Mark scheme answers

• Explain how one byte is used in ASCII but 2 bytes in Unicode 


  One byte provides 28 different values. These can represent the 128 characters in ASCII. Two bytes provide 216 different values. These can represent 65536 characters in Unicode
• Processor

  The processor consists of the Control Unit , a series of registers and the Arithmetic Logic Unit. It includes main memory. It carries out mathematical operations during the FE cycle
• Data bus

  Transfers instructions and data between processor components during the FE Cycle
• Port

  A physical channel where peripherals can be connected to enable data transfer between devices and the processor
• USB Memory Stick

  Uses flash memory. It is non volatile and has no moving parts. Its contents can be electrically erased and reprogrammed multiple times. It is random access storage medium. It has relatively high speed access and requires relatively little power. It is very compact so is very convenient method of storing and transferring data. can have a large capacity and are suitable for transferring and storing large amounts of data. USB port is available on most devices enabling data transfer between them
• Multitasking

  A single user can perform more than one application at a time but only one application is actually running at any time. The processor switches from one application to the next and resources are shared between applications.
• Multi threading

  Different copies of a single program or process can be executed at the same time. The data set for each thread is kept separate. The data sets can be at different stages of precessing. Can be concurrent or single threading
• What happens to the number of instructions executed as the clock speed increases?

  More instructions can be executed
• What is the processor type that has a smaller instruction set?

  RISC
• How does RISC affect processing speeds?

  It slows down overall processing speeds
• What is the processor type that has a larger instruction set?

  CISC
• How does CISC affect processing speeds?

  It speeds up overall processing speeds
• What is the benefit of dual-core or quad-core processors?

  Workload can be shared between cores
• What does cache size refer to?

  High speed access to frequently used data
• How does cache size affect data access speed?

  Larger cache size allows faster access
• What is one method of input mentioned?

  Using a physical/on-screen keyboard
• What is zipping used for?

  To compress files
• What type of compression does zipping use?

  Lossless data compression
• What does zipping remove from data?

  Redundancies within data
• What is a benefit of zipping files?

  Faster transfer of files
• What does a bitmap store data about?

  Individual pixels
• How does the number of bits affect color depth in bitmaps?

  More bits allow more colors
• What does JPEG use to reduce file size?

  Compression to identify repeated pixel arrangements
• What is a drawback of JPEG compression?

  It can reduce image quality
• What does file backup software enable?

  Recovery of files if originals are destroyed
• What does archive software do?

  Removes unnecessary data from systems
• What is a transaction file used for?

  To collect all data to be input
• When is data usually processed in a transaction file?

  During a quiet period or overnight
• What is multithreading?

  A process on a single set of data
• How do threads operate in multithreading?

  They process data independently and concurrently
• What is required for downloading software?

  Web access not required
• What happens when software is updated via the web?

  Users immediately access the updated software
• What does a web server do?

  Delivers webpages across the Internet
• What technology does a web server use?

  Client-server technology
• What does HTML use to define webpage structure?

  Tags
• How can HTML be created?

  Using a text editor or web page editor
• What does CSS describe?

  How HTML elements are displayed
• What is the purpose of a public key?

  To encrypt messages
• Who can decrypt an encrypted message?

  The recipient using their private key
• What are the differences between RISC and CISC processors?

  • RISC: Smaller instruction set, slower processing
  • CISC: Larger instruction set, faster processing