Computer science 1
What characteristics determine the clarity of a computer screen?
*DOT PITCH (dp) is the amount of space between adjacent pixels (square picture elements) on screen. The closer the pixels, the crisper the image. Get .25 dp or better. *RESOLUTION refers to the image sharpness. The more pixels, the better the resolution. Expressed in dots per inch (dpi) . *COLOR DEPTH (bit depth) is the number of bits stored in a dot (pixel). The higher the number the more true the colors. 24-bit color depth is better than 8-bit color depth, but it needs more video card memory. *REFRESH RATE is the number of times per second the pixels are recharged - a higher rate gives less flicker.
What is a common use of dumb terminals?
*a.k.a. Video Display Terminal (VDT) *Has display screen and keyboard *Can do input and output only - no data processing
Discuss the different types of printers and their features. (impact printer)
- impact printers (dot-matrix printer) print by striking the paper directly
Describe two situations in which scanning is useful
1.Flatbed scanners work like photocopiers - the image is placed on the glass surface, then scanned 2.Use light-sensing equipment to translate images of text, drawings, and photos into digital form
An input device that collects specific data directly from the environment and transmits it to a computer is called a(n)________________ .
Active; Passive
_________ is the science of measuring individual body characteristics.
Bio metrics
A debilitating condition caused by pressure on the median nerve in the wrist, producing damage and pain to nerves and tendons in the hands, is called ___________ .
Carpal tunnel syndrome
A(n) ________ accepts input supplied with finger and hand gestures.
Cathode Ray tube
LCD Quality Factors (viewing angle)
Determines how far you can move to the right or left side (also above and below) before the image degrades - the larger the angle the better - 150 degrees is recommended for 17 in. monitor
The measure of the number of dots that are printed in a linear inch is called or ___________ .
Dots per inch; DPI
A(n) _________ terminal is entirely dependent for all its processing activities on the computer system to which it is connected.
Dumb
____________ is the study of the physical relationships between people and their work environment.
Ergonomics
Computer users have no need to be concerned about ergonomics.
False
It has been proved that electromagnetic fields pose no danger to human beings.
False
The lower the refresh rate, the more solid the image looks on the screen.
False
The abbreviation dpi stands for "dense pixel intervals."
False - Dots per inch (DPI, or dpi) is a measure of spatial printing or video dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch (2.54 cm).
Resolution is the amount of space between the centers of adjacent pixels.
False -In computers, resolution is the number of pixels (individual points of color) contained on a display monitor, expressed in terms of the number of pixels on the horizontal axis and the number on the vertical axis. The sharpness of the image on a display depends on the resolution and the size of the monitor.
A digital pen is a specialized output device designed to produce large, high-quality graphics in a variety of colors.
False- *Writing instrument *Writers can write on paper *A tiny camera in the pen tip captures the writing *A microchip in the pen converts the pen to digital ink *The writing is sent as an image file to the computer *Some versions require special paper
Bar codes are input with pointing devices.
False: pointing devices- a generic term for any device (e.g., a graphics tablet, mouse, stylus, pointing stick, or trackball) used to control the movement of a cursor on a computer screen.
A printer that forms characters or images by striking a mechanism such as a print hammer or wheel against an inked ribbon, leaving images on a paper, is called a(n) ____________ printer.
Impact
The two main categories of printer__________, are, _______ and .
Impact; Non-impact
Discuss the different types of printers and their features.(Inkjet printers)
Inkjet printers spray onto paper small, electrically charged droplets of ink from four or more nozzles through holes in a matrix at high speed. Like laser and dot-matrix printers, inkjet printers form images with little dots. Inkjet printers commonly have a dpi of 4,800 x 1,200; they spray ink onto the page a line at a time, in both high-quality black-and-white text and high-quality color graphics.
____________ printers enabled the development of desktop publishing.
Laser
LCD is short for __________ .
Liquid Crystal Display
MICR
MICR - magnetic-ink character recognition Uses special magnetized inks Must be read by a special scanner that reads this ink Used on bank checks
LCD Quality Factors (contrast ratio)
Measure of the difference in light intensity between the brightest white and the darkest black - higher the better (ex 400: 1 is better than 15:01
A(n) ___________ is an input device that is rolled about on a desktop and directs a pointer on the computer's display screen.
Mouse
Discuss the different types of printers and their features.(Multifunction printers)
Multifunction printers Printers that combine several capabilities: Printing Scanning Copying Faxing Cost less and take up less space than buying the four separate office machines. But if one component malfunctions, so will the other functions.
OCR
OCR - optical character recognition Converts scanned text from images (pictures of the text) to an editable text format
OMR
OMR - optical mark recognition Uses a special scanner that reads bubble (pencil) marks Used in standardized tests such as the SAT and GRE
______________ consists of devices that translate information processed by the computer into a form that humans can understand.
Output hardware
A(n) ____________ is software that describes the shape and position of characters and graphics to the printer.
Page description language
__________ is short for "picture element."
Pixel
Which of the following display standards has the highest screen resolution? a. XGA b. UXGA c. VGA d. SVGA e. QXGA
QXGA
A device with a microchip that contains code numbers that can be read by a scanner's radio waves is a(n) a. optical character reader b. nanotube c. pointing device d. RFID tag e. multifunction mouse
RFID
briefly describe RSI and CTS. Why are they problems?
RSI - Repetitive Stress Injuries: Wrist, Thumb Small Screen - Vision Issues Back and Neck Injuries Lap Injuries - Burns from Older Laptops Hearing Loss CTS - Carpal tunnel syndrome: Caused by pressure on the median nerve in the wrist, through short repetitive movements.
What is pixel short for? What is a pixel?
Short for Picture Element, a pixel is a single point in a graphic image. Graphics monitors display pictures by dividing the display screen into thousands (or millions) of pixels, arranged in rows and columns. The pixels are so close together that they appear connected.
What is source data entry?
Source data-entry devices is devices that create machine-readable data and feed it directly into the computer without keyboard or mouse. There are much electronic devices that acts as source data-entry such as scanner, cameras, bar-code reader, electronic chips, and audio. Types of source data-entry devices: Scanner.
On a computer screen, the more pixels that appear per square inch, the higher the resolution.
True
Optical character-recognition software reads "bubble" marks and converts them into computer-usable form.
True
Output hardware consists of devices that translate information processed by the computer into a form that humans can understand.
True
Photos taken with a digital camera can be downloaded to a computer's hard disk.
True
Plotters are used to print architectural drawings and in computer-aided design.
True
Pointing devices control the position of the cursor on the screen.
True
Scanners use optical equipment to translate images of text, drawings, photos, and the like into digital form.
True
When people in different geographic locations can have a meeting using computers and communications, it is called__________ .
Video Conferencing
Discuss the different types of printers and their features.(laser printer)
a laser printer creates images with dots. However, as in a photocopying machine, these images are produced on a drum, treated with an electrically charged inklike toner (powder), and then transferred from drum to paper. page description language (PDL) , which tells the printer how to lay out the printed page and supports various fonts.
What is a font?
a set of type of one particular face and size
LCD Quality Factors (resolution)
based on the number of pixels (ex 3.5 megapixels, 8 megapixels, etc.) - the more pixels the better because the more pixels that you have the sharper the imagine
Which of the following is not a pointing device? a. mouse b. touchpad c. keyboard d. joystick
keyboard
LCD Quality Factors (brightness)
measure of the greatest amount of light showing when the monitor is showing pure white
LCD Quality Factors (refresh rate)
measurement of the how many times the entire screen refreshes in a second - higher is better because it minimizes blurring and "judder" - 120 or 240 herts is best
LCD Quality Factors (response time)
measurement of the time it takes a pixel to change color - lower is better because it gives smoother moving images - this is very important in gaming
Which of the following is not a source data-entry device? a. bar-code reader b. sensor c. digital camera d. scanner e. mouse
mouse
Discuss the different types of printers and their features.(nonimpact printer) - Thermal printers, Thermal wax-transfer printers, Photo printers
nonimpact printers (such as laser printers and inkjet printers) do not have direct contact with the hardcopy medium. Thermal printers: Low- to medium-resolution printers that use a type of coated paper that darkens when heat is applied to it; typically used in business for bar-code label applications and for printing cash register receipts. Thermal wax-transfer printers: Print a wax-based ink onto paper. After it becomes cool, the wax adheres permanently to the paper. Because of their waterfastness, these labels find uses in industrial label printing. Photo printers: Specialized machines for printing continuous-tone photo prints , with special paper and color dyes.
LCD Quality Factors (passive vs Active matrix display)
passive - electric current charges groups of pixels Active - electric current charges each pixel - will give brighter and sharper images and better response times than passive display
Which of the following factors does not affect the quality of a screen display? a. refresh rate b. speed c. resolution d. pixels e. color depth
speed
LCD Quality Factors (color/bit depth
the amount of information stored in bits within a dot
LCD Quality Factors (dot pitch)
the amount of space between the centers of adjacent pixels
LCD Quality Factors (aspect ratio)
the proportional relationship of the display screens width and height
Which of the following is not considered hardcopy output? a. spreadsheet printout b. microfilm c. fax report d. Word document computer file e. printed invoice
word document computer file
