SLR 3
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Define the term ‘multicore processor’
• more than one processing unit in a single processor • which can independently process instructions at the same time
A robot uses a multi-core processor. Programmers assume that the robot will execute programs more quickly than using a single core processor. Give one reason why this assumption can sometimes be true.
• it can execute multiple instructions at the same time / some instructions can be run in parallel
A robot uses a multi-core processor. Programmers assume that the robot will execute programs more quickly than using a single core processor. Give one reason why this assumption is not always true.
• some instructions may not be able to be run in parallel • an instruction may be dependent / waiting for other instructions to be completed • other factors influence processing speed - clock speed / caches / bottlenecks • program needs to be written to specifically use multiple cores
Give one advantage of films being distributed using optical media
• cheap to produce / buy • capacity big enough to hold films • does not need internet connection • portable
Giving an example other than DVDs, describe what is meant by the term ‘optical media’
• read/written to using a laser • read/written onto using a reflective surface • data is stored using pits and lands • Blu-Ray • CD
Explain the difference between RAM and ROM, including how these are used by the computer system
• RAM is volatile • used to storing programs/data/parts of OS currently in use • ROM is non-volatile • used for storing BIOS/bootstrap
A business uses virtual storage to hold regular backups of all its data. Explain why virtual storage is well-suited for storing backups
• stored away from the computer • so in case of disaster, data is not also damaged • all of the data can be backed up at the same time • can be accessed anywhere • storage can be expanded as necessary • no physical space needed for backup hardware
State an input and output device for a video game designer and a use for each
• mouse • allow the designer to select/manipulate objects • monitor • display images
Explain why adding more RAM will improve the performance of a computer system
• Allows more active/running/temporary data in RAM • It reduces the need to use virtual memory • RAM is faster to access than VM/secondary storage… • …because data in VM/SS has to be swapped with data in RAM first • Use of RAM rather than VM reduces the risk of disk thrashing • Faster bootup/ shutdown time / reduces load/access time
Describe what the BIOS will do to start up a computer.
• Contains the computer start up instructions • Loads settings/configuration (CMOS/NVRAM) • Initialises/checks hardware/peripheral devices are available/work / carry out a POST check… • …and reports errors • Determines the drive on which the OS is stored • Finds/loads the bootstrap/operating system/kernel (into main memory)
Describe how an embedded system can make a different use of ROM and why it is an advantage
• Storing firmware/ config/ operation instructions/ operating system/ device drivers… • …that can’t be overwritten / doesn’t need to be updated • …so that access is faster OR • Storing security settings/encryption keys/digital signatures… • …that must be maintained/can’t be changed OR • Could be used as primary storage… • …so no need to load programs into memory • …so would save time loading up the program OR • Could be used as secondary storage… • ….so the device will not need additional storage… • ….to reduce the size of the device
State the role of RAM in a computer system.
• Stores instructions / programs currently running • Stores data currently in use
An embedded system is often a small device that is designed to carry out a limited number of specialised tasks. Professional athletes sometimes wear small embedded systems called fitness trackers in their shirts. These can be used to track their speed, position, heart rate and other performance data during an event. The tracker transmits this data to a pitch-side server which collates the data from all the athletes. State the name of one input device that might be used in this embedded system and state what it would be used for.
• Heart rate sensor • Detects athlete’s electrical activity / heart rate • GPS (receiver) • Mapping the athlete’s movement / position/ speed • Accelerometer/gyroscope/motion sensor • To track the players acceleration/speed/movement/counting steps/measuring orientation • Button • To allow the athlete to turn it on/off
The fitness tracker manufacturers had to decide which type of secondary storage to use. Explain two reasons why flash (solid state) storage would be the best type of secondary storage for the fitness tracker system.
• Durable/flash has no moving parts… • …so will be resistant to damage if the player runs/falls/collides with something • Low power usage… • …won’t need recharging/will last during an event • Small physical size/portable… • …so it can fit on a shirt/be unobtrusive/be worn / won’t affect the athlete’s performance • Fast/real-time read/write speed… • …needed to rapidly record athlete’s data
Amaya is an amateur photographer and has bought an old second-hand computer to edit her photographs. The specifications of this computer are shown below. Explain what is meant by the term ‘virtual memory’ and why this may be needed when Amaya is editing her photographs.
• If the amount of RAM available is insufficient… • …Used to store instructions/data • …Using secondary storage. • Likely to be loading large image files (which may exceed her RAM) • Likely to be loading large programs (which may exceed her RAM)
Imogen buys a desktop computer. It comes with an operating system installed. Describe two ways that an operating system could manage physical memory.
• Paging • …blocks of memory of equal size / fixed size • Segmentation • …blocks of memory split logically /variable size
Explain one benefit of memory management to the user.
• Security • …does not let programs access memory reserved for other programs. • Multitasking • …allows multiple programs to run at once
Describe how virtual memory allows a user to run programs when physical memory is full.
• (Currently unneeded) pages moved from memory to secondary storage • …to create room in memory • pages moved back to memory when required