What the heck would we do with an octuple bit? to me this sounds very much like 1-out-of-8 states, i.e. 3 bits. Think optical photonic equivalent of TCL NAND, like the one employed here
Data boffins see the light with extravagantly bit-blessed optical PCM
As if PCM (phase change memory) wasn’t esoteric enough, we now have optical PCM, thanks to sterling boffinry efforts at Oxford and other universities. Material scientists at Oxford University, Karlsruhe, Munster and Exeter have produced the world’s first all-photonic, non-volatile memory chip. It uses Ge2Sb2Te5 (GST), a …
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Saturday 3rd October 2015 23:31 GMT Robert Helpmann??
Octuple bit?
Q: What the heck would we do with an octuple bit?
A: I don't know. Call it a byte?
It's based on a power of two, so it should, I would think, fit rather well into current methods. What is more interesting is that reads and writes can happen simultaneously and that bandwidth issues will be quite different.
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Friday 2nd October 2015 16:25 GMT simpfeld
The World's first?
Not so sure it's "the world’s first all-photonic, non-volatile memory chip", depends how you define it really. Back in the 80's there were working prototypes of slivers of Bacteriorhodopsin (a chip) , but off chip lasers/optics. The state of the molecule could be switched by red and green laser light:
First link I found to this:
https://www.fourmilab.ch/autofile/www/section2_84_18.html
Not sure why it never appeared commercially. I seem to remember it had to work very cold and maybe the optics were just too clunky and slow. Don't know.
Maybe this is full contained on a chip already so they can justify the world's first title.
One issue with optical memories is simply that light wavelengths are actually quite big these days (chips are multilayer and use ultraviolet light already for lithography). So bit densities are probably quite small ( for these days). Now the multistate buys you quite a lot here but more than electronics in a few years.
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Friday 2nd October 2015 19:33 GMT Grikath
Re: The World's first?
well, rhodopsin tends to fall back to ground state within minutes to hours, depending on circumstances, so it wouldn't class as non-volatile memory..
And as you noted... the '80's.. not really noted for the combination of the words "lasers", "small" , and "energy-efficient". adding "sub-millimeter solid-state" would have landed you with possibly a Hugo, but not with a research grant..
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Tuesday 6th October 2015 01:40 GMT Anonymous Coward
I thought I understood what was going on... until the multicoloured thing was mentioned, and suddenly I was lost. How can the crystal be melted by one colour and simultaneously be not melted by another colour? How can it be both melted and unmelted eight different ways all at the same time???!
Clearly these boffins are a lot cleverer than little old me.
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Monday 12th October 2015 16:44 GMT Anonymous Coward
Thesaurus Rex?
Phew! So 8 stored bits still make a byte... sanity is restored.
But if a bit can have any one of 8 values (parity checking schemes aside for the moment) then the value of that bit when it is ON might be 0, 1 ,2, 4,16, 256, 65536 or 4294967296 depending upon the transmission coefficient observed when reading it. In an 8-bit byte that gives me a data density improvement at the byte capacity level that is 16,777,216 times better than today's devices manage.
Provided the packaging of the photonic memory device yields physically equivalent bit densities to what we have today then the information storage densities of the future should happily allow each one of our descendants to keep everything they ever saw, did, learned or forgot in a little chip embedded in their foreheads the instant they are born. Whoopee....
Of course it also suggests that the possession of a customisable 'read-write dongle' would be great for privacy. Create a different ordering of bit-state assignments for communications with each one of your favourite correspondents.....
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Biting the hand that feeds IT
