208 lines
4.6 KiB
HTML
208 lines
4.6 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>Basic anatomy of your computer</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
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REL="HOME"
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TITLE="The Unix and Internet Fundamentals HOWTO"
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HREF="index.html"><LINK
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REL="PREVIOUS"
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TITLE="Introduction"
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HREF="intro.html"><LINK
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REL="NEXT"
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TITLE="What happens when you switch on a computer?"
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HREF="bootup.html"></HEAD
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><BODY
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>The Unix and Internet Fundamentals HOWTO</TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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>Prev</A
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VALIGN="bottom"
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>Next</A
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="sect1"
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><H1
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CLASS="sect1"
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><A
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NAME="anatomy"
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></A
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>2. Basic anatomy of your computer</H1
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><P
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>Your computer has a processor chip inside it that does the actual
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computing. It has internal memory (what DOS/Windows people call
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<SPAN
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CLASS="QUOTE"
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>"RAM"</SPAN
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> and Unix people often call <SPAN
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CLASS="QUOTE"
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>"core"</SPAN
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>; the Unix
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term is a folk memory from when RAM consisted of ferrite-core donuts). The
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processor and memory live on the
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<I
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CLASS="firstterm"
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>motherboard</I
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>,
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which is the heart of your computer.</P
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><P
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>Your computer has a screen and keyboard. It has hard drives and an
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optical CD-ROM (or maybe a DVD drive) and maybe a floppy disk. Some of
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these devices are run by <I
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CLASS="firstterm"
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>controller cards</I
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> that plug
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into the motherboard and help the computer drive them; others are run by
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specialized chipsets directly on the motherboard that fulfill the same
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function as a controller card. Your keyboard is too simple to need a
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separate card; the controller is built into the keyboard chassis
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itself.</P
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><P
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>We'll go into some of the details of how these devices work later. For
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now, here are a few basic things to keep in mind about how they work
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together:</P
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><P
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>All the parts of your computer inside the case are connected by a
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<I
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CLASS="firstterm"
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>bus</I
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>.
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Physically, the bus is what you plug your controller cards into (the video
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card, the disk controller, a sound card if you have one). The bus is the
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data highway between your processor, your screen, your disk, and everything
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else.</P
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><P
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>(If you've seen references to ‘ISA’, ‘PCI’,
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and ‘PCMCIA’ in connection with PCs and have not understood
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them, these are bus types. ISA is, except in minor details, the same bus
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that was used on IBM's original PCs in 1980; it is no longer used.
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PCI, for Peripheral Component Interconnection, is the bus used on most
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modern PCs, and on modern Macintoshes as well. PCMCIA is a variant of ISA
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with smaller physical connectors used on laptop computers.)</P
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><P
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>The processor, which makes everything else go, can't actually see any of
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the other pieces directly; it has to talk to them over the bus. The only
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other subsystem that it has really fast, immediate access to is memory (the
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core). In order for programs to run, then, they have to be <I
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CLASS="firstterm"
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>in
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core</I
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> (in memory).</P
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><P
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>When your computer reads a program or data off the disk, what actually
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happens is that the processor uses the bus to send a disk read request
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to your disk controller. Some time later the disk controller uses the
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bus to signal the processor that it has read the data and put it in a
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certain location in memory. The processor can then use the bus to look
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at that data.</P
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><P
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>Your keyboard and screen also communicate with the processor via the
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bus, but in simpler ways. We'll discuss those later on. For now, you know
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enough to understand what happens when you turn on your computer.</P
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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SUMMARY="Footer navigation table"
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="intro.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="index.html"
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ACCESSKEY="H"
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>Home</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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><A
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HREF="bootup.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>Introduction</TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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> </TD
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><TD
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WIDTH="33%"
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ALIGN="right"
|
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VALIGN="top"
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>What happens when you switch on a computer?</TD
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></TR
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></TABLE
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></DIV
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></BODY
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></HTML
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> |