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200 lines
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<TITLE> Text-Terminal-HOWTO: Why Use a Terminal ?</TITLE>
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<LINK HREF="Text-Terminal-HOWTO-6.html" REL=next>
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<LINK HREF="Text-Terminal-HOWTO.html#toc5" REL=contents>
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<A HREF="Text-Terminal-HOWTO-6.html">Next</A>
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<A HREF="Text-Terminal-HOWTO.html#toc5">Contents</A>
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<H2><A NAME="s5">5.</A> <A HREF="Text-Terminal-HOWTO.html#toc5">Why Use a Terminal ?</A></H2>
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<H2><A NAME="ss5.1">5.1</A> <A HREF="Text-Terminal-HOWTO.html#toc5.1">Intro to Why Use a Terminal </A>
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</H2>
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<P>Many of these arguments apply also to GUI "thin-client" type of
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terminal. The case for such terminals is frequently being made today
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and promoters are devising new slogans and names in an attempt to
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market the modern terminal concept under another name. For example "Cloud Computing". </P>
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<P>PC's are so powerful today that just one PC can often support
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several persons using it at once, especially if they are doing
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low-load tasks such as text editing, data entry, etc. One way to do
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this is to connect a number of terminals to a single PC (or other host
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computer) by modems or direct cable connection. To do this, it's
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usually best to have a multi-user operating system such as Linux so
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that each user at a terminal can use the computer independently. This
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has been called "time sharing" but it's not good terminology today
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since "distributed" computing over a network is also a type of time
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sharing. It might be better described as "centralized" computing.
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But the central computer may be connected to the rest of the world via
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a network so that terminal users may send email, browse the Internet,
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etc. So it's not exactly "centralized" either.</P>
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<P>Prior to about 2000, terminals were seldom used with PC's because the
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popular operating systems used for them (Windows, DOS, and Mac) were
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not multiuser until 1998 (available for MS Windows NT) and previously
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could not support terminals very well. Now that Linux, a multiuser
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operating system, is freely available for PC's, the use of terminals
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with PC's becomes more feasible. While text terminals are not smart
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enough to support the type of graphical user interface (GUI) that most
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computer users today expect, thin client type terminals are.</P>
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<H2><A NAME="ss5.2">5.2</A> <A HREF="Text-Terminal-HOWTO.html#toc5.2">Lower Hardware Costs ? </A>
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</H2>
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<P> When Computers (including PCs) were quite expensive, lower
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hardware costs was a significant advantage of using terminals. Today
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with cheap PCs, the cost savings is problematical. I wrote the next
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three paragraphs years ago when PCs were more expensive. They are still
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valid today but of less significance:</P>
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<P>If several people use the same computer as the same time, there is a
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reduction in the amount of hardware needed for the same level of
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service. One type of savings is due to code sharing. The application
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files on hard disks are shared as well as shared libraries in memory
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(even when people are running different programs provided they use
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some of the same functions in their code). Another type of savings is
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due to reduction of peak load. The hardware of a single PC may be
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idle most of the time as people slowly type in information, think,
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talk, or are away from their desks. Having several people on the same
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computer at once makes good use of much of this idle time which would
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otherwise be wasted.</P>
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<P>These savings are substantial. One may roughly estimate (using
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statistical theory) that for 9 persons (8 terminals & 1 console) the
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shared PC only needs only about 3 times as much capacity (in memory,
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disk storage, CPU power, etc.) as a single PC in order to provide the
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same level of service per person. Thus the computational hardware for
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such a shared system should only cost about 1/3 as much per user.
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However, the cost of the display hardware (CRT's, keyboards, video
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electronics, etc.) is about the same for both cases. The terminals
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have the added cost of requiring additional physical cable connectors
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(such as serial ports) at the host computer.</P>
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<P>For a fair comparison with PC's, the terminals should have the same
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capabilities as the PC monitors. Unfortunately, color graphic
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terminals for Linux (X Window) with high speed communication cost
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about as much as a PC so in this case there not much (if any) savings
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in hardware costs. But for text terminals there will be some savings,
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especially if the terminals are obtained used at low cost.</P>
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<H2><A NAME="ss5.3">5.3</A> <A HREF="Text-Terminal-HOWTO.html#toc5.3">Control of Software </A>
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</H2>
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<P> For centralized computing, software (and the updates to software)
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only need be installed and configured on one host computer instead of
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several. The person in charge of this computer may control and
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configure the software which is installed on it. This is advantageous
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if the person controlling the host computer does an excellent job and
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knows about the needs and preferences of the other users. Users can
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be restricted in playing games or surfing the Internet, etc.
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Whether or not centralized control is desirable depends on the
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situation. It's in a sense depriving users of their "right" to
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controls what they do with their computer including things that would
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improve their efficiency at work and/or entertain them.</P>
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<H2><A NAME="ss5.4">5.4</A> <A HREF="Text-Terminal-HOWTO.html#toc5.4">Hardware Upgrades </A>
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</H2>
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<P> With terminals, the computer hardware
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upgrades take place on only one computer instead of many. This saves
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installation labor effort. While the cost of the hardware for the
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host computer upgrade will be more than that for a single PC (since
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the host needs more computing power than a PC), the cost will be
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significantly less than upgrading the hardware of a number of PC's
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being used instead of terminals.</P>
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<H2><A NAME="ss5.5">5.5</A> <A HREF="Text-Terminal-HOWTO.html#toc5.5">Other Advantages of Terminals </A>
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</H2>
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<P>
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<UL>
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<LI> The elimination of noise from fans and disk drives (unless
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you're using a PC to emulate a terminal).</LI>
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<LI> The users of the terminals can share data and files and send
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e-mail to each other. But they could also do this if the used PC on a
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local network or via email over the internet.
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</LI>
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</UL>
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</P>
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<H2><A NAME="ss5.6">5.6</A> <A HREF="Text-Terminal-HOWTO.html#toc5.6">Major Disadvantages of Text Terminals </A>
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</H2>
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<P>
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<UL>
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<LI> For the case of text terminals there is no high-speed graphic
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display (or high resolution graphics) although they can often use
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graphic character sets to draw boxes, etc. This lack limits the
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software that may be used on it.</LI>
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<LI> A detailed display of progress will sometimes greatly increase
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the time taken to do the job. For example, when copying a large
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number of files and displaying the name of each, the terminal may
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only be able to display the full path names of say 30 files per
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second so only 30 files per second will be copied. But the computer
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hardware is capable of copying at a rate many times higher. This
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can often be fixed by using options of application programs for a
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minimal display of progress. See
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<A HREF="Text-Terminal-HOWTO-17.html#slow_scroll">Problem with Slow Scrolling</A></LI>
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<LI>Most new computers don't have serial ports anymore, making it
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difficult to use them to emulate text terminals that connect over a
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serial line. One could perhaps connect by dialup using an analog
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modem, but with high speed cable or DSL modems, the analog modem is
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becoming obsolete.</LI>
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</UL>
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</P>
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<H2><A NAME="ss5.7">5.7</A> <A HREF="Text-Terminal-HOWTO.html#toc5.7">Major Disadvantages of All Terminals </A>
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</H2>
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<P>
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<UL>
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<LI> If the host computer goes down, then no one can use the
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terminals either (unless there is a "standby" host computer to connect
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to).</LI>
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<LI>As compared to a laptop, it's not portable. That is, you can't
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easily take it around with you, unless you have some way of connecting
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to your host computer where ever you go.</LI>
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</UL>
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</P>
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<H2><A NAME="ss5.8">5.8</A> <A HREF="Text-Terminal-HOWTO.html#toc5.8">Are Text Terminals Obsolete ? </A>
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</H2>
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<P> Text terminals are technologically obsolete because for a slightly
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higher cost of hardware, one can build a smarter terminal (with the
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same quality of display). This wasn't always the case since around
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1980 memory cost thousands of dollars per megabyte. Today with low
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costs for memory and processors, one could turn a text terminal into a
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GUI graphic terminal for only about a 10% or 20% increase in hardware
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cost.</P>
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<P>Since a PC can emulate a terminal, almost everyone using computers had
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a terminal emulator available until PCs started removing the serial
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port from new models during the 2000-2010 decade. You might think
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that now text terminals would be more in demand since emulating a
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directly connected terminal is only feasible with newer PC's (with no
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serial ports) only if one purchases such ports. But if one wants to
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connect text terminals (including emulated ones) to a PC via the
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serial port they will be out of luck if the Linux PC doesn't have a
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serial port. Thus the disappearing serial port tends to make the text
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terminal even more obsolete.</P>
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<P>The reasons that text terminals are (or were) not fully obsolete are:
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<UL>
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<LI> The resolution of characters on the screen was better on
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monochrome terminals than for cheaper PC monitors in text mode.
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But for high resolution monitors the character resolution is fine.</LI>
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<LI> Some people don't need full screen graphics.</LI>
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<LI> Since running a text-terminal (in contrast to a GUI-graphics
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terminal) doesn't consume much of a modern PC's resources, a large
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number of terminals may be efficiently run from one PC.</LI>
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</UL>
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</P>
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<HR>
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