Year 11 CPU, Memory MS

1     (a)    Essentially the ‘brain’ of the computer – carries out tasks and has direct control over the hardware (1).
It fetches and executes instructions stored in memory (1).                                                                    [2]

       (b)   (i)    The number of individual processors in the CPU (in this case, two)                                                 [1]

              (ii)    ‘Clock speed’ refers to the number of operations carried out per second by the processor
(in this case, 2.8 billion)                                                                                                               [1]

              (iii)   ‘Cache’ refers to the size of the cache memory; a small, high-speed memory used for the
temporary storage of frequently or recently accessed data.                                                           [1]

       (c)    The second CPU is likely to perform better (1). Despite the slower clock speed it is quad-core and
has a higher cache (1). The number of cores is the most important factor (1) – as having many
slower processors is better than having one faster processor.                                                               [2]

       (d)   ‘Buses’ (1) – (i.e. the link between processor and RAM is known as the Memory Bus)                              [1]

2     (a)    (i)    Random Access Memory                                                                                                             [1]

              (ii)    Read Only Memory                                                                                                                     [1]

       (b)   Increasing the amount of primary memory available to the computer means that a larger amount of data/instructions can be stored at a time – this allows more programs to be run at once (1), and may speed up the computer (1) as it will spend less time writing to virtual memory on the hard disk.                           [2]

       (c)    Non-volatile memory is a type of memory that can retain the stored information even when not
powered (1). Because ROM is essential for starting up a computer before the operating system takes control, it needs to be non-volatile so that its data is not lost when the computer is turned off (1).                        [2]

3     Non-volatile memory which stores the boot program                                 ROM (1)                                       

Small and high-speed buffer-type memory located near the processor         Cache (1)

Where data/instructions are primarily held and fetched from while in use     RAM (1)

Temporary memory allocated on the hard disk                                           Virtual (1)                                  [4]

4     (a)    Cache memory is used to store the most frequently used instructions or data (1). Because cache
memory is faster than RAM, the overall processing time is reduced (1) as the processor spends
less time waiting for data from memory.                                                                                             [2]

       (b)   Virtual memory is used when the RAM runs out of available space to store instructions/data currently in use (1). It is temporary memory allocated on a secondary storage device (usually on the hard drive or SSD). This allows more programs to be run at once without data loss (1).                                                              [2]

5     (a)    Secondary storage provides a location to store data that is not being used by the main memory (1).
This allows computers to be switched off without losing saved work and programs (1).
Common examples include hard drive disks, solid state disks and removable media such as
CD-ROMs and memory sticks/cards (1).                                                                                               [2]

       (b)   (i)    Optical discs – i.e. CD/DVD/Blu-Ray (1)
Possible reasons include: they are reliable (1) and cheap to mass produce (1)                                 [2]

              (ii)    Hard drive or SSD (1)
Possible reasons include: they provide large capacity storage (1) ; fast read/write speed (1)             [2]

              (iii)   USB drive (1)
Possible reasons include: they are reliable (1) and portable due to their small size and weight (1)     [2]

6     Magnetic: Hard drive, Tape drive (1)

Optical: DVD, Blu-ray disc (1)

Solid State: USB drive, SD card (1)                                                                                                              [3]

7     (a)    A read/write head magnetises tiny sections on a spinning metal platter (1). The data is stored in concentric circles called tracks (1).                                                                                                                       [2]

       (b)   An SSD contains a large number of tiny ‘cells’ which can store a voltage (1). Data is written through
the use of electrical pulses (1).                                                                                                            [2]

       (c)    A laser (1) is used to burn tiny pits and troughs (1) onto the surface of the CD.                                      [2]