Important questions Flashcards
Outline what is meant by a database management system.
Database management is an application software;
That allows users to define/create/maintain a database/provides (controlled) access to the data.
Examples of database applications are computerised library, flight reservation, etc.
Describe how data is transmitted by packet switching.
Packet switching involves data being separated into specially formatted units (packets);
Each packet contains data and information such as packet number, address that identifies the sending computer and the intended receiver.;
Packets are routed from source to destinations using (different) network switches and routers;
Using these addresses, network switches and routers determine how best to transfer the packet on the path of its destination ;
Packets are reassembled at the destination using packet numbers;
If any of packet is missing it should be retransmitted.
Distinguish between random access memory (RAM) and read only memory (ROM).
RAM acts as temporary storage of data, instructions and programs
currently running (for the operating system and for the running applications)
whilst ROM is permanent memory (stores the instructions and data that
won’t change/stores the instructions that the computer needs in order to
boot up;
Memory access, both read and write operations are performed on RAM
whilst ROM works with read only operation;
If power failures happened during access to RAM then all data will be
permanently lost/RAM is volatile memory/whilst if power failure happened
during the ROM access no data will be lost/ROM is non-volatile memory;
Outline the function of an operating system in managing primary memory.
OS (memory management unit) uses virtual memory which provides secondary memory (external storage) for program that does not have enough space in RAM for execution;
After execution of the program this memory is reallocated (used by other programs)/freed;
Explain the roles of the data bus and the address bus in the machine instruction cycle
Bus is defined as a system that transfers data between hardware
components/data bus and address bus enable a processor to communicate with
the primary memory;
When the computer processor needs to fetch an instruction from the memory it
uses the address bus to specify the (physical) address (of the memory block it
needs to access);
Outline the need for higher level languages.
Higher level languages are closer to human language;
So programmers find them easier to understand/work with than lower level languages;
HLL saves programmer from knowing details of computer architecture (and using
all the specific (machine) instructions);
So giving more time to creating/developing the best way of coding a
problem/process of coding is simpler and more understandable;
Explain two benefits of using sub-procedures within a computer program.
Problem could be divided into smaller/easier parts;
Which means solving easier/smaller parts of the problem for one programmer; Or for a team of programmers, each programmer could work on different smaller parts;
Simpler testing;
Each part of the program could be separately tested;
By the programmer who created the code or someone else in the team of programmers;
Reusable code;
Sub-procedures already written/tested could be used in various programs;
Simpler maintenance and changes;
Could be done only on required sub-programs;
Identify three characteristics of a collection.
Collections have a set of methods that define operations performed on the
elements/objects of that collection;
Such as adding/removing elements to/from collection, comparing elements of
collection, searching, etc;
Which reduces programming effort (because implementations of data structures
and algorithms are provided);
Which increases performance of the program (because efficient implementations
are provided);
Describe the purpose of the following hardware components of a network
(i) router
(ii) Network Interface Card (NIC)
(i )A network router is a hardware device that is connected to multiple channels for different networks;
through an interface that is situated on each network;
Router acts as a processing unit for information packets;
it duplicates information packets for use during transmission from one network to another;
The router uses a protocol or set of rules;
to determine which information packets are to be routed to certain interfaces within the network;
(ii) Network interface cards are used to connect each computer to the network; so they can communicate with the network router to receive information packets;
Interface cards determine the infrastructure of a local area network (LAN); and allow all of the computers to connect to the network;
Outline why protocols are necessary.
Protocols define the rules that govern network communication (for example, packet format, type and size, what happens when an error occurs, and which part of the network is supposed to handle the error and how);
Define the term data encryption.
Data encryption refers to calculations/algorithms that transform plain text into a form that is non-readable to unauthorized parties (authorized recipient of an encrypted text uses a key and the algorithm to decrypt the data/ to transform
it to the original plain text version);
Evaluate the use of trusted media access control (MAC) addresses as one method of network security.
Each (wireless network) adapter has a unique label called a MAC address;
Routers uses these addresses to identify/authenticate computers (routers include an option to whitelist or blacklist certain devices based on MAC addresses, so access could be restricted to any device which is not in the whitelist);
One disadvantage is that the whitelist should be amended any time a new device is purchased / when access to guests should be granted;
Also this method is useless against hackers who use programs which intercept data passing through network and report the MAC address of any device communicating on the network;
Define the term client
A client is a computer network that utilises the resources of other network computers including other clients.
Define the term Server
A server is a network computer that share resources with and responds to requests from other network computers , including other servers.
A school has a local area network (LAN) connecting its computers and peripheral devices.
The LAN also provides access to the internet.
(a) Describe the role of a router in this network.
controls the flow of data in the network;
inspects address of data packets;
directs to the appropriate network path/ selects a path between networks (by inspecting address of data packets);
securely transmits data packets (across that path toward the intended destination);
