Computer Science Papers A1 2009 14 Reduced (1)

This document consists of 13 printed pages and 1 blank page.

UCLES 2010 [Turn over

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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Level

COMPUTING 9691/03

Paper 3 Written For Examination from 2011

SPECIMEN PAPER

2 hours

Candidates answer on the Question Paper.

No Additional Materials are required.

READ THESE INSTRUCTIONS FIRST

Write your Centre number, candidate number and name on all the work you hand in.

Write in dark blue or black pen.

You may use a soft pencil for any diagrams, graphs or rough working.

Do not use staples, paper clips, highlighters, glue or correction fluid.

Answer all questions.

No marks will be awarded for using brand names of software packages or hardware.

At the end of the examination, fasten all your work securely together.

The number of marks is given in brackets [ ] at the end of each question or part question.

M.Mushtaq Hussain

Contact the Teacher: 03215275281

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UCLES 2010 9691/03/SP/11 [Turn over

For

Examiner's

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2 (a) A bookshop contains a number of books. Each BOOK is about a single SUBJECT. There may be more than one BOOK about

each SUBJECT. A BOOK may have more than one AUTHOR and each AUTHOR may have written more than one BOOK.

Draw an entity relationship (ER) diagram to represent this data model in third normal

form and label the relationships. [7] (b) Using examples from this database, explain what is meant by: (i) a primary key,

[2]

(ii) a secondary key,

[2]

(iii) a foreign key.

[2]

M.Mushtaq Hussain


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3 (a) Explain why an interpreter may be preferred to a compiler as a translator when writing a high-level language program.

[5]

(b) Describe how the code is checked during the syntax analysis stage of compilation.

[3]

4 The contents of the Current Instruction Register (CIR) for one instruction are ADD 01011011 (Note: The ADD operation would normally be stored as a binary code.) (i) Explain what is meant by a mnemonic and why it is used.

[3]

M.Mushtaq Hussain


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UCLES 2010 9691/03/SP/11 [Turn over

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(ii) Describe how this address is used if it is an indirect address.

[2]

(iii) Describe how this address is used if it is an indexed address.

[2]

(iv) The address is actually an immediate operand which is to be added to the value

01011101 which is held in the accumulator. Carry out this addition, showing your working.

[3]

M.Mushtaq Hussain


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6 Describe how memory is managed in a typical computer system. Your answer should include an explanation of: (i) segmentation,

(ii) paging,

(iii) virtual memory.

(You are advised that diagrams may be helpful in your answers.) [9]

M.Mushtaq Hussain


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9 An import/export company is based in two offices in London and Lahore. Each office has an accounts department and a warehousing department. Each department has a network of computers. It is important that at each office the accounts and warehousing departments must be able to communicate. The London and Lahore offices must also be able to communicate electronically.

With reference to this example, explain the use of the following: (i) copper cabling,

[2]

(ii) wireless communication,

[2]

(iii) routers,

[2]

(iv) bridges,

[2]

M.Mushtaq Hussain


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UCLES 2010 9691/03/SP/11

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(v) modems.

[2]

M.Mushtaq Hussain


This document consists of 13 printed pages and 3 blank pages.

IB11 06_9691_31/2RP UCLES 2011 [Turn over

*7081239771*

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS

General Certificate of Education Advanced Level

COMPUTING 9691/31

Paper 3 May/June 2011

2 hours


No additional materials are required.

No calculators allowed.






DO NOT WRITE IN ANY BARCODES.


No marks will be awarded for using brand names for software packages or hardware.



M.Mushtaq Hussain


2

UCLES 2011 9691/31/M/J/11

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Examiner's

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1 Name three different types of bus in a processor and state what each is used for.

1

2

3

[6]

2 (a) Explain the relationship between assembly languages and machine code.

[2]

(b) Describe how an assembler produces machine code from assembly language.

[2]

M.Mushtaq Hussain


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UCLES 2011 9691/31/M/J/11 [Turn over

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(c) The address part of a low-level instruction can be the address of the data to be used. This is a direct address.

Describe the following types of addressing: (i) Indirect addressing;

[2]

(ii) Indexed addressing;

[2]

(iii) Relative addressing.

[2]

M.Mushtaq Hussain


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3 Discuss the different types of data transmission media. Include a comparison of data transfer rates and transmission ranges in your answer.

[8]

M.Mushtaq Hussain


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5 (a) Describe what is meant by the spooling of files.

[2]

(b) (i) State why files which are sent to a shared printer on a local network will be

spooled.

(ii) Explain how this spooling is carried out.

[5]

M.Mushtaq Hussain


7


For

Examiner's

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6 Describe the purpose of the following parts of a database management system (DBMS). (i) Data Description Language (DDL)

[2]

(ii) Data Manipulation Language (DML)

[3]

7 Part of the information stored in the data dictionary describes the type of data which is

being stored. A particular piece of data is 10010110. State what the data stands for if the data dictionary describes it as: (i) a two's complement binary number;

[1]

(ii) a sign and magnitude binary number;

[1]

(iii) a binary coded decimal number.

[2]

M.Mushtaq Hussain


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10 A country has a national football competition based on leagues. Each LEAGUE has a number of TEAMs but each TEAM is only in one LEAGUE. Each TEAM plays at a number of GROUNDs during the season and each GROUND will

host a number of TEAMs during the season. (i) State the relationship between LEAGUE and TEAM.

Draw the entity-relationship (E-R) diagram to show this relationship. [2]

(ii) State the relationship between TEAM and GROUND.

Draw the E-R diagram to show this relationship. [2] (iii) Explain how the relationship between TEAM and GROUND can be designed in

third normal form.

[4]

M.Mushtaq Hussain


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11 (a) Describe the differences between interpretation and compilation of a high-level language program.

[3]

(b) When a program is run the processor uses special purpose registers. Describe how the contents of each of the following registers changes during the

fetch-execute cycle: (i) Memory Address Register (MAR)

[2]

(ii) Memory Data Register (MDR)

[2]

M.Mushtaq Hussain


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12 A business uses the Internet to communicate with suppliers and to pay bills electronically. Discuss the problems of maintaining confidentiality of data on the Internet and techniques

that can be used to address these problems.

[6]

M.Mushtaq Hussain



GCE Advanced Level

MARK SCHEME for the May/June 2011 question paper

for the guidance of teachers

9691 COMPUTING

9691/31 Paper 3 (Written Paper), maximum raw mark 90

This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners meeting before marking began, which would have considered the acceptability of alternative answers.

Mark schemes must be read in conjunction with the question papers and the report on the examination.

Cambridge will not enter into discussions or correspondence in connection with these mark schemes. Cambridge is publishing the mark schemes for the May/June 2011 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.

M.Mushtaq Hussain


Mark Scheme: Teachers version Syllabus Paper

GCE A LEVEL May/June 2011 9691 31

University of Cambridge International Examinations 2011

1 e.g.-Data bus -to carry data from one location to another in processor // e.g. from MDR to CIR -Address bus -carries the address of a memory location // e.g. Address of location in memory from MAR -Control bus -Carries control signals around processor // to synchronise the operation of the processor components // by example: memory read/write completed // each line carries a different signal. Accept: system bus, memory bus, firewire, USB, PCI + explanation (2nd mark is dependent on correct bus name) (2 per -, max 6) [6]

2 (a) -One to one

-Mnemonics are used to represent operation codes -Labels are used to represent memory addresses -machine code is binary codes (only) -assembly code can not be executed // machine code can be executed -machine code and assembly language are both low level languages (machine specific) (1 per -, max 2) [2]

(b) -Labels added to a symbol table

-Labels are later looked up to determine the actual address / Assembler must allocate addresses to labels -Mnemonic looked up in opcode table to find operation code -Macro instructions used to stand for groups of instructions (1 per -, max 2) [2]

(c) (i) -Address in instruction is the address of the address of / pointer to the location...

-which contains the data to be used [2] (ii) -Address in the instruction has added to it

-the contents of the Index Register/IR [2] (iii) -Address in the Instruction is the displacement

-from the address of the first/current instruction -the value is added to the PC [2]

M.Mushtaq Hussain





3 -Coaxial cable -description/one transmission medium (copper) surrounded by insulation -Twisted pair -description/two conducting wires twisted around each other -Optic fibre -many fibres contained -description/fine glass strands carry light signals // optic fibre is very fragile -Interference free -Wireless communication -Radio signals -open to interception / latency / uses WEP keys for security -Infrared/Microwave -restricted by line of sight -transfer rate statement -range statement (1 per -, max 8) [8]

4 (a) -A system in which the output is produced quickly enough to affect the next input /current

process -a system that reacts fast enough to influence behaviour in the outside world [1]

(b) -A number of sensors stationed around apartment

-Temperature/humidity sensor sends temperature/humidity to processor -Use analogue to digital converter to convert the temperature/humidity measurements -Processor decides whether air conditioning system is in operation -(processor) compares measured temperature/humidity to required temperature/humidity -If necessary actuator is used to adjust settings/turn on cooling/heating/humidifier -Delay before next reading is taken from temperature/humidity sensor. // temperature readings are sampled // taking readings is repeated -Sensors on windows to warn if they are open during operation. (1 per -, max 4) [4]

(c) Any suitable real-time or pseudo-real-time application e.g.

-To play a racing game -So that the player can steer the car realistically -any reservation type system -to prevent double booking [2]

M.Mushtaq Hussain





5 (a) -Temporarily storing data for output later -several computers can send data to be printed at the same time -when queuing jobs sent to a single device (1 per -, max 2) [2]

(b) (i) -Jobs can be queued to ensure that none are missed

-Stops jobs being frozen/lost when printer unavailable -complete documents are printed

(ii) -print jobs are stored on secondary storage

-jobs can be given a print priority -jobs are maintained by a queue / priority queue data structure -data structure consists of reference data to each print job -When printer free, job with highest priority / at head of queue is printed -print files are sent from secondary storage to print buffer. (1 per -, max 4 per dotty, max 5) [5]

6 (i) -language to describe/alter table designs (NOT file)

-includes Identifiers/data type/relationships -any validation rules that the data must adhere to (1 per -, max 2) [2]

(ii) -designed to allow a user to query/retrieve data/sort the database

-insert / delete / update -data in the database / table(s) (1 per -, max 3) [3]

7 (i) 106 [1] (ii) 22 [1] (iii) 96 (1 per digit) [2]

M.Mushtaq Hussain





8 (a) (i) -A dynamic data structure changes size // A static data structure has the same size -dynamic data structure matches size to data requirements // static data structure takes no account of data requirements -dynamic data structure takes memory from heap as required -static data structure is predefined at compile time [2]

(ii) Advantage:

-Array is of fixed size which simplifies algorithms // or by example e.g. retrieval of data -Array controls the maximum size of the queue Disadvantage: -Queue held in an array cannot expand beyond the size of the array -If queue is small then memory space is wasted. [2]

(b) (i) Either:

Start FreeSpace

Start: 5 1 FRO 4 Start: 4 0 FRO 3

NFree: 6 2 TSI X NFree: 5 1 TSI X

3 DON 1 2 DON 0

4 ROS 2 3 ROS 1

5 BEV 3 4 BEV 2

6 5

Mark as follows ... -Start pointer + some value/arrows -All values included -Null pointer -Indication of free space Diagram in arrival order -in arrival order -with correct pointers OR Diagram in alphabetical order -with correct pointers OR Array diagram -in arrival order -correct pointers (1 per -, max 5) [5]

BEV DON FRO ROS TSI

M.Mushtaq Hussain





(ii) -Input NewItem -Store NewItem in next free space -Set Current to value at Start -Read values in list following pointers. -until Current value in list > NewItem -Pointer of Previous points to NewItem -NewItem points to Current -update free space list -Mention of any special cases e.g. NewItem being First in list // list empty // list full // no free space (1 per -, max 5) [5]

9 (a) -reverse Polish expressions can be processed directly from left to right

-Is free of ambiguities -does not require brackets -does not require use of rules of precedence (1 per -, max 2) [2]

+ _ * _ (b) e d d-e b c c c*(d-e) a a+b a+b a+b a+b (a+b)-c*(d-e)

Mark points: -at least two operators shown between transitions -a and b in first stage -a+b after first operator -e,d,c, (a+b) in stack in correct order -(d-e) -c*(d-e) -(a+b)-c*(d-e) (1 per -, max 6) [6]

10 (i) One to many [2] (ii) Many to many [2] (iii) -Link table needed...

-with primary key made up of combination of primary keys of TEAM and GROUND -Primary keys of TEAM and GROUND used as foreign keys in link table -This turns the many to many relationship into..// a many-to-many relationship can not be implemented -One-to-many and many-to-one/ 2x one-to-many relationships (1 per -, max 4) [4]

LEAGUE TEAM

TEAM GROUND

M.Mushtaq Hussain





11 (a) -Interpreter translates one instruction, runs it before going on to the next // Compiler translates all the instructions before run. -Compiler creates object code/executable file // Interpreter does not -Interpreter makes for easier debugging -Compiled programs will execute faster // interpreted code will execute slower -Interpreter must be present to run the program // compiler not needed at runtime -Interpreter will translate code in loops more than once // Compiler only once -once compiled no further translation needed // every program execution requires interpreter (1 per -, max 3) [3]

(b) (i) -Contents copied from PC -Contents changed to the operand/address part of CIR [2] (ii) -Instruction copied from memory/location to MDR when contents of MAR are from PC -Data copied from memory/location to MDR when instruction is LOAD -Data copied from ALU/Accumulator to MDR when instruction is STORE [max 2] 12 -Must safeguard against unauthorised access to the computer system

-Firewall used to restrict access to known sources -Control access to the network using accounts/user IDs with passwords // procedures in place for authentication -File contents can be encrypted -procedures in place to protect against malware -all payments/communication can be made through a secure connection -need to safeguard against bogus websites -Procedures in place for authorisation of resources -Users allocated access rights to various resources // users have access to certain files/folders only -Files can be password protected / read-only -users can access the network from certain terminals only / certain times of the day only -use of digital signatures (1 per -, max 6) [6]

M.Mushtaq Hussain


This document consists of 12 printed pages.


*2788786869*



COMPUTING 9691/31

Paper 3 October/November 2011

2 hours














M.Mushtaq Hussain


2

UCLES 2011 9691/31/O/N/11

For

Examiner's

Use

1 Describe the following components of a typical PC operating system and explain how they are used.

(a) File allocation table (FAT)

[3]

(b) Boot file

[3]

M.Mushtaq Hussain


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UCLES 2011 9691/31/O/N/11 [Turn over

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2 (a) Explain what is meant by Von Neumann architecture.

[3]

(b) Describe the use of the following special purpose registers and how they change

during the fetch-execute cycle. (i) Program Counter (PC)

[3]

(ii) Current Instruction Register (CIR)

[3]

M.Mushtaq Hussain


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3 (a) Convert the following denary numbers into 10-bit, sign and magnitude, binary numbers: (i) -390

(ii) -47

[3]

(b) Convert the following denary numbers into 8-bit, two's complement, binary numbers: (i) +93

[2]

(ii) - 69

[2]

M.Mushtaq Hussain


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For

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(c) (i) Using the binary values from part (a) work out (-390) + (- 47), giving your answer in sign and magnitude form using 10-bit binary. You must show your working.

[3]

(ii) Using the binary values from part (b), work out 93 - 69, giving your answer in two's

complement form using 8-bit binary. You must show your working.

[4]

M.Mushtaq Hussain


6

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4 A health ministry has decided that it would be useful for doctors in that country to communicate using an intranet.

Patient records could be shared and advice could be given by the doctors. (a) Describe what is meant by an intranet.

[3]

(b) Explain why an intranet was used rather than an open network like the World Wide

Web.

[5]

M.Mushtaq Hussain


9


For

Examiner's

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7 (a) Explain the difference between storing data in a flat file and in a relational database.

[2]

(b) Data about patients, doctors and treatments in a hospital are stored in a relational

database. Explain the advantages of using a relational database rather than a flat file to store the

hospital data.

[3]

(c) (i) Explain why access to the data in the database needs to be controlled.

(ii) Describe how this can be achieved.

[5]

M.Mushtaq Hussain


11


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9 (a) (i) Describe what happens during the lexical analysis phase of compilation.

[4]

(ii) Explain how syntax errors are identified during compilation.

[3]

(b) (i) Explain the value of using library routines when writing new programs.

[2]

(ii) Describe how linkers and loaders are used to make the use of library routines

possible.

[2]

M.Mushtaq Hussain



GCE A LEVEL October/November 2011 9691 31


1 (a) -disk space is organised into allocation units (clusters) -FAT is a map of which clusters are used to store which files // Individual sectors on the disk

are organised into clusters which are used to store the files -Details where files are stored on backing store -Acts as an index on the hard drive -Shows unused/unusable clusters (1 per -, max 3) [3] (b) -The boot file contains user-defined information... -to tailor the operating system // Contains parameters by which the system will operate -boot file stored on backing store/CMOSRAM... -read/written to by the boot program (held on ROM) (1 per -, max 3) [3] 2 (a) -Single processor/control unit -Sequential processing of program instructions -Instructions and data indistinguishable -Can be stored together in same memory unit -programs can be exchanged/reloaded easily to the same memory unit (1 per -, max 3) [3] (b) (i) -Contains the address of the next instruction to be fetched -Passes address to the MAR -and is then incremented -Contents altered to the operand of the instruction is a jump instruction (1 per -, max 3) [3] (ii) -Holds the current instruction... -divided into the op-code and operand -Holds the instruction while the op-code is decoded -Sends the address to the MAR. -Mark for mention of use of address to alter PC/need for other parts of instruction e.g.

addressing type used. (1 per -, max 3) [3]

M.Mushtaq Hussain





3 (a) (i) 390 = 1110000110 (ii) 47 = 1000101111 (1 for both sign bits and 1 each for the magnitude parts) [3] (b) (i) +93 = 01011101 [2] (ii) -69 = 10111011 [2] (in each case 1 mark per nybble) (c) (i) 1 1 1 0 0 0 0 1 1 0 1 0 0 0 1 0 1 1 1 1 1 1 1 0 1 1 0 1 0 1 1 1 1 =1 1 1 0 1 1 0 1 0 1 (1 for correct carries, 1 for correct answer (9 bits), 1 for correct msb) [3] f.t. (ii) 0 1 0 1 1 1 0 1 + 1 0 1 1 1 0 1 1 = 1 0 0 0 1 1 0 0 0 1 1 1 1 1 1 1 1 (1 for correct sum, 1 for correct answer (8 bits), 1 for correct carries, 1 for showing

ignoring ninth bit) [4] 4 (a) -networked communication system...// content provided by a web server -probably provided on the Internet -Restricted access... -to specific members authorised by the health ministry -Access is password controlled -Content is webpages / made available from a web server / viewed using browser software (1 per -, max 3) [3] (b) e.g.-Limited number of users speeds up access... -Information being communicated is sensitive/confidential... -needs protection from being seen by unauthorised people -Information on system will be relevant/easily updated -Less information makes it easier to navigate -easier to control who can access the content (1 per -, max 5) [5]

M.Mushtaq Hussain





5 (a) E.g. -Touch sensor/pressure sensor/infrared sensor / other sensible -Needed to tell robot when components arrive // To investigate orientation of component/ or

anything sensible E.g. -Actuator (electric motor/stepper motor/end effecter) of some sort -Needed to move robot arm // to physically interact with component // or anything sensible -(Speaker/LCD display) conditional on: -a description of error reporting (2 or 0 marks) (1 per -, max 4) [4] (b) e.g. -Cheaper, do not need to be paid -Work 24/7 -Do not require heat, light, space, ventilation, facilities -robots can work in hazardous environments -Items/actions produced are all to a consistent high standard // fewer errors -Reliable/workers can be off work/will never strike -Actions are more accurate than those of human. (1 per -, max 4) [4] (c) -May involve simply changing from one stored program to another -set new parameters for current program -edit program/writing new program code -by physically being moved through intermediate positions -which the system can then replicate (1 per -, max 3) [3] 6 -Interrupts have a priority -on receipt of an interrupt all interrupts of a lower priority are masked out/refused -Contents of registers are placed on stack -the appropriate interrupt service routine (ISR) is loaded and run -on completion of the ISR - values read from stack and loaded to registers -all interrupts are re-enabled -the interrupted process is resumed -Mention of use of vectored interrupt to point to code that needs to be run. (1 per -, max 6) [6]

M.Mushtaq Hussain





7 (a) -A flat file is a datafile with records of the same structure -A relational database consists of a number of tables that are linked -flat file may contain redundant/duplicated data [2] (b) -Reduces repetition/duplication of data items // keeps physical volume of data to a minimum

// minimises redundant data -Increases data integrity // reduces data inconsistency -(Simpler) data retrieval through queries // reports are easy to generate -Amending/searching/sorting data is easier -Amending the data structures (e.g. to include wards) is simpler to implement -Changes to the data structure will not affect existing applications programs // Program/data

independence (1 per -, max 3) [3] (c) (i),(ii) -Information on patients is sensitive -certain data needs to be restricted to certain users -avoid concurrent updates of the same record -Patient table can be encrypted -groups of users can be set up with the same privileges/access rights -Which are arranged in a hierarchy -access rights dictate what the user is allowed to see/do -Access rights relate to a table/ tables / fields/attributes /queries/reports -access rights may determine the HCI provided to the user. (1 per -, max 5) [5] 8 (a) (i) -Variable whose scope is restricted to a specific procedure/function/module/block (ii) -Variable whose scope exists across an entire program (iii) -procedure call passes the value of the parameter -local copy of data is used // discarded when procedure finished (iv) -pointer/address of the parameter/variable is passed -any changes are retained after returning to the calling code. [4] (b) -Return address is stored on stack (before control passed to procedure) -Values of parameters are placed on stack -Procedure will read same number of values from stack as parameters it was expecting -Address can be read from stack and placed in PC -Nested calls to procedures will be unwound in correct order -Problems if too many nested calls (unending recursive function) // stack overflow (1 per -, max 4) [4]

M.Mushtaq Hussain





9 (a) (i) -Strings of characters are grouped to form keywords/reserved words -Checks reserved words for validity -keywords/Reserved words/identifiers replaced by tokens -identifiers placed in symbol table -Unnecessary characters/comments/whitespace removed -final output is a token string (1 per -, max 4) [4] (ii) -the format of instruction/token string is compared - to forms for acceptable expressions and statements. - as defined by the meta language used -example of a syntax error e.g. IF THEN x=3 (1 per -, max 3) [3] (b) (i) Routines are: -Already written and can be inserted with a single command word/Saves time in writing

code -many projects require similar code e.g. sorting/searching -Already tested -Code is robust and reliable -should ensure consistency of standards -Already translated/Makes translation process faster/simpler (1 per -, max 2) [2] (ii) -Loader is used to load routine into memory when required -Ensures no memory conflicts between different routines -Linker links segments/files of code (to produce executable code). [2] 10 (a) (i) There can only be one before the letter (ii) X is not defined as a (iii) Only one is allowed after [3] (b) Mark Points: -Only one entry and one exit point used -Order correct (non-zero-digit, letter, digit) -Loop around letter to create group -Loop around digit to create two options one to include final digit, one to omit final digit (1 per -, max 4) [4]

letter non-zero-digit digit

variable-identifier

M.Mushtaq Hussain




*7117681918*



COMPUTING 9691/33

Paper 3 October/November 2011

2 hours














M.Mushtaq Hussain


2

UCLES 2011 9691/33/O/N/11

For

Examiner's

Use

1 (a) State what is meant by the boot (bootstrap) program.

[2]

(b) Explain how the boot program is used when a PC is turned on.

[4]

M.Mushtaq Hussain


3


For

Examiner's

Use

2 (a) Describe the use of the Memory Data Register (MDR). Explain how the contents change during the fetch-execute cycle.

[3]

(b) Name three types of bus that are used in a computer. For each one explain what it is

used for.

[6]

M.Mushtaq Hussain


4

UCLES 2011 9691/33/O/N/11

For

Examiner's

Use

3 (a) Convert the following denary numbers into 8-bit, sign and magnitude, binary numbers: (i) +39

(ii) - 47

[3]

(b) Convert the following denary numbers into 8-bit, two's complement, binary numbers: (i) - 3

[2]

(ii) - 47

[2]

M.Mushtaq Hussain


5


For

Examiner's

Use

(c) A particular computer uses a single 10-bit word to store a floating-point representation of a number.

The first 6 bits are used to store the mantissa and the remaining 4 bits are used to store the exponent.

(i) Explain why 000101 0100 = 21

2 using this notation.

[2]

(ii) Rewrite the binary value of this floating-point representation so that it is in

normalised form.

[2]

(iii) 011001 0011 is a normalised floating-point number. By converting each of the mantissa and the exponent into a denary number first,

write this number in denary.

[3]

M.Mushtaq Hussain


6

UCLES 2011 9691/33/O/N/11

For

Examiner's

Use

4 The health system in a country consists of a number of local surgeries. Individual doctors give medical assistance to people in the immediate area. In addition to this there are a number of main hospitals. Each hospital provides services which the doctors are unable to provide in their surgeries.

The main hospitals and the surgeries which they serve are linked by using an intranet. (a) Describe what is meant by an intranet.

[3]

(b) Explain the advantages and disadvantages of using an intranet rather than the Internet.

[5]

M.Mushtaq Hussain


8

UCLES 2011 9691/33/O/N/11

For

Examiner's

Use

6 (a) Describe the advantages of using a relational database to store data rather than a flat file.

[3]

(b) Data about guests in a hotel are stored in a relational database. One part of the database consists of a table of GUEST details. This is linked to a table ACCOUNT. Whenever a guest orders something in the hotel, the charge for that service is stored in the ACCOUNT table.

(i) State the primary key of the GUEST table, justifying your choice.

[2]

(ii) State a secondary key in the ACCOUNT table, justifying your choice.

[2]

(iii) State what is meant by a foreign key.

[1]

(iv) State a foreign key in the ACCOUNT table, justifying your choice.

[2]

M.Mushtaq Hussain


9


For

Examiner's

Use

7 (a) Explain how variables are managed during the different stages of compilation of a high-level language program.

[7]

(b) (i) Give two advantages of using a compiler rather than an interpreter to translate a

high-level language program.

[2]

(ii) Describe an advantage of using an interpreter rather than a compiler to translate a

high-level language program.

[2]

M.Mushtaq Hussain





1 (a) -A short sequence of machine code instructions -Stored in the ROM -available when the power is switched on -Used to load the operating system (1 per -, max 2) [2] (b) -Power-up process places address of first instruction in PC -Carries out the POST (power on self-test) -Uses the user-defined parameters in the boot file to configure the system -Mention of BIOS/autoexec.bat/config.sys -First instruction of OS is loaded into memory and address passed to PC (1 per -, max 4) [4] 2 (a) -during the fetch stage the contents of the address in the MAR is copied into the MDR -The contents of MDR is the instruction to be used (this is copied to the CIR) -during the execute stage (store instruction) the contents of the ACC is copied into the MDR -during the execute stage (load/add instruction) the contents of the memory location is

copied into the MDR (1 per -, max 3) [3] (b) -Data bus carries contents of a memory location/contents of a register/a data value/an

address/an instruction -Address bus carries an address of a memory location/device -the address bus carries an address from the processor to main memory/a device -Control bus - Separate wires each used to carry a control signal - the bus carries control signals to the various components - by example e.g. read operation completed // interrupt -Data bus is bi-directional // data bus used to read/write data // Address bus is uni-directional

// the control bus is bi-directional (mark as 3 2 per bus, max 6) [6]

M.Mushtaq Hussain





3 (a) (i) +39 = 00100111 (ii) 47 = 10101111 (1 for both sign bits and 1 for each magnitude part) [3] (b) (i) 3 = 1111 1101 [2] (ii) 47 = 1101 0001 [2] (in each case 1 mark per nybble) (c) (i) = (1/8 + 1/32) * 2^4 = 5/32 *16 = 2 OR: = 0.00101 * 2^4 Hence move point 4 places = 10.1 = 2 1/2 (1 mark for each underlined section, max 2. Note: Accept decimal values) [2] (ii) 010100 0010 (1 for mantissa, 1 for exponent) [2] (iii) M = + + 1/32 OR = 25/32 E = 3 Number is 25/32 * 8 = 6 (1 per line, max 3) [3] 4 (a) -networked communication system...// content provided by a web server -probably provided on the Internet -Restricted access... -to specific members authorised by the health system -Access is password controlled -Content viewed using browser software (1 per -, max 3) [3] (b) Advantages -Limited number of users speeds up access... -Information being communicated is sensitive/confidential... -needs protection from being seen by unauthorised people -Information on system will be relevant/easily updated -Less information makes it easier to navigate -easier to control who can access the content Disadvantages -may involve additional set-up costs // need to set up a LAN -extra administration // setting up users (& passwords)/access rights (1 per -, max 5) [5]

M.Mushtaq Hussain





5 (a) -Cost of creating the real thing == different braking units would need to be built -Time that would be needed to create the real thing == the parameters of the simulated

braking system can be changed immediately -Time taken to run the tests == test time can be greatly reduced -a wide variety of conditions need to be tested == e.g. it may be necessary to drive for

100000 miles/at different speeds, this could be simulated -Ability to change conditions immediately == e.g. not necessary to transport car to different

parts of the world -extreme case scenarios can be tested == conditions may never occur during real life testing (3 x 2 per advantage) [6] (b) -Speed -in order to simulate stopping distances -Weight of car and load -in order to simulate the effects of inertia with different loads -Materials used/size of structure used/methods of fixing to car -to try to reduce final cost while still remaining efficient -driving style -gentle braking/hard braking/cornering/reaction time -tyres -wear/type of tread/tyre material -road surface -roughness/material -weather conditions (temperature, wind, precipitation) -in order to replicate different climates (1 per -, max 5) [5] 6 (a) -Reduces repetition/duplication of data items // keeps physical volume of data to a minimum

// minimises redundant data -Increases data integrity // reduces data inconsistency -Simpler data retrieval through queries // reports are easy to generate -Amending/searching/sorting data is easier -Amending the data structures is simpler to implement -Changes to the data structure will not affect existing applications programs // Program/data

independence (1 per -, max 3) [3] (b) (i) -GuestID or similar -unique [2] (ii) -e.g. Type of charge (bar/restaurant/laundry/) -so that items can be accessed according to a different criteria other than by primary key

[2] (iii) -Attribute/field in one table which links to the primary key in another table [1] (iv) -GuestID -to link each account to the relevant guest // to link ACCOUNT and GUEST tables [2]

M.Mushtaq Hussain





7 (a) -during lexical analysis -identifiers and keywords are differentiated -checked against rules (e.g. length) for identifiers -Error messages produced if identifier does not match the expected rules -variable identifiers will be tokenised -variable identifiers entered into symbol table -Data type will be added to the entry in the symbol table -addresses in memory allocated to variables -during syntax/semantic analysis stage . -assignment of illegal types of data to variables is reported (1 per -, max 7) [7] (b) (i) -object code is difficult to interfere with -object code runs faster than interpreted source code -compiler can optimise executable code -the code is not translated each time the program is run -Compiler does not need to be present when the program is run -Compiled code will be free from syntax errors (1 per -, max 2) [2] (ii) -Errors are more easily located -reports errors when source code is present... -stopping at the point of the error -Parts (only) of program can be tested/testing can be started before all the program is

written -errors when found can be immediately corrected. (1 per -, max 2) [2] 8 Paging -memory is divided into equal-sized units called page frames -program/data file is divided into equal-size units called pages -one or more pages may be loaded into memory at any one time -Pages may be discontiguous -Pages swapped in and out as required -pages not in main memory are stored in virtual memory/backing store -page table/Index of pages/processes kept -absolute address is calculated by adding page address to relative address in instruction -paging is transparent to the programmer Segmentation -Memory is divided into variable length blocks -Programs can consist of many segments -Segments normally match natural divide in jobs/logical blocks -Index of segments stored which must -store base address and length of segment -programmer will organise code modules into segments (1 per -, max 4 per dotty, max 6) [6]

M.Mushtaq Hussain





9 (a) (i) -describes what is to be accomplished -not how (no algorithm written) -the user states what is to be found/set a goal -Consists of a set of facts and rules -Rules are applied to the data until the goal is reached -Mention of backtracking/instantiation (max 1) (ii) -Program describes how to solve the problem in a sequence of steps/algorithm -lends itself to top-down design/modularisation -using procedures/functions (max 1) [2] (b) (i) -A class is the blueprint from which objects are defined // a class consists of the

properties and methods that define each object -Plant/Tree/Bulb is a class [2] (ii) -One class can use the properties and methods from a parent/base/super class -Tree/Bulb inherits the properties and methods of Plant [2] (iii) -An object can only read/write a property value using methods of the class // Class

contains both properties and the methods to use it -e.g. The CountryOfOrigin property can only be output using the getCountryOfOrigin

method in the class Tree [2] 10 (a) (i) Must begin with at least one (ii) X is not defined as a (iii) A maximum of 2 digits is allowed at the end [3] (b) Mark Points: -Only one entry and one exit point used -Order correct (letter, non-zero-digit, digit) -Loop around letter -alternative path to omit number -alternative path to omit 2nd digit (1 per -, max 4) [4]

non-zero-digit

identity-code

letter digit

M.Mushtaq Hussain



IB12 06_9691_32/FP UCLES 2012 [Turn over

*6373916302*



COMPUTING 9691/32


2 hours














M.Mushtaq Hussain


2

UCLES 2012 9691/32/M/J/12

For

Examiner's

Use

1 A database is designed to store data about students at a college and the subjects that they study.

All students are based in a tutor group

A tutor supervises all the students in their tutor group

Each subject has one subject teacher only

Students study a number of subjects The following table StudentSubjects was a first attempt at the database design.

Table: StudentSubjects

StudentName TutorGroup Tutor Subject Level SubjectTeacher

Physics A SAN

Chemistry A MEB

Tom 6 SAN

Gen. Studies AS DIL

Geography AS ROG Joe 7 MEB

French AS HEN

Computing A VAR

Chemistry A MEB

Maths A COR

Samir 6 SAN

Gen. Studies A DIL

(a) (i) Explain why the table is not in First Normal Form (1NF).

[1]

(ii) Explain your answer by referring to the above data.

[1]

(b) The design is changed to the following: Student (StudentName, TutorGroup, Tutor) StudentSubjectChoices (StudentName, Subject, Level, SubjectTeacher)

M.Mushtaq Hussain


3


For

Examiner's

Use

Using the data given in the original table, show how this data is now stored in the revised table designs.

Table: Student

StudentName TutorGroup Tutor

Table: StudentSubjectChoices

StudentName Subject Level SubjectTeacher

[3] (c) (i) Explain what is meant by a primary key.

[2]

(ii) A student is not allowed to choose the same subject at A Level and AS. What is the primary key of table StudentSubjectChoices?

[1]

M.Mushtaq Hussain


4

UCLES 2012 9691/32/M/J/12

For

Examiner's

Use

(iii) There is a relationship between tables Student and StudentSubjectChoices.

Explain how the relationship is established using a primary key and foreign key.

[2]

(d) The design of table StudentSubjectChoices is:

StudentSubjectChoices (StudentName, Subject, Level, SubjectTeacher)

Explain why this table is not in Second Normal Form (2NF).

[2]

(e) The design of table Student is:

Student (StudentName, TutorGroup, Tutor)

Explain why this table is not in Third Normal Form (3NF).

[2]

M.Mushtaq Hussain


5


For

Examiner's

Use

2 A binary pattern can be used to represent different data used in a computer system. (a) Consider the binary pattern: 0101 0011 The pattern represents an integer. What number is this in denary?

[1]

(b) Consider the binary pattern: 0001 0101 0011 The pattern represents a Binary Coded Decimal (BCD) number. What number is this in denary?

[1]

(c) Consider the binary pattern: 1001 0010 This represents a twos complement integer. What number is this in denary?

[1]

M.Mushtaq Hussain


6

UCLES 2012 9691/32/M/J/12

For

Examiner's

Use

(d) Floating point is to be used to represent real numbers with:

8 bits for the mantissa, followed by

4 bits for the exponent

twos complement used for both the mantissa and the exponent (i) Consider the binary pattern:

0 1 1 0 1 0 0 0 0 1 0 0

What number is this in denary? Show your working.

[3]

(ii) The representation shown in part (d)(i) is normalised. Explain why floating point numbers are normalised.

[1]

(iii) Show the binary pattern for the smallest positive number which can be stored

using a normalised 12-bit floating point representation. Mantissa:

Exponent:

Work out its denary value.

Denary: [3]

M.Mushtaq Hussain


7


For

Examiner's

Use

(e) The developer of a new programming language decides that all real numbers will be stored using 20-bit normalised floating point representation. She cannot decide how many bits to use for the mantissa and how many for the exponent.

Explain the trade-off between using either a large number of bits for the mantissa, or a

large number of bits for the exponent.

[2]

M.Mushtaq Hussain


8

UCLES 2012 9691/32/M/J/12

For

Examiner's

Use

3 (a) Customer names are stored in the array Customer.

An algorithm is to be designed to perform a serial search of the array for a requested customer name.

The algorithm will use the variables shown in the table. Study the table and the algorithm and fill in the gaps.

Identifier Data Type Description

Customer ARRAY[2000] OF STRING The customer names

Index INTEGER Index position in the customer array

IsFound

SearchName STRING The requested customer name

//Serial search algorithm

INPUT

IsFound FALSE

Index 1

REPEAT

IF Customer [ ] = SearchName

THEN

IsFound TRUE

OUTPUT FOUND at position Index in the array

ELSE

Index

ENDIF

UNTIL (IsFound = TRUE) OR

IF

THEN

OUTPUT Customer name was NOT FOUND

ENDIF [7] (b) Comment on the efficiency of the serial search algorithm in part (a) for retrieving a data

item from an array with 2000 items.

[2]

M.Mushtaq Hussain


9


For

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(c) A binary search may be an alternative algorithm to a serial search. (i) Describe how this algorithm works. (Do not attempt to write the pseudocode.)

[4]

(ii) A binary search is made to locate Cherry.

1 Apple

2 Banana

3 Cherry

4 Kiwi

5 Lemon

6 Mango

7 Plum

List, in order, the comparisons which are made.

[3]

M.Mushtaq Hussain


12

UCLES 2012 9691/32/M/J/12

For

Examiner's

Use

5 The table shows the assembly language instructions for a processor which has one general purpose register the Accumulator.

Instruction

Op Code Operand Explanation

LDD Load using direct addressing

STO Store the contents of the Accumulator at the given address

LDI Load using indirect addressing

LDX Load using indexed addressing

INC Add 1 to the contents of the Accumulator

END End the program and return to the operating system

(a) Write on the diagram to explain the instruction shown. Show the contents of the Accumulator after the execution of the instruction.

LDD 105 Main memory

100 0100 0000

101 0110 1000

Accumulator 102 1111 1110

103 1111 1010

104 0101 1101

105 0001 0001

106 1010 1000

107 1100 0001

200 1001 1111

[2] (b) Write on the diagram to explain the instruction shown. Show the contents of the registers after the execution of the instruction.

LDX 101 Main memory

100 0100 0000

101 0110 1000

Accumulator 102 1111 1110

103 1111 1010

104 0101 1101

105 0001 0001

Index Register 106 1010 1000

0000 0011 107 1100 0001

200 1001 1111

[4]

M.Mushtaq Hussain


13


For

Examiner's

Use

(c) Trace this assembly language program using the trace table below.

500 LDD 507

501 INC

502 STO 509

503 LDD 508

504 INC

505 STO 510

506 END

507 22

508 170

509 0

510 0

Memory Address

Accumulator 507 508 509 510

22 170 0 0

[5] (d) Explain the relationship between assembly language instructions and machine code

instructions.

[1]

M.Mushtaq Hussain


14

UCLES 2012 9691/32/M/J/12

For

Examiner's

Use

6 In a multiprogramming environment the operating system includes a scheduler. (a) Explain the purpose of the scheduler.

[2]

(b) A process will at any time be in one of three states. (i) Name and describe each possible state.

1

2

3

[6]

(ii) How will the operating system keep details about the state of all processes?

[1]

M.Mushtaq Hussain





1 (a) (i) The table/each student has a repeated group of attributes // each student has a number of subjects [1]

(ii) StudentName, TutorGroup and Tutor would need to be repeated for each record [1] (b) Table: Student Table: StudentSubjectChoices

StudentName TutorGroup Tutor Student Name

Subject Level Subject Teacher

Tom 6 SAN Tom Physics A SAN

Joe 7 MEB Tom Chemistry A MEB

Samir 6 SAN Tom Gen Studies AS DIL

Joe Geography AS ROG

Joe French AS HEN

Samir Computing A VAR

Samir Chemistry A MEB

Samir Maths A COR

Samir Gen. Studies A DIL

Mark as follows .... Complete Student table [1] Repetition of StudentName in StudentSubjectchoices table [1] Complete columns 2, 3, and 4 [1]

(c) (i) primary key...

- an attribute/combination of attributes - chosen to ensure that the records in a table are unique // used to identify a record/tuple [2]

(ii) StudentName + Subject Correct Answer Only [1] (iii) - there is a one-to-many relationship // Student is the one side table

StudentSubjectChoices is the many side table. - The primary key (attribute StudentName) in Student - Links to StudentName in the StudentSubjectChoices table - (StudentName in the) StudentSubjectChoices table is the foreign key // StudentName is the foreign key that links the two tables [MAX 2]

(d) - There are non-key attributes ...

- SubjectTeacher ... - dependent only on part of the primary key (i.e. Subject) // partial dependency [MAX 2]

(e) - There are dependent non-key attributes // there are non-key dependencies

- TutorGroup is dependant on Tutor // Tutor is dependent on TutorGroup [2] [Total: 14] 2 (a) 83 [1] (b) 153 [1]

M.Mushtaq Hussain





(c) 110 [1] (d) (i) +13

mark as follows: Exponent: +4 // move the pattern four places Mantissa: +13/16 // 0.1101 Answer: 13/16 24 // or equivalent [3]

(ii) There will be a unique representation for a number

The format will ensure the number is represented with the greatest possible/more accuracy/precision Multiplication is performed more accurately/precisely [MAX 1]

(iii) Mantissa: 0100 0000

Exponent: 1000 Therefore number is * 28 // +1/512 // +29 // 0.00195 [3]

(e) choices made will effect range and accuracy

More bits used for the mantissa will result in better accuracy More bits use for the exponent will result in larger range of numbers [Max 2]

[Total: 12] 3 (a) Boolean [1]

Flags whether or not the requested customer name is found [1] SearchName [1]

Index [1]

Index + 1 [1]

Index = 2001 // Index >= 2001 // Index > 2000 [1]

IsFound = FALSE // NOT IsFound // Index = 2001 // Index > 2000 [1]

(b) - values are considered in sequence

- when an item is not found all items are considered - Few comparisons are needed if the value is near the start of the list // Many comparisons are needed/its time consuming if the value is near the end of the list - The average number of comparisons needed will be N/2 (or 1000 for this data set) [MAX 2]

(c) (i) The values must be in order Calculate the middle value and compare with the requested value If Requested value is less/greater discard the top/bottom list Repeat with a new list // compare with a new middle value Continue until value is found or list is empty [MAX 4]

(ii) Compare with ...

Kiwi Banana Cherry [3]

[Total: 16]

M.Mushtaq Hussain





4 (a) 21 [1]

(b) (i) a 5 b c + / [1]

(ii) 2 3 * 6 2 / + [2]

(c) Expressions can be evaluated without the use of brackets Operators are in execution order / No need to apply a precedence of operators [1]

(d) (i) Last item added to the stack will be the first item to leave [1]

(ii) Static structure The size of the array will be fixed / size will be defined before the array is used [2]

(iii)

5

4

3

2 7 6 9

1 3 3 21 or 21 27 27 3

1 1 1 1 [4]

[Total: 12]

5 (a) LDD 105 Main memory

100 0100 0000 101 0110 1011 Accumulator 102 1111 1110

0001 0001 103 1111 1010

104 0101 1101 105 0001 0001 106 1010 1000 107 1100 0001

200 1001 1111

Mark as follows: - Sensible annotation which makes clear 105 is the address used - Final value in Acc [2]

M.Mushtaq Hussain





(b) LDX 101 Main memory

100 0100 0000 101 0110 1011 Accumulator 102 1111 1110

0101 1101 103 1111 1010

104 0101 1101

105 0001 0001 Index Register 106 1010 1000

00000011 107 1100 0001

200 1001 1111

Mark as follows: - IR contents converted to 3 - Computed address of 101 + 3 = 104 // explanation: add contents of IR to address part of instruction - Then, direct addressing to 104 - Final value in Acc [MAX 4]

(c)

Memory Address

Accumulator 507 508 509 510

22 170 0 0

22

23

23

170

171

171

Mark as follows ... - 22 to Accumulator - Incremented to 23 - 23 copied to address 509 - 170 copied to Accumulator and incremented to 171 - 171 in address 510 [5]

(d) Every assembly language instruction is translated into exactly one machine code instruction /

there is a 1-to-1 relationship between them [1] [Total: 11]

M.Mushtaq Hussain





6 (a) Decide which process ... Gets next use of the processor (low level scheduler) // is next loaded into memory (high level scheduler) maximise system resources [2]

(b) (i) Running

The process currently has the use of the processor Runnable/Ready The process would like to use the processor but the processor is currently in use by another process Suspended/Blocked The process is not capable of using the processor / the process is currently occupied doing I/O [6]

(ii) Maintain a separate data structure for the processes in each state

one field of the Process Control Block will store the current state [1] (c) (i) Processor bound ...

The process does very little I/O // the process requires the processor most of the time 3D-graphics calculation // any plausible application I/O bound ... The process does lots of I/O // the process requires little processor time // any plausible application [4]

(ii) Priority to I/O bound processes

Otherwise they will not get a look in // processor bound jobs would monopolise the processor [2]

[Total: 15] 7 (a) a model/program of the real-world system is produced

to predict the likely behaviour of a real-world system [2] (b) Computer system suitable as ...

A computer program/system can be written/created which model the problem/application The problem can control the values of all the variables/parameters The computer can produce results very quickly // e.g. models what actually takes several days into 5 minutes processing The simulation removes any element of hazard/danger Some real-world problems are impossible to create It will be cost-effective to model the problem first [MAX 2]

M.Mushtaq Hussain





(c) Time taken to serve a customer Number of items in the customer basket Acceptable wait time in the queue Number of checkouts Time of day/day of the week Number of customers arriving Speed of the checkout operators Anything plausible ... [MAX 3]

(d) - Increase the average time taken to serve a customer

- will increase the average queue length Or anything plausible ... [2]

[Total: 9]

M.Mushtaq Hussain



IB13 06_9691_32/FP UCLES 2013 [Turn over

*3270941184*



COMPUTING 9691/32


2 hours














M.Mushtaq Hussain


2

UCLES 2013 9691/32/M/J/13

For

Examiner's

Use

1 A hospital has a number of doctors and a number of wards. A ward has a number of patients. A patient may be treated by more than one doctor and a doctor treats many patients.

Data is to be recorded in a relational database and the tables include DOCTOR and

PATIENT. (a) (i) What is the relationship between DOCTOR and PATIENT?

[1]

(ii) Show this relationship with an entity-relationship (E-R) diagram. [1] (iii) Draw an E-R diagram showing a database design which can be produced so that

the doctor and patient data are fully normalised. Explain how the relationships are implemented.

[4]

(b) (i) What is the relationship between WARD and PATIENT?

[1]

(ii) Show this relationship with an E-R diagram. [1]

M.Mushtaq Hussain


3


For

Examiner's

Use

(c) Two of the incomplete table designs are: PATIENT(PatientID, PatientName, Address, NextOfKin)

WARD(WardName, NurseInCharge, NumberOfBeds,

NumberOfOccupiedBeds, Specialism)

Explain how the relationship between PATIENT and WARD is implemented.

[2]

(d) The following Data Manipulation Language query is run. SELECT WardName

FROM WARD

WHERE NumberOfOccupiedBeds < NumberOfBeds

What useful information is produced for the Hospital Administrator?

[2]

M.Mushtaq Hussain


6

UCLES 2013 9691/32/M/J/13

For

Examiner's

Use

3 The table shows the assembly language instructions for a processor which has one general purpose register the Accumulator (ACC), and an index register (IX).

Instruction

Op Code Operand Explanation

LDD Direct addressing. Load the contents of the given address to ACC

STO Store the contents of ACC at the given address

LDI Indirect addressing. At the given address is the address to be used. Load the contents of this second address to ACC

LDX Indexed addressing. Form the address as +

the contents of IX. Copy the contents of this address to ACC

INC Add 1 to the contents of the register (ACC or IX)

ADD Add the contents of the given address to the contents of ACC

OUT Output the contents of ACC (as a denary number) to the monitor

IN Input a denary number from the keyboard and store in ACC

END End the program and return to the operating system

M.Mushtaq Hussain


7


For

Examiner's

Use

The diagram shows a program loaded in main memory starting at location 100. Two of the op-codes have been partially blanked out. Locations 200 onwards contain data which is used by the program. (a) The instruction at address 100 is fetched. Shown are the contents of the registers after

execution.

100 LD 202

101 INC ACC

ACC 102 INC ACC

88 103 LD 203

104 INC ACC

105 LDI 203

IX 106 INC ACC

2 107 END

200 38

201 205

202 88

203 200

204 48

205 126

Which mode of addressing was used by this load instruction at address 100?

[1]

(b) The instruction at address 103 is fetched. Shown are the contents of the registers after

execution.

ACC

126

IX

2

Which mode of addressing was used by this load instruction at address 103?

[1]

M.Mushtaq Hussain


8

UCLES 2013 9691/32/M/J/13

For

Examiner's

Use

(c) The instruction at address 105 is fetched and executed. Draw on the diagram to explain how this instruction is executed and show the contents

of ACC after execution.

100 LD 202

101 INC ACC

ACC 102 INC ACC

103 LD 203

104 INC ACC

105 LDI 203

IX 106 INC ACC

107 END

200 38

201 205

202 88

203 200

204 48

205 126

[2]

M.Mushtaq Hussain


9


For

Examiner's

Use

(d) Trace this assembly language program using the trace table below. The user inputs 19 followed by 37.

100 IN

101 INC ACC

102 STO 109

103 IN

104 INC ACC

105 ADD 109

106 STO 110

107 OUT

108 END

Memory location

ACC 109 110 Output

[5] (e) In (d) the program was shown in assembly language. In practice this must be machine

code in order to execute the program. Explain how the assembler software translates a program from assembly language into

machine code.

[3]

M.Mushtaq Hussain


15


For

Examiner's

Use

(b) The final stage of compilation is code optimisation. (i) Explain what is meant by code optimisation.

[2]

(ii) Give one practical example of code which would benefit from optimising.

[1]

6 A multiprogramming, multi-user operating system organises the available memory into two

fixed sized partitions.

Partition 1 size 30 Gb is used only for batch processing Partition 2 size 40 Gb is used only for interactive processing at a terminal

A program, once loaded, occupies the same memory locations until its execution is

complete. (a) Explain what is meant by: (i) Batch processing

[3]

(ii) Interactive processing

[1]

M.Mushtaq Hussain


16

UCLES 2013 9691/32/M/J/13

For

Examiner's

Use

(b) The diagram shows the current contents of main memory with a list of programs waiting to be scheduled.

OTHER

PROG8

PROG7

PROG6

PROG9

10 Gb

20 Gb

30 Gb

40 Gb

50 Gb

60 Gb

70 Gb

80 Gb

Partition 1

Partition 2

Currently waiting to be loaded are:

PROG16 (batch processing requiring 25 Gb) PROG17 (interactive processing requiring 8 Gb) PROG44 (interactive processing requiring 9 Gb) PROG45 (interactive processing requiring 8 Gb) PROG23 (batch processing requiring 15 Gb)

(i) If PROG6 completes execution, which programs (if any) can be loaded next?

[1]

(ii) If PROG8 completes execution, which programs (if any) can be loaded next?

[1]

(iii) Describe two variations on this use of partitions which may make more efficient

use of memory.

1

2

[2]

M.Mushtaq Hussain


17


For

Examiner's

Use

(c) 10 Gb of the main memory is labelled OTHER and will not be used for the execution of application programs.

Name two possible items of software this memory will be used for.

1

2 [2]

(d) Any program loaded is always in one of three possible states. One is the running state

meaning the job currently has use of the processor. Name and describe the two other states.

1

2

[4]

M.Mushtaq Hussain


18

UCLES 2013 9691/32/M/J/13

For

Examiner's

Use

7 (a) A user-defined function CountCharacter is defined, using pseudocode, as follows:

FUNCTION CountCharacter(ThisArray : CHAR, UBound : INTEGER,

ThisCharacter : CHAR) RETURNS INTEGER

The function checks each element in the array ThisArray with upper bound UBound. The function returns the number of times ThisCharacter appears in ThisArray.

If the function is incorrectly formed it will give a COMPILE ERROR.

The function is used with the three arrays shown below: Subscript/Index Identifier 1 2 3 4 5 6 7 8 9 10

City1 L O N D O N

City2 N E W Y O R K

City3 S T O C K H O L M

What is returned by the following function calls? (i) CountCharacter(City1, 6, O)

[1]

(ii) CountCharacter(City2, R, 8)

[1]

(iii) CountCharacter(City3, 9, t)

[1]

(iv) CountCharacter(City2, W)

[1]

M.Mushtaq Hussain


19


For

Examiner's

Use

(b) A programmer writes pseudocode to report whether or not a string value ThisValue is found in the string array ThisArray. This is designed as a function StringFound

which returns a Boolean value. (i) Show the function header for function StringFound.

[3]

(ii) Use the following numbers to label your function header above.

1. Function parameter(s) 2. Where the return data type is stated [2]

(iii) Write a single statement which calls the function StringFound to search for the

value LISBON in the array CapitalCities (upper bound 300). The function returns the value to variable CityWasFound in the calling statement.

[2]

M.Mushtaq Hussain


Mark Scheme Syllabus Paper


Cambridge International Examinations 2013

1 (a) (i) Many-to-many [1] (ii) E-R diagram

[1] (iii)

Link table drawn [1]

2 one-to-many relationships [1]

primary key in DOCTOR links to foreign key in link table [1] primary key in PATIENT links to foreign key in link table [1] No mention of foreign key scores max 1 for final two points

(b) (i) One to many [1]

(ii) E-R diagram

[1]

(c) The primary key of table WARD - WardName [1] Matches to WardName in the PATIENT table [1]

(d) Displays a list of the wards (names) [1] R. Number of wards Which has unoccupied beds available [1] R. the condition explained using the attribute identifiers

[Total: 12]

M.Mushtaq Hussain





3 (a) Direct addressing / LDD [1]

(b) Indexed addressing / LDX [1]

(c) Annotation to show 203 used as a forwarding address [1]

Accumulator contains 38 [1]

(d)

Memory location

ACC 109 110 Output

19 (must be the first column entry)

0

20 20

37

38

58 58 /ft 58 /ft

1 mark for each of the emboldened numbers in the correct column and sequence [MAX 5]

(e) Labels added to a (symbol) table // creates a list of addresses [1] Labels are later looked up to determine the actual address / Assembler must allocate addresses to labels [1] Mnemonic looked up to give binary code/machine code [1] Macro instructions are expanded into a group of instructions [1] The software makes two passes through the source program [1]

[MAX 3]

[Total: 12]

M.Mushtaq Hussain





5 (a) (i) The keyword table contains: all the language keywords/reserved words + with a matching token [1]

The symbol table stores:

each identifier/variable found (and its data type) [1] the values of all constants [1] the upper and lower bounds of arrays [1] [Mark as: 1 + 1]

[MAX 2]

(ii) Keywords are looked up in the keyword table [1]

Keywords are converted to tokens [1] Identifiers/Variables are looked up in the symbol table [1] Identifiers/variables are converted to actual addresses [1]

[MAX 2]

(iii) The white space // redundant characters are removed [1] Illegal identifier names are identified [1]

[MAX 1] (b) (i) Optimising

Code will execute/run/process faster [1] Code requires less memory Reduce the amount of code [1]

R. more efficient // removes redundant code

(ii) Any example where the code could be changed [1]

E.g. input of a list of number to compute the total (There would be no need to store the numbers first)

[Total: 8]

M.Mushtaq Hussain





6 (a) (i) Batch processing All input/processing/output is performed as a batch [1] There may be a time delay before processing [1] All the (data) is processed together/at the same time [1] There is no user involvement [1] Processing will not start until all the data is available/collected [1]

[MAX 3]

(ii) Interactive processing The user is constantly interacting directly with the processor [1]

(b) (i) PROG23 [1]

(ii) Any two from PROG17, PROG44 and 45 [1]

(iii) Jobs do not have to occupy a continuous block of memory [1]

Move all jobs still loaded in the partition so that when a job completes there is only ever one hole remaining [1] Make the partitions of variable size [1] Allow only part of a program to be initially loaded // paging //segmentation [1] [MAX 2]

(c) Operating system // specific modules e.g. interrupt handler/scheduler, etc [1]

device drivers [1] examples of system software or utilities [1] R. System software and Utilities [MAX 2]

(d) Runnable // Ready [1]

the program is capable of being run and is awaiting its turn for the use of the processor [1] R. explanation of (only) ready to use the processor Suspended // Blocked [1] the program is unable use the processor/ or by example, the job is currently using an I/O device [1] Note: the explanation marks are not dependant on the correct name

[Total: 14]

M.Mushtaq Hussain





7 (a) (i) 2 [1]

(ii) COMPILE ERROR // reporting an error [1]

(iii) 0 [1]

(iv) COMPILE ERROR // reporting an error [1]

(b) (i) FUNCTION StringFound(ThisArray : STRING , UBound : INTEGER, ThisValue : STRING) RETURNS BOOLEAN

Mark as follows: FUNCTION StringFound [1]

Array variable : STRING data type [1]

ThisValue : STRING // UBound : INTEGER [1]

(ii) Numbered 1 Parameter identifiers labelled [1]

Numbered 2 (RETURNS) BOOLEAN [1]

(iii) CityWasFound = StringFound(CapitalCities, 300, LISBON)

Mark as follows: CityWasFound = StringFound( ... [1]

LISBON is the correct position (f/t from their function header) [1]

[Total: 11]

M.Mushtaq Hussain





Question 8

(a) (i) Example [1]

(ii) two of the points explained ...

moveable mechanical device ... sense its surroundings ... ... clear example // temperature, etc. controlled by a program ... [MAX 2]

(b) Robotic arm [1] Explained in the context of their robot [1]

Sensor [1] Capture data [1] Actuator // Motor [1] To drive various motors to perform the robots movement [1] Microprocessor [1] To process the various inputs and execute the control program [1] Camera [1] To capture images [1] Memory [1] To temporarily store input data [1] Speaker [1] To provide audio output [1]

[MAX 4]

(c) real-time [1] [Total: 8]

M.Mushtaq Hussain




*5582893707*



COMPUTING 9691/33


2 hours














M.Mushtaq Hussain


Computer Science Papers A1 2009 14 Reduced (1)

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Transcript of Computer Science Papers A1 2009 14 Reduced (1)