Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 


Forgot your password?
Close
typodupeerror
×

Overclocking the Super Nintendo 139

Posted by CmdrTaco from the because-you-can dept.
Robert Ivy writes "The Super Nintendo is a tricky piece of hardware, but I have finally managed to overclock it up to 5.1 MHz. At this speed, the sprites scatter across the screen; this is likely a sync issue since the CPU is running so far out of spec. I plan on trying lower speeds soon and I will update the guide on UCM." Thank god we got that out of the way!
This discussion has been archived. No new comments can be posted.

Overclocking the Super Nintendo More

Overclocking the Super Nintendo

Comments Filter:

  • But does it run Linux!?! (Score:2, Funny)

    by Anonymous Coward
    SNES Beowulf clusters FTW!
  • Just imagine a whole cluster of these.

  • An A for the effort (Score:5, Insightful)

    by Opportunist ( 166417 ) on Sunday April 30, 2006 @10:59AM (#15232189)
    Don't get me wrong, great job OCing your console, but ... what purpose does it serve? If it's done to prove that it's possible, then more power to you.

    But if the plan was to get "more" out of your console, I guess it wasn't too bright. Console proggers always relied on the fact that consoles, unlike PCs, were set in stone. You had THAT CPU, THAT GPU, THAT memory and that's something you can rely on. I.e., they didn't do what PC game creators have to do today: Take into account different hardware specs and take care of timing.

    More often than not, they used the CPU clock as the timing device (everyone who ever played Wing Commander on a 486 knows the effect you get when you do that on a platform that can very well change the hardware). So if you tweak the CPU, you get a game that runs "too fast".

    But little else.

    • Re:An A for the effort (Score:2, Insightful)

      by zome ( 546331 )
      if you have to ask for the purpose, you probably won't understand it anyway :-)

    • End (Score:4, Insightful)

      by electrosoccertux ( 874415 ) on Sunday April 30, 2006 @11:26AM (#15232308)
      Overclocking old embedded devices is like power: it is not a means, it is and end.

    • Re:An A for the effort (Score:5, Informative)

      by Megane ( 129182 ) on Sunday April 30, 2006 @11:26AM (#15232309)
      The usefulness comes in with games which use the vertical sync as a timebase. If they take too many computations per frame, they will miss the vertical sync, and only sync to every other vertical frame. This causes a slowdown to half speed. Overclocking the CPU allows it to do more work per frame, avoiding slowdowns. There are released games which exhibit this problem, and not all of them are action games. In Harvest Moon, if you have more than ten cows in the barn, slowdowns will happen.

      This is known to be useful on the Dreamcast, where it improves emulator performance.

      • My ps2 has interlace sync issues in GranTurismo 4 ... if you put it in progressive mode, the studdering and synching isn't an issue.

        It's extremely annoying and does it on every ps2. Unfortunately, not every tv I have supports progressive, and 1080 mode is only interlaced.
      • When making a Tool-Assisted Speedrun [bisqwit.iki.fi], minimizing lag is one of many optimizations--sometimes a seemingly suboptimal route must be taken because it involves fewer sprites and thus less lag. Of course, hardware overclocking doesn't help those runs since they're meant to be something you could do on stock hardware if you had <16ms reaction times.
      • In Harvest Moon, if you have more than ten cows in the barn, slowdowns will happen.

        Hey, when you've got ten cows in the barn, the day's over and it's time to slow down.

      • Not even as useful as that (Score:2, Informative)

        by Anonymous Coward
        Speaking as someone who used to program for the SNES, such a mod won't even alleviate the problem of in-game slowdown without causing the problems that our friend with the 5.1MHz SNES has seen. The SNES itself had a fairly insane timing system to begin with, and countless games have taken advantage of that - including (but not limited to) reliance on cycle-exact opcode and DMA behavior. We're not even talking cycle timing on a per-opcode basis - the SNES hardware is deranged enough that accessing differen

    • Re:An A for the effort (Score:5, Informative)

      by despisethesun ( 880261 ) on Sunday April 30, 2006 @11:29AM (#15232316)
      Actually, you can overclock the NES and the Genesis both without really suffering any ill effects, but their hardware was quite a bit more simple than the SNES. You can find the Genesis guide here [epicgaming.us], and the NES one here [epicgaming.us].
    • This does not actually apply to most modern systems, though is definitely the case for anything pre PlayStation 1/Nintendo 64 generation. Modern systems generally work as the above poster said... timed to catch the retrace and if they miss it "simply" (and unattractively) slowing the game down. This is always a trade-off. Good games get it right, poor ones do not.
    • This is useless. Not because it's overclocking an old console, but because the SNES relies so heavily on the timing being in perfect sync among everything, that even overclocking the processor a few Hz is pointless. The SNES was an extremely complicated system for its day. Emulator authors are still struggling to get 100% accuracy (Though I'd say 99% has been achieved.) DSP-1 and.... Whatever is used in Far East of Eden Zero were just recently worked out, and not long before that was C4 emulation.
    • games that let you regain your health slowly. Just wait at the corner of a dungeon.

  • Heh... (Score:2, Funny)

    by kitsunewarlock ( 971818 )
    The next post will either be "how to install a cooling unit to your SNES" or "how to install a fire-extinguisher to your SNES". Just kidding, unless your playing some sort of 3rd party...cartridge...I doubt there'd be anyway to fry your SNES...or would there?
    • Yes, there would be. A game that used 99% of a stock processor would use 99% of the overclocked one. That's why this presents such a problem
  • This should make his speedrun videos that much more exciting. (And yes, I'm aware you can get the same effect from emus.)

  • Emulation (Score:5, Interesting)

    by mmkkbb ( 816035 ) on Sunday April 30, 2006 @11:09AM (#15232241) Homepage Journal
    Do they randomly overclock chips on the board? I know there are cycle-accurate Genesis emulators. If there are such for the SNES, wouldn't it make sense to hack the emulator first to see what effect overclocking particular components will have?

    • Re:Emulation (Score:5, Insightful)

      by Jagasian ( 129329 ) on Sunday April 30, 2006 @01:47PM (#15232856)
      Cycle-accurate Genesis emulation? I've never seen it. Care to elaborate? There is only one cycle-accurate SNES emulator, bsnes [wikipedia.org], and it is fairly new and extremely resource intensive. For some reason, internet saavy people put give far more credit to the accuracy of console emulation than is justified by the actual accuracy of console emulation. Few emulators are as accurate as many would like to believe. For example, most console emulators would be completely unable to win a "Turing-test" like comparison between real hardware and the emulator.

      From the looks of this mod, it appears as if it would be far easier to see what would happen by modifying the hardware, as opposed to modifying a supposedly cycle-accurate emulator, as the emulator might not be setup for such modification, and it might contain bugs that would lead the experiment to the wrong conclusion.

      On a related note, Nestopia [sourceforge.net] is a NES emulator that takes accuracy seriously. It goes beyond being just cycle-accurate, as it goes as far as to emulate the analog video signal generated by the NES's digital-to-analog converter, which turns the NES's frame buffer into a human visible video signal. Hence a side-by-side comparison of a real NES hooked up to the PC via a TV-tuner or video capture card, and the emulator running on the same PC... even a hardcore NES fan will have difficulty telling the difference. Check out a screen capture comparison [xbox-scene.com] of a real NES, Nestopia, and FCE Ultra.

      Test it out for yourself. Follow that last link and try to determine which screenshot is a real NES and which screenshot is Nestopia. Meanwhile, the screenshot of FCE Ultra sticks out like a sore thumb, even though it is comparable to what many consider to be highly accurate console emulation.

      • Re:Emulation (Score:4, Informative)

        by Mitchell Mebane ( 594797 ) on Sunday April 30, 2006 @02:59PM (#15233193) Homepage Journal
        Nestopia (as well as BSNES and ZSNES and, I believe, other emulators) use Blargg's NTSC filter [slack.net] to produce the TV-like output. Truly an amazing piece of work.

        As far as accuracy goes, the C64 emulator Hoxs64 [btinternet.com] is pretty damn accurate, going so far as to emulate analog stuff in the disk drive. Wow.
      • Agreed. While Kega Fusion is quite accurate, it's not cycle-accurate. I've written Genesis code designed to change the backdrop color mid-scanline, and on emulators it just displayed a black screen.
      • I'm old and played the NES when it first came out. Loved it - fantastic.

        Frankly, I prefer the "bad" emulation - it looks better. Making the image fuzzy on my monitor is not a good thing (imo).
        • This isn't true. The original game developers of Famicom and NES games designed the graphics with the NTSC distortion in mind. Hence they used various dither patterns, which are only blended correctly, yielding the correct gradients and colors when viewed through NTSC distortion.

          Check out these comparisons out [io.com]. The left-side column is what the graphics are supposed to look like, while the right-hand column is what they look like in most emulators. Note the hood of the truck in "Snake's Revenge". The di
    • Yes, but it wouldn't be a great indicator of what will happen on real hardware.

      The emulators still have some differences with the way the hardware behaves. And many emulators are programmed just to make the most games run.
    • Most systems don't need cycle-accurate emulation. The Atari 2600 is a notable exception, because the games depended upon the timing between the CPU and video (three pixels per clock cycle).

      Console games generally do fine with emulation that is more permissive than the real hardware, but this can be a problem for people writing homebrew games because the emulator will let them do things that the real hardware is not capable of. And some emulators are more permissive than the real hardware in other ways, s

  • All right! (Score:3, Funny)

    by Megane ( 129182 ) on Sunday April 30, 2006 @11:14AM (#15232265)
    Now I can have the full twelve cows in Harvest Moon without the slowdowns!

  • Whaddaya mean "what purpose"? (Score:5, Insightful)

    by user24 ( 854467 ) on Sunday April 30, 2006 @11:14AM (#15232266)
    I'm sickened by the amount of people on here saying "... but why?".

    Why?? WHY?? Because he's a GEEK, Dammit! Just because it doesn't have a buzzword associated with it, or because it's not to do with google, or didn't come out in the last 15 minutes, doesn't mean it's not cool.

    *wanders off mumbling about these younguns..*

    • A True Geek would've waited till he had a fully functional overclocked SNES.

      And would've benched his improved SNES against a regular one, too.

    • Your point is understandable, but I think you are missing a key idea: I don't think nerds really appreciate something technologically if it involves destroying a perfectly good piece of equipment. If I wrote up an article about modding an Xbox 360 into a totally awesome endtable that fell over every time I put a can of coke on the edge of it, that would probably piss most nerds off.

      Nerds see the potential in things. An ordinary person looks at a 400MHz computer with a faulty power supply and sees someth

      • An ordinary person looks at a 400MHz computer with a faulty power supply and sees something heading to the junkyard. I might see it as a mailserver, after I put some work into it.

        If he'd modded his snes into a mailserver, we might have something really cool to talk about!!
    • "Dammit! Just because it doesn't have a buzzword associated with it"

      But the article does have a buzzword: overclock. And that's all the article is about, typical geeky dick-waving that accomplishes little else. What's the next submission going to be? "ZOMG, I put an R-type sticker on my Honda!"
    • But it is not cool. Simple as that. It's just dumb. Just because something takes some technical ability and involves computer parts doesn't make it cool.
    • I think the "But why?" in this case would be expanded to "But why did you waste our time by announcing that you made your SNES run so fast that it was useless?" I could also talk about how I dropped my Newton in a puddle and now it sometimes shocks me when I turn it on, but I doubt anybody would care about that useless bit of information either.

    • Re:Whaddaya mean "what purpose"? (Score:5, Insightful)

      by elgatozorbas ( 783538 ) on Sunday April 30, 2006 @02:19PM (#15233005)
      I'm sickened by the amount of people on here saying "... but why? Why?? WHY?? Because he's a GEEK, Dammit!".

      Not agreed. I don't know why so many replies have been modded toll. 'Why' is a completely justified question because the hack is trivial (you only have to know the pinout of the processor), not particularly elegant and doesn't serve an obvious goal. It is an insult to real hacks, be them in software (e.g. trying to run Linux on everything) or hardware (e.g. making a super high-res camera of a flatbed scanner) that anything anyone does is automatically wonderful.

      *wanders off mumbling about these younguns..*

      Can't believe an old-schooler would be impressed with this.

      Ps: don't want to bash this mod, but take it for what it is, a simple mod.

      • Look, I agree, it's nothing incredible, but it's these kind of hacks that sometimes turn into incredible things. I was just annoyed at the mentality that seemed to be saying "If it's not amazing then it's useless".

        (I also don't know why so many comments have been deemed trollery.)
    • Actually, the real question here is "Wii"?

  • Secret of Mana (Score:5, Interesting)

    by siegesama ( 450116 ) on Sunday April 30, 2006 @11:15AM (#15232268) Homepage

    This may actually be useful! There are a number of games, among them that holy-of-holies, The Secret of Mana, that during very busy scenes with all three characters and a number of enemies, will experience slow-down and flickered sprites as an error. Does a sped-up CPU do anything at all to remedy this?

    Once he's got it so it's only sped (and not fucked) up, I'd love to find out if that would help prevent those slow-downs

    I'll bet nobody was expecting an actual response to this story, heh

    • snes9x.

      'nuff said.

      • Re:Secret of Mana (Score:1, Funny)

        by Anonymous Coward
        No shit, an emulator exists? Dear dumbass, talking about hardware.
    • Because of how consoles are usually programmed with regards to timing (i.e., developers tend to use the clock for timing rather than real world seconds), it probably will only make the sprites flicker faster.

    • Re:Secret of Mana (Score:3, Informative)

      by j1mmy ( 43634 )
      just run it in an emulator. I've played through countless roms (including secret of mana) at 2, 3 or even 4x normal game speed. Many games aren't much more difficult that way, and you spend far less time waiting for useless cutscenes and wandering around.
    • What I'd like to know is, for Secret of Mana to run properly on next-gen hardware, will I have to overclock my Wii? Nintendo's been known for "perfect emulation...right down to the slowdown [ign.com]."
      • Emulating the slow down of a NES isn't difficult at all. Nesticle was released roughly a decade ago, and it emulated the slow down common in NES games. Of course, back then, Nintendo claimed that emulation was a tool of the devil. Now they plan on adding a feature to the Wii that has been possible on PCs and even the Xbox 1 for years now? Too little too late.
    • Flicker comes from the hard limit of 32 sprites per scanline (and 34 sprite tiles). Games have to flicker the sprites otherwise the ones outside the limit would disappear entirely. On the NES this was a lot more noticeable since the limit was a measely 8 per line.

  • Headline should read... (Score:4, Insightful)

    by e4g4 ( 533831 ) on Sunday April 30, 2006 @11:17AM (#15232275)
    The headline should read: "taking a soldering iron to an snes renders it completely unplayable" ... I don't mean to bash too hard, but seriously, clock speed is something you can take as a constant for console video game development. Now, if he could get it to boot linux, and wire an ethernet cable through one of the controller ports, and play two player SNES games over the internet (in emulation), that would be cool.
  • Get that mechanical marvel up to blazing 9 MPH by modding your valves!

    Next up: Adding neon to your Whitney Cotton Gin.

  • Video Sync - 3.58MHz (Score:1, Insightful)

    by Anonymous Coward
    My melano-deficient caucasoid friend. I believe your problem is that the SNES PPU is set to run at 3.58MHz, which is the NTSC frequency. Running the CPU faster is going to screw things up. Not sure, entirely the setup of the SNES architecture, between the CPU and PPU, and what exactly you're over-clocking. But the TV signal generated by the PPU must be closely at 3.58MHz (NTSC), otherwise you're out of sync, and would get a B/W signal (since the TV wouldn't lock onto the Color burst phase refence in the Hsy

    • What? (Score:3, Informative)

      by DigitlDud ( 443365 )
      3.58 Mhz isn't the "NTSC frequency."

      Anyway you can't update the sprite data on the SNES during h-blank reliably because the PPU pre-fetches sprite data. Also the sprite memory address selector is invalidated outside V-Blank so you can't write to the sprite memory anyway. You can only update sprites during V-blank.

      Chances are it's not a syncronization issue but he just broke the processor by running it at that speed and is lucky the game runs at all.
      • It's (3.579545 MHz) the NTSC color-burst frequency.
        • The similar clock-rates are by pure coincidence though. The clock rate of a CPU has nothing to do with the frequency of an NTSC signal.
          • It's usually a matter of saving a few dollars in parts cost. Color-burst crystals are cheap due to huge production volume, plus they can be used as the clock source for the NTSC video encoder.
  • It's time to break out NBA JAM again....

  • Amusing but impractical (Score:4, Insightful)

    by Craig Ringer ( 302899 ) on Sunday April 30, 2006 @12:05PM (#15232451) Homepage Journal
    Consoles encourage the old school method of timer programming:

    for (int i = 0; i < SOME_BIG_NUMBER; i++) { int fakeval = 0; }

    In fact, I don't know how many consoles, especially old consoles, would even have a system timer, let alone one (a) sufficiently high resolution and (b) with low enough access costs to make it practical to use for game timings.

    Anybody remember the "turbo" button - ie the "underclock my PC when this is off" button? That was necessary for older games written for the 80386 that assumed a small range of clock frequencies and did delays that way. You'll run into the same issue with this console - it's going to be like turning "turbo" on for an old game. Well, probably.

    • Re:Amusing but impractical (Score:4, Interesting)

      by Dwedit ( 232252 ) on Sunday April 30, 2006 @12:29PM (#15232519) Homepage
      All the consoles know when the signal for the TV has reached VBLANK, so they use that to synchronize. Only badly made games would use decrement loops to count time, when you have a steady 60Hz timer already. This caused problems when games were brought to Europe, with their 50Hz TVs.
      • That's fascinating. I actually thought the frequencies were the other way around, but this article (http://hometheater.about.com/cs/television/a/aav i deoresa.htm) set me straight. PAL and SECAM are lower frequency but higher resolution than the US NTSC format.

        Sadly, when it comes to consoles, "only badly made games" is quite likely to encompass a lot of them. Especially once they figured out that crappy delay loops might let them work around display timing issues... ugh. I still see software written /now/ t
      • Only badly made games would use decrement loops to count time, when you have a steady 60Hz timer already.

        Or games that need to wait for an interval less than 1/60 second. On the NES, for example, counting CPU cycles is the only way (on pre-MMC3 cartridges, at least) to know when you've reached a certain screen position, which is necessary for certain visual effects.

    • "Anybody remember the "turbo" button - ie the "underclock my PC when this is off" button? That was necessary for older games written for the 80386 that assumed a small range of clock frequencies and did delays that way."

      80386? Dude! In my dreams! The "Turbo XT" generation of PCs introduced the "Turbo" switch, because the new generation of 8086's ran at a blindingly fast 8 MHz, when the original PC/XT ran at 4 MHz. You had to down-clock to 4 for games that assumed 4 MHz. The Turbo switch on later PCs (w
  • I wonder how well StarFox would run on it. That game really could use a better frame rate. Or I could just grab my N64... I'm sure there are some games, perhaps StarOcean for example, that would run better with an OC'ed SNES?

  • Experienced hacker? (Score:3, Interesting)

    by elgatozorbas ( 783538 ) on Sunday April 30, 2006 @12:23PM (#15232502)
    Nice to see anyone is busy with hardware for a change but what have we come to if this hack is frontpage news on /.??? The guy just changed the clock to whatever random one he had lying around. I derive this from two facts:

    - apparently the system does not run very stable
    - he is rather desperate to get an oscillator in between 35 and 25 MHz. You can just _buy_ these things in most electronics part shops and I can think of at least four people including myself who have a high chance of having one in their garbage collection.

    On top of this it would surprise me if he was a very experienced electronics hacker as those would never punt ground high and power low in circuit (of course I don't know him).

    Kudos to the guy, but get real people: he changed an oscillator. That's it.

    • Kudos to the guy, but get real people: he changed an oscillator. That's it.

      Kudos, indeed. I don't see the point of this. Sure it's 1337 to say "I overckd my SNES aren't I t43 1337 h4x0rz?" but why would you risk destroying such a fragile piece of gaming history? It's hard to find a working SNES and carts round these days (broken, or semi-functional ones are a dime a dozen).

      Would not a modification such as this run the risk of damaging the system. Start with the heat from the soldering iron. Let's add

  • well i want to encourage the guy, but at the same time, it's a first pass and not working yet, why does it deserve a post on slashdot? just to help him find crystals from 23-25 MHz? try digikey. that's more like local newsgroup/scene/bbs level topic, not slashdot material.

    and to those who ask, yes there are definitely games where even though
    programmers *should* have been planning on a fixed number of cycles, they
    made bad decisions, and they slow down when the action gets intense. A mod
    like this might he

  • shouldn't this be in the 'men-who-dont-date' department?

  • Why is this so silly? (Score:4, Insightful)

    by dnamaners ( 770001 ) on Sunday April 30, 2006 @12:56PM (#15232620) Journal
    I see quite a few negative comments here about this and I really wonder why. When I was a student and a budding EE I used to tear apart all sorts of things and "tweak" them. I was always proud when I could get a meaningful result, an "improvement" or at lease a change that suited me (or hinted that with abit of work it could). I used to enjoy making contrived serial data transmitter adapters out of old cordless phones or other even more completely nutty things. Was I cool, probably not. Such silly junk experiments may seem simple and contrived to a real EE, but at the time I learned quite a bit from them, as much by failure as by success. As silly as it may sound in the end I really learned to properly rework and make my own simple boards. Such useful skills don't come easily to some, as many of you may know, it takes practice. Doing such projects just for fun, was if little else practice. Ultimately this curiosity taught more meaningful skills.

    When I did a project well I wanted to tell others and show them, because at my level of skill it was cutting edge cool, for me. To all those that ask "why do his to a SNES?," I say this. There is no crime here, this may be one of the few simple projects that could have mass appeal to a certain subset of the slashdot crowd. Heck, thinking back, I wish I had tried doing something this cool as an undergrad. Keep up the good work.
  • Some versions can clock up to 2 mhz, and you can add a potentiometer and vary the clock from below 1hz upwards (much below - you could run it at 1 cycle per week).

    How cool would it be to slow a game down for a tricky part?
    • I think you'll find it exceptionally hard to get a 555 circuit to operate with very long (greater than a few minutes) periods.

      I tried to do so for a project once, and after much frustration I switched to a more reasonable clock frequency and a series of frequency dividers to achieve the slower switching frequency I needed. (I wanted the circuit to output ON one minute of every thirty, if I recall correctly.)

      To try to successfully get the 555 to cycle very slowly, you need to choose your component types and
  • So what? Anybody with a soldering iron can install an oscillator. Knowing how to do so whilst still maintaining the intended usability of the hardware is useful overclocking. This is nothing more than a clueless idiot with a soldering iron and a little time. He hasn't overlocked his SNES. He's broken it. I can do that myself, with a hammer, and it'll be a lot more satisfying. Can I have a Slashdot headline, too?

    Move on, folks. Nothing to see here.
    • it's a bit harsh. Sure he doesn't have all of it working, but it's still interesting to see what others are doing. This is coming from an electronic tech by trade.
      • Yes, by all means, tinkering with electronics (and even rendering them non-functional in the process) is a good thing, and should be encouraged. I've broken lots of electronics in my life, and I've learned a whole lot doing it, too. But does it deserve a Slashdot headline when we do it? Absolutely not! Electronics geeks who break things because they don't quite know what they are doing are not newsworthy.

        My favourite part of his page is where he says, "these pins are very fragile, and breaking this pin
  • when you've got such a sprite-scattering issue? If so, I'd like to declare success on my overclocked TI-82 that promptly burst into flames in 2004.
  • SNES games run at a fixed 60 frames per second (they're syncronized with the TV signal) and most games have no trouble moving all the graphics around each frame. I can't see overclocking doing anything but screwing the games up.
    • actually it helps just imagine that on each frame,the snes calls the vid interrupt that calls the code to the next frame,and then it calculates the physics,update the sprites,updates the scroll,sent some command to SPC700 to play a SFX,gets the controller input and stuff then goes idle,waiting for the next interrupt then we have it doing this 60 times per second right? not in all cases, you see,in 60 frames per second we have 16 ms to do all the stuff above and if you code takes more than that (and assumin
      • It's no problem accomplishing all of that in a single frame, most things you listed are neglible:

        Updating sprites - 544 byte DMA transfer (assuming ALL sprites which is unlikely)
        Updating scroll offsets - 12 bytes of register writes (3 layers, 16-bit x, y offsets)
        Sending a command to the SPC - A couple bytes (doesn't happen most frames)
        Controller input - 2 byte reads per controller

        You can easily accomplish these things during Vblank and then you have the rest of the frame to do your game logic and "physics".
  • It's great and all he was able to do this, but should'nt we be working on something more crucial, like getting those god-awful slowdowns out of the PS1 port of Chrono Trigger?
  • He sure gets a lot of light in his parents basement. I'm thinking it's a walkout.

Slashdot Top Deals

"jackpot: you may have an unneccessary change record" -- message from "diff"

Close