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On Sun, 16 Aug 2009 01:06:12 +0200, clipka <ano### [at] anonymous org> wrote:
>Stephen schrieb:
>>> What voltage does CMOS use anyway? IIRC, TTL can be driven with a
>>> triplet of 1.5 V batteries.
>>
>> Why don't you look it up as I can't remember,
>
>74HCxx: 2V to 6V (i.e. a doublet or triplet of 1.5 V batteries will do
>fine, even when quite depleted already)
>
>74HCTxx: 5V, +/- 0.5V (i.e. a triplet will probably do quite well if
>still good)
>
>Power consumption is virtually zero at low frequencies.
An example: Around 1975 I made a digital clock out of TTL and the power
consumption was 20 amps. About 1977 I made another using CMOS, it ran for years
on a PP3 battery.
--
Regards
Stephen
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On Sun, 16 Aug 2009 09:16:51 +0100, Orchid XP v8 <voi### [at] devnull> wrote:
>OOC, exactly how much space do you recon it would take to build 64KB out
>of discrete NAND gates?
For memory you could use a D type flip-flop which can be made using 4 NAND gates
and an inverting gate. It would be better to use a Master-slave D type flip-flop
which would double the components. So for each *bit* of memory you would need 2
X 7400s and 1/3 X 7404. or a 7474 or a 7479.
What size of word are you thinking of? IIRC the typical power consumption of TTL
is about 250 ma. You will need a robust power supply.
--
Regards
Stephen
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>> OOC, exactly how much space do you recon it would take to build 64KB out
>> of discrete NAND gates?
>
> For memory you could use a D type flip-flop which can be made using 4 NAND gates
> and an inverting gate. It would be better to use a Master-slave D type flip-flop
> which would double the components. So for each *bit* of memory you would need 2
> X 7400s and 1/3 X 7404. or a 7474 or a 7479.
>
> What size of word are you thinking of? IIRC the typical power consumption of TTL
> is about 250 ma. You will need a robust power supply.
Of course, I have no serious *intention* of making more than about a
dozen bytes of RAM using only NAND gates. ;-) But I'm aware that way
back in prehistoric times, they used to do it this way.
No wonder computers cost more that housing estates - they were *bigger*
than housing estates! :-D
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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triple_r wrote:
> a computer that gets upset when you make programming errors! There must be
> room for an "In Soviet Russia..." joke somewhere around here.
In Soviet Russia, the computer hacks you.
> - Ricky
-Aero
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On Sun, 16 Aug 2009 14:09:32 +0100, Orchid XP v8 <voi### [at] devnull> wrote:
>
>Of course, I have no serious *intention* of making more than about a
>dozen bytes of RAM using only NAND gates. ;-)
Surprise me :D
> But I'm aware that way back in prehistoric times, they used to do it this way.
>
Back in prehistoric days, at least when I started working in computing, RAM was
ferrite-core memory. Literally ferrite or ceramic toroids threaded with wires to
store information via the polarity of the magnetic fields.
http://en.wikipedia.org/wiki/Core_memory
>No wonder computers cost more that housing estates - they were *bigger*
>than housing estates! :-D
It was the air conditioning that took up the room :)
--
Regards
Stephen
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On 16-8-2009 15:09, Orchid XP v8 wrote:
>>> OOC, exactly how much space do you recon it would take to build 64KB
>>> out of discrete NAND gates?
>>
>> For memory you could use a D type flip-flop which can be made using 4
>> NAND gates
>> and an inverting gate. It would be better to use a Master-slave D type
>> flip-flop
>> which would double the components. So for each *bit* of memory you
>> would need 2
>> X 7400s and 1/3 X 7404. or a 7474 or a 7479.
>>
>> What size of word are you thinking of?
let's assume 8 bit and that we need about as much logic to select the
bits. That'll be a breadboard if about 25 by 25 meter (modulo arithmetic
errors), so not too bad.
> IIRC the typical power
>> consumption of TTL
>> is about 250 ma. You will need a robust power supply.
Cooling was a more difficult problem than the logical design of
supercomputers.
> Of course, I have no serious *intention* of making more than about a
> dozen bytes of RAM using only NAND gates. ;-) But I'm aware that way
> back in prehistoric times, they used to do it this way.
I don't think they did it with 7400s. The description of the ENIAC
suggests that they did something similar, though I would not be
surprised if they used a slightly different design. By that time the
tubes were much more versatile than simple transistors.
A popular one afrom the beginning of mainframe computers was core memory
(see e.g. http://www.columbia.edu/acis/history/core.html).
> No wonder computers cost more that housing estates - they were *bigger*
> than housing estates! :-D
That was only in a very short period of time. Aside the analog computers
then were just as big.
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On Sun, 16 Aug 2009 16:55:46 +0200, andrel <a_l### [at] hotmailcom> wrote:
>A popular one afrom the beginning of mainframe computers was core memory
>(see e.g. http://www.columbia.edu/acis/history/core.html).
Just wandering down memory lane I looked up the Honeywell H316 as it was the
first computer that I worked on. At one time marketed as "The Honeywell Kitchen
Computer" LOL http://en.wikipedia.org/wiki/Honeywell_316
http://www.bitsavers.org/pdf/honeywell/series16/h316/70130072179A_RealTimeClk_May69.pdf
I found a site with lots of documents even circuit diagrams
http://www.bitsavers.org/pdf/honeywell/series16/h316/
36 Meg pdf
http://www.bitsavers.org/pdf/honeywell/series16/h316/70130072166AV_316_ModulesAndParts_Nov74.pdf
Bookmark 2-07 gives the "Principles of Magnetic Core Operation"
--
Regards
Stephen
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Orchid XP v8 schrieb:
> It appears I had the right pins, they're just not numbered in the order
> I was expecting.
That /might/ lead to incorrectly wired circuitry :-P
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>> It appears I had the right pins, they're just not numbered in the
>> order I was expecting.
>
> That /might/ lead to incorrectly wired circuitry :-P
The point being, it *is* the two corner pins, as I expected. It's just
that those corners aren't numbered 1 and 14 for some reason.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Since I'm currently using the onboard video adapter (Radeon 3200, they
call it), I wasn't expecting to play many games until I bought a new
video card.
However, I'm quite impressed by the performance of it. Company of
Heroes runs fine (with options turned down, of course ;) ), and HL2 ran
well enough that I decided to get Ep 1&2 (they're on sale, and I've
never gotten around to playing them).
Ooh... I should install Civ IV again! That should run just fine :)
(As if I needed more ways to waste my time ;) )
...Chambers
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