ICF Lessons

October  5, 2010

Hello every one  specially to my  first year students,

This weeks Lesson Features……

LOOKING AT OPERATING SYSTEMS

  ŸOperating system or environment is collection of programs designed to control computer’s interaction and communication with user ŸEssentially performs two important functions –Manages input devices, output devices, and storage devices –Manages files stored on the computer and recognizes file types ŸEvery computer requires operating system to function ŸExamples of operating systems include: –DOS –Windows –Unix –Linux –Apple Operating System ŸWith the exception of Unix, all other computers use a graphical operating system –Graphical user interface (GUI) allows person to use mouse and other devices to point and select desired functions rather than remember commands.

DOS

MICROSOFT WINDOWS

MAC OS

UNIX

 LINUX

HANDHELD OS

I got sick this week and I want to make it up with my students

Our weeks lesson

Looking at Printers :

PRINTERS   ŸConsidered output devices as they display what was onscreen once you activate the print command

      All applications allow you to print the file, and offer different options for printing the file –

     Options will vary depending on printer installed Ÿ

    Number of different types of printers available to purchase Ÿ

   Which one you choose or use will depend on needs, and cost considerations.

Below are the different Printers

DOTMATRIX PRINTER

  ŸConsists of print head constructed with matrix of 9 or 24 pins that “hammer” onto ink ribbon to print text and graphics

     –The more pins, the better quality of output –Models with 9 pins called Near Letter Quality (NLQ) –Models with 24 pins called Letter Quality (LQ) ŸAverage printer prints 192 characters per second (cps); high-speed models print up to 550cps ŸUseful for printing multi-part documents ŸAdvantage of tractor feed for continuous, fan-folded computer paper ŸVery affordable to buy and maintain –Cost of consumables less than other printers ŸPrint quality acceptable for text but only supports low-resolution graphics

Look at this

   Ink Jet Printer

 Developed after laser printer and considered
“laser comparable” as print quality very close .

Uses tiny nozzles in the print head to inject ink directly onto paper and dries instantly Ÿ

Average ink jet printer has about 64 nozzles and can print resolutions from 300-1200 dpi Ÿ

Print speeds measured in terms of pages per minute (ppm) or characters per second (cps) Ÿ

Costs less than laser printer and produces
high-resolution text and graphics Ÿ

Disadvantage is cost of consumables ŸResearch how many pages ink cartridges
produce on average, and at what price Ÿ

Most ink jet printers use ordinary cut sheet plain paper .

May need heavier bond or special paper depending on what is being printed.

  Bubble Jet Printer

  ŸDifference between ink jet and bubble jet is how the print head propels ink

ŸPrinting mechanism creates characters and graphics by firing droplets of ink onto paper through nozzles in the print head .

Ink pushed out of nozzles by expanding bubbles ŸAverage of 64 nozzles and capable of producing 300 to 1200 dpi resolution.

ŸCost less than laser printers and produce high-resolution text and graphics output .Ÿ

Research cost and output of bubble jet printer ink cartridges .

ŸPlain paper can be used in most models, although special paper made be needed for higher resolution output.

  Laser Printer

  ŸUses same laser beam electrostatic printing method as photocopier Ÿ

Uses laser light to “write” document images onto photosensitive drum which attracts toner powder to print dark portions of document Ÿ

Produces high quality print on all kinds of media

ŸCapable of printing from 300-1200 dpi Ÿ

Cost of laser toner cartridge higher than other printers, but actual cost per page is lower

ŸMaintenance also tends to be quite low Ÿ

Do cost analysis prior to printing large amount of copies on color laser versus sending to printer for reproduction Ÿ

Productivity can increase significantly by increasing amount of RAM memory installed on printer

   Miscellaneous Types of Printers

  ŸCombination of aforementioned, and/or combine number of general office devices
into printer ŸA “Printer All-in-One” model type of printer can be very cost effective for a small business –Can purchase one device instead of two or three devices to handle common tasks ŸSize of the machine will vary based on features the printer comes with ŸCheck specifications for device to ensure it has all the features you may want or need now and in the future

  Plotters ŸPrint images onto very large pieces of paper ŸMany companies who manufacture plotters have replaced this technology with color lasers that can handle large size paper sheets

  Photo Printers ŸDesigned to connect directly with digital camera (or video camera) to print
directly onto photo paper inserted in
printer’s paper tray ŸWill get exceptional quality as they
were designed to handle photographic images ŸCome in variety of sizes and features

    Replenishing Printer Supplies

ŸOne consideration you need to include in the printer choice is the cost and disposal of printer supplies Ÿ

Paper can be recycled using the same standards for handling paper mailings or general correspondence Ÿ

Simply throwing away printer cartridges can be damaging to environment Ÿ

Whenever possible, consider recycling printer cartridges by refilling them or taking them to a supplier who can dispose of the cartridges in a safe manner Ÿ

A number of organizations will also pay for specific types of cartridges or give a discount on new or refilled  cartridges for each one you recycle Ÿ

Alternatively, donate your used printer cartridges to charity and they will recycle them