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December 1st, 2013, 10:18 PM
I should like to learn more about how this stuff works, if anyone will take the time to clue me.
As I perceive it, info in is stored in Random Access Memory (RAM). Would that be correct?
Is RAM content lost when PC is shut off? If not, can RAM content be manually deleted? Or is it simply replaced (written over) by new data being introduced?
How do Temporary Internet Files relate to the RAM?
Thanks in advance! jocular
Modern computers have a bewildering variety of memory systems. RAM, or main memory, traditionally has consisted of dRAM chips. the "d" stands for "dynamic", and the implication is that the chips only store information for a brief time unless refreshed. Typical dRAM systems automatically refresh themselves several times a second, I am not sure of the exact timing. If the computer's power is turned off, these chips lose the data stored in them.
However, various sorts of static RAM are becoming popular. Static RAM chips retain their information indefinitely even if power is turned off. The individual circuits that store each bit of information are more complex than in dRAM, so sRAM has traditionally been more expensive per number of bytes stored. However, that is changing. Why?
My understanding may be imperfect, but I think the main issue affecting relative price is "overhead". In addition to the actual memory cells, memory chips need a ton of logic gates and circuit paths to allow the computer to specify exactly which cells to access. dRAM chips also have to have circuitry that refreshes the memory cells over and over. As chips are made with ever-increasing numbers of memory cells, the overhead circuitry associated with accessing and refreshing them is growing in complexity and this "overhead" circuitry has grown so complex that the cost of making the actual memory cells is becoming a smaller and smaller fraction of the total cost of the chip, and thus the difference in cell cost matters less, especially since the overhead circuitry on sRAM chips is more complex than dRAM due to the need to refresh the cells.
Desktop computers still use primarily sRAM for main memory, with some sort of secondary storage for permanent memory. Most desktops, particularly older ones, use a hard disk drive for this purpose. Some new ones (including the one I am typing this with) have a "solid state drive", which is basically a collection of sRAM chips engineered to look like a traditional hard drive to desktop operating systems. Server blades have long used sRAM instead of hard drives. Portable devices such as ipads and phones use sRAM exclusively. Laptops have traditionally used small hard drives similar to those in desktops but are switching over to sRAM even faster than desktops. Few new laptops contain hard drives any more.
1/ Info is usually stored on a Hard Disk Drive or HDD/CD/DVD/USB etc and is loaded into RAM (Random Access Memory) from the respective drive for manipulation and processing via the computers CPU (Central Processing Unit).Originally Posted by jocular
2/ RAM is 'volatile' in that its contents will disappear when the power is switched off. There are some types of RAM like FRAM which are 'non volatile' in that they retain their contents without power. There are newer drives called Solid State Drives (SSD's) that can be comprised of NAND based Flash Memory which is non volatile or even standard RAM with battery backup to retain their contents. Most standard HDD's these days utilise volatile RAM as a cache to speed their performance.
3/ Temporary Internet files are stored in your Internet browser cache on your HDD and they can be physically removed (in Windows anyway) by opening up Control Panel/Internet Options. This cache is usually loaded into the paging file (virtual memory) on your computer to boost the access speed of data from your disk drives.
In Control Panel/Internet Options, on the first General page, you can also select options to delete you browsing history or set it to delete these files each time you exit your browser. If you click on the Settings button in the Browsing History section you can also see further details (storage space used on your HDD) and options with regards to your Temporary Internet files.
You can think of the RAM in the computer as working memory. The programs and any data that is required to be kept permanently (that best selling novel, etc) is stored on disk. Stuff is read from disk into RAM as needed (the processor can only directly access RAM).
DRAM is used for large amounts of memory - the gigabytes of memory in your PC - because it is cheap. It is cheap because each memory cell (1 bit) only requires a single transistor. Therefore, you can get more bytes on a given silicon area. It has the disadvantage, as danhanegan notes, of needing to be continually refreshed (every few milliseconds) which means it always consumes power, even if you are not accessing it.
There isn't really a way of deleting the content of RAM while the computer is running - because the code the computer is running is in RAM (the operating system, any applications and data) you would crash the machine if you tried to change it. But the data will disappear within milliseconds of power being removed.
SRAM will store data without it being refreshed as long as power is supplied (sorry danhanegan). However, it can do this because it uses 4 or 6 transistors for each bit which makes it much more expensive. (Silicon chip pricing is primarily determined by (a) chip size and (b) number of units sold.) However, it has the advantages of being faster to access and only using (significant) power when it is accessed. It is therefore used for on-chip memory, caches, etc.
Then there is non-volatile memory (such as flash). This will retain data even when the power is turned off. It is used for mobile devices and increasingly, again as danhanegan said, for solid state "disk drives" (with no disk!). These also only use 1 transistor per bit (nowadays, they might store 2 or 4 bits per transistor). But the transistors are slightly larger then DRAM and the market is not so big so they are still more expensive. But they are becoming more and more widely used.
Temporary Internet files are a temporary (really?) store of stuff you have accessed from the web - copies of web pages, images, etc. They are stored on disk when you access a web site so that when you go back to that web site, you computer can access these local copies instead of downloading it all from the web again (it checks the date of the web site against the files to see if it needs to download a new version of the page). This speeds up your browser.
Say I could store a charge in a battery or a magnet or anything else that can store a charge for a time. Charge will dissipate to the outside environment eventually. Very few things store charge permanently. You can make expensive permanent magnets. But they are expensive. In some countries charge dissipates faster than others for example in hot countries normal batteries drain really quickly. So using batteries for RAM in hot countries wouldn't make much sense so you'd use a magnet because a battery would be impractical. You could make a RAM chip using glass or mirrors. Its the materials you use affecting how long the RAM chip's memory stays. The computer uses a series of logic gates or switches. In the form of transistors, electromagnetic relays etc. To access this memory now how you access and read this memory requires you to make a system able to interpret this data and then output this data or process this data into a form that is interpretable by a Cathode Ray Tube on a fluorescent screen (think old televisions). Or some other means of processing the data. For example a factory control switch, Robotic arm, Pick and Place machines etc. Old computers didn't even use electricity. if anybodys interested there is a really good episode of how its made that explains the process of making CDs etc in much more detail with images.
You can't store a charge in a magnet.
Flash memory is guaranteed to maintain data (stored as charge) for several years. For longer term storage, you wouldn't want to use electronics.Charge will dissipate to the outside environment eventually. Very few things store charge permanently.
Of course expensive permanent magnets are expensive. On the other hand, cheap permanent magnets are cheap.You can make expensive permanent magnets. But they are expensive.
Why not use non-volatile memory, rather than battery-backed SRAM?So using batteries for RAM in hot countries wouldn't make much sense so you'd use a magnet because a battery would be impractical.
And how would you use a magnet to power an SRAM?
What are you talking about?You could make a RAM chip using glass or mirrors.
No it isn't.Its the materials you use affecting how long the RAM chip's memory stays.
And then you descend into even more nonsense. Irrelevant nonsense at that. Luckily, most people know to ignore what you write.
The dRAM, then, retains memory info without a source of power? Like the little "thingy" stuck into our digital camera, where the batteries may be replaced without loss of content? What is the physical means by which these devices work? jocular
I have done this, and usually delete all the junk. [/QUOTE]
It is obvious, I have a long way to go! jocular
Some forums will not do a quote post, if nothing is written below the quote. I'm testing that right now, for this forum. jocularYou can think of the RAM in the computer as working memory. The programs and any data that is required to be kept permanently (that best selling novel, etc) is stored on disk. Stuff is read from disk into RAM as needed (the processor can only directly access RAM). Pretty much the way I pictured things. Can you explain this processor access? Which processor?
DRAM is used for large amounts of memory - the gigabytes of memory in your PC - because it is cheap. It is cheap because each memory cell (1 bit) only requires a single transistor. Therefore, you can get more bytes on a given silicon area. It has the disadvantage, as danhanegan notes, of needing to be continually refreshed (every few milliseconds) which means it always consumes power, even if you are not accessing it. So, power is not constantly used to maintain dRAM memory, just has to be made available rather frequently (refreshed?), to keep data from "dying out"?
There isn't really a way of deleting the content of RAM while the computer is running - because the code the computer is running is in RAM (the operating system, any applications and data) you would crash the machine if you tried to change it. But the data will disappear within milliseconds of power being removed. This, the, accounts for the time used after turning PC "on", as the operating program is drawn from H.D. and placed in RAM?
SRAM will store data without it being refreshed as long as power is supplied (sorry danhanegan
Then there is non-volatile memory (such as flash). This will retain data even when the power is turned off. It is used for mobile devices and increasingly, again as danhanegan said, for solid state "disk drives" (with no disk!). These also only use 1 transistor per bit (nowadays, they might store 2 or 4 bits per transistor). But the transistors are slightly larger then DRAM and the market is not so big so they are still more expensive. But they are becoming more and more widely used. Again, by what physical means are these things able to retain memory without back-up power? As I understand it, the H.D. still requires back-up power, either from being plugged in, or a back-up battery in the box somewhere? When I studied digital computers in their infancy, the state of the art was supposedly a new development called "bubble memory", which I believe required no back-up power, could be wrong, though. Over the years, I have never heard the term bubble memory again. Probably was a fluke.
Temporary Internet files are a temporary (really?) store of stuff you have accessed from the web - copies of web pages, images, etc. They are stored on disk when you access a web site so that when you go back to that web site, you computer can access these local copies instead of downloading it all from the web again (it checks the date of the web site against the files to see if it needs to download a new version of the page). This speeds up your browser. Does this imply that every page accessed is stored forever on H.D.? Seems impossible, given the amount of data. If so, are settings available to allow user to use RAM exclusively for storage of browsed info?
Ha! Well, the truly astute might use the inductance of an electromagnetic device, good iron core, fat windings, low resistance, lots of inductance, paralled with a high-efficiency big capacitor, jolt it to resonance, drop it in liquid air. You just might be able to modulate the amplitude to impress information on it, and store it awhile!
Sheesh! Am I nuts? joc
Double posted, "through no fault of my own!" Sorry
Old-school core memory was something somewhat similar: Magnetic-core memory - Wikipedia, the free encyclopedia
At this point, you've got too many open questions. They'd be easier to answer if you took them one at a time. To begin with, a brief overview of modern computer architectures and the terms used might be in order.
The most fundamental thing in computers is the transistor. Nearly everything else is made from those. But you seem to be familiar with them already, and they're actually too low level. They've been abstracted and delegated away and you never deal with them as transistors unless you're doing research on new kinds of memory or new ways to optimize circuit planning programs.
The transistors are used to build more function pieces such as a bit of memory or an arithmetic logic unit (Arithmetic logic unit - Wikipedia, the free encyclopedia). The ALUs, which work on one bit each, are chained together to work on a 32-bit or 64-bit word. Along with some other logic, this makes up one core of the central processing unit (a.k.a. the CPU or processor). In modern computers, several cores are put together along with a clock (if you hear about the MHz of a computer, it probably means the CPU clock speed, although other parts often have their own clocks) and some delegation/scheduling/threading logic to make a single processor.
Now, the CPU takes instructions and carries them out, but it needs memory to hold both the list of instructions (the machine code) and the operators to use those instructions with. In modern CPUs these are mostly kept separate while a program is running, but files (such as those on your hard drive) can be used as either programs or data depending on a number of things.
When you start a program, a piece of code written into the operating system (such as Windows) called the loader takes the file on the hard drive, copies it into the program memory, does some set up and then begins executing that list of instructions. That program can then instruct the CPU and OS to load other files into memory. But the CPU runs much faster than the memory does so computer scientists and engineers have come up with all kinds of tricks to keep things moving. For example, if one of the instructions is a conditional branch (if x is greater than 4, which you wouldn't know if that's true or false until you finish loading x and executing the comparison) the CPU will actually execute both possibilities until it knows for sure which to throw away. Another solution to the same problem would be to try and guess which branch to take.
As an aside, the reason branches slow things down is because the CPU is actually trying to execute many instructions at one time. The entire execution process is broken down into a number of pieces like fetching the instruction, then fetching the data, then executing the instruction, etc. Each core of a CPU can do each of those steps all at once, until it hits a branch and it doesn't know which instruction to fetch until the branch makes it all to the last step or two. This is called instruction pipelining and provides a massive increase in speed.
Back to the mismatch between CPU speed and memory speed. The CPU is consuming instructions much faster than they can be delivered by the memory. So instead, the designers put some very fast (and very expensive) memory right on the CPU chip. Then the main memory can deliver large blocks of instructions in its own time while the CPU churns away on those already in its memory. This is called caching. Now, you can't just load a block the size of the cache or you'll have to pause everything in between the blocks. Instead, you chop the cache into pieces called pages and load one page at a time.
Now, the concept of caching has been heavily used all through out the design of modern computers and operating systems. In reality, a modern CPU doesn't have just one area of cache memory. It has three (last time I looked). Each one is a little bigger but a little slower. Then comes your SRAM (the stuff often referred to as the computer's memory) which may have a cache of its own as a transfer buffer. Then there's the hard drive which is again bigger but slower which stores most of your programs and data. And finally there's removable storage like CDs and DVDs which are slower still but theoretically unlimited in that you can simply change the discs out.
It's not just the hardware that uses caching though because the internet can be seen as yet another layer of storage. One common caching strategy (as guessing what to store in what cache is something of an art) is to simply assume anything you've used recently you might use again, which is what your browser does with all the text and images you look up. It caches those on the hard drive so if you hit the back button (or go to another page that uses the same background) it won't have to download that file again.
BTW, if you hear of cache misses, that's when the caching strategy guessed wrong and has to go out another layer to get the data it needs. Since the next layer out is slower, this causes delays, sometimes noticeable delays.
Then there's the swap file, which is sort of like caching in reverse. Because you only have say 8 GB of memory, but would probably like to have more, the OS makes a copy of those pages of memory that aren't being used and moves them out to the hard drive. This frees up memory for things you're using more often, at least until you need that data that got moved out of memory and it has to go load it back off the hard drive. I can't say for sure, but the same general idea is probably used throughout the caching hierarchy.
Of course, CPU and memory are probably the most important pieces of the puzzle, but they're not the only ones. There's also things like the bridges (there are typically two, called the northbridge and the southbridge) connecting every thing together, the graphics card (which handles many of the details of filling out millions of pixels sixty times per second) and the input and output devices like the keyboard, mouse and monitor. (There's a picture showing roughly how it all fits together here: http://en.wikipedia.org/wiki/Northbridge_(computing).)
You may also run across the term bus, which is a set of parallel wires, one for each bit, which carries (relative) large amounts of data from one place to another quickly. There are typically several things connected to one bus and some extra stuff to make sure everything gets to the right place.
Edit: That may be my biggest post yet. Hopefully it's not too much of a wall of text.
The info is usually regarded as a HDD file in HTML (Hyper Text Markup Language) although it is originally stored in RAM and then stored on your drive via the system BUS.
Bus (computing) - Wikipedia, the free encyclopedia
Computer systems generally consist of three main parts, the central processing unit (CPU) to process data, main memory to hold the data to be processed, and a variety of peripherals to communicate that data with the outside world...
In a modern system we might find a multi-core CPU, DDR3 SDRAM for memory, a hard drive for secondary storage, a graphics card and LCD display as a display system, a mouse and keyboard for interaction, and a Wi-Fi connection for networking. In both examples, computer buses of one form or another move data between all of these devices.
The Flash memory is non volatile so it doesn't need power to retain its contents although it has limitations in that there is usually a fixed number of times that data can be written to the memory before it becomes unreliable. There are many different ways to extend the life of Flash memory so the reliability is increasing although the HDD equivalent MTBF (Mean Time Before Failure) is usually much higher. The SSD's are expensive and do replace HDD's although they are expensive and due to their limitations they are usually used to speed up your computers startup (boot) time by storing commonly used Operating System and Application files. When plain RAM is used as a SSD battery backup is necessary and when the batteries fail the contents disappear.
Yes the cookies do come from visiting sites although they don't really impact on speed unless the cookie is a tracking cookie (i.e. reports your browsing preferences/history to a central site) and most good AV (Anti Virus) programs disable these types of cookies when they scan your system. Most cookies are limited to holding details used by sites to retain your selected preferences etc to save you having to type or supply them each time you visit the site.
Things change continually with IT but the general principles stay the same.
What is the best tablets with a larger screen and why?
And future generations of memory might use magnetic technology again, as we get to the end of CMOS technology's life (in the next 10 to 20 years or so).
search, Best Computer Build....Youtube or Google
Thanks. Already did that. I wanted computer people's opinions.
Jiminy Walker! Your knowledge of the subject is, to me, humbling! I did ask many questions; their number prompted your "biggest post yet"?The term bus, then, as used in computer jargon, was somewhat decipherable!
Your first link led me to a great number of further "reference-clicks" from within it. It seems I told myself years ago, that as computing speeds grew ever-faster, the technology would necessarily have to approach practical working in the realm of molecular size. My searching confirmed that. HDD "sweep" distance of "tens of nm"! A nanometer is [B]one-billionth of a meter; in terms of my world-sizing, that would be about 4 exponents beyond my own ability of measuring a thickness of material to 0.00000254 meter (I hope that's 1/10,000 inch!). My Dad taught me the use of a micrometer at age ten. Technology has now gone beyond my comprehension! jocular
Here is what's troubling me about cookies: My settings delete Temp. Net Files upon shut-down. Upon re-start, immediately after obtaining homepage (Yahoo), within seconds, several hundred cookies have again invaded the Files. I delete them, then proceed to browse, and often, NO MORE will appear. Sometimes, one or two. How/why are these cookies being dumped in every time the PC is turned on? joc
Yes the cookies do come from visiting sites although they don't really impact on speed unless the cookie is a tracking cookie (i.e. reports your browsing preferences/history to a central site) and most good AV (Anti Virus) programs disable these types of cookies when they scan your system. Most cookies are limited to holding details used by sites to retain your selected preferences etc to save you having to type or supply them each time you visit the site.
This is pretty close to my area of expertise. I'm a computer programmer/scientist, not a computer engineer, but they make us take some of the basic architecture classes. I'm glad you found it helpful.
There's a couple of different possibilities as to why you'd get a bunch of cookies at first start, assuming they weren't still there from before. You might try something like Malwarebytes and/or Microsoft Security Essentials (if you're using Windows) and make sure there's no unknown programs adding cookies behind your back (though they typically would continue to do so as you browse). It might also be that your delete-temp-files settings aren't deleting cookies (there's usually some finer controls since not everyone wants to delete everything all the time). You could try checking the temporary files folder before starting your browser and see if the files are actually already there from last time.
A tablet with a Windows Operating system (vs phone based OS's) can at least load standard Anti Virus software and afford a reasonable level of protection to the user.
The ASUS Transformer Book T100 is a 10.1" laptop/tablet and the Toshiba Encore 8" is a smaller tablet but both have similar processors and win OS.
Most sites don't tell you when they load cookies on accessing their website but some do. Might be better to set another page as your home page (in Internet Options) to avoid these cookies being loaded in the first place.
If you click on Control Panel/Internet Options then click on the Settings button and then click on the View Files you will be able to see what cookies are persistent and were not removed. You can also delete them manually from there (hi light then press del, at your own risk, some may be important) but it's probably safe to assume that if your AV hasn't flagged them as malicious and removed them then they are benign.
Thank you. As my husband is tech not interested....I have to kind of give him some options!A tablet with a Windows Operating system (vs phone based OS's) can at least load standard Anti Virus software and afford a reasonable level of protection to the user.
The ASUS Transformer Book T100 is a 10.1" laptop/tablet and the Toshiba Encore 8" is a smaller tablet but both have similar processors and win OS.
Exactly what I do. Upon start-up, while checking the Temp. files, they begin piling in, taking as long as several minutes before they stop. This is before I open my home page, I open up operation by opening "In Private": InPrivate is turned on
When InPrivate Browsing is turned on, you will see this indicator
InPrivate in the address bar
InPrivate Browsing helps prevent Internet Explorer from storing data about your browsing session. This includes cookies, temporary Internet files, history, and other data. Toolbars and extensions are disabled by default. See Help for more information.
To turn off InPrivate Browsing, close this browser window.
Under "Delete Browsing History", I have clicked "on" every choice offered to be deleted, temp. files, cookies, history, download history, form data, tracking protection, and passwords. Is this a mistake, do you think? Some time ago I asked here on the forum, about cookies, and the general response was, just forget about them! After completely deleting, I proceed to browsing, this forum, home page, a few other forums, and over several hours time, at most, 4 or 5 cookies will have accumulated. Upon start-up there are initially none, then they begin piling up. I have clicked "on" "Delete Browsing History on Exit". I am using Windows 7. jocular
Sorry if in my ignorance I implied the cookies showed up while home page is displayed. Some, a few only, do. Please see my explanation of my efforts above in response to MagiMaster. jocMost sites don't tell you when they load cookies on accessing their website but some do.
If you click on Control Panel/Internet Options then click on the Settings button and then click on the View Files you will be able to see what cookies are persistent and were not removed. You cMight be better to set another page as your home page (in Internet Options) to avoid these cookies being loaded in the first place.
an also delete them manually from there (hi light then press del, at your own risk, some may be important) but it's probably safe to assume that if your AV hasn't flagged them as malicious and removed them then they are benign.
Hmm, have you tried a different browser like Google Chrome? It has an incognito window that serves a similar purpose.
You can open the same folder without a browser open at all. You just have to look up where each browser stores its files on your drive.
You can also open the cookies themselves (in the browser or outside) and sometimes work out where they've come from. (In the browser, it should tell you where it came from.)
Ouch! Both yours, and the following post, sound good to me, but in my low level of competence here, I have little idea how to go about following the recommendations. To use your suggestion, does this mean using Google Chrome as a "home-page"? I would not blame you for laughing!Hmm, have you tried a different browser like Google Chrome? It has an incognito window that serves a similar purpose.jocular
Internet Explorer is a web browser, but it's not the only one. Just the only one that comes preinstalled on Windows. Just type "google chrome" in google.com (yes, it's their browser) to find a download link and then install it like you would any other program.
I am in too many places that won't use Chrome or Safari...which is why I stick with IE
No, just browse to any page that you want to be your home page in IE, open Internet Options, and then click the Use Current button.Ouch! Both yours, and the following post, sound good to me, but in my low level of competence here, I have little idea how to go about following the recommendations. To use your suggestion, does this mean using Google Chrome as a "home-page"? I would not blame you for laughing!
Chrome is actually another internet browser like Internet Explorer (IE) from Microsoft. A lot of the nasties out there target IE because it has been around for so long although any browser with many users are targeted. Chrome will copy your bookmarks and settings etc from IE and make itself the default browser during the install.
If you go to Google and search for chrome you will find that the first link will be to install Google Chrome.
I just saw MagiMasters post.
I'm surprised that any site would limit themselves to 1/4 of internet browser users.
Usage share of web browsers - Wikipedia, the free encyclopedia
Browser Statistics
Don't know. I just find myself constantly kicked when I have tried other browsers.....for certain places that I go.....and no..*laughing* not pornI'm surprised that any site would limit themselves to 1/4 of internet browser users.
Usage share of web browsers - Wikipedia, the free encyclopedia
Browser Statistics
You used the piece of magic too many people seem oblivious to, the enigmatic "paragraph", so all is good and very informative.
Thank you, and MagiMaster both! I shall follow your leads, and report back. Have additional questions which I will limit to only a few at a time. For all who have accumulated such a wealth of PC usage ability, especially if acquired without formal training, I applaud and envy you! jocNo, just browse to any page that you want to be your home page in IE, open Internet Options, and then click the Use Current button.Ouch! Both yours, and the following post, sound good to me, but in my low level of competence here, I have little idea how to go about following the recommendations. To use your suggestion, does this mean using Google Chrome as a "home-page"? I would not blame you for laughing!
Chrome is actually another internet browser like Internet Explorer (IE) from Microsoft. A lot of the nasties out there target IE because it has been around for so long although any browser with many users are targeted. Chrome will copy your bookmarks and settings etc from IE and make itself the default browser during the install.
If you go to Google and search for chrome you will find that the first link will be to install Google Chrome.
I just saw MagiMasters post.
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