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Technology

The Basics Of RAM 79

Posted by Hemos from the learn-more-be-better dept.
Segfault 11 writes: "Ars Technica has Part 1 of their RAM series, which discusses the way that static and dynamic RAM work, in addition to covering memory modules. To get started, click here to learn more."
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The Basics of RAM More

The Basics of RAM

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  • > when you know how to do basic things to it. Not
    > to mention pride of ability. So for those same
    > men/women out there who can change their

    pride of ability? puh-leeze. at least half of all CS-majors nowadays are in it for the money.

    anyhow, most people can't even program their vcr. if you study technology's history, you'll find that there's always been a huge difference between "experts" and "users".

    > I Agree with the guy who said that users should
    > take basic computer classes, and agree that
    > porgrammers should take classes to know what
    > the effing hardware they are interfacing with

    grammar is ok, spelling...no so ok.
  • As for installing new software of windoze machines, I know that if the system is 'stable' then I won't unless I really need to, that is where most windoze problems come from, because every new program just installes it's own versions of system libs (this is one of the major reasons that windoze is so unstable, and why MSCE's can do it right) I think that admin should be for System Admins, and using computers should be for Computer Users, lets not get the two mixed up!
  • Young man, back in MY day we didn't have DIPs soldered onto the motherboard. We simply didn't have DIPs to solder onto the motherboard. For that matter, we didn't have motherboards to solder DIPs onto. We had CORE . Talk about newfangled.

    ROM basic? Phew! Real men load kernels by TOGGLING the phucking SWITCHES!

    (Feel free to reply with completely made up story about vacuum tubes and CRT memory :)

  • You dope, your cache is static RAM. L1, L2, the whole works - those are mostly SRAM, with some exceptions.
  • Comparing the workings of a car to the workings of a computer is like comparing owning an Erector set to owning a construction company.

    A car, while still a complex machine, is simple in that it had one main use...carting some person's butt from location a to location b. I suppose it can be used to store stuff, pot plants, live in, and so on, but the set is very limited.

    A computer can be used to accomplish such a wide variety of tasks. Yes, they can all be boiled down to a processing of binary data, but I think it is the wide array end results that can be accomplished that make the distinction.

  • Two things. Firstly it took a long time, 50 years or so, before it was possible to operate a car with such little knowledge of its operating principles. A lot of reliability engineering was needed, and a lot of user interface standardisation (like the steering wheel, and which way it turns).

    Secondly, one of the truly remarkable things about computers, and software is how much it is possible to gain from using them, even when you don't actually understand very much about how to use them, or anything about how they work, and even when they work pretty badly and unreliably (like most current software). Just think how much we'll be able to do when (a) they're built right, and (b) we all know how to use them
  • Your car example is specious. The original example was people who can't install their own software. That requires no knowledge of the internals of an OS. The car analog to installing your own software IS putting gas in.

    Furthermore, you know a LOT more about your car than how to put the gas in. You know how to operate your car (which pedal makes it go faster, which stops it, how to steer), how to operate the "peripherals" (radio, AC, etc), how to read the feedback (odometer, speedometer, warning lights), traffic laws (no right on red, right side of road, four way stops, etc) and communication with other users (turn signals, honking, hand gestures, etc).

    In fact, if you want to argue that computer usage and car usage (should) require similar levels of knowledge, you'll have to further argue that, unless you can prove basic proficiency and safety, you should be allowed to operate a computer. Just like a driver's license.

    You are right that computers are powerful--but power by itself is useless. You need knowledge to apply that power usefully and safely.
    --
  • I know nothing about how my car works. I am not at all comfortable with upgrading it or maintaining it. The most complicated act I am able to perform is to put gas in it.

    I'll bet you, and most other people know more about cars then that. Even ignoring the whole driving part.

    You know to take it to regular mantinace, otherwise you wouldn't be able to drive it for very long. You know when the little red lights show up on the dash that you should call someone. Hopefully you know which little red lights mean "turn the engine off now now now" (hint: lack of oil can destroy an engine very very fast), if your lucky you know which ones means "you can probbably drive me ok for a bit, but you won't get me to start again". You probbably know not to turn the engine off in the middle of a drive (unless you have the car in neutral).

    I'll bet you even know how to change a spare tire (if you don't, go out to your car and look, it ain't that hard, and you might rather learn now then in the rain...when your cell phone is dead...and your late for a job interview). And where the engine is. And maybe even have a general idea of what some of the engine parts look like and are for. Many people do.

    On the other hand most computer owners won't know similar things. What dialog boxes mean "get help now", and what ones mean "click this away and finish what your doing"? If you open the box, what part is the CPU and what is the RAM? Are there any parts of a computer that wear out and need mantiance? (I figure it's a good idea to back up disks, and check to see if the fans still spin every once in a while)

    I admit, today this scenario does not exist in as ideal a fashion as I have laid out. But that doesn't imply it cannot exist. Computers are fundamentally no different than cars - just more complicated. Thus, while it should take more work on our part, a system is able to be designed which fullfills these criteria. It is a challenge to computer scientists to create this system.

    No, it's a chalange to marketing folks somewhere. A chance to get folks to spend $25 a year on a "computer oil change" millions of folks...

    It's not much of a technical change. People use computers will little knolage of how the hardware works, and it only hurts them when they go to buy a new one (same as someone lack of car knolage...except there are fewer decent reviews of new computers, but you can still drag a "smart" friend to the store). Oh, plus it hurts when they forget to back up valuable data...but more from software fuckups.

    Now the lack of software knolage, that hurts people all the time. Fixing that (by incresing knolage, or decresing need) is a way harder chalange. (and I have noticed a genneral increse in the amount of computer knolage the avrage person has)

    Furthermore, the digital computer is so powerful a tool that it should not be withheld from the majority of society for any reason. It has the power to radically alter our entire society, and if that means the loss of comfort for the "computer elite" (which I do not believe it does) than so be it. Why should society be denied such benenfits simply because a few people prefer computers to be special hi-tech playthings? I am happy that the car was not denied society in a similiar fashion.

    Who's been denying? Apple and Microsoft have been working on making computers easyer to use, and people have been learning more about them for years. Decades. They made lots of progress at first, and have slowed quite a bit. But that is because the problem is hard, and keeping your current users happy makes it harder. Not because they have some insane desire not to increse the number of potential buyers by tenfold or more.

  • Very true, however automobiles, and their most basic processes have been a part of society for a century. What is needed to be known about such a pervasive part of society is ingrained at every turn. For instance your dad forcing you to hold the flashlight at 1AM as he futzes with changing the belts then takes it to the mechanic. That type of knowledge (subliminal if you will) has grown since the car became a commodity. Do you think that in the early days of the automobile, everyone that had one knew as much as you do about yours, which is significantly more complex, but works on the same principles? Sure, mechanincs and automobile 'geeks' of the day knew what they were doing, but there was not as much burden, as there increase in automobile usage was not nearly as exponential an increase as there is in computer usage.

    Technology, computing specifically, is new to the majority of users, the know that they CAN use the computer as a tool, but they lack the basic skills and knowledge to manipulate that tool to its fullest. They lack the knowledge to proctec themselves from spammers, virii, ect. WHY DO YOU THINK WE ALL HAVE JOBS???

    As time goes on, computing will become safer, and easier for the masses. At the same time the masses will gradually accumulate more of the basic knowledge to keep from annoying so much, so we will have more time for our QUAKE 15 deathmatch.


    www.mp3.com/Undocumented [mp3.com]
  • Well they cant charge me til i'm driving about 77mph so it's not that much of a big deal to people here.

    The other day some guy got so pissed off with my 85mph pace that him and someone else undertook me and squeezed in the gap between myself and then rv i was overtaking.

    But then my point was really that quite a large proportion of the populous here feel that driving at that speed is within their capabilities. One wrong move and i'm sure my car would end up torn to shreds, and yet it's these same people who wouldn't plug a dimm in because they might damage it.
  • Check the list of topics under the "Recent" heading on the right hand column of the Ars-Technica home page. That's where /. gets its list, not the current article headers.
  • Although I wouldn't be quite so harsh on them as that, it does annoy me when articles attempt to simplify something, and end up being wrong.

    I'm sorry, but EDO, fast page and the like are not methods for refreshing less, but ways to get the data out of the device faster.

    Perhaps explaining that reading DRAM is destructive would help understanding as well.

  • Isn't that why SDRAM is so much nicer than DRAM? It concentrates all of the timing issues at the interface to the chip, rather than (for DRAMs) having timing issues leak throughout the system, which causes every part of the system to insert the necessary worst case slop, which adds up after for or five of these are chained together...
  • > but how many know what the correct pressure for
    > their car is or how to inflate tyres correctly?

    Easy! The tire says what the correct pressure is on the sidewall. Have you ever tried to run Windows NT with the suggested amount of ram (24MB I think)? Those bastards at Redmond are lying pigs.

    Ryan

  • Re:Computers are for everybody (Score:3)

    by FFFish ( 7567 ) on Wednesday July 12, 2000 @06:43AM (#940827) Homepage
    Everyone and their dog is going to say that you know lots about your car.

    What they're ignoring is the validity in what you say. Instead of focusing on your point, which I think was very well made, they're going to nitpick at the illustration you used to carry the concept.

    Well, then, let's change the illustration:

    I know bugger all about how my microwave works. If it went on the fritz, I wouldn't know the first thing to do. It'd hit the garbage, and I'd buy a new one. There's enough scary things in it that I *don't* want to muck about trying to repair it!

    I don't know how my television works. There's a couple of lines into it, and a couple buttons on it, and it works. If anything goes wonky, it's off to the repair shop.

    Same goes for the VCR. If it ate a tape, I'd recognize that that's a different sort of problem than a wobbly picture. In both cases, it'd go to a technician.

    There a people who see their computer the same way I see a microwave: a scary black box that does magic.

    I can't blame them for not wanting to dink around with it. After all, if you let the smoke out, it stops working!


    --
  • There are times when "I don't want to do that" is perfectally acceptable.

    Too true, I didn't mean to speak in absolute terms.

    And yet the idea of minimum level of competence still hold true. It protected you for an incompetant tech.

  • The place I found a definition [webopedia.com] of NVRAM listed both descriptions - a battery-backed SRAM or an EEPROM, though, upon closer reading, the latter is more of a combination of an SRAM chip and an EEPROM.
    --
    Your friendly neighborhood mIRC scripter.
  • I know bugger all about how my microwave works. If it went on the fritz, I wouldn't know the first thing to do. It'd hit the garbage, and I'd buy a new one. There's enough scary things in it that I *don't* want to muck about trying to repair it!

    Heh... last time I and a couple o' guys wound up with an old high-voltage power supply and a bit of broken down equipment we ended up burning holes in bricks with the CO2-laser [sunsite.auc.dk] (linked page in Danish) we 'accidentally' built. I don't suppose anyone could spare a broken microwave for a particle accellerator?


    Martin
  • Difference between disk space and RAM is easy to teach. Try explaining directory structure and file system layout to a newbie ...
  • That article did a fantastic job of explaining the basics of RAM. I read many articles before, but none were as in-depth or as clear as this one. I suggest everyone takes the time to read this. I know many people say, "sure, I know exactly how RAM works, because I'm a computer geek." Well, I thought this too, and was partially right, but the articles really makes me feel like I was the guy who first designed DRAM, it really tells you that much. A must read article.

  • Computers are for everybody (Score:4)

    by bolan ( 45665 ) on Wednesday July 12, 2000 @04:13AM (#940833)

    I know nothing about how my car works. I am not at all comfortable with upgrading it or maintaining it. The most complicated act I am able to perform is to put gas in it.

    But I still use it, and need to use it, every single day. Ignorance about the internals of my car does not preclude me from using it in a valid fashion. Granted, if I were more informed about its workings I would probably be able to use it more efficiently, and more productively. But this gain is not worth the hassel I feel it would be to learn these things.

    Computers are no different. They are a tool - nothing more, nothing less. The average person doesn't care how data is actually stored in their computer, or how interrupts work, or anything. They want a machine which is perfectly intuitive and can let them write reports or generate presentations or email their friends, and they do not care how these feats are accomplished.

    I admit, today this scenario does not exist in as ideal a fashion as I have laid out. But that doesn't imply it cannot exist. Computers are fundamentally no different than cars - just more complicated. Thus, while it should take more work on our part, a system is able to be designed which fullfills these criteria. It is a challenge to computer scientists to create this system.

    Furthermore, the digital computer is so powerful a tool that it should not be withheld from the majority of society for any reason. It has the power to radically alter our entire society, and if that means the loss of comfort for the "computer elite" (which I do not believe it does) than so be it. Why should society be denied such benenfits simply because a few people prefer computers to be special hi-tech playthings? I am happy that the car was not denied society in a similiar fashion.

    Philip Quirk
  • Yeah much as I dont like x86 assembler much, and detest the r2k assember we did at uni last year, it does give a good insight into how things come together. It's also damn handy when u need to remove irritation limitations from trial software (that last point makes it painfully obvious how few programmers do put any great depth into their programs). I was trying to help a friend of a friend with Dragon Naturally Speaking Pro (quite an expensive program i think). He's disabled and had been given it from his college but when his windows died (shock horror) he went to reinstall it and had no serial number. Yet it took me about 20 mins to reverse the installsheild script and skip the sn check... and these people are supposed to be skilled coders!? Personally i'm all for open source since it avoids all these problems - like the me having to remember asm one :)

    But when I first fumbled my way onto the internet five years ago i'd have loved to have a book that just gave brief descriptions of things like: modem, ppp, ip, tcp, ftp, bbs, dns etc... since it would have made my life a lot easier. However those first two weeks trying to get an SMTP deamon runnning on a Mac so i'd receive email taught me so much about how things worked that retrospectively i'd never have skipped them for a one click sign up.
  • I try not to respond to trolls but here goes. First of all your comments are even less relevant to the article. I started on the idea that I found it useful and it filled in a number of things I was unclear about, and went on to comment more on the purpose of the article rather than the content. To be fair there are comparatively few content based discussions that can take place on a comment like this, and it does seem to have provoked a reasonable amount of justified discussion. As for the +1 thing I forgot i'd just got that and didn't think to turn it off - sorry!
  • You may laugh this off as excessive worrying, but this is a serious problem. I've overclocked a few chips, and they've all died pretty quickly -- and that was without static RAM. High-powered memory zapping around would kill the chip even more quickly. And what if that chip is powering some mission critical application like a space shuttle flight or an air traffic controller?

    I believe he was being facetious if not its still funny :P moderate accordingly :P


    If you think education is expensive, try ignornace
  • If you know to put gas in your car, you know more about cars than most people know about computers. You know, at least, that it needs gas and regular maintenance. Most folks don't even know that much about the computers they drive. If people drove their cars they way they use their computers, they'd drive until they ran out of gas. Then they would call tech support.

    I'm not trying to be elitist. I agree that it would be nice to have a computer that would operate the way you'd like it to. But you admit that we aren't yet at that point. Until that day, it behooves people to learn some basics about how computers work - such as the difference between disk space and RAM.
  • The ArsTechnica /box seems to feed off of the "Recent:" box on the ArsTechnica page, not off of the articles mentioned on the main page itself.

    Once Ars puts a front page story into the "Recent:" category, the Ars /box picks it up w/o trouble.

    The same thing happenned with the "Securing Win2k" story Ars ran last week. It pays to visit Ars in person now and again. :)
  • Man, that didn't help me fix my truck at ALL.

    I've got a '76 RAM, and the article didn't mention at all how I'm supposed to use ferrite core memory in a circuit.

    :)

    Actually, I do have a '76 Dodge Ram, and I do have some (approximately) '76 ferrite core memory. As much as I hate to admit it, the former is significantly more useful than the latter (especially since it gets me to work every day). The core is some of the *very last* ferrite core memory, with incredibly tiny little beads on what looks like a very uniform piece of windowscreen.

    It's amazing that the stuff actually worked. I'd love to find out how to use it so that I can hook it up to my computer just for fun. Ya know, my old Pentium 166MMX will really scream when I add that extra 256 bytes of 750nS RAM to it.

    DODGE 4EVAH!

    Amen, brother. I've destroyed 7 Honda Civics with my old truck, and they're always the ones with the tinted windows, the chainsaw mufflers, the big stereos and the "Powered By Honda" stickers. (Yah, it's a *Civic*, what do you *think* it's powered by? Put that sticker on a Toyota, and I might be impressed.) They keep on cutting me off, and like lemmings jumping off a cliff, they don't understand the fatal implications of their actions. I mean, 4,500lbs of Detroit steel coming at their silly little tinfoil cars. The first one really pissed me off, because he actually bent my bumper. (In all fairness, I did push his taillights into his back seat.) How many are you up to?

    Interesting people don't drive Hondas.

    [BigBlockMopar submits quickly, before he has a chance to think too much about the karma implications this posting will have.]

  • Perhaps explaining that reading DRAM is destructive would help understanding as well.

    Yes, that would be helpful. However, this is another case of the article simplifying something down to the point of being wrong. A direct quote from the article is:

    Reading from or writing to a DRAM cell refreshes its charge, so the most common way of refreshing a DRAM is to read periodically from each cell

    Just periodically reading from each DRAM cell will wipe your memory to all 0's. He meant to say that memory cells should be periodically read from and then written back to.

    ./configure
    make comment
    make post

  • Re:hmm. they don't cover ECC RAM (Score:5)

    by Detritus ( 11846 ) on Wednesday July 12, 2000 @05:38AM (#940841) Homepage
    It's a false economy, plus at one time, Intel and other vendors were telling people that they didn't need parity or ECC RAM.

    ECC RAM is more expensive and it can be hard to find. Many stores don't stock it. In some computers it can be a bit slower than regular RAM.

    After having repeatedly dealt with RAM with pattern sensitivity problems, I am a firm believer in ECC RAM. Trying to diagnose and repair a computer that crashes every few days, or only when certain programs are run, can be a major headache. Is the problem the RAM, other hardware, application programs, device drivers or the flakey operating system?

  • I would debate that by "using computers for more than a week" one would know the difference between SRAM and DRAM. I thought the article was great; it didn't require any sort of electrical degree to understand.

    So perhaps the article wasn't useful to an expert, but it's pretty damn useful to someone who wants to become an expert.

  • I believe most dram chips automatically write back to an address after it was read. So forcing a read of all the address would infact refresh the chip.

  • Static RAM got me in the balls. (Score:5)

    by BigBlockMopar ( 191202 ) on Wednesday July 12, 2000 @06:55AM (#940844) Homepage

    Yes. Static RAM can be highly dangerous.

    Especially if you're out in the middle of the woods, on a moonless night, camping with your friends. The campfire has died down, and you've just finished off a six-pack of your favorite beer. You're now heeding nature's call, staggering away from the glowing embers in the firepit...

    And then BANG!, the tailgate that you just *knew* you should have closed gets you in the balls. You lie writhing on the ground for a few minutes, then regain some control over yourself as the pain subsides, start to get up and you clock your head on the back bumper, which you didn't realize you were under.

    Never turn your back on a static Ram. Or any other pickup truck that you've parked in the woods on a camping trip.

  • Okay, so I'm wrong.. I thought I very well could be.. :) I just seem to remember them saying on that Candid Camera program that it was illegal in some states (I thought it was WA, maybe it's just OR .. it was somewhere in the north-west USA) to pump your own gas (their whole premise for this stunt rested on this as it was meant to be a 'shifty' sort of deal) .. I wonder if anyone else knows of this law or has seen that program and remembers the details (because I don't)

    Anyway.. my real point was that there ARE people out there that don't know how to pump their own gas.. and that's a little scary.. but it marries up well with the analogy of installing software is like putting gas in the car .. simple stuff... but some people are afraid/unsure of it.
    --
  • Ah.. this is it: .. Yes it's Oregon, not Washington ..

    Dumb Laws - Oregon [dumblaws.com]

    You may not pump your own gas in service stations.

    Weird.
    --
  • I am not quite sure how often /. syndicates news but its really rather trivial so I imagine its quite often.

    So.. What makes the difference is how often the sites /. is syndicating from update their XML data. The RDF format files that carry the headlines. I think /. grabs them often enough.

    Jeremy
    Go grab /code and see :0


    If you think education is expensive, try ignornace
  • Man, that didn't help me fix my truck at ALL.

    DODGE 4EVAH!

  • Isn't static RAM dangerous? (Score:3)

    by vertical-limit ( 207715 ) on Wednesday July 12, 2000 @03:32AM (#940849)
    I know a question like this is probably old hat (or is that "red hat" :P) to you Linux veterans, but as a long-time BeOS user, I've never quite understood why people insist on using static RAM. Everyone knows that the inside of a computer need to be cool and safe -- remember that incident where Pentium chips kept melting down? Static RAM is dangerous; it can't be relied on to not burn out when it really counts.

    (Why is that? Everyone know that static energy is actually a form of electricity. And electricity produces heat when it moves, thus causing the interior of the computer case to heat up. See Jager et. al [sciencemag.org] -- subscription required, sorry.)

    You may laugh this off as excessive worrying, but this is a serious problem. I've overclocked a few chips, and they've all died pretty quickly -- and that was without static RAM. High-powered memory zapping around would kill the chip even more quickly. And what if that chip is powering some mission critical application like a space shuttle flight or an air traffic controller?

    Just my two cents,
    - vl

  • I say the RAM information is well written out and gives a good overview of RAM in general that even a person that doesn't have alot of technical known-how could understand....Heres to the writers....GOOD JOB! -Sarkdas (Only 70 FPS? Wow thats low...)
  • A 30-pin SIMM, like our TM4100GAD8, can only spit out 8 bits of data at a time.
    Hmm... this may have been true in the bad old days, but this chip [ti.com] does a lot better - and it's only a minor upgrade. The designers of the TM4100GAD8 clearly got their act together after the all the fuss of their bodged original release.
  • Doh once again forgot to make it plain text

  • Ars Technica /box? (Score:3)

    by ethereal ( 13958 ) on Wednesday July 12, 2000 @03:36AM (#940853) Journal

    So why hasn't this made it into my Ars Technica slashbox? It seems like the list of articles in that box stays the same for a month, and then all of the sudden there are 5 new ones in a day. Does /. not update the /boxes very often, or is the problem at the Ars end?

  • Actually, static ram doesn't retain its data without power. That would be NVRAM (Non-Volatile RAM). DRAM simply employs capacitors which are leaky, and hence must be refreshed to maintain integrity. Static RAM needs an applied voltage, but doesn't need to be refreshed.
  • Quit freakin whining, these articles are the bread and butter of what this community stands for, intelligent computing practices.

    Perhaps you knew the whole article already, which makes it quite simple for you to not read it. Or, better yet, since you know so much about the article, give us some good feedback and earn yourself some mod points.

    Otherwise, if you want to keep crying, you can kiss my Ars.

  • In the UK certainly we are required to know quite a bit about how to use a car before we are allowed to drive one.

    Certainly turning on a car is no different in complexity from turning on a PC.

    But driving on the highway is quite a complex task. People on the public roads are a lot less tolerant of people who cant drive in a straight line or at the 'correct' speed than we are on the information superhighway.

    I'd hazard a guess that you do know how to change lanes without being a danger to other people, how to slow down when a drunk person steps into the road, and that you can park your car without denting those around it.

    Similarly I dont think it's too much to expect that users can connect a modem to their pc, can install the software, can set up their ppp dialer and configure their dns.

    Personally I find using the internet far less challenging than driving at 80mph, whilst having to pay attention to other road users, police speed traps, making sure the radio is on the right station, finding change for tolls etc...
  • At the same time, do you know how to change the oil in your car? How about the spark plugs, wires, distributor, etc? As far as gaskets and some belts/chains go, they are generally deep within the engine, and so much more of a pain to change, but, i think you see where i am coming from. It is not required information, but it does make it a lot easier/cheaper to own said vehicle when you know how to do basic things to it. Not to mention pride of ability. So for those same men/women out there who can change their own oil, check their fluid levels, and know the basics of how an engine works, why are those same people so scared of computers (ie, "I didnt want to mess it up"). Someone, generally dad, took the time to explain the processes, and now the people know. I think all people should know basic computer components and terminology. They may not need to understand what makes the difference between PC66 and PC133 SDRAM, or what is different between SDRAM and RDRAM. But they should know that RAM is as important to a computer as CPU, the should be able to identify a cpu and differentiate it from a, say, hard drive. they should be able to clean the dust from their mobo's once every so often. they should know that certain companies have a tendancy to produce good software, and certain companies have a tendency to publish bad software. agreed, we /.'rs tend to know the difference, and we can help said newbies learn about the differences, but them again, so can the guys working the floor at CompUSA, BestBuys, CircuitCity's Computer Department, etc. I Agree with the guy who said that users should take basic computer classes, and agree that porgrammers should take classes to know what the effing hardware they are interfacing with does.

    well at this point, i think i have come full circle from trying to argue that this wasnt a troll, to agreeing with you that he didnt make much sense. i should probably hit back instead of submit, oh well, here goes
  • I didn't mean to say that the RAM retained its data without power. What I was trying to get across was that if power wasn't applied to the unit (whatever that unit is - could be a computer or an embedded device, whatever), SRAM would allow the data to be retained by using a battery to supply power to it. You can do this with DRAM too (think Palm Pilot) but it uses more battery power. Sorry for the confusion.
  • Though, in most cases, NVRAM isn't really RAM, but a sophisticated EEPROM (in which you can erase specific bytes instead of the entire chip).
    --
    Your friendly neighborhood mIRC scripter.
  • My bad - wasn't aware that most EEPROMs are erased one byte at a time; must have been thinking of Flash memory (which is erased in blocks).
    --
    Your friendly neighborhood mIRC scripter.

  • Re:memory modules (Score:3)

    by Detritus ( 11846 ) on Wednesday July 12, 2000 @05:47AM (#940861) Homepage
    Heh!

    When we asked for a ROM, they handed you a PC board covered with diodes and a pair of wire cutters.

    Bonus geezer points for anyone who knows what a "schmoo chart" is.

  • Yes, very well written and clear - hope you're listening over at Ars Technica. 8-)

    If only all technical explanations could be so well done (fancy explaining how to drive the IBM SOAP toolkit someday ?).

  • I personally thought the article was very good at explaining the differences between SRAM and DRAM. I loved the comment that using DRAM is "...trying to make memory work that shouldn't..."
    Anyways, I unfortunately have had experience trying to get DRAM to work in an embedded system. Yes, it is a royal pain in the ass compared to SRAM. Basically all I had to do for the SRAM was plug it in, and connect up the appropriate address/data bus signals and control signals to the processor and it just worked.
    DRAM on the other hand is definitely not that simple. Using signals off of the processor, it entailed writing writing/burning my own PLD (programmable logic device) because the timings for DRAM must be generated.
    For instance the piece of DRAM I was using (which was a piece of crap BTW) was 1MB and 80ns. So its a bitch to write logic that keeps the DRAM refreshing 256 times every second, and then when you want to read/write timing the RAS and CAS appropriately...(the best part was that I was doing this in a system controlled by a 80188...)
    There's my take on it..
  • OT

    Well they cant charge me til i'm driving about 77mph so it's not that much of a big deal to people here

    This is wrong unfortunately, they *can* charge you but tend not to. My sister received six points for doing 72mph. And only that. Not wreckless driving or anything else, but just speeding. The 10% thing is a general rule, but don't take it as Gospel.

    As for the undertaking, I am not doubting that in your case it was unjustified, but I do find that drivers that sit in the outside lane when they could pull in to let a faster (even if obviously limit-breaking) car past tend to cause annoyance and sometimes accidents. And if it was on the M1 on Saturday or Sunday, and you drive a Blue BMW, then it was probably me, cause that Blue BMW really pissed me off having not pulled back in after pulling out in front of me.. ;-)

    /OT

    Digression aside, my thought is though that just as there are people that won't plug DIMMs in, just in case, and believe in their ability to drive faster whether they can or not, there are people that can design their own motherboards and recompile their own kernels, but would scare the shit out of you or me if we were their passenger.

    The people that feel that driving at 85mph+ is within their capabilities probably includes a section of people that do not believe they are able to change an air filter in case they damage it. People using the internet is therefore analogously(for want of a real word) going to contain a section of people that whilst fully capable of partaking, wouldn't have the confidence to add memory to what they see as a closed box with warning labels not to open on it!



    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~

  • No! If you do not know about how your car works, if you do not know about torque steer (fwd) or powersliding oversteer (rwd), then you are _more likely to kill somebody_ than me, who knows that I can accellerate into a corner in my starlet, and not a 200sx or people will die. Knowing about your computer is a choice, knowing about your car is something you _must_ undertake if you deserve to take others' lives into your hands.

    I've seen what a car can do to a human being, don't even assume to compare it to handling a computer

    </rant>
  • What that page doesn't say is which laws are enforced and which aren't.

    E.g. 'whispering in your lover's ear' isn't, in my experience, enforced.

    The pumping gas one is.

  • The first one really pissed me off, because he actually bent my bumper.

    What you do is you get one of those 3" tube bumper setups like I did for my Trooper. Yeah, they make you look like a wannabee poseur -- but you can plow into one of these little unibodies, bend it double, back out, touch up the paint a bit, and drive off. Pretty damned good investment, actually.
  • The original example was people who can't install their own software. That requires no knowledge of the internals of an OS. The car analog to installing your own software IS putting gas in.

    Yea... and what are those states that drivers that grow up in them don't even know how to pump gas as it's ILLEGAL there? .. Washington and Oregon I believe. I remember seeing a show of Candid Camera and it had people offering 'cut price gasoline' to these drivers if they pumped it themselves and LOTS of drivers just DIDN'T KNOW HOW! .. Now having drivers that don't know how to pump gas but can drive on the roads is just SCARY.

    I want computers to be used by everyone too .. but it seems to be a common theme that everything has to be 'dumbed down' in order for the 'public' to use them .. that's just crap as it makes these people even LESS likely to learn anything useful that can help THEM by training them not to ask such stupid questions or do such stupid things but to FIND OUT FOR THEMSELVES (a novel concept in this age where everyone expects everything to be handed to them on a plate). Everyone that's ever dealt with inexperienced users knows that it can get very tiresome when these people don't want to learn for themselves but it's very gratifying if they go on to take at least a passing interest in learning about the computers they use.

    Maybe it's just this pervasive societal idea that morons should be able to use computers without contributing anything to learning about them that's the problem ... i.e. AOL.
    --
  • I know nothing about how my car works. I am not at all comfortable with upgrading it or maintaining it. The most complicated act I am able to perform is to put gas in it.

    Let's put things into perspective for the computer industry. This is going to seem long and drawn out (aren't all my posts?), but it sheds a new light on the computer.

    As a car nut, let's do a quick brief:

    The first mass-produced car came out just after the turn of the last century. Almost 100 years ago. With the first affordable car came the first "backyard mechanics", people who maintain their own cars.

    In those days, cars were unreliable enough that you could expect to have to fix something every thirty miles or so, and most drivers did it themselves.

    Continual refinement brought us to self-adjusting hydraulic brakes, engines that self-cranked, automatically adjusted the ignition timing, and had pressurized lubrication systems by the 1930s. (Prior to that, you had to deal with clutch, throttle, cable-operated brakes, shifting, setting the ignition timing as well as steering - it took a lot of experience and theoretical understanding of how the car worked.)

    The 1940s found the first "modern" cars: anyone who can drive a stickshift can drive a car from the 1940s or later, even if they are a little more temperamental. One car that I love to drive is a friend's all-original 1948 Chevrolet Business Coupe. But, even so, the thing doesn't have enough power to be able to get up to freeway speeds.

    By the late 1950s, the automatic transmission, was initially available in two speeds (the GM "PowerGlide"). Bigger engines came out, allowing the new cars to cruise easily on the new Eisenhower Interstate System. By the early '60s, Chrysler had brought out their legendary TorqueFlite 727 automatic, a nearly bulletproof three-speed automatic transmission with a really neat planetary gearset design which has since been copied into most modern automatic transmissions.

    In the 1970s, user features increased, drivetrain and mechanical manufacturing tolerances were increased, tire technology increased. Electronic ignition replaced points and condensors, making yet another part of the car virtually maintenance-free. But reliability still sucked, primarily because of new federally-mandated emissions controls.

    The 1980s brought us EFI systems, which greatly improved reliability and driveability over the primitive emissions control systems of the 1970s. The 1974 oil crisis was working its way into automotive designs, and by 1980, the first of the modern and efficient OHC 4-cylinder engines were hitting the showroom floor. Four speed automatics were coming out, negating a big fuel-efficiency issue that kept the sales of stickshifts up. As the earlier cars were gradually retired and replaced with their more reliable equivalents, the service centers at the side of the freeways started to convert their service bays into fast food franchises.

    Today, cars are easy to operate, with very few parts that require periodic adjustments. Machining technology means better fit between parts, less oil leaks, etc. And the sophistication of today's engines and engine management systems makes people feel uncomfortable about taking things into their own hands and fixing an oil leak or other small problem. Spark plugs now usually last 60,000 miles or more - and even if the backyard mechanic of today knows how to change them, they're often difficult to get at. Cars today aren't perfect, but they do represent 100 years of continual refinement and design experience.

    So, where does that put us, relative to computers?

    I'm going to guess that the majority of computers, running Windows 9x/NT/2K, are now at about the point that cars were at in the late 1960s. To use them really effectively and to avoid being stranded by the side of the road, you should understand how they work and keep a few tools in the trunk. But you can still toss the keys to the wife so she can do the grocery shopping.

    That's very impressive: it took the car industry almost 70 years to get from the first mass-produced cars to that relative level of sophistication. With the computer industry, it's been approximately 20 years since we were typing "pr#6" on our Apple IIs to read the disk drive.

    In a few years, when computer OSs are actually stable, Plug and Play works, software is always easy to install or remove, and everyone has got a system powerful enough to watch DVD movies, I'll suggest that the computer industry will have reached the level of maturity that the automobile industry is currently at.

    The future? Flying cars, and computers with working voice recognition.

  • Secure deletion of data... [rootprompt.org] Tells you how much data is kept in these supposedly volatile memory chips, and how to go about getting it out.
  • Good article. I hate the web presentation, though. They spoon-feed you a page at a time, so you have to look at new ads to read the next page. And then it turns out that only the first part is on line. Ars Technica retains the bad features of print media, despite not having a print version.
  • What you do is you get one of those 3" tube bumper setups like I did for my Trooper. Yeah, they make you look like a wannabee poseur -- but you can plow into one of these little unibodies, bend it double, back out, touch up the paint a bit, and drive off. Pretty damned good investment, actually.

    I agree with you about the bumper. A big tube bumper is great for menacing Hondas. But a Trooper? That's just a step above a Toyota "Rectal Assault Vehicle" (RAV-4), Honda CR-V or a Subaru Outcast.

    Come on, man! Fire up your MIG welder, and gusset your frame! Weld some nice box-section steel bar as the hypotenuse of a triangle from your bumper bracket on each side to the chassis' center bar, just under the engine. You'll more than double the strength of the front end of your frame.

    My old Dodge has a box-section frame made of 3/8" thick plate steel, which is a lot more substantial than almost any modern vehicle. Sure, it gets about 7 miles per gallon as a result of the sheer mass, but that's okay. I view the extra gas cost as that kind of insurance that State Farm just won't sell; a policy that, by simple laws of physics, dictates that anything else (short of a Peterbilt) that gets in my way will be obliterated.

    The only other vehicles that I fear on the road are Jeep Grand Cherokees, Dodge Dakotas and Dodge Durangos. They're all based on mostly the same frame, a really tough box-section frame that could do serious damage, even if it is wrapped up in painted plastic bumpers. (Sadly, the modern Dodge Ram frame is a C-channel frame, which is great for load-hauling, but nowhere near as imposing. And the Cherokee Classic, while an excellent 4x4, is a unibody, and therefore doesn't compete in this Bad Ass league.)

  • Slashdot editors: thanks -- this article is good to learn from.

  • At least programmers should (Score:3)

    by Trinition ( 114758 ) on Wednesday July 12, 2000 @03:50AM (#940874) Homepage
    I think every programmer should at least take a course in assembler, operating systems and computer organization. The sort of insight actually can help a programmer.
  • Ars is a great place for technical articles. I like the hign end technical details, 'cause If I read something and understand all of it, I didn't learn anything. Ars always seems to have something that's just a little over my head, if I find it interesting I'll follow up on.

    Any way on the Does anyone else think that there should be some sort of computer proficiency test question.

    I think there should be a proficiency test not to buy or use a computer, but to be elligable for tech support. Back in the day I used to do tech support for a very large ISP, and it was bad. Not all bad mind you, but the bits that were bad were very bad. At least once a day I'd get the
    "I don't want to do that"
    And I was honestly trying to help these people, they either didn't want to do what I suggested or didn't understand a word I said.

    So there it is, Anyone can by a computer but there should be a minimum level of proficency to be eligible for tech support.

  • I'm not sure if you're being serious or not, but just in case you are, I'll bite.

    Static RAM has nothing to do with static electricity. It's called static because if you stop clocking the chip, the contents of the memory remain valid. Dynamic, otoh, requires that you constantly refresh the the contents of the memory or else it will 'forget' what's in it.

    The tradeoff is that for a given amount of memory, dynamic is much more efficient (uses fewer transistors) and therefore is smaller. Put another way, you can get more DRAM on a given die size than SRAM. Also it's cheaper. The above two factors are why computers use DRAM for main memory. However, SRAM has it's place. For one thing, it's faster than DRAM and if you must retain the contents of memory when power is not applied, SRAM uses less battery power than DRAM.

    If your post was just a joke, disregard the above.
  • I tend to disagree... driving at 80 mph is indeed challenging, because if you screw around you may end up dead. No one has ever been killed by a bad RAM install (despite reports to the contrary).

    The Divine Creatrix in a Mortal Shell that stays Crunchy in Milk

  • You know more than you think (Score:3)

    by barzok ( 26681 ) on Wednesday July 12, 2000 @04:52AM (#940878)
    You know your car requires oil and coolant, right? You know that when it won't turn over, you probably have a dead battery. You know that if you leave the lights on, you'll run your battery down. You know that the gas goes from the tank into the engine, mixes with air, gets ignited by a spark, and that's what makes the power, right? And I'm sure you're familiar with what happens when you move/adjust each knob, lever and pedal. There are some very basic troubleshooting processes that you know whether you know it or not.

    That's a LOT more than the average computer user knows about their computer. They know that the "E" on their desktop is "the internet" and they know how to turn the system on and off. If you opened the hood of your car, I bet you could easily identify a dozen parts, and yet you claim to know knothing about how your car works. Can the average computer user even ID FOUR parts inside their computer?

    I believe that the requirements for obtaining a driver's license (at least in my state) are a bit "easy" - at the very least, require that people demonstrate how to change a tire and handle one or 2 other roadside emergencies. Should all of society be denied access to computers because they aren't geeky enough? No. However, with the proliferation of viruses that prey on user stupidity/error, and the increasing toll these viruses take on the rest of the computing world, and the increasing complexity of, well, everything, I think there does need to be a "curb" for people to get over before they can play in the sandbox.

  • memory modules (Score:3)

    by cthulhubob ( 161144 ) on Wednesday July 12, 2000 @04:55AM (#940879) Homepage
    I don't know about this newfangled "modular memory". Back in MY day, we had the DIPs soldered onto the motherboard. And we liked it!

    That's the problem with you young whippersnappers today. "Modular" this and "DDR" that. When I was kneehigh to a grasshopper, we didn't even have init! We loaded our kernels into memory by breaking into ROM basic and POKEing our 64K of RAM just the right way. Taught us a real valuable life lesson, it did.

  • if you cant wait for part 2.... (Score:3)

    by benshutman ( 202482 ) on Wednesday July 12, 2000 @04:55AM (#940880) Homepage
    firingsquad did this article a while ago. pretty informative. http://firingsquad.gamers.com/guides/hiwmemory/def ault.asp
  • I've read all the little comments under this thread, and I want to make a statement of my own here. I am a hardware engineer. More specifically, I am a hardware engineer helping to design a Sparc64 clone. Even more specifically, I am designing the logic for the L3 cache on a Sparc64 clone. This includes (as you might imagine) extensive work with SRAMS and ECC. Enough background... I just wanted to point out that I know excatly what I am talking about. ECC RAM really isn't any different than regular RAM. And, to correct the person who said ECC RAM is redundant... you are wrong. ECC RAM is not redundant... it just keeps a 'signature' for each piece of data. Take a regular RAM (SRAM or DRAM... doesn't matter), and add a few more bits of storage space. 8 bits of storage space for each 64 bits of data, to be precise. Now you have room to hold the ECC bits. Add a little logic that implements a slightly complex algorithm (SEC-DED-S4ED Error Correcrion Code), and you have the ECC part of your RAM. The RAM itself is no different, but you've added logic that "filters" the data as it comes out of the storage array, detecting errors in the data and correcting them if possible. If you *really* want to know more about ECC, there are books galore and websites a-plenty with details on how to implement the correction and detection algorithms used for ECC RAMS. As for the person who claimed that it didn't really make any difference if you had ECC RAMS or not.... Try and find a supercomputer or high-end engineering computer that doesn't use ECC. Just try it! I'll bet my dollar against your dime that you can't. If you have a machine that is running mission critical applications or has some ungodly important function (like in a NASA shuttle or satellite) you can NOT afford to have a seg fault due to the processor fetching an instruction from memory that has one of it's bits flipped. ECC is a #1 Must Have for hard core workstations. As for your home PC... it probably doesn't matter. If I get a segfault, I simply spit and cus and restart the application or (god forbib) the whole machine. Unreal Tournament is hardly "mission critical", even when I'm kicking some serious butt, so I don't feel any need to have ECC RAM in my PC. Just my expert point of view on this. later, Sir Poopsalot
  • ... a long long time ago. Slashdot told me to complain to Ars. Ars didn't respond. So I started including Ars in my daily surf, cause I couldn't count on scanning the slashboxes to find headlines of interest.

    Maybe some renewed complaining would motivate Ars to review their policy and change their RDF data to list their current headlines, not stuff thats been up for a while.

  • Sheesh, unbelievable. As Hannibal said, he was "laying the foundation" in order to build off and develop the dicussion. In spite of that, there still was a lot for the computer veteran to learn -- I'll even admit to my eyes glazing over at a few points. Either you are just trolling or are incredible arrogant.


    --------

  • I read somewhere that SDRAM can stall if you somehow do something on one bank on the chip while another is doing something.

    Are there any performance benefits to possibly trying to tune memory accesses to somehow correspond with bank layouts of SDRAM?
  • In my experience NVRAM (ala Dallas Semiconductor) is usually an SRAM chip with an embedded lithium battery. Flash and EEPROM are usually called "flash" and "eeprom", respectively.

    Ryan
  • funniest damn thing I've read in a long time. hilarious. I walked right into it. brill delivery. thanks for making me wake the house.
  • > And relying on error correcting components is
    > not the proper way.

    WTF are you talking about?

    Say your ecc ram can correct 90% of problems it runs into. Also, let's say that your next level redundancy corrects 99% of problems IT runs into. The combination will then correct 99.9% of problems, which is better than 99%. Funky correlations not withstanding.

    Redundancy is good. More redundancy is even better. Just like whip cream & cherries.

    Ryan
  • You say you don't know much about your microwave oven but you know more than you think. You know your microwave uses electricity to heat water molecules, right? You know that if the display doesn't turn on the machine is unplugged. You know that if the interior light doesn't come on it needs to be replaced, right? You know that spoons and forks are a Bad Idea. You know that
    cdroms burn with attractive blue sparks.

    If you opened up your microwave I'm sure you could identify at least a dozen parts. The gray metal thing with three wires and says "Sanyo 150rpm"; the small brown rice-shaped thing with yellow, purple, orange, and gold stripes; the green disk that says "103 npo", the little white ceramic tube that says "15A 250V"; the black plastic thing says "MC33274D QAT124" and has the same logo as that cell phone company; etc.

    You know more about your microwave than you think. Compare that to your average car driver who can't even drive when there is snow out.

    Ryan

  • hmm. they don't cover ECC RAM (Score:1)

    by Anonymous Coward
    And that brings up another point: why are so many servers configured without ECC RAM? I've even seen systems decked out with hardare RAID but no ECC RAM...
  • Does anyone else think that there should be some sort of computer proficiency test ...

    I do, but for their own good, not so much to save us from the morons (though that would be a nice side effect). They make you take a driving test before you get on the highway, you should know how to operate a computer before getting on the information superhighway (if they ever get around to building one).

    Also, in response to the other guy who said all programmers should take assembler. Damn right! I learned more about how computers operate in my assembly language class than in all my EE classes combined.

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