Forums

crazy memory ideas?

Started by Joseph H Allen November 6, 2013
Well here is one: Use a selenium-coated laser printer drum pretty much as
intended.  Impart a charge on it's surface, fire laser to erase charge for a
0 or leave it for a 1, then use some kind of electrometer to read the bit
later.  Recycle this back to the laser for recirculating memory.

I'm wondering if there is any way to make a large scale CCD shift-register
memory which can be made at home.  I'm imagining tin-foil electrodes glued
to some kind of reasonably high-mobility but fully-depleted material..  but
is there such a material besides a single-crystal semiconductor?

Hmm, which reminds me: does anyone have a good description of how
bucket-brigade devices really work?  The equivalent schematic the datasheets
always show can not possibly work (the mosfet switches will cause charge to
be shared between the two capacitors they connect, and not moved in one
direction: you would need buffers between stages for the discrete device
version of this to work).
-- 
/*  jhallen@world.std.com AB1GO */                        /* Joseph H. Allen */
int a[1817];main(z,p,q,r){for(p=80;q+p-80;p-=2*a[p])for(z=9;z--;)q=3&(r=time(0)
+r*57)/7,q=q?q-1?q-2?1-p%79?-1:0:p%79-77?1:0:p<1659?79:0:p>158?-79:0,q?!a[p+q*2
]?a[p+=a[p+=q]=q]=q:0:0;for(;q++-1817;)printf(q%79?"%c":"%c\n"," #"[!a[q-1]]);}
On Wed, 6 Nov 2013 16:40:52 +0000 (UTC), jhallen@TheWorld.com (Joseph H Allen)
wrote:

> >Well here is one: Use a selenium-coated laser printer drum pretty much as >intended. Impart a charge on it's surface, fire laser to erase charge for a >0 or leave it for a 1, then use some kind of electrometer to read the bit >later. Recycle this back to the laser for recirculating memory. > >I'm wondering if there is any way to make a large scale CCD shift-register >memory which can be made at home. I'm imagining tin-foil electrodes glued >to some kind of reasonably high-mobility but fully-depleted material.. but >is there such a material besides a single-crystal semiconductor? > >Hmm, which reminds me: does anyone have a good description of how >bucket-brigade devices really work? The equivalent schematic the datasheets >always show can not possibly work (the mosfet switches will cause charge to >be shared between the two capacitors they connect, and not moved in one >direction: you would need buffers between stages for the discrete device >version of this to work).
Nice code: int a[1817];main(z,p,q,r){for(p=80;q+p-80;p-=2*a[p])for(z=9;z--;)q=3&(r=time(0) +r*57)/7,q=q?q-1?q-2?1-p%79?-1:0:p%79-77?1:0:p<1659?79:0:p>158?-79:0,q?!a[p+q*2 ]?a[p+=a[p+=q]=q]=q:0:0;for(;q++-1817;)printf(q%79?"%c":"%c\n"," #"[!a[q-1]]);} -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
"Joseph H Allen" <jhallen@TheWorld.com> wrote in message 
news:l5drek$uc8$1@pcls7.std.com...
> Well here is one: Use a selenium-coated laser printer drum pretty much > as > intended. Impart a charge on it's surface, fire laser to erase charge > for a > 0 or leave it for a 1, then use some kind of electrometer to read the > bit > later. Recycle this back to the laser for recirculating memory.
Sounds like the Atansoff-Berry computer memory, IIRC? But with frikkin' lazers instead of electrodes. If you swap laser for electron beam, doing it in a vacuum, you've got something very much like the storage tube (CRT). That helps because secondary emission is pretty easy to deal with, and helps keep the charge in place. The photoelectric effect would do just as well of course.
> I'm wondering if there is any way to make a large scale CCD > shift-register > memory which can be made at home. I'm imagining tin-foil electrodes > glued > to some kind of reasonably high-mobility but fully-depleted material.. > but > is there such a material besides a single-crystal semiconductor?
Jeri Ellsworth made her own MOSFETs... nothing's impossible. Rather than wafers, it might be easier to start with something dumb, like evaporated CdS or something. Food for thought: http://sparkbangbuzz.com/cds-fet/cds-fet.htm
> Hmm, which reminds me: does anyone have a good description of how > bucket-brigade devices really work? The equivalent schematic the > datasheets > always show can not possibly work (the mosfet switches will cause charge > to > be shared between the two capacitors they connect, and not moved in one > direction: you would need buffers between stages for the discrete device > version of this to work).
IIRC, it has to do with the buried charge layer in the substrate, beneath the MOSFET. As it turns off, the charge gets 'squeezed' into the next stage. There should still be attenuation though, as any normal (constant) capacitance should act to 'dilute' the effect of the variable capacitance, attenuating the signal. I think. Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
In article <l5dt2j$f15$1@dont-email.me>,
Tim Williams <tmoranwms@charter.net> wrote:
>"Joseph H Allen" <jhallen@TheWorld.com> wrote in message >news:l5drek$uc8$1@pcls7.std.com...
>Jeri Ellsworth made her own MOSFETs... nothing's impossible. Rather than >wafers, it might be easier to start with something dumb, like evaporated >CdS or something. Food for thought: >http://sparkbangbuzz.com/cds-fet/cds-fet.htm
Cool, I'm going to have to try this. Instead of water you could use window defrost heater repair paint. This guy made his own DRAM for his relay computer: http://www.northdownfarm.co.uk/rory/tim/tim-8.htm I don't see any refresh circuits in his design.. I guess programs have to be aware of memory decay time :-). Oh, another one I want to try is to make an acoustic delay line: but I want to run it at audio frequency and use the air as the delay line.. (instead of wire or crystal), so that you can listen to it.. Another is analog TV + camera in a feedback loop, you can get bits to walk across the screen with the right camera angle. -- /* jhallen@world.std.com AB1GO */ /* Joseph H. Allen */ int a[1817];main(z,p,q,r){for(p=80;q+p-80;p-=2*a[p])for(z=9;z--;)q=3&(r=time(0) +r*57)/7,q=q?q-1?q-2?1-p%79?-1:0:p%79-77?1:0:p<1659?79:0:p>158?-79:0,q?!a[p+q*2 ]?a[p+=a[p+=q]=q]=q:0:0;for(;q++-1817;)printf(q%79?"%c":"%c\n"," #"[!a[q-1]]);}
"Joseph H Allen" <jhallen@TheWorld.com> wrote in message 
news:l5e02o$37q$1@pcls7.std.com...
> This guy made his own DRAM for his relay computer: > http://www.northdownfarm.co.uk/rory/tim/tim-8.htm > > I don't see any refresh circuits in his design.. I guess programs have > to > be aware of memory decay time :-).
Heh, relay contacts have less leakage than DRAM cells (in absolute terms, probably not, but adjusted by scale, absolutely). I'd be surprised if a bit decays (becomes unable to trip the relay coil) by the time he gets bored with running it. :)
> Oh, another one I want to try is to make an acoustic delay line: but I > want > to run it at audio frequency and use the air as the delay line.. > (instead > of wire or crystal), so that you can listen to it..
Beware of reflection and dispersion -- keeping bits in place (the step response) may be challenging.
> Another is analog TV + camera in a feedback loop, you can get bits to > walk > across the screen with the right camera angle.
Heh. Which goes back to your CCD comment before. :) (Probably over half the data ends up stored in the CCD -- or Vidicon if you're nostalgic -- and the rest in phosphors and wiring.) Seems to me they always faded to blue. Wonder if that's something with NTSC, or just a coincidence? Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
On Wed, 6 Nov 2013 16:40:52 +0000 (UTC), jhallen@TheWorld.com (Joseph
H Allen) wrote:

> >Well here is one: Use a selenium-coated laser printer drum pretty much as >intended. Impart a charge on it's surface, fire laser to erase charge for a >0 or leave it for a 1, then use some kind of electrometer to read the bit >later. Recycle this back to the laser for recirculating memory. > >I'm wondering if there is any way to make a large scale CCD shift-register >memory which can be made at home. I'm imagining tin-foil electrodes glued >to some kind of reasonably high-mobility but fully-depleted material.. but >is there such a material besides a single-crystal semiconductor? > >Hmm, which reminds me: does anyone have a good description of how >bucket-brigade devices really work? The equivalent schematic the datasheets >always show can not possibly work (the mosfet switches will cause charge to >be shared between the two capacitors they connect, and not moved in one >direction: you would need buffers between stages for the discrete device >version of this to work).
We could distribute software on vinyl disks, 45s or LPs. We'd have to agree on a coding format. You could melt pits into the surface of wax or ice with a laser, and read it back with a lower power laser. Bulk erase. There was actually an early computer whose memory was a drum decorated with discrete capacitors. It rotated against a row of contact brushes. That could be done on a pcb, surface-mount. Possibly the FR4 could be the capacitors. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
On 11/6/2013 5:34 PM, John Larkin wrote:
> On Wed, 6 Nov 2013 16:40:52 +0000 (UTC), jhallen@TheWorld.com (Joseph > H Allen) wrote: > >> >> Well here is one: Use a selenium-coated laser printer drum pretty much as >> intended. Impart a charge on it's surface, fire laser to erase charge for a >> 0 or leave it for a 1, then use some kind of electrometer to read the bit >> later. Recycle this back to the laser for recirculating memory. >> >> I'm wondering if there is any way to make a large scale CCD shift-register >> memory which can be made at home. I'm imagining tin-foil electrodes glued >> to some kind of reasonably high-mobility but fully-depleted material.. but >> is there such a material besides a single-crystal semiconductor? >> >> Hmm, which reminds me: does anyone have a good description of how >> bucket-brigade devices really work? The equivalent schematic the datasheets >> always show can not possibly work (the mosfet switches will cause charge to >> be shared between the two capacitors they connect, and not moved in one >> direction: you would need buffers between stages for the discrete device >> version of this to work). > > We could distribute software on vinyl disks, 45s or LPs. We'd have to > agree on a coding format. > > You could melt pits into the surface of wax or ice with a laser, and > read it back with a lower power laser. Bulk erase. > > There was actually an early computer whose memory was a drum decorated > with discrete capacitors. It rotated against a row of contact brushes. > That could be done on a pcb, surface-mount. Possibly the FR4 could be > the capacitors.
That was the Atanasoff-Berry Computer mentioned upthread. And software _was_ distributed on audio cassettes! Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 USA +1 845 480 2058 hobbs at electrooptical dot net http://electrooptical.net
In article <527B018C.8020305@electrooptical.net>,
Phil Hobbs  <pcdhSpamMeSenseless@electrooptical.net> wrote:
>On 11/6/2013 5:34 PM, John Larkin wrote: >> On Wed, 6 Nov 2013 16:40:52 +0000 (UTC), jhallen@TheWorld.com (Joseph >> H Allen) wrote:
>>> Well here is one: Use a selenium-coated laser printer drum pretty much as >>> intended. Impart a charge on it's surface, fire laser to erase charge for a >>> 0 or leave it for a 1, then use some kind of electrometer to read the bit >>> later. Recycle this back to the laser for recirculating memory.
>>> I'm wondering if there is any way to make a large scale CCD shift-register >>> memory which can be made at home. I'm imagining tin-foil electrodes glued >>> to some kind of reasonably high-mobility but fully-depleted material.. but >>> is there such a material besides a single-crystal semiconductor?
>>> Hmm, which reminds me: does anyone have a good description of how >>> bucket-brigade devices really work? The equivalent schematic the datasheets >>> always show can not possibly work (the mosfet switches will cause charge to >>> be shared between the two capacitors they connect, and not moved in one >>> direction: you would need buffers between stages for the discrete device >>> version of this to work).
>> We could distribute software on vinyl disks, 45s or LPs. We'd have to >> agree on a coding format.
Kansas City?
>> You could melt pits into the surface of wax or ice with a laser, and >> read it back with a lower power laser. Bulk erase.
>> There was actually an early computer whose memory was a drum decorated >> with discrete capacitors. It rotated against a row of contact brushes. >> That could be done on a pcb, surface-mount. Possibly the FR4 could be >> the capacitors.
A disk version should be easy. I calculate 62 pF each for 16 sectors of a 10 inch PCB, but surface mount is so easy.. only problem is that brushes are terrible.
>That was the Atanasoff-Berry Computer mentioned upthread. And software >_was_ distributed on audio cassettes!
Records too! http://en.wikipedia.org/wiki/File:FloppyRom_Magazine.jpg -- /* jhallen@world.std.com AB1GO */ /* Joseph H. Allen */ int a[1817];main(z,p,q,r){for(p=80;q+p-80;p-=2*a[p])for(z=9;z--;)q=3&(r=time(0) +r*57)/7,q=q?q-1?q-2?1-p%79?-1:0:p%79-77?1:0:p<1659?79:0:p>158?-79:0,q?!a[p+q*2 ]?a[p+=a[p+=q]=q]=q:0:0;for(;q++-1817;)printf(q%79?"%c":"%c\n"," #"[!a[q-1]]);}
John Larkin <jlarkin@highlandtechnology.com> wrote:
> We could distribute software on vinyl disks, 45s or LPs. We'd have to > agree on a coding format.
There is another theory, which states that this has already happened. http://en.wikipedia.org/wiki/File:FloppyRom_Magazine.jpg
> You could melt pits into the surface of wax or ice with a laser, and > read it back with a lower power laser. Bulk erase.
Why did my read error rate go up when I moved from Toronto to Phoenix? :) Matt Roberds
In article <l5drek$uc8$1@pcls7.std.com>,
 jhallen@TheWorld.com (Joseph H Allen) wrote:

> Well here is one: Use a selenium-coated laser printer drum pretty much as > intended. Impart a charge on it's surface, fire laser to erase charge for a > 0 or leave it for a 1, then use some kind of electrometer to read the bit > later. Recycle this back to the laser for recirculating memory. > > I'm wondering if there is any way to make a large scale CCD shift-register > memory which can be made at home. I'm imagining tin-foil electrodes glued > to some kind of reasonably high-mobility but fully-depleted material.. but > is there such a material besides a single-crystal semiconductor? > > Hmm, which reminds me: does anyone have a good description of how > bucket-brigade devices really work? The equivalent schematic the datasheets > always show can not possibly work (the mosfet switches will cause charge to > be shared between the two capacitors they connect, and not moved in one > direction: you would need buffers between stages for the discrete device > version of this to work).
Some early memory designs had a rotating loop of magnetic wire. If you wanted to access address X, you waited X*bits clock cycles after the sync marker then read or wrote bits. Memory density wasn't too bad for that era but latency was awful. Scientists have tried similar tricks sending light pulses around loops of fiber optic cable. It works with all the same limitations as the loop of magnetic wire. There's also short-term storage using piezo elements that bounces mechanical waves through a little plate of quartz. Longer term storage can be performed by sending mechanical waves through long coils of spring wire, like old guitar amps that have a reverb effect. Ultra-short storage uses bits of coax cable. I don't know semiconductor physics, but I believe the bucket-brigade chips slide a clump of electrons down a continuous FET having hundreds of gates. It's essentially creating a moving pocket of conduction that the electrons must follow. It's not a chain of FET amps like some equivalent schematics. CCD sensors use the same tech to slide images off the optical area to amplifiers at an edge.