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GCSE Computer Science · 1.5

Systems Software

Section A: 10 multiple choice questions, 10 marks. Section B: 5 written questions, 17 marks. Total 27 marks.

Name

Class

Date

Mark  / 27

Section A

Circle the letter of the correct answer. One mark each.

  1. 1Which of these is an example of utility software?1
    1. AA disk defragmenter
    2. BA video game
    3. CA web browser
    4. DA spreadsheet program
  2. 2What does the operating system do during memory management?1
    1. AConverts programs into machine code
    2. BIncreases the total amount of RAM installed
    3. CStores files permanently on the hard disk
    4. DAllocates memory to programs and keeps them separate so they cannot overwrite each other
  3. 3How does an operating system make several programs appear to run at once on a single core?1
    1. AIt switches between processes very rapidly, giving each a small slice of CPU time
    2. BIt runs each program at a lower clock speed
    3. CIt runs them on the graphics card instead
    4. DIt compresses each program so they fit together
  4. 4What is a device driver?1
    1. AA cable connecting a peripheral to the computer
    2. BA utility that defragments a disk
    3. CSoftware that translates operating system instructions into commands a hardware device understands
    4. DThe person who installs new hardware
  5. 5Why does fragmentation slow down a magnetic hard disk?1
    1. AThe read write head must move to several locations to read one file
    2. BThe operating system has to decompress each fragment
    3. CFragmented files take up more space
    4. DThe disk spins more slowly when fragmented
  6. 6Why should an SSD not be defragmented?1
    1. ASSDs defragment themselves every hour
    2. BIt would delete the data
    3. CSSDs cannot store fragmented files
    4. DThere are no moving parts to benefit, and it wastes limited write cycles
  7. 7Which backup type is quickest to create but slowest to restore?1
    1. AFull
    2. BMirror
    3. CIncremental
    4. DDifferential to disk
  8. 8What is one advantage of a command line interface over a graphical user interface?1
    1. AIt shows previews of files
    2. BIt requires no typing
    3. CIt uses far fewer system resources
    4. DIt is easier for beginners to learn
  9. 9Which is NOT a function of an operating system?1
    1. AManaging files and folders
    2. BEditing a photograph
    3. CManaging user accounts
    4. DControlling peripherals
  10. 10User access levels set by the operating system are used to:1
    1. AIncrease the amount of available RAM
    2. BControl which files and features each user can reach
    3. CSpeed up the processor for administrators
    4. DEncrypt every file automatically

Section B

Answer in the space provided. The number of marks tells you how many separate points to make.

  1. 1StateState three tasks carried out by an operating system.3
  2. 2ExplainExplain how an operating system uses multitasking to allow several programs to run at the same time.3
  3. 3ExplainExplain how defragmentation software improves the performance of a magnetic hard disk drive.4
  4. 4CompareCompare a full backup and an incremental backup.4
  5. 5ExplainA company issues laptops to employees who work while travelling. Explain why encryption software should be installed on these laptops.3

Mark scheme

Section A

1A2D3A4C5A6D7C8C9B10B

Section B

1 State three tasks carried out by an operating system. 3

One mark for each of the following, to a maximum of 3.

  • Manages memory or provides multitasking
  • Manages peripherals and device drivers
  • Manages files, users or provides the user interface

Model answer. An operating system manages memory, allocating it to programs and freeing it when they close as well as handling multitasking. It manages peripherals, using device drivers to communicate with input and output hardware. It also manages files and folders on secondary storage, and provides the user interface through which the user interacts with the computer.

2 Explain how an operating system uses multitasking to allow several programs to run at the same time. 3

One mark for each of the following, to a maximum of 3.

  • Each program or process is given a small slice of CPU time
  • The operating system switches rapidly between processes
  • The switching is so fast that the programs appear to run simultaneously

Model answer. The operating system allocates each running process a very small slice of processor time, and then switches the CPU rapidly from one process to the next according to a scheduling algorithm. Because each switch happens in a fraction of a second, far faster than a person can perceive, every program appears to be making continuous progress, giving the impression that they are all running at the same time even on a single core processor.

3 Explain how defragmentation software improves the performance of a magnetic hard disk drive. 4

One mark for each of the following, to a maximum of 4.

  • Over time files become fragmented and stored in separate parts of the disk
  • The read write head must move to several locations to read one file
  • Defragmentation rearranges the data so file parts are stored together
  • Less head movement is required so files are accessed more quickly

Model answer. As files are created, edited and deleted, gaps appear on the disk and new data is written wherever space is available, so parts of the same file end up stored in several separate locations, which is known as fragmentation. Because a magnetic hard disk reads data using a physical head on a moving arm, opening a fragmented file requires the head to move to each of those locations in turn, and this mechanical movement is by far the slowest part of the operation. Defragmentation software reorganises the contents of the disk so that all the parts of each file are placed together in contiguous blocks and the free space is gathered into one area. The head then only needs to move a short distance to read a whole file, so access times fall and the drive performs noticeably better.

4 Compare a full backup and an incremental backup. 4

One mark for each of the following, to a maximum of 4.

  • A full backup copies every file
  • An incremental backup copies only files changed since the last backup
  • Full backups take longer to create and use more storage
  • Incremental backups are faster to create but slower to restore because multiple backups must be applied

Model answer. A full backup makes a complete copy of every file in the selected data, whereas an incremental backup copies only those files that have been created or changed since the previous backup of any kind. This produces opposite strengths. A full backup takes considerably longer to create and requires much more storage space, because the same unchanged files are copied every time, but restoring is fast and simple because everything needed is contained in a single backup set. An incremental backup is very quick to create and uses very little storage, but restoring is slower and more complex, because the most recent full backup must be restored first and then every incremental backup since must be applied in the correct order, and if any one of them is missing or corrupted the restore may fail.

5 A company issues laptops to employees who work while travelling. Explain why encryption software should be installed on these laptops. 3

One mark for each of the following, to a maximum of 3.

  • Laptops carried outside the office are at higher risk of loss or theft
  • Encryption scrambles the data using a key so it cannot be read without that key
  • If the device is stolen, confidential company or customer data remains protected

Model answer. Laptops that leave the office are at a much higher risk of being lost or stolen, whether left on a train, taken from a hotel room or snatched in a public place. Encryption software protects against this by scrambling all the data on the drive using a key, so that the contents are meaningless to anyone who does not have that key, even if they remove the drive and connect it to another computer. This means that if a laptop is stolen the company loses the hardware but not the confidential business information or the personal data of its customers, which also helps the company meet its legal obligations under data protection law and avoid the penalties and reputational damage that follow a data breach.