Chapter 3.2 A - Input devices FINAL BOARDS Flashcards
What is a barcode
a series of dark and light parallel lines of varying thickness
What happens after the barcode is read (supermarket)
The barcode is looked up in stock database
When the barcode number is found, the stock item record is looked up
The price and other stock item details are sent back to the checkout or the POS
the number of stock items in the record is reduced by 1 each time the barcode is read
this new value for number of stock is written back to the stock item record
the number of stock items is compared to the re-order level; if it is less than or equal to this value, more stock items are automatically ordered
once an order for more stock items is generated, a flag is added to the record to stop re-ordering every time the stock item barcode is read
when new stock items arrive, the stock levels are updated in the database.
What is a key field
how does it relate to a barcode
the field that uniquely identifies a record in a file
barcode acts as a key field for items in a supermarket
What is the POS
point of sales terminal
Advantages of barcodes (managers)
Automatic stock control
More up-to-date sales information and sales trends
Much faster and easier to change prices on stock items
Advantages of barcodes (customer)
Faster checkout queues
Errors in billing are reduced
An itemized bill is given to the customer
What is a QR code
a matrix of dark and light squares which represent data
Full form of QR
Quick Response
How can a QR code be read
QR code apps and smart phone cameras
Common uses of QR codes
Advertising
Restaurant menus
Storing boarding passes of flights and trains
Advantages of QR code compared to Bar code
More information
Few errors - QR Codes have a built in error checking systems. This helps guard against badly printed, damaged QR codes
Easy to read - don’t need a laser or an led light source
Disadvantages of QR codes
Can be used to transfer malicious codes. It is very easy to embed malicious code into a QR code. This code could be a virus, etc.
What is the process of transferring malicious codes through a QR code called
Attaging
What is a Frame QR code
a type of QR code that includes a space for advertising
What colour system do most cameras use
24-bit RGB Colour system - 3 primary colours, each get 8 bits.
What does the number of pixels in the picture determine
size of the file used to store the photograph
What does the quality of the image (camera) depend on
Recording device (how good the camera lens is and how good the sensor array is)
Number of pixels used (the more pixels used, the better the image)
Levels of light and how the image is stored (JPEG, raw file, png, etc)
What is a DAC (full form and def)
Digital to analogue converter - device that converts digital data into electric currents
What is a virtual keyboard
an onscreen keyboard which uses the features of the touch screen to emulate a physical keyboard
How does an ergonomic keyboard tackle RSI
these have the keys arranged differently
They are also designed to give more support to the wrists and hands when doing a lot of typing.
What is RSI (full form and def)
repetitive strain injury - pain felt in the muscles,
nerves and tendons caused by a repetitive action (for
example
What does a microphone do
Converts sound waves into an electric current. The current is then converted to a digital format so that the computer can process/store it
What is the nature of the current gen by the microphone
analogue
What is a CMOS (full form and func)
complementary metal oxide semiconductor - a chip that generates an electric current when light falls on its surface
