OCR GCSE Computer Science Teaching and Learning Resources
Chapter 12: Systems software
ANSWERS TO QUESTIONS IN THE STUDENT’S BOOK
Page 98
Question
1. What are the main functions of an operating system?
Answer
·
Manages computer hardware
·
Manages programs installed and being run
·
Manages data transfer between memory locations, CPU and secondary storage
·
Provides a file system for storage and retrieval of files
·
Manages security
·
Provides a user interface
·
Provides an interface between the hardware and the applications
Question
2. Explain why multi-tasking is needed in an operating system.
Answer
Multi-tasking allows several applications to work, apparently, at the same time. The
processor works very quickly, so time spent waiting for access to data, user input, and
so on, is used to run more than one task or application by switching between them
very quickly. This means the CPU is used more effectively.
Question
3. Describe the following utility programs:
a) device drivers
b) anti-virus software
c) defragmenter
d) system clean-up.
Answer
a) Device drivers provide the interface between the peripheral device, the
hardware and the applications.
OCR GCSE Computer Science
© Hodder & Stoughton Limited 2016
OCR GCSE Computer Science Teaching and Learning Resources
b) Anti-virus software monitors incoming files or scans the hard drive to identify
and remove potentially harmful software.
c) A defragmentation utility scans the hard drive for fragmented files and
reorganises the files on the disk surface so that individual files and free spaces
are put together.
d) System cleanup is a utility that identifies files that are no longer required and
removes them from the hard drive to free up more space.
Question
4. Describe the advantages and disadvantages of a using a full backup system
compared to an incremental backup system.
Answer
Full backup is able to restore the data very quickly and only requires the last backup
file to do so.
Incremental backup is generally much slower when restoring data and requires the full
backup and all incremental backups in order to restore the data.
Full backup is the slowest method for backing up data, requiring a full copy of the
system to be made each time and stores lots of duplicated data.
Incremental backup requires just one full backup, then subsequent backups only add
data that is changed. It takes up far less space than full backup and does not store any
duplicated data.
Question
5. What are the advantages of setting auto update for an operating system?
Answer
Using auto update ensures the operating system and utilities are always using the
latest versions. This improves security, fixes bugs and can improve the performance
of the system. Some updates are not necessary and can simply take up space; others
may be incompatible with software on the system and cause issues with running that
software.
Question
6. Describe two utilities that are available to improve the performance of the hard
drive in a computer.
OCR GCSE Computer Science
© Hodder & Stoughton Limited 2016
OCR GCSE Computer Science Teaching and Learning Resources
Answer
Some examples:
·
Disk checking and repairing: Used to locate and solve problems on the disk
drive, such as bad links between file segments, bad sectors of the disk. The
utility reorganises the data to restore links and maps bad sectors so they are
not used in future.
·
Encryption software: Used to encrypt files to keep them secure on the system
or in transit. Uses keys to scramble the data. A key is needed to unscramble
the data in order for it to be read.
·
Compression software, e.g. zip: Used to compress data into a smaller file.
Used frequently for emailing large files or for putting large files on limited
space media.
·
File search utilities, e.g. spotlight: Used to locate files by name or content
when the location is not known.
OCR GCSE Computer Science
© Hodder & Stoughton Limited 2016