Another Semester Exam Session for Computer Science students

SECTION A

Outline how backups can prevent data loss
If we create backup regularly or periodically, any damaged data that occurred will be no problem. Because, once the data is damaged, we still have a copy of it and simply restore it. However, for large amount of data, manual backup seems too complicated, therefore additional several tools/software  may be required to do the backup process

Outline what happens in RAM when the Operating System starts an application
When OS starts an application, it begin to be loaded into memory, they are loaded in block sizes determined by the operating system. This means, in RAM, there will be part of the application stored there, ready to start.

Convert the decimal number 56 to binary
111000

Convert the binary number 01011100 to hexadecimal
5C

Outline two essential functions of a compiler
A compiler is responsible for translating a source code, which is written in a programming language, into a target language. This is most commonly done in order to create an executable program. A compiler is mainly used for programs that translate a source code into an assembly language or machine code, which are both a lower level language than the source code. A compiler can also be used to analyze the complex program that consist of hundreds module or even more.

Outline a software solution that can reduce the amount of time required to transmit data in a Wide Area Network
WAN Optimization
WAN Accelerator

Explain what a truncation error is, including an example of when it might occur
In numerical analysis and scientific computing, truncation error is the error made by truncating an infinite sum and approximating it by a finite sum. For instance, if we approximate the sine function by the first two non-zero term of its Taylor series, as in for small , the resulting error is a truncation error.
In programming, it normally happened in File Operation, when user needs to truncate the file and the operation has not succeeded, led to file corruption or damage.

Outline one advantage of creating a prototype before designing a computer system.
Prototype is built to understand the requirements
By using this prototype, the client can get an “actual feel” of the system, since the interactions with prototype can enable the client to better understand the requirements of the desired system
Users are actively involved in the development
Since in this methodology a working model of the system is provided, the users get a better understanding of the system being developed.
Errors can be detected much earlier.
Quicker user feedback is available leading to better solutions.
Missing functionality can be identified easily
Confusing or difficult functions can be identified
Requirements validation, Quick implementation of, incomplete, but functional, application.

An external hard-disk is considerably slower than an internal hard-disk. Explain two reasons that an external hard-disk is better than an internal hard-disk for making backup copies, despite the slower speed.
External hard disk is commonly portable, make it easier for user to carry it.
External hard disk is different device/system; if the user make backup in their own internal hard disk, once the device is broken, they also lost the backup

SECTION B

A computer game uses a lot of graphics and the CPU needs to spend time to process this data without continually being interrupted by input from the user. Because the user’s input is much slower than the computer’s processor, input is queued and retrieved when the CPU is ready.
(a) Describe 4 characteristics of data structures required to implement a queue:
(i) static data structure. [3 marks]
(ii) dynamic data structure. [3 marks]
(b) Explain one advantage of the implementation using (a) (i) over (a) (ii) and one advantage of using (a) (ii) over (a) (i). [4 marks]
(c) Concerning abut what kind of data that can be stored, distinguish between array and pointer. [5 marks]

Array (Static Data Structure)
Has a fixed allocation memory
It’s not possible to define additional storage during the process
If we don’t use all the storage, it can’t be used by other application
It consists of the same data type
Pointer (Dynamic Data Structure)
Unlimited allocation memory
The size depends on what we need
It can have different data type

Linked lists are really nice when it comes to inserting at random positions (as long as you have a pointer to the adequate list item). If your operation involves adding lots of elements dynamically and traversing all elements anyway, a list might be a good choice.

An array is very good when it comes to index accesses. If your application needs to access elements at specific positions very often, you should rather use an array.

An array will store the data, could be somewhere in memory’s computer
A pointer will store the memory address that store the data.

An electricity company is designing a form that will be posted to customers. The customers will be expected to read their own electricity meters and record the reading on the form before posting it back to the company. The forms that arrive at the customers’ homes already have the unique number of the electricity meter, the name of the customer and the address.
(a) Outline one advantage and one disadvantage of this type of data capture. [2 marks]
The forms are generated by computer and read back into the computer when the customer has completed and returned them.
(b) Outline a suitable method of generating the forms by computer and describe how the customer information can be retrieved when the forms are read back. You should include the input device needed to read the forms as well as any processing that may be needed. [6 marks]
The numerical reading that the customers will record on the form can have values between 0 and 99999. Automatic machines will be used to read these numbers from the form.
(c) State the most suitable method for recording this information on the form and describe how it works. [3 marks]
(d) Discuss why it is the most suitable method by comparing it with one other method of data capture. [4 marks]

The advantage: It’s universal. Even for customers that not familiar with computer can do this.
The disadvantage: If the form is missing, then it will become big problem, since the customer does not have any copy of it
Customers can take a picture using their smartphones and keep the file for later use.
The numbers will be automatically increased and if it connected using cable, an extra device can be used to retrieve the value
The last method is better, since the data can be captured and save in extra device and it’s possible from this device to send it to central database

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