A-LevelComputer ScienceHardware9618/12 · May/June 2024 · Q217 Marks

A computer game is being designed that users will be able to play using a virtual reality (VR) headset.

(a)Complete the description of the principal operation of a VR headset. A headset can have one or two that output the image to the user. The headset has speakers that output surround sound to give a realistic experience. The user's head movements are detected using a sensor. This sensor is a . The data is transmitted to a microprocessor that analyses the data to identify the of movement. Some headsets use that record the user's eye movements for analysis.[4]
(b)The computer uses a buffer when transmitting data to the VR headset. Explain how a buffer is used when data is transmitted between the computer and the VR headset.[3]
(c)The VR headset has Electrically Erasable Programmable Read Only Memory (EEPROM). Explain the benefits of using EEPROM instead of other types of Read Only Memory (ROM) in the VR headset.[3]
(d)(i)Describe how the data for a bitmapped image is encoded.[3]
(d)(ii)Describe the contents of a vector graphic drawing list.[2]
(d)(iii)The bitmap video is not compressed before transmission to the VR headset. Give two reasons why the video does not need to be compressed. 1 2[2]

Mark scheme

Marking points from the official mark scheme (May/June 2024). The mark or mark type is shown in brackets.

[1] (a) (LCD) displays/screens/lenses
[1] (a) gyroscope/accelerometer
[1] (a) direction/speed
[1] (a) digital cameras
[1] (b) The buffer is used as a temporary store for data going to the headset
[1] (b) Data is transferred into the buffer by the computer
[1] (b) Data is retrieved from the buffer by the headset
[1] (b) When the buffer is empty/full an interrupt is sent to the computer requesting more data/stopping further data being sent
[1] (b) When the headset has enough data/needs more data, an interrupt is sent by the headset to the computer to stop sending data from buffer
[1] (c) EEPROM allows frequent/multiple read/write/erase operations
[1] (c) so the headset can take advantage of new features
[1] (c) without fully erasing the contents of the firmware in the headset first // can erase a particular byte or the whole EEPROM
[1] (c) without removing the chip(s)/firmware from the headset
[1] (c) the contents of the firmware in the headset can be changed by the user without technical expertise
[1] (c) Cheaper to manufacture so headset will be cheaper to purchase
[1] (d)(i) Image is made of pixels and each pixel has one colour
[1] (d)(i) Each colour has a unique binary code
[1] (d)(i) Code for the colour of each pixel is stored in sequence
[1] (d)(ii) List of objects in the drawing
[1] (d)(ii) A list that stores the command/description/equation required to draw each object
[1] (d)(ii) Properties of each object e.g. the fill colour, line weight/colour
[1] (d)(iii) Dedicated connection to the headset // not sharing bandwidth
[1] (d)(iii) Already fast connection that can transmit the data without slowing
[1] (d)(iii) Video may already be a small file size and does not need further reduction
[1] (d)(iii) Video is not saved so storage is not an issue in the headset