Computer Architecture : is 0 really 0 ?
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Rob Philpott wrote:
What sort of logic was this?
In computing - Three state logic. In formal logic there is also ternary logic, in one scheme: +1: True 0: Unknown/ Indeterminate -1: False You've probably already used this without realising, nullable bit fields in SQL work along ternary logic lines.
Alberto Brandolini:
The amount of energy necessary to refute bullshit is an order of magnitude bigger than to produce it.
Certainly, at a software level. But I've yet to see any sort of bus that uses three logic levels.
Regards, Rob Philpott.
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The answer is it depends. The signals sent are either RZ (Return to Zero Volts - I assume with a small error) or NRZ (Non-Return to Zero volts - a small voltage). I have no idea which the main in a typical PC bus uses, I assume RZ as it consumes less power and there is no need to detect if the signal is active. [Edit] See glenPattonPUB's reply - he knows what he's talking about.
Alberto Brandolini:
The amount of energy necessary to refute bullshit is an order of magnitude bigger than to produce it.
Why, thanks kind sir!,[Yosser Mode] Gissa a job, electronics, I can do that![/Yosser Mode] :laugh:
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Certainly, at a software level. But I've yet to see any sort of bus that uses three logic levels.
Regards, Rob Philpott.
Look to FPGA's (Lattice) for that, I have worked on some Tri-State video busses (migraine guaranteed!) :(
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Certainly, at a software level. But I've yet to see any sort of bus that uses three logic levels.
Regards, Rob Philpott.
the 205 from Kings Cross to Paddington via the Mall? [edit] to put correct bus number before I was corrected[/edit]
You cant outrun the world, but there is no harm in getting a head start Real stupidity beats artificial intelligence every time.
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in computers' circuits is the bit 0 really represented by no currency or it is a small signal that the computer is made to treat as 0 ? thank a lot !
You can check the spec sheets for processors, generally these days they run on less than 5V, more like 3.3V or less. A range 0V through 1.5V will be treated as 0, and 1.5V to 3.3V will be treated as a 1. Docs like this [^] will help (table 3 - min high level, max low level)
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in computers' circuits is the bit 0 really represented by no currency or it is a small signal that the computer is made to treat as 0 ? thank a lot !
Both 0 and 1 in a chip are usually represented by a voltage rather than a current, because they're made out of FETs instead of BJTs. Anyway, a closed transistor doesn't reach infinite resistance, not even the silicon oxide around it has infinite resistance, so you'll always have some non-zero voltage (and current).
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-5v? I can't see how you can have tristate binary. What sort of logic was this?
Regards, Rob Philpott.
Rob Philpott wrote:
-5v? I can't see how you can have tristate binary. What sort of logic was this?
Quantum computers use tri-state binary.
Jeremy Falcon
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Certainly, at a software level. But I've yet to see any sort of bus that uses three logic levels.
Regards, Rob Philpott.
Rob Philpott wrote:
Certainly, at a software level. But I've yet to see any sort of bus that uses three logic levels.
Check out what a qubit is for quantum_computers[^]. It's the future of tech, at a really early stage though.
Jeremy Falcon
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the 205 from Kings Cross to Paddington via the Mall? [edit] to put correct bus number before I was corrected[/edit]
You cant outrun the world, but there is no harm in getting a head start Real stupidity beats artificial intelligence every time.
Bergholt Stuttley Johnson wrote:
[edit] to put correct bus number before I was corrected[/edit]
I try to avoid buses as they're always full of 'them', so have no ideas about numbers. That said, bearing in mind all you have to do is follow the Euston Road to make such a journey it surprises me that you take The Mall in on the way. Either way, I'm reasonably sure that they don't use -5v.
Regards, Rob Philpott.
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Rob Philpott wrote:
-5v? I can't see how you can have tristate binary. What sort of logic was this?
Quantum computers use tri-state binary.
Jeremy Falcon
Yeah, perhaps out of scope of the original question. Quantum computers do my head in. Witchcraft, I tell you!
Regards, Rob Philpott.
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-5v? I can't see how you can have tristate binary. What sort of logic was this?
Regards, Rob Philpott.
Chuck Norris has a three-state one-two punch.
You'll never get very far if all you do is follow instructions.
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-5v? I can't see how you can have tristate binary. What sort of logic was this?
Regards, Rob Philpott.
There is a problem with ternary logic. "Bit" is short for "binary digit". What would you shorten "ternary digit" to? The problem is equally terminological as technical! PS. In the UK, I am aware that a tit is a kind of bird.
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in computers' circuits is the bit 0 really represented by no currency or it is a small signal that the computer is made to treat as 0 ? thank a lot !
Usually the logical levels are represented by voltages, not currents. You may have either active-higth or active-low signals, see Logic Level at Wikipedia[^].
THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?! -- C++ FQA Lite
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Depends on the chip. Some read -5V as 0 and +5V as 1. Some are tri-state using -5V, 0, and +5V. It's actually voltage and not current that it is using. At least the chips I worked with years ago were that way. [Edit] And yes, some chips used 0V as 0 and +5 as 1. [/Edit]
There are only 10 types of people in the world, those who understand binary and those who don't.
That was some pretty good info. Thanks :-)
Regards, Nish
Check out 7 reasons C++ devs will love the VS 14 CTP by Nish Sivakumar Blog: voidnish.wordpress.com
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There is a problem with ternary logic. "Bit" is short for "binary digit". What would you shorten "ternary digit" to? The problem is equally terminological as technical! PS. In the UK, I am aware that a tit is a kind of bird.
Quote:
PS. In the UK, I am aware that a tit is a kind of bird.
Amongst other things yes. ;)
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Rob Philpott wrote:
-5v? I can't see how you can have tristate binary. What sort of logic was this?
Quantum computers use tri-state binary.
Jeremy Falcon
I thought it was just a complex superposition of 2 states, which ends up giving you 3 dimensions to work in so you can get things like 30 degrees away from true. :-D
Curvature of the Mind now with 3D
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Bergholt Stuttley Johnson wrote:
[edit] to put correct bus number before I was corrected[/edit]
I try to avoid buses as they're always full of 'them', so have no ideas about numbers. That said, bearing in mind all you have to do is follow the Euston Road to make such a journey it surprises me that you take The Mall in on the way. Either way, I'm reasonably sure that they don't use -5v.
Regards, Rob Philpott.
24v 64hp London Omnibus
You cant outrun the world, but there is no harm in getting a head start Real stupidity beats artificial intelligence every time.
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There is a problem with ternary logic. "Bit" is short for "binary digit". What would you shorten "ternary digit" to? The problem is equally terminological as technical! PS. In the UK, I am aware that a tit is a kind of bird.
Vivic wrote:
tit is a kind of bird
Nah, it's what birds have two of.
You'll never get very far if all you do is follow instructions.
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Usually the logical levels are represented by voltages, not currents. You may have either active-higth or active-low signals, see Logic Level at Wikipedia[^].
THESE PEOPLE REALLY BOTHER ME!! How can they know what you should do without knowing what you want done?!?! -- C++ FQA Lite
CPallini wrote:
voltages, not currents
Yes, but can you have one without the other?
You'll never get very far if all you do is follow instructions.
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CPallini wrote:
voltages, not currents
Yes, but can you have one without the other?
You'll never get very far if all you do is follow instructions.
Current Flows, Voltage is Pressure to use the water metaphor...