<berndj>
bart416, i thought czochralski rigs used silica crucibles (with the side benefit of introducing oxygen impurities).  or what all this "you need high carbon steel" for?
<berndj>
lol @ refractory materials above 10kK
<bart416_>
<berndj> bart416, i thought czochralski rigs used silica crucibles (with the side benefit of introducing oxygen impurities).  or what all this "you need high carbon steel" for? <-- was it a czochralski crucible?
<berndj>
actually i'm not sure anymore what you guys were discussing; i thought it was CZ but when i looked again you might've been talking about making copper wire
<bart416>
Yeah it was confusing what sort of furnace he was talking about
<bart416>
What I do know is that CaO is the worst material ever to make a furnace
<bart416>
And it's the last you'd want to use to grow crystals
<B0101>
Hi azonenberg
<azonenberg>
hi
<azonenberg>
How goes the lab setup?
<B0101>
going well... though my neighbors are a little worried about me doing experiments in my own home
<azonenberg>
Not surprising
<azonenberg>
Just be up front about it and dont try to hide
<azonenberg>
it looks better that way if anybody comes asking questions
<bart416_>
Are your neighbours constantly looking through your windows or something?
<B0101>
nope
<berndj>
worried like grandmas worry about their grandkids or worried like they might call 911 on you
<B0101>
the former
<azonenberg>
oh, then thats fine
<azonenberg>
the second is what you want to be cautious about lol
<B0101>
well once, my friend and her child came over, but somehow, the child got into my room and was playing with my 50KV power supply
<bart416_>
Always lock away your lab equipment
<bart416_>
That's a basic rule
<azonenberg>
bart416_: We just dont allow kids in the place, it'd be too hard to childproof given the random stuff we have lying around
<azonenberg>
when i get a house of my own the lab will all be in dedicated rooms with auto-closing doors and card readers
<bart416_>
That's just paranoid :|
<azonenberg>
bart416_: no, its good policy :p
<bart416_>
auto closing doors I'll agree on
<bart416_>
But card readers...
<azonenberg>
all the labs at school do that
<azonenberg>
card readers mean i can give friends cards rather than keys
<azonenberg>
keep audit logs if something breaks
<bart416_>
you let other people use your equipment?
<azonenberg>
i plan to construct a building with a living area and a lab space
<azonenberg>
cleanly separated
<azonenberg>
so for example friends staying over wont be allowed into the lab without someone present
<azonenberg>
and if i have someone working on a project with me and i trust them enough they'd have 24/7 lab access but not be allowed into the living spaces under normal circumstances
<bart416_>
Heh, you don't have a plan for the house you want yet?
<azonenberg>
bart416_: not floor plan level, that will be done based on the plot of land i pick
<azonenberg>
but at list-of-requirements level, yes
<bart416_>
No ideas yet of what you want?
<azonenberg>
You mean, at the floor plan? No
<azonenberg>
I know i want a class 1000 cleanroom, a machine ship, an electronics lab, a dedicated server room
<azonenberg>
conference room/media center on the border between the lab and the living area
<azonenberg>
some sort of armory in the basement where i keep all of the stuff i go target shooting with
<azonenberg>
That'd be a separate card list, just me
<B0101>
azonenberg: wow, you plan to build your own lab and house
<azonenberg>
B0101: Its at least ten years out
<azonenberg>
~5 for the phd and that much again of workign full time to save up enough to build it
<azonenberg>
But yes
<azonenberg>
Then a SEM somewhere, probably in the cleanroom area
<B0101>
wow, here, u got to ask for permission even if you wanted to change the window
<azonenberg>
B0101: I'd buy an empty plot of land (or one with an old building and tear it down)
<azonenberg>
Get all of the necessary building permits
<cheater>
azonenberg: you could also have guest areas with direct access to the work area, for people who want to be able ti live-in and work but don't want to bother with the social stuff.
<azonenberg>
And design/build the whole place from scratch
<azonenberg>
cheater: I might
<azonenberg>
Like the media center for example
<cheater>
eg being seen by your wife and kids with only their boxers on.
<azonenberg>
which would double as a conference room for the lab
<azonenberg>
And that would not be allowed
<azonenberg>
dress code for the lab area is fully clothed plus lab coat if necessary
<azonenberg>
or bunny suit, in the cleanroom
<B0101>
Azonenberg: in here... almost EVERY building is controlled by government
<azonenberg>
if you arent wearing anything under the bunny suit, who cares
<cheater>
it was just an example, but being unshaved or uncombed are other options
<azonenberg>
oh, yeah
<azonenberg>
B0101: Not in the good old usa, here you can own the building
<cheater>
B0101: where is that? sounds like russia
<B0101>
Singapore
<cheater>
actually no, russia has got those freedoms
<cheater>
communist russia didn't
<cheater>
singapore.. i feel with yo
<cheater>
u
<azonenberg>
cheater: If i build a guest-bedroom type facility i might put it on the border as well
<azonenberg>
have two doors
<B0101>
cheater: the democratic communist state of Singapore (as some people call it)
<cheater>
yes
<cheater>
B0101: yes
<azonenberg>
cheater: i'd probably have the shared area in the middle and put the front door there
<azonenberg>
Both sides can get into it
<azonenberg>
and enter/leave the building through it
<azonenberg>
then you need a card to leave in either direction
<azonenberg>
leave the common area*
<azonenberg>
i.e. into the lab or the living spaces
<cheater>
how about a chinese wire puzzle instead
<B0101>
hmm, biometrics or card system?
<azonenberg>
lol
<azonenberg>
B0101: Not fingerprints
<azonenberg>
a) doesnt work with gloves on
<azonenberg>
b) you leave them everywhere, easy to clone
<azonenberg>
Retinal / iris scans are expensive
<cheater>
you can clone them off the reader
<cheater>
with gelatin
<azonenberg>
if i can get them, i'll use them
<azonenberg>
cheater: there are a lot of ways
<cheater>
why
<azonenberg>
point is, they arent that strong
<cheater>
why do you need so much security :)
<azonenberg>
cheater: its in part the convenience factor
<azonenberg>
not having to carry around keys
<azonenberg>
also, due diligence and liability
<azonenberg>
significantly reduces the risk of a visitor getting hurt by stupidity
<cheater>
what when the power is off
<azonenberg>
since they cant get into anything dangerous unless i trust them enough to give them access
<azonenberg>
cheater: then the doors revert to being key or combination locks
<azonenberg>
i'd have a key in a safe in the common area
<azonenberg>
that i could use in emergencies like that
<azonenberg>
the point is, i dont have to give out keys
<B0101>
hmm, password protected lock...
<azonenberg>
to let someone in
<azonenberg>
Same reason hotels use cards
<azonenberg>
easier to add/remove a serial number than to rekey a door
<azonenberg>
Also, audit trail
<azonenberg>
if someone goes into a lab and breaks something i know who was in there recently
<azonenberg>
I just see it as being better for all involved
<B0101>
azonenberg: I have seen keypad locks with card readers
<azonenberg>
B0101: I might do something like that too
<azonenberg>
battery backup?
<azonenberg>
so you can combo in if the card system is down?
<azonenberg>
The only potential downside would be privacy but "john doe was here at 2 AM and used the electron microscope for 45 minutes, then left" is not something most people would care if the world knew
<B0101>
Azonenberg: the keypad and card lock I'm talking about requires you to scan your card then enter a password
<azonenberg>
B0101: Combination is probably overkill
<azonenberg>
if i did two factor it'd be card + biometric or combo + biometric
<azonenberg>
cheater: also, i could integrate it with a burglar alarm (since the equipment would obviously be expensive)
<azonenberg>
if you key in you need to disarm the alarm at the keypad
<azonenberg>
but if you card in, it does both in one step
<B0101>
O.o
<B0101>
now people want to see my lab???
<azonenberg>
"people"?
<azonenberg>
neighbors or police? lol
<B0101>
the people i'm talking about are well: my friends
<azonenberg>
oh, lol
<azonenberg>
Once people find out i have a setup this nice they usually want to see it
<azonenberg>
Get used to it :p
<azonenberg>
idk if you've seen my lab lately but http://imgur.com/a/Bnwst is the current state (last night)
<azonenberg>
a couple of experiments in progress so not the most tidy on the workbenches
<B0101>
looks like my current eletronics work area, without the chemicals
<azonenberg>
Three sit-down workbenches (for soldering/wet work, electronics testing/assembly, and microscopy)
<azonenberg>
and two standing (for spin coating, baking, and contact lithography)
<azonenberg>
then the server rack
<B0101>
azonenberg: well you have a great lab
<azonenberg>
thx
<azonenberg>
Not sure if you can see in the pics but we have full fire sprinkler coverage
<azonenberg>
the entire building has a dry-pipe system
<azonenberg>
The binder on the vertical shelf next to the safety glasses is a MSDS book
<B0101>
oh
<azonenberg>
*prints out msds for diamond polishing compound* cant forget that
<B0101>
anyone fancies a "warning: trespassers with me used for experiments" sign?
<azonenberg>
lol
<azonenberg>
i've seen that
<azonenberg>
Might not go over too well with the neighbors :p
<B0101>
If i told them my neighbors that I bought uranium, i'm sure that they will kill me
<bart416_>
I suppose it's clear we were melting small batches of metal
<bart416_>
lol
<azonenberg>
Not really clear, the same suit can be used for close range firefighting
<bart416_>
If you ever have to wear one, be sure to have something to pad your shoulders ;)
<azonenberg>
lol
<azonenberg>
Hopefully i never do
<bart416_>
That's my only suggestion
<bart416_>
The pants are weirdly enough comfortable
<bart416_>
It's the vest that's the problem
<bart416_>
Well, I suppose it's still better than those throw away overalls
<azonenberg>
lol
<azonenberg>
i wear a disposable tyvek lab coat for splash protection when doing etching
<azonenberg>
gets annoying
<azonenberg>
But weighs practically nothing
<azonenberg>
i need to get myself a real cotton lab coat at some point
<bart416_>
We were fairly lucky in that aspect, we got to wear scrubs under our throw away overalls
<azonenberg>
what was that for? Or can you not say
<bart416_>
To avoid contaminating our own clothes
<bart416_>
We were working with dangerous chemicals in that lab where I did my internship
<azonenberg>
Makes sense
<bart416_>
Not to mention it's easier to remove scrubs instead of regular clothes
<azonenberg>
Yeah
<bart416_>
Incase of accidents
<azonenberg>
When you say "dangerous" do you mean corrosive? toxic? both?
<azonenberg>
biohazard?
<bart416_>
Among those yes
<berndj>
re retinal / iris scans, am i the only person in the world who remembers seeing _Demolition Man_ ?
<bart416_>
No
<bart416_>
Demolition Man was an awful movie
<bart416_>
It praises uncivilised behaviour
<berndj>
i was planning to test out my auto-darkening helmet a bit later azonenberg; glad to hear you foind it a night and day difference!
<berndj>
of course, but it's only a matter of time before crooks start routinely poking eyes out and chopping fingers off
<berndj>
the fact that it won't work doesn't console me!
<bart416_>
For a fingerprint scanner it'd sort of work...
<mrdata>
so, would 99.999% pure silicon be good enough for homecmos?
<bart416>
What sort of impurities are we talking about?
<bart416>
If it's not a dopant it'll fall under crystal defects
<mrdata>
oh, usually aluminum is the worst to remove
<bart416>
The latter will decrease the yield but shouldn't prevent succesful junctions
<bart416>
Al might be problematic
<azonenberg>
bart416: For my current MEMS, its probably good enough
<azonenberg>
i am not using it as a semiconductor, only a structural material
<azonenberg>
Though i am relying on it being monocrystalline
<bart416>
yeah for MEMS and simple conduction it should do fine
<bart416>
If you're forming junctions aluminium might be problematic
<mrdata>
how does it affect the result?
<bart416>
It shifts the levels of the energy bands in certain locations
<bart416>
Resulting in improper junction behaviour or schottky diode effect
<mrdata>
oh, and that will screw with the device properties..
<mrdata>
i see
<bart416>
the latter might be more problematic actually
<mrdata>
what sorts of devices would be less sensitive to that?
<mrdata>
i know solar cell applications are okay
<mrdata>
but, what else would be relatively unaffected?
<mrdata>
imagines making an array of devices, that differ slightly in their properties due to impurities; and recording test results for later use
<mrdata>
say, if each one is an artificial neuron
<bart416>
MEMS
<bart416>
well, some of them
<mrdata>
ok
<bart416>
as long as you don't need junctions MEMS should do
<bart416>
Might lead to some capacitive defects but nothing you can't compensate for
<mrdata>
and junctions would be the most problematic?
<bart416>
At a junction you want perfection
<mrdata>
can i take a probablistic approach to making junctions? eg: mark as bad, the ones that dont work, in an array?
<bart416>
yeah, what do you think semiconductor manufacturers do?
<bart416>
Making computer processors is a game of statistics
<bart416>
But the lower your purity, the lower the yield
<mrdata>
so, they make redundancy and test and re-route?
<bart416>
they don't reroute
<bart416>
They just make large enough batches and refine the process to maximise yield
<mrdata>
so do they typically throw out a lot of stuff?
<mrdata>
eg: half?
<mrdata>
or more
<bart416>
Depends on the complexity of the production, the process, purity of materials
<bart416>
50% won't be enough to run a profit at consumer prices I guess
<bart416>
maybe good for an asic run of a low quantity IC
<mrdata>
i hear that for small parts, like NPN transistors, they are made in batches, and each one tested, and then categorized as 2n2222 vs 2n3904 for example
<mrdata>
so, everything in the same bin has a specified range of properties
<bart416>
Yeah, but some are also defective
<bart416>
+ NPN are two junctions
<bart416>
fairly simple design
<mrdata>
yeah
<berndj>
or sometimes they sell the ones with defects in the cache as "celeron"
<berndj>
and 2n3055 is what it gets called if it doesn't make spec for anything else
<berndj>
dammit, why do i answer first then notice they've quite :(
<azonenberg>
Or if the error is in logic circuitry
<azonenberg>
they sell a quad core as a triple :p
<berndj>
oh yes, i should turn the time machine dial back to 2010s
<berndj>
but, i thought logic is just a miniscule part of CPUs these days? that almost all of the die area is memory of one sort or another?
<XgF>
L2/L3 Cache is about half of the die these days
<azonenberg>
berndj: Cache is a big chunk
<azonenberg>
But depends on the part
<berndj>
register file is surprisingly big, due to the number of ports it has
<azonenberg>
for example, gtx 480 has 15 of 16 shaders active
<azonenberg>
and i'm too familiar with that lol
<azonenberg>
mips register file in a simple 5-stage pipelined implementation is triple ported, two read and one write
<azonenberg>
i have five ports (one write, two execute-stage read, two decode-stage read) in my 8-bit arch
<azonenberg>
trying to build a 5-port 16-element 8-bit register file
<azonenberg>
out of 16x1 bit dual port ram
<azonenberg>
now that was fun :p
<berndj>
isn't there an O(2^n)Â Â [n = # of ports] size factor?
<azonenberg>
You can do linear in number of ports
<berndj>
or is it not quite as bad as that
<azonenberg>
if you only have one write port
<azonenberg>
Make N copies of the array, where N is the number of independent read ports
<azonenberg>
writes go to everything
<azonenberg>
then each read port addresses its own independent image of the memory
<azonenberg>
thats what i did in both my triple and 5-ported reg files
<berndj>
yeah, i guess i was thinking of n-write-ports files
<azonenberg>
oh, n-writes?
<azonenberg>
shudders
<azonenberg>
no thanks
<berndj>
indeed
<azonenberg>
But in a classic pipelined cpu architecture, you are reading all over the place
<azonenberg>
but only writing during the writeback stage
<berndj>
well, pentiums have for years been retiring at least two writes per clock
<azonenberg>
x86 is a horse of a different color
<azonenberg>
i said classic
<berndj>
afaik & iirc & ianal etc
<azonenberg>
as in simple risc
<berndj>
true enough
<azonenberg>
not multiplie-issue superscalar
<azonenberg>
my goal in these designs is minimal gate count and relatively high clock frequencies
<berndj>
x86 is why there are now more transistors than ants
<berndj>
last i looked there was a ia64 with > 1 gigatransistor
<berndj>
mostly cache though
<azonenberg>
Woudlnt surprise me, gpus are up there already
<azonenberg>
Let me put it this way, my 8-bit arch uses 122 flipflops, 545 LUTs, and 312 spartan-3a slices
<berndj>
(probably rather ARM's fault rather than intel's - just due to number of cores out there)
<azonenberg>
which is under 20% of a 200k gate spartan-3a (this is equivalent to about 35k gates)
<azonenberg>
Clocks at upwards of 100 mhz in a spartan-3a -5 speed fpga
<berndj>
wow, you could have built that in 1979 then!
<azonenberg>
16x 8-bit registers
<berndj>
(but not at 100MHz)
<azonenberg>
Lol
<azonenberg>
8-bit memory address space (i.e. 256 bytes)
<azonenberg>
and 16-bit IO address space using pairs of registers
<berndj>
do you think we'll ever run out of 64-bit address space?
<azonenberg>
The idea was a design that could fit *anywhere*
<azonenberg>
even in the smallest fpga xilinx still makes
<azonenberg>
and no, i do not
<azonenberg>
We may eventually have >2^64 bytes of memory
<azonenberg>
per system
<azonenberg>
but we will be using distributed memory message passing architectures
<azonenberg>
2^32 per core is a little cramped but 2^48 is probably enouhg
<berndj>
i wouldn't either, but # bits is roughly linear with time, according to moore's law
<azonenberg>
by the time you need 256GB of memory you should not be using an SMP anymore
<azonenberg>
it doesnt scale
<berndj>
so 64 bits should last (at least) twice as long as 32 bits did
<azonenberg>
look at blue gene for an extreme example
<azonenberg>
my school's BG/L has 32768 compute nodes each with 512MB of 1GB of memory
<azonenberg>
or 1GB*
<azonenberg>
these are 32 bit procs
<azonenberg>
addressing i think 12T of total ram
<berndj>
nice toy!
<azonenberg>
Because its not all on one compute node
<berndj>
can it play tic tac toe?
<azonenberg>
So thats where i see things heading
<azonenberg>
lol, no idea - all i've used it for is matrix multiplication during the class :p
<berndj>
yeah, NUMA ftw
<azonenberg>
all of my HPC since then has been on my cuda cluster
<azonenberg>
My current preferred arch for HPC is a NUMA system consisting of a bunch of SMP systems with a relatively fast multicore CPU (i7 or similar) and one or more GPUs each
<azonenberg>
connected by sockets
<azonenberg>
this is a deeper hierarchy than needed for some project
<azonenberg>
sometimes a bunch of powerpc over MPI is all you need
<azonenberg>
iow, bg/l or successors
<azonenberg>
In any case, if you are designing a reasonable architecture
<azonenberg>
you should never attempt to fit that much ram onto one address space
<azonenberg>
Use hundreds of TB of ram by all means
<azonenberg>
But not SMP
<azonenberg>
use explicit NUMA aka message passing
<azonenberg>
and keep your data local
<azonenberg>
preferably in L1 cache
<berndj>
hehe, one of my pie in the sky dreams is a attaxx machine that has TB of ram
<azonenberg>
lol
<azonenberg>
Mine is a little more reasonable
<azonenberg>
only $6K and change
<berndj>
it would basically be just a counter, some combinatorial logic, and huge continents of ram