3 HardwareAS Level

3.1 Computers and their components

8 of 8 objectives have lessons · 0 studied · 0 secure

Lessons

Input, output, memory and storage: why you need all fourWhy every computer system needs input devices, output devices, primary memory and secondary storage, including removable storage. 4 min, not started
Embedded systems: tiny computers hiding everywhereWhat an embedded system is, what is inside one, and the benefits and drawbacks of using one in a device. 4 min, not started
Laser printers: printing with static electricityHow a laser printer uses a charged drum, a laser, toner and a fuser to print a page, as a step-by-step method for exam answers. 5 min, not started
3D printers: building objects layer by layerHow a 3D printer turns a CAD design into a solid object by slicing it into layers and adding material one layer at a time. 4 min, not started
Microphones and speakers: the same trick, both waysHow a speaker turns a digital sound file into sound using a DAC, an amplifier, a coil and a magnet, and how a microphone does the reverse. 5 min, not started
Magnetic hard disks: spinning platters and flying headsHow a hard disk drive stores bits as magnetised areas on spinning platters and how its heads find, read and write data in tracks and sectors. 5 min, not started
Solid state (flash) memory: trapping electronsHow flash memory stores bits as electrons trapped on floating gates, why it is non-volatile, and how an SSD compares with a hard disk. 5 min, not started
Optical discs: reading with reflected lightHow an optical disc reader uses a laser and a photodiode to read pits and lands on a spiral track, and how discs are written and rewritten. 5 min, not started
Touchscreens: resistive and capacitiveHow resistive and capacitive touchscreens detect where they are touched, and how to choose between them. 5 min, not started
Virtual reality headsets: fooling your eyesHow a VR headset uses two screens, lenses, motion sensors and fast processing to make a 3D world that responds as you move your head. 4 min, not started
Buffers: smoothing out speed differencesWhat a buffer is, why it is needed between devices that work at different speeds, and how a print buffer and interrupts let the processor keep working. 5 min, not started
RAM and ROM: what's different and who uses whichThe differences between RAM and ROM, and how a range of devices use each one, including the boot process of a computer. 5 min, not started
SRAM and DRAM: two ways to build RAMHow static RAM and dynamic RAM store bits, why DRAM must be refreshed, and why cache uses SRAM while main memory uses DRAM. 5 min, not started
PROM, EPROM and EEPROM: ROM you can writeHow PROM, EPROM and EEPROM are programmed and erased, how they differ, and which one suits a device's job. 4 min, not started
Monitoring or control: watching versus doingThe difference between a monitoring system and a control system, and the parts each one uses, from sensor and ADC to processor and actuator. 4 min, not started
Sensors and actuators: the system's senses and musclesWhat temperature, pressure, infra-red and sound sensors measure, how to pick the right sensor for a job, and how actuators let a computer change the world. 4 min, not started
Feedback: how a control system checks its own workWhat feedback is in a control system, why it matters, and how a greenhouse heater uses it to hold the temperature near a target, in words, a graph and pseudocode. 5 min, not started

Syllabus objectives

8 objectives

What Cambridge says you should be able to do, in our words. Codes are the topic number plus the objective’s position.

3.1.1

Understand the need for input, output, primary memory and secondary (including removable) storage.

Taught in: Input, output, memory and storage: why you need all four · 6 questions

3.1.2

Understand embedded systems.

Including the benefits and drawbacks of embedded systems.

Taught in: Embedded systems: tiny computers hiding everywhere · 6 questions

3.1.3

Describe the principal operations of hardware devices.

Including laser printer, 3D printer, microphone, speakers, magnetic hard disk, solid state (flash) memory, optical disc reader/writer, touchscreen and virtual reality headset.

Taught in: 3D printers: building objects layer by layer, Solid state (flash) memory: trapping electrons, Magnetic hard disks: spinning platters and flying heads, Laser printers: printing with static electricity, Microphones and speakers: the same trick, both ways, Optical discs: reading with reflected light, Touchscreens: resistive and capacitive, Virtual reality headsets: fooling your eyes · 46 questions

3.1.4

Understand the use of buffers.

Taught in: Buffers: smoothing out speed differences · 6 questions

3.1.5

Explain the differences between Random Access Memory (RAM) and Read Only Memory (ROM).

Including their use in a range of devices and systems.

Taught in: RAM and ROM: what's different and who uses which · 6 questions

3.1.6

Explain the differences between Static RAM (SRAM) and Dynamic RAM (DRAM).

Including the use of SRAM and DRAM in a range of devices and systems, and the reasons for using one instead of the other depending on the device and its use.

Taught in: SRAM and DRAM: two ways to build RAM · 7 questions

3.1.7

Explain the differences between Programmable ROM (PROM), Erasable Programmable ROM (EPROM) and Electrically Erasable Programmable ROM (EEPROM).

Taught in: PROM, EPROM and EEPROM: ROM you can write · 6 questions

3.1.8

Understand monitoring and control systems.

Including: the difference between monitoring and control; the use of sensors (including temperature, pressure, infra-red and sound) and actuators; the importance of feedback.

Taught in: Feedback: how a control system checks its own work, Monitoring or control: watching versus doing, Sensors and actuators: the system's senses and muscles · 18 questions