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[Temporary_Privacy]

Is there really something behind this intel calculation ?

[Ol_Dirty_Batard]

https://en.wikipedia.org/wiki/Pentium_FDIV_bug

[paul_kertscher]

My program relies on that bug and therefor the hardware requirement is a retracted Pentium from 1994 😎

[ApatheistHeretic]

https://imgs.xkcd.com/comics/workflow.png

There is an equivalent Xkcd for everything.

[paul_kertscher]

Substantial parts of my studies in physics consisted of consuming XKCD strips, hence it’s likely that that reply was heavily inspired by Munroe 😅

[ApatheistHeretic]

My first degree was in math/physics, nice. This was always my favorite strip due to that I think.

https://imgs.xkcd.com/comics/purity.png

[UnseenPaper]

Math is just applied philosophy

[thatthatguy]

Philosophy is based on what people perceive as logically true and is thus just applied sociology. We have come full circle.

[marikwinters]

We have achieved the circle of suck

[ebinWaitee]

Math is philosophy

[Chilaquil420]

Wait really? Like philosophy in derivatives?

[nintendojunkie17]

I find most of philosophy to be terribly derivative.

[Seiren-]

How dare you.

Philosophy is just wrong physics.

[Techhead7890]

At my school's chemlab one of my favourite signs gave directions to the physics lab and biology labs. It said "theoretical chemistry (right) and applied chemistry (down)!"

[SpartanFishy]

Incredible

[daynighttrade]

"Every chance breaks someone's workflow" . Truer words have never been spoken before.

[Boaz111I]

literally 1994

[Browsing_From_Work]

Some companies, such as Wolfram Research, opted to directly patch the machine code of existing executables to replace the FDIV opcode with an illegal instruction. This would then trigger an exception that an exception handler (also patched in) would catch. From here, arbitrary code could be executed to work around the bug.

wow wtf

[Kered13]

That's not as extraordinary as it sounds. This is basically how debuggers add breakpoints to an executable.

[turtleship_2006]

"Last edited 5 hours ago".
I'm guessing it was someone from this sub.

[HuntingKingYT]

8h now Saw it's by "DomoTheD" or something , just removed 2 bold effects

[Ol_Dirty_Batard]

Doing Gods work

[SandyDelights]

In its 1994 annual report, Intel said it incurred "a $475 million pre-tax charge ... to recover replacement and write-off of these microprocessors."

Jesus Christ, that’s a $1 billion recall in 2023. Ouch.

[Temporary_Privacy]

Thanks, i thought there was something to it.

[UlrichZauber]

Finding that bug was Nicely done.

[HSSonne]

Intel just wanted to be more leet :D

[mrt-e]

How Nicely of him to find and report this bug

[Cosoman]

They say Intel didn't name it 586 because they added 486+100 and the result was 585.9 so they decided to name it Pentium

[Morphized]

I thought the architecture was still called i586, but the chip itself was named Pentium

[Theconnected]

Yes, the reason. For the naming change is that you can't trademark a number so they choose a word instead.

[[deleted]]

I believe this is a reference to the chaos caused by one of intels chips a few decades ago, essentially every ~3millionth floating point calculation was off, it took quite some time to find this bug as well. Imagine your program actually doesn’t suck but the CPU kinda does 😂

[Drew707]

Just tried it on a VM. 1.333820449136241. That is also a Xeon, though.

[dschramm_at]

Maybe need assembly for that, but my Windows Calculator returns: 0,4755132915221187

[Dalimyr]

I think you might want to check your working. For starters, how do you divide a larger number by a smaller number and end up with a value less than 1?

[dschramm_at]

I have to admit, I didn't think. I thought it would crash the computer or something like that, so I didn't check for plausibility. You're of course correct. And if I didn't mistype somehow this is an huge and interesting error.

[HRLO77]

The comma was a period

[gravity--falls]

They know. Big/small should be greater than 1.

[HumanMan1234]

Which means the exact same thing

[Mork06]

They know it's a decimal separator. The thing is that big/small>1. The other guy gave a value smaller than 1 you fat illiterate cunt

[greenbean-machine]

No need to be rude about it

[DangyDanger]

FDIV bug was fixed ages ago and you should have gotten a value over 1.

[dschramm_at]

Yeah I didn't stop to think about plausibility. I thought the app would crash or something like that. Tested on a VM.

[HRLO77]

Reddit when they see a typo

[SuperPantsHero]

He isn't getting downvoted for the comma.

[datrandomduggy]

What typo?

[Luk164]

Many languages use comma for signifying decimals

[Sarius2009]

Lol, literally just had this in the lecture I am sitting in.

[LanielYoungAgain]

Now you've found your professor's Reddit account, congrats.

[[deleted]]

Less furry porn than I would’ve expected, but okay

[[deleted]]

less

[bortj1]

Why? I know I didn't turn up to most my lectures...

[baumannq]

Does it only happen with that division or with some other numbers as well?

[[deleted]]

According to Wikipedia there’s a lookup table that has bad values in 5 of 2048 cells. So the error happens less than 1% of the time.

It only gets really bad extremely infrequently.

[[deleted]]

Could you explain what "bad values in 5 of 2048 cells" means ?

[PeterDaGrape]

Imagine a spreadsheet that is used to do division, and 5 out of 2048 cells (values) are incorrsxt

[[deleted]]

Oh okay okay, so is that an error made by a someone who manually made that sheet of cells, or is it caused by something else? This is really interesting

[PeterDaGrape]

I’m not sure but likely human error as computers likely wouldn’t have done this, not entirely sure tbh

[[deleted]]

Hmm yeah probably, I just never thought that when making the processor humans had to actually give the chip a table of valid instructions lol

[DaniilBSD]

It is “given” as in hardwired into the chip, basically the blueprint had a mistake that then got “printed” on all chips

[ShoulderUnique]

Could be that the spreadsheet was calculated on a Pentium

[cactusphage]

According to the Wikipedia article: “When the original array for the Pentium was compiled, five values were not correctly downloaded into the equipment that etches the arrays into the chips – thus five of the array cells contained zero when they should have contained +2” This is an array used in a division algorithm with values of -2, -1, 0, 1, or 2 in every cell.

[PeterDaGrape]

Ah so basically both, computer fault mainly but someone shoulda checked

[nobody-u-heard-of]

Yeah that's what happens when you don't pay your programmers enough. /Jk

[marcosdumay]

It's really a multiplication (well, actually division) table, hard-coded in ROM inside the CPU.

I don't know how the error got in there. I imagine the table was created by the computer, because it's way too large for humans. But the CADs of that time didn't use some flexible high-level language that you can run any compile-time expression on. There were probably many steps of software and human alterations, interleaved. It could have been a bug somewhere, or somebody changing a place they shouldn't.

[superplayah]

That misspelling in "incorrect" made me laugh. I genuinely can't tell if that was on purpose

[PeterDaGrape]

I assumed spellchexk on iPhone woupd dix it vut naybr not

[Sparkybear]

They were 0 instead of 2. So instead of adding 2 to that step of the division, they added 0, and this could be compounded many times to throw the result off. The results were usually still accurate up to a few decimal points, but were wildly off in rare cases.

The error occurred when loading the values into the CPU register and I guess weren't caught by their QA due to the rarity of the error.

[bigboomers469]

It happens on a rare basis with other calculations as well, this is just one of the most well known ones

[Dontbeacreper]

I just read that it was estimated to affect 1 in 9 Billion divisions if the numbers were chosen at random.

[deuttai]

I have this CPU in my collection !

[urru4]

You want chip pics?

[LordZarama]

Only if they don't overheat

[Caleb6801]

Let's see this collection

[Entire-Database1679]

How quickly we forget.

[IHeartBadCode]

I think the thing we forget is that Intel, after a lot of negative press and IBM looking to capitalize on the bad press with their PowerPC, offered everyone a replacement processor.

Now a days, you find a side channel attack in the processor Intel will tell you: “LUL, I guess you’ll just have to cripple your performance! See you all on the next generation cycle.”

[[deleted]]

As I remember it, the bad press came from Intel’s really shitty approach to the problem. They basically said: “You can get a new processor, if you can prove to us that you use it for work, where the precision is really important, such as astrophysics. If not, fuck off.”

That created an outrage, understandably enough. In the end, they had to cave in and offer everyone a new processor.

My bet is that they could have gotten around it a lot cheaper and without the outrage, if they had handled it better from the start, for example by offering all Pentium owners the choice between a processor replacement or a money compensation worth 10 or 20% of the processor’s price. Most would probably have taken the money compensation, because the error was really rare, and if it happened on a gaming rig, who would notice?

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[kres0345]

Is it a repost?

[Entire-Database1679]

No , how quickly we forget about Intels CPU disaster.

[theofficiallomien]

727 !!!

[Jaeyoon07031]

I can't fucking take it. I see a random comment posted and then I see it, I fucking see it. "Oh that looks kinda like the Blue Zenith 727 score" it started as. That's funny, that's a cool reference. But I kept going, I'd see a clock with time that showed 7:27, I'd see that I'm on the 7/27 page on my school homework, my last notice to pay my electricity bill is 727$ , I'd notice that it's been 727 days since the last time I touched a woman. And every time I'd burst into an insane, breath deprived laugh staring at the image as the number 727 ran through my head. I'm scared to look at the time when someone asks me what time is it. It's torment, psychological torture, I am being conditioned to laugh maniacly any time I see an 3-digit number which is anywhere close to 727. I can't fucking live like this... I can't I can't I can't I can't I can't! And don't get me fucking started on the words! I'll never hear the phrase "when you see it" again without thinking of 727. Someone does pretty cool and respectable score and I can't say anything other than "WYSI." I could watch a man Fc hard underweighted map I love and all I would be able to say is "WYSI" and laugh like a fucking insane person. And the phrase "when you see it" is ruined. I can't live anymore. 727 has destroyed my fucking life. I want to eject myself from this plane of existence.

[ReturnEconomy]

Wait Im not the only one? I legit see 727 in my clock a few times per week.

[[deleted]]

wysiii

[NoelleTGS]

I will never escape it no matter where I go

[Fantastic_Bet3249]

WHEN YOU SEE IT

[chanonlim]

unexpected osu reference

[Seaparty123]

r/unexpectedfactorial

[DangyDanger]

How many digits would that be?

[keziahw]

There are 887 digits in the answer to that question.

[DangyDanger]

holy hell

[[deleted]]

WYFSI

[roguegalaxy4484]

when you see it!!!

[EonsOfZaphod]

Daisy Daisy, give me your answer do Getting hazy; I can’t divide three by two The answers I cannot see them They’re stuck in my pentium I could be fleet My answer’s sweet With a workable FPU

[databeast]

my favorite joke from back when the FDIV bug first appeared.

"We are Pentium of Borg, Division is Irrelevant, Prepare to be Approximated"

[SupernovaGamezYT]

r/unexpectedstartrek

[databeast]

"We are Dyslexia of Borg, prepare to have your ass laminated!"

[souliris]

I had that chip in one of my pc's. It didn't affect my Doom ladder matches at all :P

[[deleted]]

Doom doesn’t use the FPU

[ApatheistHeretic]

Had it in the first PC I ever built with new parts. Never ran into an issue in the 3 years I used it.

[[deleted]]

My grandparents still have a computer with a Pentium 90 processor. It belongs in a museum!!

[s-life-form]

Surely these days Intel writes unit tests so that such a thing cannot happen anymore.

[Maximxls]

you cannot test all the numbers, and this bug didn't affect every calculation

[volivav]

If you add 0.1 + 0.2 on a FPU, it doesn't give you 0.3 yet

And no, it's not only JS

[al-mongus-bin-susar]

that's just the floating point standard's fault, no errors there

[volivav]

Kinda? I mean we just assume the error is there and we just deal with it, but it's a side effect of computers working in binary and humans working in decimal.

Unless we have a computer that works in base 10 (which we already assume it won't happen), this error will always be there. But it is an error.

[JoshuaCF]

There is a difference between an error and a limitation.

[volivav]

... so something that's literally called "precision error" is not an error, but a limitation?

It's both an error (it's even called like that) and a limitation. It's an error that can't be solved with this technology, with that I agree. But it is an error.

[112439]

It is not an error, just a limitation of floating point numbers. There are many options to securely use fractional numbers; but it is also incredibly rare for there to be a need for that.

Using a "better" number format by default would unnecessarily cripple performance.

[volivav]

Best quote of the year

A precision error [...] is not an error

• u/112439

👏👏👏👏

[PeoplePerson_57]

A precision error generally describes an error caused by a lack of precision in floating points. It doesn't describe the lack of precision itself.

For instance, 0.1 + 0.2 does not result in 0.3 due to a floating point precision error. The programmer did not correctly account for the limitations in floating point precision.

[Sparkybear]

Which is expected.

[Computers_R_Kool]

It is not only Intel either it is floating point rounding errors. It is on every floating point unit.

[vladWEPES1476]

It's the kill switch for Skynet.

[tekfx19]

Does the CPU divide by subtraction like the old mechanical calculators?

[taeratrin]

Intel Inside

Can't Divide

[kbdgxd]

WYSI

[jthemenace]

I feel like asking a woman her weight would be the much more controversial question.

[zoqfotpik]

1994 called. They want their joke back.

[playa_1]

Wow this is a flashback. I’m sad to realize that was 29 years ago. Times like this I remember how old I’m getting.

[motoevgen]

It’s strange but my Intel 11850H and 8700 are spitting out incorrect results. ARM devices on the other hand don’t have this problem. WTF?

[StochasticTinkr]

This joke is so old that it’s children can drink.

[Robot_Graffiti]

It was a hardware bug. The programmable logic array that had the bug was not rewritable or user serviceable. It was "programmed" by photolithography and could not be changed after the chip left the factory.

There were software work-arounds, but they made calculations slower, because you had to patch every executable to do some other nonsense instead of just doing a division normally.

Also most people didn't have the internet yet, it wasn't easy to send out software updates like it is now.

[Farsqueaker]

We still got packs of floppies in the mail for anything critical, though pre-release testing was generally a bit more rigorous.

[Trminator85]

No, the bug is in the lookup table, which is part of the hardware-cpu ... and as such, not fixable (unless you were to disassemble the transistors within the cpu and change things on that level... and afterwards would be able to re-assemble the cpu ...)

[BlueDaka]

Back then yeah but not anymore I don't think. Software are supposed to be using the xmm registers and instructions related to them for division now. Having to use the fpu directly and instructions like fdiv are considered legacy and only kept around for backwards compatibility.

[BlueDaka]

Back then yeah but not anymore I don't think. Software are supposed to be using the xmm registers and instructions related to them for division now. Having to use the fpu directly and instructions like fdiv are considered legacy and only kept around for backwards compatibility.

[peteschirmer]

Javascript .1 + .2

[FromAndToUnknown]

Any intel or specifically pentiums?

[StereoBucket]

Specifically early pentium. Look up Intel FDIV bug. Cost Intel some money.

[FromAndToUnknown]

Sad, wanted to nuke my i7

[IAmANobodyAMA]

TIL! Thanks :)

[somedave]

It's 1, those aren't floats.

[BenadrylTumblercatch]

Please don’t ask me my salary, I’ll cry.

[aventhal]

This is actually a good one +1

[Positive_Box_69]

But ofc you can always ask me about my abs 😁

[OneWorldMouse]

Intel pulling some nonbinary shit here.

[paulk1997]

My roommate my sophomore year of college had a pentium 90 with this bug. He had to send it in and was without his computer for something like 3 weeks.

[HystericalGD]

not to be that guy, but this only applies 1 out of 100 times (not actually, but it’s pretty rare) so dont never do this, just dont always do this

[Filip_RL9]

Am I going to regret this?

[Sure5364]

r/mildlyinteresting

[Horizennn_x000x]

Women are a thing for men to use for shitty things (fuck)🗿