U2: Fundamentals of Computer Science Flashcards
What is Hardware?
The physical components of a computer system.
Give some examples of hardware.
▪ Screens ▪ Keyboards ▪ Mice ▪ Printers ▪ Cabling ▪ Mobile devices ▪ Servers
What is an MFD?
Multi-functional devices are those that perform multiple functions.
Give examples of MFDs.
▪ Printers - often combine the functions: printing, scanning, faxing and photocopying
▪ Smartphones - combine the functions of a: phone, camera, computer, touchscreen, etc.
What are PCs?
A personal computer is a general-purpose computing device that is small and cheap enough to be used by individuals. The term personal computer usually refers to desktops and laptops.
What is a general-purpose computer?
Devices capable of performing the most common computing tasks.
What are the professional uses of PCs?
They are used for anything useful to the organization, which normally requires the use of software programs such as word processors, spreadsheets, databases, programming environments, and other software applications.
What are the features of Desktop PCs?
▪ Not portable so are usually left in one place.
▪ Cabled connection to a network.
What are the features of Laptop PCs?
▪ Portable
▪ Moved within a wireless, WIFI network.
▪ Uses for individuals who want flexibility
What is the motherboard and what does it do?
The motherboard is the main circuit board that connects the attached components and allows them to communicate with one another. These components include; the CPU, RAM, Secondary storage and external components such as; the keyboard, mouse, monitor, printer, network.
What is the CPU?
The central processing unit (CPU) is a chip that plugs into a compatible socket in the motherboard. This components processes code, by working out any calculations, logical operations or relational comparisons.
What is RAM?
Random access memory (RAM) stores files and software that is in use.
What type of RAM is used in PCs?
DDR RAM
What is secondary storage and how is it connected to the motherboard in a PC?
Secondary storage is where files and software are stored when they are not in use. It is connected to the motherboard via a cable.
What storage types are used in secondary storage for PCs?
The most commonly used type of storage is HDD. However, SSD storage is becoming more popular.
What are expansion slots for in a PC?
Expansion slots are used to connect expansion cards, such as graphics cards to the motherboard.
What is an expansion card?
Expansion cards are cards that allow the user to add additional, specialist capabilities to the PC.
What are graphics cards and what are they used for?
Graphics cards contain a GPU and VRAM, used to perform tasks involved in rendering graphics. They are used for rendering video games and for aiding in the production of digital art.
What are Mobile devices?
Mobile devices are MFDs that can consist of a computer, camera and, in some cases, phones.
What are the main features of mobile devices?
▪ Compact
▪ Light-weight
▪ Long battery life
▪ Wireless connection to the internet
Give some examples of Mobile Devices.
▪ Smartphones
▪ Smartwatches
▪ Tablets
▪ Mobile Phone
Modern Mobile devices
Recently there has been a lot of development in mobile devices and recent mobile devices are almost as powerful as PCs, have good internet connection and a long battery life.
What is the name of the integrated circuit which holds the main internal components of a mobile device?
System-on-a-Chip
What is the SoC?
The SoC is a circuit that holds a mobile devices CPU, GPU, Storage, Memory and other important components.
What are the disadvantages of the SoC?
▪ No parts are replaceable
▪ no individual components can be upgraded
What are the advantages of the SoC?
▪ Saves space and allows the device to be smaller
▪ the size allows a larger battery to be used
▪ Efficient
▪ Produces less heat so a fan is not needed.
▪ Reduces power consumption
What type of memory and storage does the SoC use?
▪ LPDDR RAM - uses less power than normal DDR RAM.
▪ Flash memory as storage - less power consumption.
What CPU architecture does the SoC use?
ARM Architecture.
What advantage do desktop PC components have over mobile and laptop PC components?
Desktop PC components are removable, so they can be replaced and upgraded when necessary or when the user desires to.
What is a server?
Servers are computers that run a network operating system, and allow users access by login on workstations (or client computers).
Give some examples of types of servers and what they do.
▪ Web servers: Hosts web pages & associated files
▪ Mail Servers: Sends & Receives emails
▪ File Servers: Stores & manages users access to files & folders on a network
▪ Print Servers: Manages & provides access to printers on a network
What is the difference between PC and Server CPUs?
Server CPUs have :
▪ More cache
▪ (sometimes) more cores, which they can make more efficient use of.
What do severs use for main memory?
DDR RAM and, more likely also, ECC.
What is ECC?
Error correcting code: designed to correct error that might appear in volatile memory.
Why is ECC used in servers used in servers and not PCs?
The volatile memory in servers in often considered to be more important.
What type of storage do servers use?
Mainly HDD due to the large storage requirements but SSD can be used for boot drives.
However, the HDD storage in servers in not the same as that used in PCs.
Why do server HDDs have to be different to PC HDDs?
Normal HDDs have moving parts, when they are tacked in servers this causes a large amount of vibration. This can lead to dgamage so server HDDs are made with more protection.
What type of GPU do servers usually have?
Servers don’t usually have any graphics card or integrated GPU in the motherboard as servers are not usually used for graphically intensive tasks.
What are the main features of server internal components?
▪ expensive for similar speed & capacity
▪ Greater quality checks
▪ Better error prevention
▪ Greater energy efficiency
What type of GPU do servers usually have?
Servers don’t usually have any graphics card or integrated GPU in the motherboard as servers are not usually used for graphically intensive tasks.
What are the main features of server internal components?
▪ expensive for similar speed & capacity
▪ Greater quality checks
▪ Better error prevention
▪ Greater energy efficiency
What is the CPU?
The CPU is a processor that executes instructions, logical and arithmetic operations.
What are the main factors that affect CPU performance?
▪ Number of Cores
▪ Clock Speed
▪ Cache Size
What is the Number of Cores and how does it affect CPU performance?
How many instructions can be processed simultaneously. A higher number will increase performance as processing speed increases.
What is the Clock Speed and how does it affect CPU performance?
How many cycles can be executed per second or instructions per second. 1GHz = 1 billion instructions per second. High clock speed improves execution speed.
What is the Cache size and how does it affect CPU performance?
Cache is high speed memory that stores frequently used data and instructions for the CPU to process.
What other feature must be considered when choosing a CPU?
Sockets. The sockets in the motherboard must match the CPU.
What is main memory in a computer?
RAM
Is RAM volatile? What does it mean?
RAM is volatile memory.
This means that when the computer is turned off, the contents are deleted
What factors affect the performance of RAM and which is the list important?
▪ Memory Size - most important
▪ Memory Speed
▪ Compatability with motherboard
How does memory size affect the performance of RAM?
All active files and software is copied into RAM which requires a large amount of memory. If RAM isnt large enough, virtual memory will be used which is alot slower, so the devices performance would be slower.
How does memory speed affect the performance of RAM?
RAM speed is a combination of clock speed (cycles per second) and timings (number of cycles need to perform a task).
Higher RAM speed will produce a better performing system.
How does compatability affect the performance of RAM?
If a motherboard has slots for DDR4 RAM but you want to implement DDR3, the system will not be able to function.
What are the two major components contained within a graphics card?
▪ GPU (Graphics processing unit)
▪ VRAM (Video RAM)
What is the advantage of installing a graphics card?
The GPU & VRAM reduce the load on the CPU and RAM. They are also specialised to perform graphics processing more efficiently than the CPU.
What factors affect the performance of graphics cards?
► GPU Cores/Clock Speed: GPUs have thousands of cores as graphics processing involves performing many similar operations simultaneously. Clock speed will be slower than that of the CPU, but it us still important for performance.
► VRAM Size/Clock Speed: VRAM is used to store data the GPU will need to render images, such as textures & the frame buffer. It will often be a similar size to RAM but it will be specialised for graphics processing tasks and tends to have a higher clock speed.
How is the graphic card connected to the motherboard?
Graphics cards are connected using a PCI Express expansion slot.
There are different types of PCI Express slots, but they are backwards compatible, so you’ll still be able to connect your modern graphics card in an older slot (albeit with a hit on performance).
What is an input device?
A device that allows users to enter information into the computer. This can be as data or instructions.
Give some examples of input devices:
▪ Keyboard ▪ Mouse ▪ Microphone ▪ Webcam ▪ Scanner ▪ Graphics tablet ▪ Sensor
How do keyboards allow user input?
Keyboards have keys that allow users to input data or instructions.
What affects the performance of keyboards?
▪ Sensitivity - more expensive gaming keyboards use mechanical keys, rather than a membrane, which allows for greater sensitivity to touch. They’re also more durable to extensive use.
How do mice allow user input?
Mice are pointing devices that allow the user to select options from the GUI.
What affects the performance of mice?
▪ Sensitivity (measured in dots per inch (DPI)). A higher DPI will detect smaller movements and many expensive mice will allow you to alter the DPI for different situations.
How do microphones allow user input?
Microphones allow sound transmission over the internet. They also allow users to give voice commands to the computer/device.
What affects the performance of microphones?
▪ Sound quality - This is mostly measured by the sample rate and bit depth of the microphone.
How do webcams allow user input?
Webcams are video cameras that allow the transmission of moving images through an internet connection. This can be combined with microphones to allow users to communicate with another.
What affects the performance of webcams?
▪ Resolution
▪ Colour depth - how many colours can be represented
How do scanners allow user input?
Scanners allow physical documents to be converted into digital data so that they can be viewed and edited on a computer. This is done by shining light on the document which reflects onto a CCD array.
What affects the performance of Scanners?
▪ Resolution
▪ Colour Depth
How do graphics tablets allow user input?
The stylus is used to enter data. It is commonly used to produce illustrations.
What affects the performance of graphics tablets?
▪ Resolution
▪ Pressure Sensitivity - this allows a greater range of pressure to be detected from light to heavy touch.
How do Sensors allow input?
Sensor take environmental readings such as temperature, light and motion.
What affects the performance of sensors?
the factors that affect the performance of sensors depends on the type of sensor.
What is an output device?
A device that sends data from a digital device to a user or other device.
Give some examples of output devices:
▪ Monitor
▪ Printer
▪ Speakers
▪ Actuator
How do monitors allow output?
Monitors produce a visual display of a GUI.
What affects the performance of monitors?
▪ Resolution
▪ Refresh Rate
What is Resolution?
The Number of Pixels that make up an image.
What is refresh rate?
Number of images per second
How do printers allow outputs?
Printers produce physical copies of images and documents.
What affects the performance of printers?
▪ Print Speed
▪ Horizontal Resolution
How do speakers allow outputs?
Printers produce audio output by converting digital audio signals from a computer into analogue signals. They are often used to listen to music.
What affects the performance of speakers?
▪ Output wattage - has a big impact on volume.
How do actuators allow output?
They control and produce motion, usually in sensors.
What affect the performance of actuators?
▪ Torque - The amount of force it can produce.
What units are used to measure resolution?
Lines per inch
What units are used to measure refresh rate?
Hertz
What is an input/output device?
A device that can produce both inputs and outputs.
Give some examples of input//output devices:
▪ USB
▪ Joystick
How do USBs allow both inputs and outputs?
USBs can be used for input devices such as keyboards & mice, but they can also be used for output devices such as printers, flash drivers & external hard disks.
How do joysticks allow both inputs and outputs?
Thy are generally input devices that allow users to control an aspect of a video game. However, some of these devices also produce haptic feedback.
What is haptic feedback?
Haptic feedback is a type of output. It is a tactile sensation that users feel in their hands in response to something happening in the software.
What type of storage are HDDs used for?
▪ Primary Storage
▪ External portable Storage
How do HDDs work?
HDDs area form of magnetic storage. It consists of a number of magnetic plates that become magnetised or demagnetised in certain places to represent (1s or 0s) the data.
What are the advantages of using HDDs?
▪ High capacity for a low cost
▪ Reliable - with long life span
What are the disadvantages of HDDs?
▪ Slow read/rite speeds
▪ Contain moving parts - this is risky in portable devices
▪ Large compared to SSDs - cant be used in laptops or mobile devices.
What type of storage are SSDs used for?
▪ Primary Storage
▪ Flash Memory
How do SSDs work?
They store data using semiconductor chips. The chips can be turned on and off, 1 being on and 0 being off.
What are the advantages of SSDs?
▪ Fast read/write speeds
▪ Low power consumption
▪ No moving parts - reliable even when used as portable devices
What are the disadvantages of SSDs?
▪ Expensive, compared to HDDs, for the same amount of storage.
▪ Finite number of writes
What are the other forms of flash memory?
▪ SD cards
▪ USB flash drives
Designed as portable devices (Light-weight, Small)
Give some examples of optical disk drive devices and their uses:
▪ CD - Music
▪ DVD & Blu-Ray - films, tv, software
How do optical disk drives work?
A laser marks the disk in a pattern which is read by sending light to bounce off the disk. This light is then read back differently depending on weather it hit a pit or a land.
Pit - Marked area (binary 0)
Land - Un-Marked area (binary 1)
What are the advantages of optical disk drives?
▪ Cheap
▪ Small
▪ Portable
What are the disadvantages of optical disk drives?
▪ Small capacity
▪ Easily damaged
▪ Finite number of writes.
What is RAID?
Redundant Array of Independent Disks is a technology used to store data in multiple locations across separate disks. It has redundancy to protect data nd improve performance.
What is disk striping?
Dividing data into multiple blocks and sharing them across multiple disks.
What are the advantages of disk striping?
It improves performance as you can read & write simultaneously s each disk can perform different operations at the same time.
What is disk Mirroring?
Duplicating data across multiple disks, creating a redundant copy in case of failure so no data is lost.
What is RAID Level 0? What is its tolerance? and how many drives does it have?
▪ Features: Block level striping to spread read/writes across the drives, making a fast system.
▪ Tolerance: None
▪ No of Drives: 2+
What is RAID Level 1? What is its tolerance? and how many drives does it have?
▪ Features: Mirroring to create identical copies on other drives.
▪ Tolerance: All but one can fail
▪ No of Drives: 2+
What is RAID Level 2? What is its tolerance? and how many drives does it have?
▪ Features: Bit level striping with hamming code error correction to enable rebuilding data with spread read/writes.
▪ Tolerance: One drive failure
▪ No of Drives: 3+
What is RAID Level 3? What is its tolerance? and how many drives does it have?
▪ Features: Byte level striping with parity error correction to enable rebuilding data with spread read/writes.
▪ Tolerance: One Drive Failure
▪ No of Drives: 3+
What is RAID Level 4? What is its tolerance? and how many drives does it have?
▪ Features: Block level striping with parity error correction to enable rebuilding data with spread read/writes
▪ Tolerance: One Drive Failure
▪ No of Drives: 3+
What is RAID Level 5? What is its tolerance? and how many drives does it have?
▪ Features: Block level striping with parity error correction to enable rebuilding data with spread read/writes
▪ Tolerance: One Drive Failure
▪ No of Drives: 3+
What is RAID Level 6? What is its tolerance? and how many drives does it have?
▪ Features: Block level striping with double parity error correction to enable rebuilding data with spread read/writes
▪ Tolerance: Two Drive Failure
▪ No of Drives: 4+
What is hamming code error correction?
Code used in RAID to utilise parity bits to rebuild corrupted data.
What is parity error correction?
An error-checking technique by which an extra bit is placed at the end of each byte to make the number of 1s even (for even parity) or odd (for odd parity). Double parity is when RAID writes another set of parity across the drives as extra protection.
What is NAS
Network attached storage is a simple file server that connects to a network and provides one or more backing storage devices. - alternative to cloud storage.
What are the main uses of NAS?
▪ Collaboration - NAS can be connected to the network and allow users access to the contents through the server on different devices which is useful in group projects that require collaboration.
▪ Backups - Used for backups and recovery if data is lost.
Give some examples of flash storage
▪ USB flash drive
▪ SSD
What type of storage provides the larges amount of storage?
HDD
Why is RAID used?
▪ It provides redundancy to protect data
▪ Improves read/write performance of storage devices.
What are the main factors that affect user experience?
▪ Ease of Use
▪ Performance
▪ Availability
▪ Accessibility
What is Ease of Use for user experience?
How simple and intuitive a system is to navigate and perform tasks on. Can first-time users easily navigate the system?
What is Performance for user experience?
How powerful the device is for things such as processing, memory, graphics & storage.
What is Availability for user experience?
How often he device can be used or whether the device is in stock.
What is Accessibility for user experience?
How available the device is to be used by anyone. Accessibility or adaptability of hardware may affect the choice of hardware, especially if the user require specialist devices.
Which of the pervious factors is the most important?
None of them are objectively more important.
Different factors become more or less important depending on the requirements of the client.
How does user needs affect choice of hardware?
What the user wants the device for will affect the hardware that would be more appropriate.
How does compatibility affect choice of hardware?
If components aren’t compatible, they will not work with the computer. This is an extremely important consideration when purchasing new hardware. This can be hardware compatibility, connection compatibility …
How does cost affect choice of hardware?
The code of different hardware components can differ drastically. Some users will be able to afford the more expensive components while others wont. The cost of running the device must also be considered.
How does efficiency affect choice of hardware?
Efficiency is how efficiently hardware devices can complete tasks with as little wastage as possible. For companies this also includes staff and time that will be required to complete these tasks and maintain the device or system. A device can also be energy efficient , requires less power to run.
How does implementation affect choice of hardware?
Implementation is about the time it takes to put a new system into place. It involves timescales, testing and migration.
What are the main factors of implementation and what are they?
▪ Timescales - Time for the new hardware to be delivered.
▪ Testing - Ensuring the hardware functions correctly and that it is compatible with remaining hardware and software.
▪ Migration - Th process of transferring data, software and files from the old system to the new one.
How does productivity affect choice of hardware?
Productivity is how quickly tasks can be completed. A higher rate of productivity is more desirable for perspective buyers. This can have a large impact and significance in businesses.
How does security affect choice of hardware?
This is how safe a device is from threats such as viruses and hackers. Some devices are more susceptible to these threats and would therefore be undesirable.
What are the main two types of operating system?
Single-user and Multi-tasking.
What is an RTOS?
A real-time OS is an operating system that monitors external events and processes data consistently within a time limit. E.G. RTLinux, Windows CE, VxWorks
In what type of system are RTOSs used?
Used in embedded devices with specific tasks:
▪ Aircraft: air traffic control systems and autopilot
▪ Automobiles: airbag deployment and self-driving features
▪ Automatic Systems: Robotics on a manufacturing line
What is a single user, single task OS? and where are they found?
A system that can only be used by one user at a time to perform one tasks. They are seen within old mobile phones, personal digital assistants and palm devices (Palm OS).
What is a single user, multi-tasking OS?
A system that one person can use at a time to perform multiple operations. EG. Windows 10, Android, MAC OSX
In what type of system are single user, multi-tasking OSs used?
▪ Smartphones
▪ Tablets
▪ Laptops
▪ Desktops
What is a multi-user OS?
Operating system that allows many different users to make use of a computer system and its resources at once. E.G. UNIX, Windows Server
In what type of system are multi-user OSs used?
Used in expensive, powerful devices where it would be inefficient to save all processing capabilities for a single user such as:
▪ Servers
▪ Supercomputers
▪ Mainframes
These will commonly be connected to by multiple people and will need them to make use of the system resources
What is networking and its role in a computer system?
Networking is what allows you to connect to the internet. It is controlled and managed by the OS.
TCP/IP?
Fundamental protocols for networking, including connecting to the internet.
What is utility software?
Utility software is software that comes with and runs alongside the OS to carry out routine tasks to maintain and optimise the system operation. It is there to add features and functionality to the OS to keep the computer running well. The OS also contains utility programs to maintain the network.
What is the purpose of the built-in drivers in the OS?
The drivers allow most network interface cards to communicate with other parts of the computer system.
Does the OS contain any security?
The OS has a range of protection methods for threats such as viruses and hackers.
What protection methods are built into the OS?
▪ Authentication - OSs apply methods such as usernames and passwords or biometrics (usually fingerprints) to prevent unauthorised, malicious users from accessing the system.
▪ Backups & Recovery - OSs have built-in backup and recovery software allowing users to schedule regular backups manage them, and restore data if needed.
▪ Firewall & anti-virus - Prevent a wide range of common security threats.
What does the kernel do?
▪ Executes processes: Loads software into memory, allocates resources, Runs and terminates.
▪ Interrupts: Processes events occurring outside the currently executing process.
▪ Modes: Switches between user mode (to run apps) and system (kernel) mode (to run low-level code the OS needs for operations such as reading memory).
▪ Memory Management: Allocates RAM to running programs and reuses RAM when programs end.
▪ Multi-tasking: Allocates sufficient CPU and peripheral time to running programs so they work simultaneously.
▪ Disc Access: read/write backing storage
▪ File systems: controls how data is storage in backing storage.
▪ Device drivers: allow OS to communicate with hardware to best use their features.
What happens when an interrupt occurs?
The kernel saves the process of and stores the currently running program so it can be returned after the interrupt is handled. Then the CPU continues processing its previous task.
What are interrupts?
They are usually i/o interrupts E.G. click of a mouse, press of a key, arrival of a network packet
What is kernel mode?
The CPU starts here. It has unrestricted access to hardware so any task can be processed.
What is user mode?
CPU is in this mode when it is running applications but it will switch to kernel when core operating system processes must be run. No direct access to hardware so some processes cant be completed.
Why does the OS rely on the kernel?
The OS requires the kernel to allocate a memory slot for it in order for it to run.
When there are multiple software applications open, what is the job of the kernel?
The kernel allocates resources to allow for the best performance.
How do computers process instructions simultaneously?
They don’t. Part of each task are allocated time systematically so it appears that they are being processed at the same time.
What is the kernels role in disk access?
The kernel handles all I/o to peripherals. It manages all read/writes to/from disks. It creates queue for managing priorities.
What is the kernel role in file systems?
It can implement file systems, controlling how data is stored and retrieved. File systems are important as they allow you to name and add extensions to files so they are identifiable and useful.
What is FAT32?
file system popular with flash drives and SSDs. It supports up to 16TB of data with a maximum file size of 4GB.
What is exFAT
A file system designed for portable devices up to 512TB .FAT32 & exFAT have better compatibility than NTFS (which is largely used for windows).
What is NTFS?
Default file system used by windows. Provides additional features such as permissions, shadow copies, encryption and disk quota limits.. Maximum 16EB (exabytes) and individual files can be 256 TB.
What is a device driver?
A device driver is a program that controls the devices you connect to your computer. It can be thought of as a translator between the computer and the peripherals. It converts instructions from the peripherals into instructions the computer can understand.
Is there only one device driver?
No there are different device drivers for different devices.
Why isn’t kernel mode used when the CPU is processing application software instructions?
▪ Stops applications from damaging our operating system.
▪ Ensures application crashes don’t crash our entire system.
What would the impact be if we didn’t have device drivers?
You’d require specific programs for every combination of hardware and software.
What is a GUI?
A graphical user interface is what most computer OSs use to provide the user with a way to interact with the PC.
What type of interface is a GUI?
WIMP (windows, icons, menus & pointes)
What are the advantages of using a GUI?
▪ Easy to use
▪ Easy to move data between applications (drag and drop).
What are the disadvantages of using a GUI?
▪ Uses a lot of processing power and memory to run.
▪ Slow to perform more complicated tasks for an experienced user.
What is a CLI?
A Command line interface are simple text-based interfaces. There were mainly used when computers weren’t powerful enough for a graphical interface.
What are the advantages of using a CLI?
▪ Experienced users who know the commands find it much quicker to complete tasks.
▪ The simplicity means it requires much less memory and processing power in order to run.
What are the disadvantages of using a CLI?
▪ To use it you need to know the various commands.
▪ The interface is not intuitive and it will require some training to get basic use.
What is a Menu-based Interface?
An interface that presents the user with a menu that contains a list of options to choose from. They can also contain sub-menus, so the user can find their specific function.
What are the advantages of using a menu-based interface?
▪ Very easy to use - simple with limited possibilities.
▪ Easily adapted to different users. - easy to translate into different languages.
What are the disadvantages of using a menu-based interface?
▪ Frustrating when there are a lot of sub-menus - can take a long time to navigate.
▪ Limited options - can perform complex operations
What can affect the performance of an OS?
▪ Hardware
▪ Malware
▪ Virtual Memory
How does hardware affect the performance of an OS?
OSs have minimum hardware requirements. GUIs often require a lot of power and then every application that is opened after that will also required some power and memory. If the hardware doesn’t meet these requirements the PC can crash.
HDDs can also become fragmented over time which can slow down retrieval time, decreasing performance.
How does malware affect the performance of an OS?
Malware can corrupt data which can affect network traffic and disable various functions of the OS. This can cause a significant slow down of the system can cause a crash. In some cases it can damage the OS enough to
How does virtual memory affect the performance of an OS?
Virtual memory is a portion of the HDD reserved as a backup to main memory when there is no RAM remaining. The use of main memory reduced performance, this is especially true when the OS has to switch between main and virtual memory. this is known as thrashing.
What is disk fragmentation?
Disk fragmentation occurs when files, of different sizes, are created and deleted, leaving gaps in the disk.
How does disk fragmentation reduce performance?
Because of the small gaps left, when a large file is added there wont be a consecutive slot for it to fit into. This means that the file will be split into chunks across the disk. This means that it will take longer for the file to open as it is harder to find all the parts.
What is disk defragmentation?
This is the analysis and regrouping of data on a hard disk. This will increase execution speed when opening and saving files.
What factors can affect backup time?
▪ Disk fragmentation - slow
▪ Viruses & Malware - slow and corrupt
How can the storage location affect backups?
Backing up to the cloud can take a long time but backing up to external disks can take longer depending on connection..
How does disk/registry cleaner affect performance?
When the hard disk becomes cluttered with unused data such as temporary files or old unused files. This can reduce performance and read/write times.
How doe software updates affect performance?
If software updates are not complete the system can be come unsecure and slow. if they are not completed often enough they can take a long time to update.
How does antivirus affect performance?
Malicious software such as viruses can have catastrophic affects on you system. anti-virus maintains performance as it detects and removes suspicious programs tat could decrease the performance of your computer.
How do firewalls affect performance?
Firewalls monitor traffic into the computer. Firewalls try to stop malware from reducing your PCs performance. However if malware is targeted at the firewall, it can cause it to stop working properly.
Lynda is finding that her operating system is suffering from a lot of screen freezing and even crashing entirely. Her anti-virus has said she doesn’t have any malware infecting her computer and she has no applications open while the freezing is happening. Which of the following could be the cause of the problem?
Virtual memory thrashing.
Operating system minimum requirements not met.
In virtual memory terms, what is a pagefile?
The area of the hard disk reserved for virtual memory.
What utility tool will group together related data on a hard disk to make it quicker to read/write to?
Disk Defragmenter
Ben has found his operating system is starting up very slowly. Which of the following utility programs could he use to improve this?
Anti-Virus
Disk Defragmenter
Disk Cleaner
Ben is running the software updater utility, however he has found it is taking a very long time to complete. What is the most likely cause?
Slow internet connection
Umar is running his disk defragmenter utility. It is taking several hours to complete. Which of the following is the most likely cause of this?
He has lots of other software running in the background.
He hasn’t run it in a very long time.
Umar is also concerned about security threats to his computer. What utilities will help protect him from threats like malware and hackers?
Firewall
Anti-Virus
What is productivity software?
Software often used in businesses to allow users to produce documents, spreadsheets, presentations and other information more efficiently.
What is word processing?
Software is used to create and manipulate text and images to produce documents.
What is a spreadsheet?
software is used to organise data into a grid and allows you to perform calculations on the data
what is a database?
software is used to create, edit and manage databases
presentation
software is used to produce slideshows in order to present information to an audience.
How is graphics/multimedia software used?
it is used to produce graphics and multimedia products on a computer system.
What is CAD?
Computer-aided design is software used to produce precise technical illustrations
What is graphics editing?
Software is used to create or manipulate images on a computer.
Desktop publishing
software used to arrange text and graphics to produce professional documents for print.
Video editing
software used to rearrange and manipulate video footage.
What is communication software?
software that allows users to share information by passing it from one device to another.
software is used to electronically send messages over the internet
Web browsing
software is used to access, view and navigate web pages
VoIP
voice over internet protocol software is used to hold real-time voice and video conversations over the internet.
instant messaging
software is used to hold real-time text-based conversations over the internet.
What is a integrsted development environment?
Software used to create software by programming and designing interfaces.
home finance
software is used to manage personal accounts
multi-media player
Software is sued to watch films and tv as well as to listen to music
What is application software?
Software that allows users to interact with their computer to perform many different functions.
What can affect the choice of application software?
compatability
use
user experience
What is computability?
Can it run on the OS
Can it run on the hardware
Can it work and communicate with other software applications
What is use?
can it be used for its intended purpose?
What is user experience?
Is it easy to use. Eg a switch from windows to mac can be difficult.
What is open source software?
Open-source give user the permission to use the software and access, view and modify it.
What are the advantages off open-source software?
¬ No licensing - free to use and open to any modifications.
¬ source code is available so you can modify the software to adapt to your needs.
¬ Developed and maintained by a large community so there is a fast update cycle to fix bugs and security holes.
¬ adheres to open standards - better compatibility with other applications.
What are the disadvantages of open-source software?
¬ development can be abandoned, there is no responsibility to keep it updated.
¬ maintaining updates is more difficult as there are often many due to a fast update cycle. This makes extra work for administrators
¬ no professional support
source code being available could led to malicious users identifying flaws and exploiting them to cause harm to your system.
What is proprietary software?
Licenced software that gives the end-user to use the software but retains intellectual property. So you cannot view the source code.
What are the advantages of proprietary code?
¬ Comes with rights and expectations of ongoing support and updates, patches, big fixes, etc
¬ Updates are often simpler to install
¬ Software is usually well supported by the company that released it.
¬ greater usability, more time is spent on he interface. A smaller set of more comprehensive features
What are the disadvantages of proprietary software?
¬ Licencing is restrictive and complicated. - often expensive - may or may not be perpetual
¬ Source code is not available for viewing or modification.
¬ Reliant on the developer for updates or fixes
¬ proprietary standards- make it difficult to switch to different software as data transmission can be difficult.
What are the three stages of data processing?
1) input - input devices are used to collect data
2) processing - software applications provide instructions to the CPU.
3) Output - Output devices provide the results from the processing.
Give some examples of industries that use data processing
¬ retail - take card details and process payment
¬ healthcare - track patient life signs
¬ banking - collect customer information
¬ manufacturing - computers are used to design components. the designs are then used as instructions for machines.
What are the advantages of automatic data processing?
¬ Computers perform processes quicker
¬ Processing is performed to a consistent standard
¬ Processes can be performed over long periods of time.
¬ Computers can store huge quantities of inputs and processing outputs without forgetting
¬ the efficiency of computers can save money in the long run.
What are the disadvantages of automatic data processing?
¬ Lacks common sense - wont notice physical errors (GIGO)
¬ If the instructions are processed incorrectly, it will all be wrong
¬ Initially expensive.
¬ Has left employees redundant.
What is the role of hardware in data processing?
Hardware pays a key role in the collection of inputs. devices such as keyboards are very flexible with what you can input., although data input like this is very slow.. There are automatic input devices that are much more efficient.
Give some examples of automatic data collection devices:
¬ optical mark readers are used to enter data from pre-printed forms. - used commonly for lottery tickets and school registers.
¬ barcode readers for inputting product details
¬ Sensors to take readings from the environment.
What is the role of software within data processing?
Software provides the input interface that collects data for processing. The design can have a big affect on accuracy. (clear labelling, alternative inputs, validation checks)
It is also used to stored data in an organised format. Using software makes the process quicker and easier
What is aggregation?
Combining multiple pieces of data into one, to summarise the data
What information do you need for the aggregation of data?
¬ data to be aggregated
¬ how you want to group the data
¬ calculations you want to use
What is data analysis?
This involves looking at data to identify its meaning. It supports discussions in businesses and science as it gives a well formed decision
Conversation in data processing
Changing data from one format to another for moving data between systems. sometimes data will need to be exported and imported.
Reporting in data processing
Outputting information produced from processing data. To present the data in an appropriate format for the task and audience or for efficiency.
Sorting in data processing
organising data into a meaningful order to make it easier to understand and visualise. E.G. sort alphabetically
Validation in data processing
checking data to ensure it has been entered sensible and reasonable. It doesn’t ensure that data is accurate.
What are the main types of validation?
¬ range check - min and max for numerical data
¬ length check
¬ type check
¬ presence check
¬ format check
¬lookup check - matches predetermined value
access when storing data across multiple systems
you may not be able to gain access to the data whenever you want. It can be improved by sorting data using cloud storage but if you have no internet connection, you couldn’t access your data. you could also store them on a server but if the server goes down, you cant access it.
cost when storing data across multiple systems
For businesses this can lead to high costs because of data replication. Setting up a file server is not cheap. Waste employee time and loss of productivity.
implementation when storing data across multiple systems
systems require extensive testing and will cost to set up and maintain. It could require the set-up of a server and network connection for the internet, along with encryption and other measures for security.
productivity when storing data across multiple systems
splitting data across multiple systems could reduce productivity as you try to find files. Especially if its on a completely separate device such as a laptop. Could also slow you down, even if its just on a fiel server. You could end up repeating work
security when storing data across multiple systems
More locations that the data could be stolen from. Data could also be stolen while being transferred between devices if it isn’t encrypted.
Storing backups
Backups can be resource-intensive. performance could be decreased significantly due to processor time being used as well as large amounts of reading/writing.
What are the most important factor about taking backups?
¬ how often -
¬ Time or day
What are the three main types of backup?
¬ Full
¬ Incremental
¬ Differential
What is a full backup?
a backup of everything - excellent protection but is time consuming and requires a large amount of storage.
What is an incremental backup?
Backup of the data that has changed since the previous backup. - quicker and requires less storage.
What is a differential backup?
Mixture. EG. A business may take a full backup at the end of the week and incremental backups every night.
Where to store backups.
Important to keep secure. Could be stored in a remote location. - this creates issues with connection type. not secure from physical theft.
What is the Vonn Neumann architecture model?
Most common model used by computer systems. The computer system is split into 4 main components, input, CPU, memory and output
In the Bonn Neumann architecture, what are the lines between the components?
Buses, wires that are used to transfer data between components
What are the main features of von Neumann?
programs and instructions are stored in main memory.
processors have a number of registers on the CPU for storing data and instructions. This is because it is faster fetch from the CPU than main memory
What is the fetch-decode-execute cycle?
Instructions are fetched one at a time and passed to a single CPU over the system bus. The CPU will the decode the instruction before fetching another instruction and repeating until all instructions are processed.
What is Harvard architecture?
Harvard architecture has 2 types of memory, one for instructions and the other for data. The advantage is that instructions will be able to be fetched while data is also being read/written.
What is cluster computing?
There are more than one computer connected together and will appear and perform as a single system. The individual computers (nodes) connect to eachother through a very fast local area network made up of fibre optic cables
Gets more powerful processing capabilities at lower cost. Most supercomputers are comprised using cluster computing.
What is UMA
Uniform memory access - processors use the same memory, memory controller and memory bus. Each process or has equal access but it can be slow as the CPU may have to wait for instructions.
What is NUMA
Non-uniform memory access- each processor has it’s own memory, memory controller and memory bus. CPU will be connected together by a very fast connection so the CPU could still access the memory for a different CPU. Accessing memory further away will take longer. More scalable because of their own memory.
What is emulation
Where acomputer program will imitate a hardware or software platform. Used go run software on a system that is not compatible. And used for testing software.
It has a big impact on performance and is very resource hungry, taking a significant amount of RAM
Choice of architecture: hardware
Availability of hardware will affect choice. Von Neumann is generally use for laptops because of the cost and complexity of Harvard.
Harvard is used in small embedded devices because they are not general purpose so instructions wont be in RAM
Choice of architecture: software
OSs may not be compatible may make inefficient use of numa
Different brands use different low-level programming instructions. Which causes compatibility issues
