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Output: SummaryThe results of processing are output as hard copy (printed) or soft copy (displayed on a screen or played as sounds). Printers have different features to consider such as the kind of paper used, color printing or not, the speed of printing, the quality of print, the kind of cable needed to connect to the computer, the number of ink or toner cartridges, and the physical size compared to where you want to put it. Color printers use CMYK colors: cyan, magenta, yellow, and black. Impact printers are still used for multi-copy forms but sheet printers (laser or ink jet) have taken over most of the market otherwise. LCD monitors are standard now with thin screens that take much less space than CRT monitors. Colors are created using just 3 colors in subcells, red, green, and blue. The eye blends these together to make millions of colors. Other output devices include projectors for presentations, 3D printing of objects, microfilm, speakers, medical devices like EEG and EKG recordings, and scientific devices like seismographs. Output: Quiz For each question, click on Top of Form 1. When a computer prints a report, this output is called_____.
2. Output which is made up of pictures, sounds, and video is called_____.
3. An impact printer _____.
4. A dot-matrix printer uses ____ to form the letters.
5. For a test print of a newly created document, you should use____ quality print.
6. A laser printer is an example of a _____ printer.
7. An individual dot on a computer screen is called a(n)_____.
8. A screen which can only display white letters on a blue background is a _____ monitor.
9. Which of the following is not an output device?
10. The speed of a printer can be measured in_____.
Storage: Intro What is Storage?
Storage refers to the media and methods used to keep information available for later use. Some things will be needed right away while other won't be needed for extended periods of time. So different methods are appropriate for different uses. Earlier when learning about processing, we saw all the kinds of things that are stored in Main Memory. Main Memory = Primary Storage Main memory keeps track of what is currently being processed. It's volatile, meaning that turning the power off erases all of the data. For Main Memory, computers use RAM, or Random Access Memory. These memory chips are the fastest, but most expensive, type of storage. Top of Form Bottom of Form
Auxiliary storage holds what is not currently being processed. This is the stuff that is "filed away", but is ready to be pulled out when needed. It is nonvolatile, meaning that turning the power off does not erase it. Auxiliary Storage is used for:
So, Auxiliary Storage is where you put last year's tax info, addresses for old customers, programs you may or may not ever use, data you entered yesterday - everything that is not being used right now. Storage: Magnetic Disks Of the various types of Auxiliary Storage, the types used most often involve some type of magnetic disk. These come in various sizes and materials, as we shall see. This method uses magnetism to store the data on a magnetic surface.
A drive spins the disk very quickly underneath a read/write head, which does what its name says. It reads data from a disk and writes data to a disk. (A name that actually makes sense!) Types of Magnetic Disks Hard Disks Credit: Western Digital A hard disk consists of 1 or more metal platters which are sealed inside a case. The metal is one which is magnetic. The hard disk is usually installed inside the computer's case, though there are removable and cartridge types, also. Diskette / Floppy Disk (extinct?) Both sizes are seem to be extinct in work places. The only remaining flocks of such disks are hiding among the dust balls in back storage closets, waiting for someone to decide what to do with them. Sizes:
Both sizes are made of mylar with an oxide coating. The oxide provides the magnetic quality for the disk. The "floppy" part is what is inside the diskette covers - a very floppy piece of plastic (i.e. the mylar).
Several other kinds of removable magnetic media are in use, such as the Zip disk. All of these have a much higher capacity than floppy disks. Each type of media requires its own drive. The drives and disks are much more expensive than floppy drives and disks, but then, you are getting much larger capacities. There are other kinds of storage devices that are not magnetic, such as flash drives and optical discs (CD and DVD) or that are not disks, such as magnetic tape. These will be discussed later. Care of Hard Disks To keep your hard disk happy and healthy you must observe a few precautions. Each medium has its own particular weaknesses and hazards to avoid. Be careful or suffer the consequences - lost data, which means, at best, lots of lost time and effort!
Credit: Western Digital Hard disks are protected by being sealed in air-tight cases. But when damage does occur, it is a more serious matter that with removable media. Larger amounts of data can be lost and hard disks are much, much more expensive that removable disks. Hard disks can have problems from magnetic fields and heat, but these are rare. Most problems occur when the read/write head (looks like a pointer in the photo) damages the metal disk by hitting or even just touching it. This is called a head crash.
So the goal here is to keep that read/write head where it belongs, just barely above the hard disk, but never, ever touching it. Storage: Disk Format All magnetic disks are similarly formatted, or divided into areas, called tracks sectors cylinders The formatting process sets up a method of assigning addresses to the different areas. It also sets up an area for keeping the list of addresses. Without formatting there would be no way to know what data went with what. It would be like a library where the pages were not in books, but were scattered around on the shelves and tables and floors. You'd have a hard time getting a book together. A formatting method allows you to efficiently use the space while still being able to find things. Tracks
Sectors
Clusters
Cylinders
What happens when a disk is formatted?
Storage: Disk Capacity The capacity of a magnetic disk depends on several factors. We always want the highest amount of data stored in the least possible space. (People are so greedy this way!) So the capacities of storage media keep increasing while cost keeps decreasing. It's a lovely situation for the user! Capacity of a Disk depends on:
Capacity of Disks
The future??? Advances in technology for the read/write head and for the densities on the disks are bringing larger and larger disk capacities for about the same price. In fact, you cannot find a small capacity drive to buy, even if you wanted one! 2 TB drives are plentiful (July 2010) and for the same price that we used to buy 1 Gig drives (under $200). It's enough to make you cry to think of what we paid over the years and what we could get for those dollars today. Ah, well. That's the way the computer world works! Date: 2015-01-11; view: 1404
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