Paper 1 Computer Science Revision Flashcards
Name one input device and one output device that might be part of Bertie Butler. For each
device give a reason for it being built into the virtual assistant.
Input Devices:
- Microphone to allow the device to hear spoken requests.
- Buttons to turn the device off or on / To mute
device/ to put device in privacy mode
Output Devices:
-Speaker to play the device’s responses
LEDs to indicate the device is on/listening
Screen to show visual information
Define the term ‘embedded operating system’.
System software/software used to manage the device which is built into the device itself, stored in the device’s ROM/cannot be changed specific to the hardware/purpose
Define the term ‘multicore processor’
more than one processing unit in a (single) processor which can independently process instructions at the same time.
The code uses direct addressing. Describe one other mode of addressing.
- Immediate addressing operand is the value to be used.
-Indirect Addressing operand is the memory location holding a value representing the memory location to be used.
-Indexed Addressing Operand is added to contents of Index Register to get memory location
of value needed.
Giving an example other than DVDs, describe what is meant by the term ‘optical media’.
One from read/written to, using a laser read/written onto a reflective surface data is stored using pits and lands
Example = Blu-Ray/CD
Give one advantage of films being distributed using optical media
Cheap to produce/buy Capacity big enough to hold film Robust enough to be used over long periods/ moved around Portable Does not need an internet connection
State the purpose of a device driver.
A program that enables communication between an operating system and a (hardware) device.
Explain the advantages and disadvantages of owning films that are streamed or downloaded
on demand rather than owning a physical copy.
Advantages
Can access film (and indeed entire library) from anywhere with an internet connection
No physical storage needed No risk of films being stolen/damaged/lost
Optical/disk player hardware not required to play film
Disadvantage
Reliant on having an (fast enough) internet connection.
Need enough storage for download − Reliant on servers of the company
providing the connection.
People like having a physical copy
If the company providing the stream goes out of business, copy is lost.
State the name of a data structure that could be used to store a single site’s details.
tuple / record / list
Define the term ‘utility’.
A program with one purpose/piece of system software used for the upkeep/maintenance of the system
State how an application differs from a utility.
Application performs tasks for the user (rather than computer). Performs generic (rather than specific)
tasks
Explain what is meant by Extreme Programming and why it is a suitable approach in this
case.
Extreme programming is a software development methodology Focus is on good quality code It is an agile paradigm it is designed to allow development to respond to changing user requirements. Involves paired programing Program is regularly reviewed/iterative process. Suited to this scenario Types of virus/threat is continually changing/updating − In order to detect virus effectively there needs to be an emphasis on code quality.
Explain why the programmers of anti-virus software may make use of virtual machines when
developing the updates.
Allows them to run the update on a
number of different systems/OSs without needing multiple physical
machines. They can put viruses on the VM to test
if the update can catch them
- …but protect the physical machine
from the virus/the VM can quickly be
reset to its original state.
Explain why a First Come First Served scheduling algorithm would not be suitable in this
situation.
FCFS means jobs are completed in the
order they arrive ineffective in catching viruses/the virus
may run first the virus checker may never run/take
a long time to start running the virus checker may be continuously running this will temporarily stall the system/
all other processes have to wait.
Describe what the effect would be of a computer having its BIOS overwritten.
The computer would not be able to boot/load the OS Or set up its initial configuration/hardware checks Making the computer unusable
Explain what is meant by referential integrity, giving an example which refers to the database
described above.
Ensuring that changes are consistent 3 across a database if a record is removed all references to
it are removed A foreign key value must have a corresponding Primary key value in another table. In this case, a user being removed will result in their reviews being removed/ a restaurant being removed will result in
its reviews being removed.
State what is meant by the term ‘server’.
A device which provides a central point of control/access
Explain why it is important that the review score that the user entered is also checked server-side.
Client side processing can be modified And can sometimes be disabled on the browser To prevent malicious code (such as an
SQL injection/XSS) To prevent a non validated review (one with a score of over 5) being sent to
the server
Describe what is meant by the term ‘Atomic’ in the context of ACID transactions. You should
refer to the example of a review being added.
A transaction/review can only fully complete or not complete / cannot partially complete In this case, it should not be possible
for the review to be added without the (average) rating being updated.
State what the letters CID refer to in ACID
Consistency - the total value of funds in both the accounts is the same at the start and end of each transaction.
Isolation - property of a database where no data should affect the other one and may occur concurrently
Durability - ensures that changes made to the database (transactions) that are successfully committed will survive permanently
Give an advantage and disadvantage of changing character sets from ASCII to Unicode UTF-32.
Advantage
More characters can be represented may include foreign alphabets may include emojis
Disadvantage
Reviews take up more storage (4 times their previous storage size).
Discuss the positive and negative impacts computers are having on the environment.
The materials and fuel used in producing and transport computers has an environmental impact digital devices have short life spans and are quickly disposed of they often end up in landfill or are sent to less economically developed countries to be dismantled due to the value of some of the materials inside them, devices made up of toxic materials like mercury these can harm people disposing of the waste and damage/pollute the area in which they are buried/burned
People have many digital devices, these all need charging this means there is an increase in demand for electricity, means an increase in fossil fuels being burned
Computers are being used to automate the use of things like central heating, this can reduce electricity consumption
Computers have encouraged a paperless approach both in the workplace and in terms of companies sending bills to homes this has potential to reduce deforestation
Developments in digital storage reduced the need for physical media to be produced reducing plastic use
Allowed people to work at home and communicate from afar this means they dont have to travel, reducing pollution
Can analyse data which can be used in improving efficiency - data mining
The web development company is looking to recruit a programmer to build websites.
Discuss the technologies the programmer would need to know and use and the importance of
each one.
HTML they understand how to write web pages
CSS they understand how to define the formatting of websites
JavaScript they understand how to write client side code allowing them to add interactivity to the website
Understanding of HTML/CSS and JavaScript is essential for the role. Without knowing
HTML it is impossible to handcode webpages.
Whilst WYSIWYG tools exist these often produce inefficient code and at any rate it will
be necessary at some point to hand tweak the code. (As the role is ‘programmer’ it is
reasonable to expect that the site will be coded.)
CSS is nearly as essential. Whilst HTML can be used for a lot of the formatting, this is
considered bad practice. CSS will allow them to make consistent looking sites.
JavaScript is also essential as most websites have an interactive element (e.g.
validation of forms)
Knowledge of Server-side processing/PHP/ASP etc…
…allowing them to write dynamic websites.
This is important if the company wants to produce websites with content that changes
Databases…
…allowing them to allow websites to store and retrieve data.
Some knowledge of databases will be useful if writing dynamic sites. This will largely
be focussed around SQL.
Photo editing…
…allowing them to prepare images for the website.
This is less essential as in many cases the assets will be pre-prepared. A basic knowledge, Knowledge of software engineering practices…
…allowing them to work as part of a team when building the website.
The importance of this will depend on the size of the team working on the site.
May mention more advanced technologies e.g. AJAX, SOAP, JSON etc.
State two features of the Von Neumann architecture.
(Single) Control Unit
(Single) Arithmetic Logic Unit
(Special) registers within CPU
Instructions and Data stored in same area of memory Instructions and Data stored in same format
A single set of buses / same bus for instructions &
data (to connect CPU to Memory and I/O)
