x86 standards

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slacker

x86 standards

Post by slacker »

why do x86's use old ibm standards?
Tim

Re:x86 standards

Post by Tim »

Because IBM made the first widely-used machine which included the 8086. The specs were relatively open, so it was easy for other manufacturers to clone their machines. The rest is history.
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Re:x86 standards

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in other words, this is because you don't have just an x86, but a x86-based PC (and the PC has been defined by IBM). One could build up a completely different computer around the X86 processor, but noone would know how to access its video memory (for instance) nor how it is booted :)
Tim

Re:x86 standards

Post by Tim »

For instance, I have a Psion Series 3 organiser. It is based on a 186-compatible CPU (an NEC V30 chip) yet the surrounding hardware is completely different. It has an MMU, for instance. :)
slacker

Re:x86 standards

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so IBM came up with the personal computer?
slacker

Re:x86 standards

Post by slacker »

also...when new technology arrives, like ultra DMA or a more advanced keyboard controller...how do the ports change? do the ports change?
slacker

Re:x86 standards

Post by slacker »

also does a manufacturer (im guessing motherbaord manufacturer) have to get approval by IBM before making the components because if they didnt, couldnt they go assigning different ports different numbers...?
Tim

Re:x86 standards

Post by Tim »

Yes, yes, and no.

IBM only have a de-facto standard. If a manufacturer comes up with a new piece of hardware, they're free to design it how they want. However, it's in their interests to design it in a way compatible with everything else.
slacker

Re:x86 standards

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how do computers send data through wires?
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Re:x86 standards

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using transistors, they can establish a connection between the wire and the power source (+5V, for instance) or between the wire and the mass (0V) ... This is known as driving the line from a chip ...

similarily, other circuits are able to change their internal state (this is, acting on transistors) depending on the voltage on the wire ...

datas are sent by moving the wire voltage to +5 and 0 following predefined timing patterns, etc.
Well, this is just a gross abstract, but there are sooo many things to be said about this (nyquist, shannon, mfm, manchester coding, error checking, etc ... )

i'm not sure this really the best place to get info about this (try to get info about the physical protocols in networks, or how the serial/parallel cable work).
slacker

Re:x86 standards

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all of that deals with electrical engineering?
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Re:x86 standards

Post by Pype.Clicker »

roughly yes. I don't have book references here, but if you find a book about microelectronic ... Networking books also usually talk about how to make 0V and +5V (well, in fact in network we rather use +5V and -5V to have no continuous component in the signal, i.e. the mean voltage on the wire is 0V) become 1s and 0s, in their introduction chapters ... maybe you can get a look at this document -- but it's only courses notes ...
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