Modern day RAM, static or dynamic?
-
They are amazing and has changed so much from when I started doing this many years ago. I'm like you can't really think of a project so I've just started interfacing to peripherals. Example I tore apart an old OkiData printer the other day and got a butt load of stuff out of it including DC and stepper motors, photo interrupters, ec.. That's why I've been up all night creating a library to control the motors using C++. Well that and I'm trying to learn GIT in an XP VM. Had some problems with SVN earlier today and spent 2 hours trying to get SVN to do what I wanted it to do instead of what it wanted me to do. I've been looking to get away from SVN for some time and this might be the time.
VS2010/Atmel Studio 6.1 ToDo Manager Extension Some days, it's just not worth chewing through the restraints.
you got more luck than me. i need to use a microcontroller for my course completion project on computer science... nobody could think of anything to do with that thing :sigh:
I'm brazilian and english (well, human languages in general) aren't my best skill, so, sorry by my english. (if you want we can speak in C# or VB.Net =p) "Given the chance I'd rather work smart than work hard." - PHS241
-
Mineral spirits might not work that well (they are a petroleum derivative and a fair solvent for paint and suchlike, but I've not had a lot of success with them for organic glues). If Isopropyl doesn't work too well, try normal Meths - it's watered down IMS with a colourant and still a pretty good solvent in it's own right, but it's not as volatile as Isopropyl which can evaporate too fast to "soak" stubborn stains! :laugh:
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
It never stops being useful to have been a chemist in real life: There are two considerations when removing goops and glues. 1 - Like Cleans Up Like: How polar is it? This would describe the degree of partial charge on the molecules that make up the stuff. Polyethylene is extrmely non-polar (very few things can even stick to it) whilst PVC, due to the C (which in this case stands for the Chlorine content of the molecules) is quite polar. Solvents, too, have a full range of polarity. The plain hydrocarbons (such as are distilled from crude oil) are basically non-polar and differ (for your purposes) in their volatility: Natural Gas, LPG, Vaseline, and even the earlier mentioned polyethylene, are, for all practical purposes, the same (yeech!). They're not too useful for cleaning very polar goops because the bonding between the goop is too strong to let the solvent in to soften and disperse it. Water is the most polar solvent you're likely to come across Methanol (wood alcohol) is quite polar, but less so than water (they mix easily) Going down the line, we have grain alcohol (ethanol) and rubbing alcohol (isopropanol), each less polar than the preceding item and thus able to tackle different jobs (there will always be overlap!). Think of mixing gasoline and water: they form to layers (functionally, the water keeping the gasoline out). It's actually a good parallel for why some solvent remove your glue and some don't. Gasoline can dissolve candle wax - water not so much. There are neat things that span the world, such as the chlorinated solvents. Acetone. Soap works this way: it has a polar end and a long non-polar tail. It's actually very interesting (neat words like micelles and vesicles). The can bridge the gap between water and oil, so to speak, because they're in both worlds at once. 2 - What Hardened It? To be very simplistic, there are two types of hardening for gluing things. Thermal plastic and polymerization (thermal, chemical, or photo induced). The thermal route is like using a hot-glue gun: the material softens and gets sticky, holding things together when it cools. The polymerization, on the other hand, is when a bunch of smaller molecules react chemically to harden (like epoxy glue, crazy-glue, gorilla-glue, etc.). The hardened adhesive is like one big molecule (and invariably polar). Even epoxy can be softened and removed (for example, with dimethly formamide - you don't want to play with this). One does tend to learn from experience -
-
A can of flux cleaner from the local Radio Shack or other electronics supply house works great! It's almost as good as triclhor. Also I've used the butane fuel (used for refilling the old flip lighters). The local library uses butane to remove stickers from their books. Do I need to invoke the don't use near open flame disclaimer? :laugh:
It was broke, so I fixed it.
Only if you add the traditional "Don't try this at home" :laugh:
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
-
It never stops being useful to have been a chemist in real life: There are two considerations when removing goops and glues. 1 - Like Cleans Up Like: How polar is it? This would describe the degree of partial charge on the molecules that make up the stuff. Polyethylene is extrmely non-polar (very few things can even stick to it) whilst PVC, due to the C (which in this case stands for the Chlorine content of the molecules) is quite polar. Solvents, too, have a full range of polarity. The plain hydrocarbons (such as are distilled from crude oil) are basically non-polar and differ (for your purposes) in their volatility: Natural Gas, LPG, Vaseline, and even the earlier mentioned polyethylene, are, for all practical purposes, the same (yeech!). They're not too useful for cleaning very polar goops because the bonding between the goop is too strong to let the solvent in to soften and disperse it. Water is the most polar solvent you're likely to come across Methanol (wood alcohol) is quite polar, but less so than water (they mix easily) Going down the line, we have grain alcohol (ethanol) and rubbing alcohol (isopropanol), each less polar than the preceding item and thus able to tackle different jobs (there will always be overlap!). Think of mixing gasoline and water: they form to layers (functionally, the water keeping the gasoline out). It's actually a good parallel for why some solvent remove your glue and some don't. Gasoline can dissolve candle wax - water not so much. There are neat things that span the world, such as the chlorinated solvents. Acetone. Soap works this way: it has a polar end and a long non-polar tail. It's actually very interesting (neat words like micelles and vesicles). The can bridge the gap between water and oil, so to speak, because they're in both worlds at once. 2 - What Hardened It? To be very simplistic, there are two types of hardening for gluing things. Thermal plastic and polymerization (thermal, chemical, or photo induced). The thermal route is like using a hot-glue gun: the material softens and gets sticky, holding things together when it cools. The polymerization, on the other hand, is when a bunch of smaller molecules react chemically to harden (like epoxy glue, crazy-glue, gorilla-glue, etc.). The hardened adhesive is like one big molecule (and invariably polar). Even epoxy can be softened and removed (for example, with dimethly formamide - you don't want to play with this). One does tend to learn from experience -
Always good to learn something new!
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
-
Back in the days I knew about hardware there were two types of RAM, the cool static RAM which does exactly what RAM should, and the far more common dynamic which needed refreshing. If I remember correctly, each bit was a tiny capacitor which would slowly leak charge so periodically you'd have to recharge it. The bits were arranged in a grid of rows and columns and there was some concept of RAS and CAS (Row/Column address select) but can't remember the details. That was nearly 30 years ago now I think about it. So, can anyone tell me how it's done these days? I suspect dynamic RAM is a thing of the past. And who can remember wiping the non-volatile memory of the day with UV light? I feel quite nostalgic.
Regards, Rob Philpott.
Rob Philpott wrote:
So, can anyone tell me how it's done these days? I suspect dynamic RAM is a thing of the past.
Dynamic RAM lives on, although with several refinements and improvements. Wikipedia has a very good article on it and works well as a starting point to all things DRAM in the known universe. CAS before RAS [^] :cool: -- RP
-
Back in the days I knew about hardware there were two types of RAM, the cool static RAM which does exactly what RAM should, and the far more common dynamic which needed refreshing. If I remember correctly, each bit was a tiny capacitor which would slowly leak charge so periodically you'd have to recharge it. The bits were arranged in a grid of rows and columns and there was some concept of RAS and CAS (Row/Column address select) but can't remember the details. That was nearly 30 years ago now I think about it. So, can anyone tell me how it's done these days? I suspect dynamic RAM is a thing of the past. And who can remember wiping the non-volatile memory of the day with UV light? I feel quite nostalgic.
Regards, Rob Philpott.
Rob Philpott wrote:
And who can remember wiping the non-volatile memory of the day with UV light?
I can! I can! I think I still have an EPROM eraser in storage! Marc
Testers Wanted!
Latest Article: User Authentication on Ruby on Rails - the definitive how to
My Blog -
Interesting point. I had (without much consideration) thought that dynamic RAM would probably have been succeeded by something newer and better. But for static if you can make a single bit out of two logic NANDS (or something like that - can't remember) with say 8 transistors then as you say for 8GB you are talking about one unattainable level of chip fabrication. Obvious really, when you think about it.
Regards, Rob Philpott.
Rob Philpott wrote:
But for static if you can make a single bit out of two logic NANDS (or something like that - can't remember) with say 8 transistors then as you say for 8GB you are talking about one unattainable level of chip fabrication. Obvious really, when you think about it.
Yup; especially since modern DRAM doesn't have to make space on the chip for a capacitor; instead it uses the miniscule amount of parasitic capacitance inherent in a transistor to store the charge.
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason? Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful? --Zachris Topelius Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies. -- Sarah Hoyt
-
Interesting point. I had (without much consideration) thought that dynamic RAM would probably have been succeeded by something newer and better. But for static if you can make a single bit out of two logic NANDS (or something like that - can't remember) with say 8 transistors then as you say for 8GB you are talking about one unattainable level of chip fabrication. Obvious really, when you think about it.
Regards, Rob Philpott.
-
Both. Caches on the CPU are usually static RAM, and the RAM that's referred to as RAM is practically always dynamic RAM (there are some weird other techs out there like phase change RAM, not seen in PCs as of yet) otherwise it would be huge and cost millions. 8GB of static RAM? You wish.
-
A can of flux cleaner from the local Radio Shack or other electronics supply house works great! It's almost as good as triclhor. Also I've used the butane fuel (used for refilling the old flip lighters). The local library uses butane to remove stickers from their books. Do I need to invoke the don't use near open flame disclaimer? :laugh:
It was broke, so I fixed it.
S Houghtelin wrote:
Do I need to invoke the don't use near open flame disclaimer?
Oh no too late! I have some white camping gas I wonder?
VS2010/Atmel Studio 6.1 ToDo Manager Extension Some days, it's just not worth chewing through the restraints.
-
Look for one of these: http://www.pool-spa-supplies.com/index.php/miscellaneous-parts/extractor-eprom-ic-5-60-9003.html[^] - they prevent scratching of the tracks under the chip by holding the ends firmly. There is a higher tech version: http://www.inovauto.com/index.php/reparacao-auto/componentes-chips-1/eprom/plcc/plcc-ic-extractor.html[^] but while these are brilliant for PLCCs in carriers they are too "sharp" to grip an eprom properly.
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
Ok my curiosity is piqued, why in the hell would a pool/spa supply house carry a EPROM extractor tool? They pull a lot of em out of the bottom of pools? :)
VS2010/Atmel Studio 6.1 ToDo Manager Extension Some days, it's just not worth chewing through the restraints.
-
Ok my curiosity is piqued, why in the hell would a pool/spa supply house carry a EPROM extractor tool? They pull a lot of em out of the bottom of pools? :)
VS2010/Atmel Studio 6.1 ToDo Manager Extension Some days, it's just not worth chewing through the restraints.
At a guess, software updates. If they supply the controller software on an EPROM it's another way to make a little money.
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt -
At a guess, software updates. If they supply the controller software on an EPROM it's another way to make a little money.
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
OriginalGriff wrote:
If they supply the controller software on an EPROM it's another way to make a little money.
Yeah that makes more sense then the idea I had that they recorded porn on it so they could display at bottom of pool? :)
VS2010/Atmel Studio 6.1 ToDo Manager Extension Some days, it's just not worth chewing through the restraints.
-
OriginalGriff wrote:
If they supply the controller software on an EPROM it's another way to make a little money.
Yeah that makes more sense then the idea I had that they recorded porn on it so they could display at bottom of pool? :)
VS2010/Atmel Studio 6.1 ToDo Manager Extension Some days, it's just not worth chewing through the restraints.
That's either gonna be seriously low res pr0n, or a bad case of premature ejaculation! :omg:
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt -
That's either gonna be seriously low res pr0n, or a bad case of premature ejaculation! :omg:
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
I never said it was a good idea. :)
VS2010/Atmel Studio 6.1 ToDo Manager Extension Some days, it's just not worth chewing through the restraints.
-
Back in the days I knew about hardware there were two types of RAM, the cool static RAM which does exactly what RAM should, and the far more common dynamic which needed refreshing. If I remember correctly, each bit was a tiny capacitor which would slowly leak charge so periodically you'd have to recharge it. The bits were arranged in a grid of rows and columns and there was some concept of RAS and CAS (Row/Column address select) but can't remember the details. That was nearly 30 years ago now I think about it. So, can anyone tell me how it's done these days? I suspect dynamic RAM is a thing of the past. And who can remember wiping the non-volatile memory of the day with UV light? I feel quite nostalgic.
Regards, Rob Philpott.
Who cares? Not that I'm a electronics engineer hell bent on inventing the next great RAM device ... Whatever works right now. Incidently, you might look at things like this. Photoshop 64-bit will run on 64-bit OS using 64-bit enabled memory addressing. And the user knows this because he can literally watch all of his RAM being used by whatever process apes the allocation grapher in Task Manager. That's all he cares about. But! The next thing he notices is that his graph goes to "all used up" and his Photoshop tool use starts to lag. he then says to himself "I need more RAM". Then goes out and buys another computer with more RAM. Gets home and installs Photoshop on his new box and notices that he has more power because he just sprung for more RAM! Simple as that. Who cares?
