Hardware (2) Flashcards
(Exam-style question)
Zakir wants to buy a new laptop.
Explain why the laptop needs both hardware and software. (2)
Any one from:
- Software allows instructions to be passed to the hardware so that it can carry out tasks
- Software is the set of instructions that controls the hardware
Give some factors that affect the performance of the CPU.
- Clock speed
- Number of processor cores
- Size of cache
- Type of cache
Give one benefit of having a higher clock speed.
Any one from:
- More instructions can be carried out per second
- Processes run faster
- Programs executed faster
Give one drawback of having a higher clock speed.
Any one from:
- The CPU/computer could overheat
- More cooling required
- Needs more power
(Exam-style question)
Increasing the size of the cache will improve the performance of the CPU.
Explain how increasing the size of the cache improves the performance. (2)
Any one from:
- Cache stores frequently used data so the processor does not have to wait because cache is checked before main memory / because RAM is further away from the processor
- It speeds up processing because cache is a faster type of memory
Describe the speed, closeness and accessibility of each level of cache.
- Level 1 (L1) cache - extremely fast, usually embedded in the CPU, closest to the processor
- Level 2 (L2) cache - slower than L1 cache, one stage further from the processor, may be located on CPU or separate chip
- Level 3 (L3) cache - specialised memory that works to improve performance of L1 and L2, can be significantly slower than L1 or L2 cache, usually double speed of RAM
Describe the effect having a greater number of cores has on the performance of the CPU.
- The performance increases
- CPUs with multiple cores have more power, allowing for more processes to be ran at the same time with greater ease
Give some differences between primary storage and secondary storage.
Primary:
- Volatile
- Short-term
- Directly accessed by CPU
- Limited storage capacity
Secondary:
- Non-volatile
- Long-term
- Programs/data must be transferred to memory in order for them to be accessed by CPU
- Large storage capacity
(Exam-style question)
Describe one reason a computer needs both primary and secondary storage. (4)
- Primary storage is needed to provide the CPU with fast, direct access to the program instructions and data that it is currently using - it only retains its contents temporarily
- Secondary storage is non-volatile and is needed to keep programs and data for the long term when not in use
Give the three main types of secondary storage.
- Magnetic
- Optical
- Solid-state
Describe how how data is stored using magnetic storage.
- Use of read-write heads that contain electromagnets
- Parts of surface is either magnetised (1) or demagnetised (0), read-write heads control this when writing and can tell what state surface of disk is in when reading
Describe how data is stored on optical media.
Write data:
- Laser used to burn pits and lands into surface of disk
- More reflective areas ‘lands’ represent 1s and less reflective areas ‘pits’ are 0s
Read data:
- Laser beam shone onto surface of disk - light that hits a land reflects differently to where it hits a pit
- Amount of light reflected translates to 1s & 0s by a sensor
Describe how data is stored on a solid-state drive.
Write data:
- Electrical current applied to transistor, forcing electrons through a barrier and trapping them in pools
- Full pool represents 0 and an empty pool 1
Read data:
- Small voltage is applied
- If electron pool is empty, transistor turns on and 1 is read - if full, transistor does not turn on and 0 is read
Give instances in which magnetic storage is used, and give advantages and disadvantages of using this form of secondary storage.
Used in:
- HDDs
- Internal/external hard drives
- Tape drives
Advantages:
- High capacity
- Fast data access
Disadvantages:
- Has moving parts that will eventually fail
- Noisy
Give instances in which optical storage is used, and give advantages and disadvantages of using this form of secondary storage.
Used in:
- CD, DVD and Blu-ray drives
Advantages:
- Portable
- Disks are cheap
Disadvantages:
- Slow to access
- Prone to scratches
