A keyboard (キーボード) is an input device that sends characters, digits, symbols and operating commands to a computer when you press its rows of keys.
Area
Where it sits
Main use
Character keys
The large central area
Typing kana, letters and symbols
Numeric keypad
A block of digits on the right edge
Entering amounts, quantities and other numbers in a row
Function keys
One row across the top
Calling up whatever the current software assigns
Each key press sends the character code or command tied to that key to the computer. The layout is divided into areas such as the numeric keypad (テンキー), which gathers the digits 0 to 9 and the arithmetic signs in one place, and the function keys (ファンクションキー) named F1 to F12 along the top row.
AnalogyPicture the numeric keypad as a calculator's button pad bolted onto the side, and the function keys as a row of empty drawers that each program fills with something different.
How to rememberThe Japanese name テンキー literally means "ten key", a reminder that it is the block holding the ten digits 0 to 9.
Exam points
ExamThe numeric keypad (テンキー) is the area that groups the digit keys and the arithmetic keys together, used to enter numbers quickly one after another.
ExamWhat the function keys (ファンクションキー) do is not fixed; the operating system or each application decides it.
An image scanner (イメージスキャナー) is an input device that shines light on an original such as a sheet of paper, reads it, and brings the page into the computer as image data.
Shine light on the original
Measure reflection point by point
A set of dots = image data
OCR turns the characters into text
When the characters are to be handled as text, OCR recognizes the letter shapes in the image and replaces them with character codes.
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What comes in is an image made of dots, so the words in it cannot be rewritten as text as they stand. OCR (optical character recognition) is what recognizes handwritten or printed letter shapes and replaces them with text in character codes. How finely the scanner reads is stated in dpi (how many dots one inch is split into), and a larger value means a finer reading.
AnalogyA photocopier prints a copy of the original on paper, while a scanner makes the same copy as an image file inside the PC. That copy is just a picture, so fixing the words in it takes a separate step of transcribing them.
How to rememberTo scan means to run your eyes over something line by line, just as a strip of light runs down the original.
Exam points
ExamOCR (optical character recognition) is the technology that recognizes handwritten or printed characters in an image and converts them into editable text in character codes; a device that does this (an optical character reader) is also called OCR.
Examdpi is a unit for the number of dots per inch; for an image scanner (イメージスキャナー), a larger value means more of the original's fine detail is captured.
A barcode reader (バーコードリーダー) is an input device that shines light on a barcode, which encodes digits and other characters as lines of varying width and spacing, and reads them from the differences in reflection.
What it reads is a number that identifies a product or item, and the computer uses that number to look up the name and price in its own records. Barcode readers are used for checkout at shop registers and for logging goods in and out of warehouses.
AnalogyThink of the number label on the spine of a library book, read not by eye but with a single quick sweep of light.
How to rememberBar as in a stick: the widths of the sticks and the gaps between them are themselves a code for the digits.
Exam points
Mix-upA barcode reader (バーコードリーダー) decodes the stripes back into a number by fixed rules, whereas an image scanner (イメージスキャナー) receives the page as an image made of dots.
A webcam (Webカメラ) is a small camera that films the people or scenery in front of it and streams the footage to the computer as video without a break.
An image sensor turns the light coming through the lens into electrical signals and passes them to the PC without interruption. Some are built into the top of a laptop screen and others plug in over USB, and they are used for video meetings and live streaming.
AnalogyAn eye attached to the PC that keeps showing what it sees on the other person's screen as it happens.
How to rememberThe "web" in the name comes from its use in sending pictures across the internet.
Exam points
Mix-upA webcam (Webカメラ) takes in ongoing motion as continuous video, whereas an image scanner (イメージスキャナー) scans each page laid on it, one sheet at a time, into a still image.
Image Scanner vs. Webcam
Aspect
Image Scanner
Webcam
What it captures
A page laid on the glass
The people or scenery in front of it
Key differenceHow it takes it in
Scans one sheet into a still image
Films continuously into video
Main use
Digitizing paper originals
Video meetings and streaming
Key points
The numeric keypad is the area for digits and arithmetic signs, while the function keys are keys whose job the software decides.
An image scanner produces an image, and turning it into text you can rewrite takes OCR.
How finely a scanner reads is stated in dpi, and a larger value means finer detail.
A webcam uses an image sensor to turn light into electrical signals and hands what it films to the PC without a break.