PRIFYSGOL BANGOR
BANGOR UNIVERSITY
PRIFYSGOL
BANGOR
UNIVERSITY
YSGOLORIAETH MYNEDIAD
ENTRANCE SCHOLARSHIP
2013
Cyfrifiadureg
Computing
Computing Scholarship 2013
Answer all questions
2 hours
Section A - Computer Architecture and Operating Systems
1. List four storage devices. [4]
2. How does programmed 10 work? [3]
3. What is the difference between physical and virtual memory? [3]
4. What is an ALU? [3]
5. Describe the fetch-execute cycle. [4]
Section B - Files and File Systems
1. List three text compression algorithms. Which of these usually provides the best
compression? [4]
2. Explain the term 'disk fragmentation'. [2]
3. What is meant by the term 'file extension' and what is its major purpose? [2]
4. Explain what is meant by a sequential file, and describe how records are added and how
records are deleted from a sequential file. Why is an indexed sequential file often used in
preference to a standard sequential file? [5]
5. Computer files can be encrypted. What is the purpose ofencryption and how does it
operate? [2]
6. Records within a file can befixed length or variable length. Describe the difference
between/Deed and variable length records. Give an advantage and disadvantage of
variable length records. [5]
Section C - The Internet, Networking and Security
1. Explain the meaning of the following terms: 'IP'; 'HTTP'; 'ISP'; 'internet'; 'intranet';
extranet'; 'portal'; 'website'; 'the cloud'. [9]
2. Routers are used in computer networks. Explain what is meant by the term router and
describe the function of a router in a computer network. [2]
3. What is search engine optimisation? What things can you do to a website in order to
improving the website's search engine ranking? [3]
4. Explain what is meant by circuit switching and packet switching in a computer network
and give two advantages of packet switching over circuit switching [3].
5. Security is very important in many areas of life, for instance in controlling staff access to
government buildings. Biometrics are often used to increase security in this situation.
Describe how iris scanning might be used in this situation and name one other type of
biometric. [4]
Section D - Data Representation and Computer Logic
1. Convert the binary number 1011 0111 into decimal. [2]
2. Convert the hexadecimal number BBC into decimal. [2]
3. What are the results of the following bitwise operations on 8-bit variables with no carry:
a.
15 OR 31
b.
15 AND 31
c.
NOT 15
d. 255XOR16[8]
4. Why was Unicode invented? [3]
5. Explain how the two's complement system canbe used to represent negative integer
values. Illustrate your answer with an example. [3]
Section E - Programming
1. Procedural programs are constructed using sequencing, iteration and selection. Explain
the meaning of these three terms.[6]
2. Describe two data structures with which you are familiar.[4]
3. Explain the terms below as they are used in object oriented programming:
•
Instance Variables
•
Classes
•
Methods
•
Inheritance [8]
4. Write some code in any programming language with which you are familiar to sum the
first fifty odd numbers (i.e. 1 + 3 + ...) and the first fifty even numbers (i.e. 2 + 4 + ...).
When these sums have been computed they should be displayed on the screen.
Indicate which programming language you have used. [6]
Ysgoloriaeth Gyfrifiadureg 2013
Atebwch bob cwestiwn
2 awr
Adran A - Saerniaeth a Systemau Gweithredu
Cyfrifiaduron
1. Rhestrwch bedwar dyfais storio. [4]
2. Sut mae 10 wedi ei raglennu'n gweithio? [3]
3. Beth yw' r gwahaniaeth rhwng cofffisegol a rhithgof? [3]
4. Beth yw ALU? [3]
5* Disgrifiwch ycylchred cywain-gweithredu. [4]
Adran B - Ffeiliau a Systemau Ffeiliau
1. Rhestrwch dri algorithm cywasgu testun. Pa un ohonynt sy'n cywasgu orau fel rheol? [4]
2. Eglurwch y term 'darnio disg'. [2]
3. Beth yw ystyr y term 'estyniad ffeil* a beth yw ei brifbwrpas? [2]
4. Eglurwch ystyr ffeil ddilyniannol) a dtsgofiwch sut caiffcomodion eu hychwanegu at
ffeil ddiJyniannol a sut cant eu dileuo ffeil ddilyniannol. Pamy defhyddir ffeil
ddilyniannol fynegedig yn ami yn lie ffeil ddilyniannol safonol? [5]
5. Gelliramgryptio ffeiliau cyfrifiaduroL Bethyw pwrpas amgryptio a sut mae'ngweithio?
[2]
6. Gallcofnodion mown ffeil fod o hyd sefydlog neu amrywiol. 0 D 0 Q Disgrifiwch y
gwahaniaeth rhwng cofhodion hyd sefydlog ac amrywioL CODD Nodwch un o
fanteision ac un o anfanteision cofnodion hyd amrywiol. [5]
•
-i
.
--i
Adran C - y Rhyngrwyd, Rhwydweithio a Diogelwch
1. Eglurwch ystyr y termau canlynol: 'IP'; 'HTTP'; 'ISP'; 'rhyngrwyd'; 'mewnrwyd';
'allrwyd'; 'porth'; 'gwefan'; 'y cwmwl'. [9]
2. Defhyddir llwybryddion mewn rhwydweithiau cyfrifiadurol. Eglurwch ystyr y term
'llwybrydd' a disgrifiwch swyddogaeth llwybrydd mewn rhwydwaith cyfrifiadurol. [2]
3. Beth yw optimeiddiaeth peiriant chwilio? Beth allwch ei wneud i wefan er mwyn gwella
ei safle mewn canlyniadau peiriant chwilio? [3]
4. Eglurwchystyr switsio cylcheda switsiopecynmewnrhwydwaith cyfrifiadurol a
nodwch dwy fantais sydd gan switsiopecyno gymharu a switsiocylched. [3]
5. Mae diogelwch yn bwysig iawn mewn amryw o feysydd bywyd, er enghraifft er mwyn
rheoli mynediad staff i adeiladau'r llywodraeth. Defhyddir biometreg yn gynyddol i wella
diogelwch mewn sefyllfaoedd felly. Disgrifiwch sut gellirdefhyddio'r dechneg o sganio
irisau mewn sefyllfaoedd felly ac enwch un math arall o fiometreg. [4]
Adran D - Cynrychioli Data a Rhesymeg Cyfrifiadurol
1. Troswch y rhif deuaidd 1011 0111 yn rhif degol. [2]
2. Troswch y rhif hecsadegol BBC yn rhif degol. [2]
3. Beth yw canlyniadau'r gweithrediadau bitwise canlynol ar newidynnau 8-did heb gar-rif:
15 0R31DD
a.
a
b.
15 AND 31
c.
NOT 15
d. 255XOR16[8]
4. Pam cafodd Unicode ei ddyfeisio? [3]
5. Eglurwch sut gellir demyddio system gyflenwad deuol i gynrychioli gwerthoedd
cyfanrifol negyddol. Rhowch enghraifft i gefhogi eich ateb. [3]
Adran E - Rhaglennu
1. Caiff rhaglenni trefhiadol eu hadeiladu trwy ddemyddio dilyniant, iteriad a dewis. D D
DD Eglurwch ystyr y tri therm hyn. [6]
2. Trafodwch ddau strwythurdata yr ydych yn gyfarwydd a hwy. [4]
3. Eglurwch y termau isod yng nghyd-destunrhaglennu gwrthrych-gyfeiriadol:
•
Newidynnau enydynol ('instance variables')
•
Dosbarthiadau
•
Dulliau
•
Etifeddiaeth [8]
4. Ysgrifennwch god mewn unrhyw iaith raglennu yr ydych yn gyfarwydd a hi i swm yr
hanner can odrif cyntaf (h.y. 1 + 3 + ...) a'r hanner can eilrif cyntaf(h.y. 2 + 4 + ...). • D
Pan fydd y symiau hyn wedi eu cyfrifo dylid eu harddangos ar y sgrin.
Nodwch yr iaith raglennu a ddemyddiwyd gennych. [6]