1.1.3 lesson 1 input, output and storage devices Flashcards
what is an input device
peripherals that allow you to provide/pass data + control signals into the computer system
what is an output device
peripherals that can take data stored in digital form and convert it into another format that humans can process i.e. sound, images or vibrations
what is a storage device
- any device used for temporary or permanent storage of data
what are the 2 types of storage device and give examples of each
- internal (RAM, SSD, magnetic hard disk)
- external (optical disk, USB, memory card, external hard drive)
what input devices would a cashpoint have
- card reader, keypad, buttons, camera (security purposes)
what output devices would a cashpoint have
- monitor, printer (for receipt), speaker (gives audio feedback), actuator/motor (delivers cash)
what storage devices would a cashpoint have
- internal hard drive, RAM
give examples of input devices (the list is exhaustive lol)
- keyboard
- mouse
- trackpad (touchpad)
- graphics/drawing tablet
- mic
- flatbed scanner
- OMR (optical mark recognition) scanner
- magnetic stripe card reader
- smart card and barcode readers
- NFC reader
- touchscreen
- camera
- sensor
- remote control
what is the purpose of a keyboard
- Allows user to enter character data and it often has function / special purpose keys to perform common user tasks such as sending signals to control the volume or to switch between windows.
what is the purpose of a mouse
Allows user to ‘point and click’ to select icons, or to position cursor on screen.
what is the purpose of a touchpad and where are they commonly found
- Offers same functionality as mouse but user controls movement of cursor using their fingers.
- Commonly found on laptop computers.
what is the purpose of a drawing tablet
creates digital drawings with special Stylus by pressing tip on tablet surface.
what is the purpose of a mic and name a use of this input device
- Captures analogue sound waves + converts them into electronic signals.
- Common uses include capturing voice whilst on call or recording live music to be stored digitally
what is the purpose of a flatbed scanner
- Allows users to scan physical document I.e. photograph, handwritten note etc and save as a digital bitmap image.
what is the purpose of an optical mark recognition scanner
- This technology is often used to input answers / marks that a candidate has made on a multiple choice test paper.
give a use of a magnetic stripe card reader. And what is this input device capable of doing
- hotel door access cards contain a magnetic strip that holds data.
- This input device is capable of reading data.
what is the purpose of a smart card reader. And where are they used mainly
- Reads data from embedded integrated circuit (IC) chip.
- Most retail shops have smart card readers that read data taken from the chip found on a customers bank card to enable transactions
what does a NFC (near field communication) reader do? And where are they used
- Reads data from an NFC tag.
- Common use = contactless payment in shops. Here, an NFC reader uses radio waves to read data from bank card / mobile phone when the two devices are close to each other.
what is the purpose of a touchscreen
- The input device allows user to use finger / stylus to select icons, use on-screen keyboard, and perform navigation tasks
why are touchscreens technically both input and output devices
- output provided due to input
- the display screen usually listed as an output device but touchscreens are designed so that the same device can be used to input data.
now, give examples of output devices
- speakers
- inkjet printers
- laser printers
- plotters
- 3D printers
- display screens (monitor)
- headphones
- digital / data projector
- actuators
what is the purpose of speakers. can they be built in, external or both?
- generates sound waves from data being received from sound card. Often built into devices but can also be connected as external peripherals.
what are inkjet printers (include ink they use)
- Non-impact printer that uses liquid ink to produce black+white or colour prints,
why are inkjet printers favourable for photographers
- rich in colour –> suitable for photos
- high-end inkjet printers have good paper handling capabilities + print at very high resolutions —> ability to show large amount of detail
what is the biggest drawback of inkjet printers
- COST! (ink cartridges cited as 1 of most expensive commodities)
what users favour this type of printer
- photographers (REASONS MENTIONED EARLIER)
- Inkjet printers used at home (low upfront cost).
What are laser printers used for (include ink used)
- print docs using powdered ink (toner)
- they tend to not print photos
what are the advantages of laser printers
- print whole page at a time –> faster than inkjet (high-spec laser printers have capability to produce hundreds of pages per min)
- toner = cheaper than liquid ink + lasts longer.
what are the disadvantages of laser printers
- doesn’t use rich colours (don’t use for photos)
- other parts like drum need to be replaced occasionally
what are plotters
- large device that uses 1 or more pens to draw an image. can also handle wide paper
- They are lifted / applied to paper as required, to produce very precise drawings.
where are plotters used
- Used in engineering and architectural practices.
what are 3D printers
- Works by interpreting a set of instructions that model object into 3D space
describe process of how 3D printing works
- 3D designs on a computer printed in solid form using filament, usually in the form of plastic-based resin, which is heated and printed layer (slice) by layer to form a solid object.
what subject area does a 3D printer have potential for and why
- Has potential in science –> bioprinters to make living body parts.
what 2 types of display screens are there
- stand-alone monitor
- built-in screen.
what are LCD screens, stating what “LCD” means and state 1. advantage and 2. main use
- liquid crystal display screen
1. low cost
2. most common display in offices and on standard desktop and laptop computers
what are LCD screens being superseded by and why?
- LED screens
- teach uses less power that LCD —> cheaper + more environmentally friendly
what variant of LED screens exists today.
- OLED (organic light-emitting-diode)
what are the benefits of OLED screens
- lighter + more flexible than LED displays –> good option for phones and tablets.
give examples of storage devices
- CD
- DVD
- Blu-Ray
- USB/Flash drive
- SD card
- Portable solid-state drive
- internal solid-state drive
- Magnetic hard drive
- Mass storage tape
- External hard drive
- Cloud storage
factors to consider when choosing an appropriate device and method for data output
- Cost
- Compatibility
- Print resolution (printers)
- Max. voltage (motors)
(Some output devices can be quite specialised so would require more specific criteria)
factors to consider when choosing an appropriate device and method for data input
• Cost
• Speed
• Accuracy
• Reliability
in terms of the criteria needed to be considered for data input, what would score poorly in all those areas and why
- humans
- when human inputs data manually, work = expensive, slow + less accurate as we get distracted, tired + can make errors.
when a human inputs data manually, what process should happen to reduce errors
- data validation to catch all possible errors. use a verification technique like double entry.
- Well-designed systems will disable the functionality to copy paste these fields so that you can’t replicate input error
what is a biometric
- physical characteristic I.e. fingerprints, facial images, irises, and voice that can be used as a reliable recognition technique
what is biometric spoofing
- method of fooling biometric scanners. it can be easy to spoof with things like fingerprints —> obtaining copies = easy
what is the most secure form of human authentication
- Iris recognition since iris is well protected by the cornea.
fill gaps:
- there are a wide range of ________ systems where sensors act as _________ inputs. The _________ signal is converted to digital form by an __________ __ _______ ______________ (ADC).
1.control
2. analogue
3. analogue
4. analogue to digital converter
where are sensors used and give examples of different types in mobile phones
- robotics, building control and flight control systems
- accelerometers, ambient light sensors, GPS receivers, barometers
what are digital cameras + their composition and describe the 2 sensors it may use
- uses CCD (charged-coupled device) or CMOS (complementary metal-oxide semiconductor) sensor comprising of millions of light sensors (photo sites) arranged in a grid forming millions of pixels of image. ADC used to form binary data from each sensor which is recorded onto image processing engine so image can be reproduced
what do the photo sites measure
- light/colour intensity which is then used to determine the colour of each pixel
what is the bayer filter used for
- provides array of red, green, blue filters. these colours detected at each photosite. final value from each pixel derived from own colour intensity
what does the image processing engine do automatically for mobiles
- compress to JPEG
what influences the image quality for digital cameras
- size + nature of sensor.
- Larger image sensors have more photosensitive points —> can capture images with greater fidelity/accuracy
recall the 2 sensors used in digital cameras then state benefits and drawbacks of each
- CCD and CMOS
- CCD = high quality but expensive. CMOS use less energy —> mobiles / other power intensive devices
what is RFID technology
- uses both input (read signal from RFID chip) + output (wirelessly transmit signal in form of radio waves from active tag).
- use of radio signals = system doesn’t require line of sight between tag + reader
what is RFID tech made up of
- antenna i.e. reader (for receiving + transmitting radio frequency signals)
- chip i.e. tag (processes signals). Each tag has unique identifier + often stores additional data in a non-volatile memory cell
where is RFID technology used
- tiny sticky ‘labels’ attached to items for sale
- transport cards
- embedded in employee / student ID cards used to open doors / barriers
- track movements of pets (inserted into fleshy part of neck + can be read by handheld reader)
what are passive devices/tags. include range of system and what passive device relies on to work properly
- don’t contain battery (cheaper)
Instead, device relies on radio waves transmitted by reader. Antenna collects energy from transmitter to activate chip. - range of passive system = up to 1m
what are active devices/tags. include range of system and common use
- small battery within tag + device transmits identifier at regular intervals.
- range up to 200m but depends on battery
- common in shops (battery-powered tags secured onto items). tags deactivated / removed when goods paid for. reader is situated at exit + alarm triggered if active tag detected when person exits
what are barcode readers
- means of representing data in machine-readable form, representing data using set of parallel lines of varied width + spacing.
- each character in barcode represented by 7 equal sized bars that are black + white
what feature to barcodes have for validation
- full code printed in case needed to enter manually
- check digit (extra digit / character added to end of code)
- using algorithm, long code entered + check digit calculated + compared to value on barcode
what aspect of barcode acts as reference point to barcode reader
- guard bars (pairs of longer bars at either end + middle of barcode)
how is a barcode read and how does it give feedback that barcode has been scanned
- barcode scanner which uses laser light to illuminate barcode to capture reflected light. More light reflected from white areas than black bars.
- set of electrical pulses generated that correspond to black + white stripes in barcode. These pulses are processed + converted to binary number that represents code.
- read successfully by sounding a beep / showing green light.
what are QR codes.
- quick response codes
- provides links to webpages/email/app that hold data like tickets or travel info
criteria to choose suitable printer:
- speed, print resolution (measured in dots per inch - dpi), quality of colour reproduction, paper handling + cost of consumables.
what are impact printers, what were their common use + drawbacks (x3)
- produce characters by striking paper.
- common for printing on multipart stationery (sheets carbonated to produce 2 or+ copies)
- noisy, slow and print quality = poor
how does a laser printer work?
- bitmap image of page is created.
- negative charge applied to print drum + laser used to change polarity on drum, in line with bitmap image.
- drum exposed to positively charged toner that attracts to negatively charged areas on drum.
- sheet of paper passed under drum + toner transferred onto paper.
- paper passes to heating stage to ensure toner sticks to paper.
give the 2 types of displays devices and factors to consider to choose screen/monitor
- stand-alone monitor or built-in screen
- screen size, resolution (ppi), colour reproduction so colours precisely calibrated
what are the 3 types of display
- LCD, LED and OLED
what is LCD. state advantages and disadvantages
- liquid crystal display
- cheap
- being superseded by LED which is better
what are LED screens and state advantages
- light emitting diode
- use less power than LCD —> less heat generated, cheaper + more environmentally friendly
- brighter light = sharper definition
what are OLED screens. state advantages + 1 drawback
- organic LED
- no need for backlight —> consume less power (in portable device = longer battery life)
- brighter, thinner + lighter, screen = plastic
- downside = wear out faster + sensitive to water (not good if portable)
what are the benefits of automated systems. use example of greenhouse control system (temp)
- cheaper, safer + efficient
- computer + temp probe to monitor heat. once temp reached, control system sends signal to set of actuators to open / close windows
describe some input devices (there’s 3!) that can be used for ppl with physical disabilities i.e. a person may not be able to use keyboard
- sip/puff switch - pneumatic device that allows user to control computer systems by drawing / blowing air into sensor reader. Some sip/puff systems can be used to switch devices on + off, while some used to control keyboard input based on frequency of user actions.
- Foot switches - allow user to control input to system through series of pedals.
- Braille keyboard for users who can read Braille (keys have two raised representations of characters: printed character + Braille equivalent)
describe some output devices that can be used for ppl with physical disabilities
- speakers - peripheral for people with visual impairments, to allow access to content through screen readers + text-to-speech utilities.
- screen reader = software application to read contents of screen to user.
- If user can read Braille, refreshable Braille display can be used to display characters as a series of dots formed by pins that protrude through the flat surface of device. As info on computer screen changes, so do Braille characters on display so user can read what’s on screen.
