CHAR)
(h) understand that relational operations on alphanumeric strings depend on binary codes of the
characters
(i) input and validate data
(j) output data onto screen/file/printer, formatting the data for output as necessary
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
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5. Syllabus content
2.5 Writing maintainable programs
Content
2.5.1 Declaring and using variables and constants
2.5.2 Self-documented code, including identifiers, annotation and formatting
Learning outcomes
Using an appropriate procedural programming language, candidates should be able to:
(a) define, understand and use the following terms correctly as they apply to programming: variable,
constant, identifier, reserved word/keyword
(b) declare variables and constants, understanding the effect of scope and issues concerning the choice
of identifier (including the need to avoid reserved words/keywords)
(c) select and use meaningful identifier names
(d) initialise variables appropriately, before using them
(e) annotate the code with comments so that the logic of the solution can be followed
(f) use indentation and formatting to show clearly the control structures within the code
2.6 Testing and running a solution
Content
2.6.1 Types of programming errors
2.6.2 Testing strategies and test data
2.6.3 Debugging
2.6.4 Installation and execution
Learning outcomes
When developing software to solve a problem, candidates should be able to:
(a) describe types of errors in programs (syntax, logic and run-time errors) and understand how and when
these may be detected
(b) describe testing strategies including white box testing, black box testing, alpha testing, beta testing
and acceptance testing
(c) select suitable test data for a given problem, including normal, borderline and invalid data
(d) perform a dry run on a given algorithm, using a trace table
(e) describe the use of a range of debugging tools and facilities available in procedural programming
languages including translator diagnostics, break points, stepping, and variable check/watch
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
11
5. Syllabus content
Section 1: Computer systems, communications and software
This section provides candidates with an understanding of the following core aspects of computer systems:
• components of a computer system and modes of use
• system software
• data: their representation, structure and management
• hardware
• data transmission and networking.
The systems development life cycle is studied with reference to particular applications, so candidates are
expected to look at a range of different types of application areas. Although candidates are not expected to
have specific knowledge of every one of these, they should be able to make use of relevant examples for the purpose of illustration.
This section also provides candidates with understanding of the following aspects of computer systems:
• systems development life cycle
• choosing applications software for application areas
• handling of data in information systems
• implications of computer use.
1.1 Components of a computer system and modes of use
Content
1.1.1 Types of hardware
1.1.2 Types of software
Learning outcomes
Candidates should be able to:
(a) define the terms hardware, software, input device, storage device and output device
(b) describe the purpose of input devices, storage devices and output devices
(c) define the different types of software: operating system and generic/common applications software
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
12
5. Syllabus content
1.2 System software
Content
1.2.1 Operating systems
1.2.2 User interfaces 1.2.3 Utility software
Learning outcomes
Candidates should be able to:
(a) describe the purpose of operating systems
(b) describe the characteristics of different types of operating systems and their uses: batch, real-time,
single-user, multi-user, multi-tasking and network systems
(c) identify a range of applications requiring batch processing and a range of applications in which a real
time response is required
(d) describe different types of user interface: forms, menus, GUI, natural language and command line,
suggesting the characteristics of user interfaces which make them appropriate for use by different
types of user
(e) describe the purpose of a range of utility software e.g. disk formatting, file handling, hardware drivers,
file compression and virus checkers
1.3 Data: its representation, structure and management
Content
1.3.1 Data types
1.3.2 Data structures
1.3.3 Data management
Learning outcomes
Candidates should be able to:
(a) explain the use of codes to represent a character set (e.g. ASCII and Unicode)
(b) explain the representation of different data types: integer, Boolean, date/time, currency and character
(c) express positive integers in binary form
(d) understand the structure of arrays (one and two dimensional), including initialising arrays, reading data
into arrays and performing a simple serial search on an array
(e) describe the LIFO and FIFO features of stacks and queues
(f) explain how data is stored in files in the form of fixed length records comprising items in fields
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
13
5. Syllabus content
(g) define and explain the difference between serial, sequential, indexed sequential and random access
to data, using examples and stating their comparative advantages and disadvantages
(h) describe how serial, sequential and random organisation of files may be implemented using indexes
and hashing as appropriate
(i) select appropriate data types/data structures for a given problem and explain the advantages and
disadvantages of alternative choices
(j) explain the procedures involved in backing up data and archiving, including the difference between
data that is backed up and data that is archived
1.4 Hardware
Content
1.4.1 Processor components
1.4.2 Primary and secondary storage
1.4.3 Peripheral devices
Learning outcomes
Candidates should be able to:
(a) describe the function and purpose of the control unit, memory unit and arithmetic logic unit (ALU) as
individual parts of a processor
(b) explain the difference between types of primary memory and their uses (RAM, ROM)
(c) describe the basic features, advantages, disadvantages and use of secondary storage media
e.g. magnetic, optical and solid state
(d) describe use of buffers and interrupts in the transfer of data between peripheral devices and primary
memory
(e) describe a range of common peripheral devices in terms of their features, advantages, disadvantages
and uses
(f) relate the choice of peripheral device to a given application, justifying the choices made (g) understand the potential problem of speed mismatch between peripheral and processor
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
14
5. Syllabus content
1.5 Data transmission and networking
Content
1.5.1 Data transmission
1.5.2 Circuit switching and packet switching
1.5.3 Protocols
1.5.4 Networking
Learning outcomes
Candidates should be able to:
(a) describe the characteristics of a local area network (LAN) and a wide area network (WAN)
(b) show an understanding of the hardware and software needed for a local area network (LAN) and for
accessing a wide area network (WAN)
(c) describe the different types of data transmission: serial and parallel; simplex, half duplex and full
duplex modes
(d) explain the relationship between bit rates and the time sensitivity of the data
(e) recognise that errors can occur in data transmission; explain the use of parity checks, echoing and
check sums in detecting and correcting these errors, and the use of parity blocks to aid self checking
(f) explain the difference between packet switching and circuit switching
(g) define the term protocol
(h) describe the need for communication between devices, and between computers, and explain the
need for protocols to establish communication links (candidates will not be expected to have detailed
knowledge of specific protocols)
(i) explain the need for both physical and logical protocols and the need for layering in an interface (detail
regarding layers is not required)
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
15
5. Syllabus content
1.6 Systems development life cycle
Content
1.6.1 Identification of problem
1.6.2 Feasibility study
1.6.3 Information collection
1.6.4 Analysis of a problem, based upon information collected, including producing a requirements
specification
1.6.5 Design of system to fit requirements 1.6.6 Development and testing of system
1.6.7 Installation of system
1.6.8 Maintenance of system
1.6.9 Obsolescence
Learning outcomes
Candidates should, with reference to particular applications, be able to:
(a) explain the importance of defining a problem accurately
(b) describe the function and purpose of a feasibility study
(c) explain the importance of determining the information requirements of a system and describe
different methods of fact finding, highlighting the advantages and disadvantages of each method
(d) describe what is involved when analysing the requirements of a system, explaining the nature of the
requirements specification and its content, identifying inefficiencies/problems, user requirements and
hardware and software requirements
(e) design the data structures, inputs, outputs and processing using diagrammatic representations where
appropriate (including the use of dataflow diagrams (DFDs) and system flowcharts)
(f) explain the importance of evaluating the system against initial specifications
(g) explain the content and importance of documentation in the system life cycle, including the
requirements specification, design specification, program specification and documentation
(h) explain the importance of testing and installation planning, including the method of installation
(i) explain the reasons for maintaining the system
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
16
5. Syllabus content
1.7 Choosing appropriate applications software
Content
1.7.1 Custom written software versus off-the-shelf software packages
1.7.2 Applications software
Learning outcomes
Candidates should, within context, be able to:
(a) distinguish between custom-written software and off-the-shelf software packages, and discuss the
advantages and disadvantages of each in given situations
(b) identify the features of common applications found in business, commercial and industrial
applications, e.g. stock control, payroll, process control, point of sale systems
(c) identify suitable common generic applications software for particular application areas, e.g. word
processors, spreadsheets, desktop publishers (DTP), presentation software, drawing packages, and
justify the choices
(d) identify application areas for which generic applications software is not appropriate
(e) describe the purpose and impact of different types of generic applications software, e.g. word
processors, spreadsheets, desktop publishers (DTP), presentation software, drawing packages
1.8 Handling of data in information systems
Content
1.8.1 Data capture, preparation and data input
1.8.2 Validation and verification of data
1.8.3 Outputs from a system
1.8.4 Knowledge based systems
Learning outcomes
Candidates should, within a context, be able to:
(a) describe manual and automatic methods of capturing and inputting data into a system, including form
design, keyboard entry, barcodes, Optical Mark Recognition (OMR), magnetic stripe cards, Optical
Character Recognition (OCR), sensors and data logging, touch screens, chip and pin
(b) describe image capture by use of a scanner, video capture card and digital camera/camcorder
(c) explain the techniques of validation and verification, and describe validation tests which can be carried
out on data
(d) describe possible output formats such as graphs, reports, interactive presentations, sound, video,
images and animations stating the advantages and disadvantages of each format
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
17
5. Syllabus content
(e) discuss the need for a variety of output formats according to the target audience
(f) describe knowledge based (expert) systems, how they are created and how they function
(g) explain the use of knowledge based (expert) systems as a diagnostic tool
1.9 Designing the user interface
Content
1.9.1 Interface design
Learning outcomes
Candidates should be able to:
(a) discuss the importance of good interface design
(b) discuss human computer interaction (HCI) design issues such as the use of colour, layout, and
content
(c) identify the required characteristics of a user interface with respect to information, type of user,
physical location and current technology
1.10 Logic gates
Content
1.10.1 Uses of logic gates to translate Boolean concepts into physical uses
Learning outcomes
Candidates should, within a context, be able to:
(a) understand the effects of logic gates AND, OR, NOT, NAND and NOR on binary signals in a processor
(b) calculate the outcome from a set of logic gates given the input
(c) understand how logic gates can be used within the processor as a form of refreshable memory and
as an accumulator
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
18
5. Syllabus content
Section 2: Practical programming techniques
This section provides candidates with an understanding of the techniques required for programming through
a study of the following topics:
• designing solutions to problems
• the structure of procedural programs
• data types and data structures
• common facilities of procedural programs
• writing maintainable programs
• testing and running a solution.
2.1 Designing solutions to problems
Content
2.1.1 Design of the input, output and interface
2.1.2 Use of structure diagrams to describe the modular nature of a solution
2.1.3 Use of program flowcharts and pseudocode to describe the steps of an algorithm
Learning outcomes
Candidates should be able to:
(a) discuss the importance of good interface design
(b) design and document data capture forms, screen layouts, report layouts or other forms of input and
output (e.g. sound) for a given problem
(c) explain the advantages of designing a solution to a problem by splitting it up into smaller problems
(top-down/modular design)
(d) produce and describe top-down/modular designs using appropriate techniques, including structure
diagrams, showing stepwise refinement
(e) produce algorithms to solve problems using both a program flowchart and pseudocode
(f) understand algorithms presented in the form of program flowcharts and pseudocode
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
19
5. Syllabus content
2.2 The structure of procedural programs
Content
2.2.1 Basic programming constructs/control structures
2.2.2 Use of subprograms/subroutines, including procedures and functions
2.2.3 Recursion
Learning outcomes
Candidates should be able to:
(a) define and correctly use the following terms as they apply to procedural programming: statement,
subroutine, procedure, function, parameter, loop
(b) identify the three basic programming constructs used to control the flow of execution: sequence,
selection and iteration
(c) understand and use selection in pseudocode and a procedural programming language, including the
use of IF statements and CASE/SELECT statements
(d) understand and use iteration in pseudocode and a procedural programming language, including the
use of count-controlled loops (FOR-NEXT loops) and condition-controlled loops (WHILE-ENDWHILE
and REPEAT-UNTIL loops)
(e) understand and use nested selection and nested iteration statements
(f) understand, create and use subroutines (procedures and functions), including the passing of
parameters and the appropriate use of the return value of functions
(g) use subroutines to modularise the solution to a problem
(h) identify and use recursion to solve problems; show an understanding of the structure of a recursive
subroutine, including the necessity of a stopping condition
(i) trace the execution of a recursive subroutine
(j) discuss the relative merits of iterative and recursive solutions to the same problem
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
20
5. Syllabus content
2.3 Data types and data structures
Content
2.3.1 Data types: integer, real, Boolean, character, string
2.3.2 Data structures: arrays (one and two dimensional), records
2.3.3 Storing, retrieving and searching for data in files
Learning outcomes
Candidates should, when writing a program in a procedural language, be able to:
(a) define and use different data types e.g. integer, real, Boolean, character and string
(b) define and use arrays (one- and two-dimensional) for solving simple problems (this should include
initialising arrays, reading data into arrays and performing a simple serial search on a one-dimensional
array)
(c) design and implement a record format
(d) estimate the size of a file from its structure and the number of records
(e) store, retrieve and search for data in files
(f) use the facilities of a procedural language to perform file operations (opening, reading, writing,
updating, inserting, appending and closing) on sequential files
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
21
5. Syllabus content
2.4 Common facilities of procedural languages
Content
2.4.1 Assignment statements
2.4.2 Arithmetic, relational and Boolean operations
2.4.3 String manipulation
2.4.4 Input and output facilities
Learning outcomes
Using an appropriate procedural programming language, candidates should be able to:
(a) understand and use assignment statements
(b) understand arithmetic operators including operators for integer division (+, -, *, /, MOD and DIV) and
use these to construct expressions
(c) understand a range of relational operators, e.g. =, <, <=, >, >= and <> and use these to construct
expressions
(d) understand the Boolean operators AND, OR, and NOT and use these to construct expressions
(e) understand the effects of the precedence of standard operators and the use of parentheses to alter
the order of evaluation
(f) evaluate expressions containing arithmetic, relational and Boolean operators and parentheses
(g) understand and use a range of operators and built-in functions for string manipulation, including
location (LOCATE), extraction (LEFT, MID, RIGHT), comparison, concatenation, determining the length
of a string (LENGTH) and converting between characters and their ASCII code (ASCII and CHAR)
(h) understand that relational operations on alphanumeric strings depend on binary codes of the
characters
(i) input and validate data
(j) output data onto screen/file/printer, formatting the data for output as necessary
Cambridge International A & AS Level Computing 9691. Examination in June and November 2012.
22
5. Syllabus content
2.5 Writing maintainable programs
Content
2.5.1 Declaring and using variables and constants
2.5.2 Self-documented code, including identifiers, annotation and formatting
Learning outcomes
Using an appropriate procedural programming language, candidates should be able to:
(a) define, understand and use the following terms correctly as they apply to programming: variable,
constant, identifier, reserved word/keyword
(b) declare variables and constants, understanding the effect of scope and issues concerning the choice
of identifier (including the need to avoid reserved words/keywords)
(c) select and use meaningful identifier names
(d) initialise variables appropriately, before using them
(e) annotate the code with comments so that the logic of the solution can be followed
(f) use indentation and formatting to show clearly the control structures within the code
2.6 Testing and running a solution
Content
2.6.1 Types of programming errors
2.6.2 Testing strategies and test data
2.6.3 Debugging
2.6.4 Installation and execution
Learning outcomes
When developing software to solve a problem, candidates should be able to:
(a) describe types of errors in programs (syntax, logic and run-time errors) and understand how and when
these may be detected
(b) describe testing strategies including white box testing, black box testing, alpha testing, beta testing
and acceptance testing
(c) select suitable test data for a given problem, including normal, borderline and invalid data
(d) perform a dry run on a given algorithm, using a trace table
(e) describe the use of a range of debugging tools and facilities available in procedural programming
languages including translator diagnostics, break points, stepping, and variable check/watch
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