Английский для пользователей компьютеров. Ч.2. Белобородова М.Л - 6 стр.

    The main softcopy output devices are cathode-ray tube (CRT) video
screens and flat video screens. Computer output microfilm/microfiche systems
and voice output systems are sometimes considered to be softcopy output
systems, but we have categorized them as hardcopy.
    The CRT, which is used with terminals connected to large computer
systems and as a monitor for microcomputer systems, has an electron gun
that fires at phosphors on the inside of the screen, causing them to glow.
The glowing phosphors become the picture elements — pixels, for short. It
takes a group of pixels to form one character, and there is a finite number
of characters that can be displayed on the screen at once. The three factors
used to measure resolution are the lines of resolution (vertical and
horizontal), the raster scan rate, and the bandwidth. Vertical resolution is
found by multiplying the number of vertical pixels in the character box by
the number of lines displayed on the screen; horizontal resolution is found
by multiplying the number of horizontal pixels in the character box by the
number of characters displayed on the line. Raster scan rate refers to how
many times per second the image on the screen is refreshed — how many
times the fading phosphors are relit. The higher the raster scan rate, the
better the quality of the screen image and the less strain on the eyes. The
bandwidth refers to the rate at which data is sent to the electron gun — the
higher the bandwidth, the faster the electron gun can be directed to do its
job.
    CRTs can display images in one color (monochrome) or several colors. The
RGB (red, green, blue) monitor uses three electron guns to illuminate red, green,
and blue phosphors.
    The most notable disadvantages of CRTs are their large size (to accommodate
the electron gun setup), their high rate of power consumption, and their fragility.
The disadvantages of the CRT and rising interest in portable and laptop
computers led to the development of flat screen technology, which is becoming a
favored alternative to the CRT. The three most common types of flat panel
displays are liquid crystal display (LCD), electroluminescent (EL) display, and
gas plasma display. Computer output systems are often used by companies that
don't want to take up space with a lot of regular hardcopy output, like paper, but
have needs not met by softcopy output. These systems capture computer output
on microfilm or microfiche —both approaches can be referred to as СОМ. СОМ
systems are fast, produce output condensed in size, and are not particularly
expensive. However, special equipment is needed to read the output that has been
stored.
    Voice output systems can be used in situations where hardcopy is
inappropriate and commonly used softcopy output devices are inconvenient.
    As with input and storage, care must be taken to ensure that output is
responsibly generated, shared, and disposed of. Control methods should be
established to ensure that only authorized users see sensitive output and that
output is properly secured.