What is Bug: Definition and 100 Discussions

A software bug is an error, flaw or fault in a computer program or system that causes it to produce an incorrect or unexpected result, or to behave in unintended ways. The process of finding and fixing bugs is termed "debugging" and often uses formal techniques or tools to pinpoint bugs, and since the 1950s, some computer systems have been designed to also deter, detect or auto-correct various computer bugs during operations.
Most bugs arise from mistakes and errors made in either a program's design or its source code, or in components and operating systems used by such programs. A few are caused by compilers producing incorrect code. A program that contains many bugs, and/or bugs that seriously interfere with its functionality, is said to be buggy (defective). Bugs can trigger errors that may have ripple effects. Bugs may have subtle effects or cause the program to crash or freeze the computer. Other bugs qualify as security bugs and might, for example, enable a malicious user to bypass access controls in order to obtain unauthorized privileges.Some software bugs have been linked to disasters. Bugs in code that controlled the Therac-25 radiation therapy machine were directly responsible for patient deaths in the 1980s. In 1996, the European Space Agency's US$1 billion prototype Ariane 5 rocket had to be destroyed less than a minute after launch due to a bug in the on-board guidance computer program. In June 1994, a Royal Air Force Chinook helicopter crashed into the Mull of Kintyre, killing 29. This was initially dismissed as pilot error, but an investigation by Computer Weekly convinced a House of Lords inquiry that it may have been caused by a software bug in the aircraft's engine-control computer.In 2002, a study commissioned by the US Department of Commerce's National Institute of Standards and Technology concluded that "software bugs, or errors, are so prevalent and so detrimental that they cost the US economy an estimated $59 billion annually, or about 0.6 percent of the gross domestic product".

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  1. Ibix

    Bug Minor alert bug

    I got an alert yesterday for a post by stefanoquattrini. Here's a screenshot showing it, where I've long-pressed it so you can see the URL. Note that it says "quoted your post". But physicsforums.com/posts/7060332 quotes Sagittarius A-Star, not me. The link in the post's quote header says...
  2. S

    BUG in PF? What is Research?

    My second attempt. Somebody asked, "What is Research"? Would someone here with physical science Phd tell the meaning of "Research"? My own way to give a meaning is to compare with cooking food; but that it is just far more precise. I used copy&paste to put in the title.
  3. BiGyElLoWhAt

    Bug Edit preview bug with Mozilla

    It seems as though it's not only with latex, but with previewing in general. Sometimes restarting Firefox will fix it for me, but I've restarted it 2x now and nothing. It just doesn't preview. You hit preview, it locks out editing, but doesn't show you what your post looks like
  4. jtbell

    Y2K22 Bug: Microsoft Working to Fix Email Glitch

    Remember the Y2K bug, 22 years ago? Now we have the Y2K22 bug. Microsoft Exchange servers overflowed a 32-bit integer at the beginning of the new year, causing them to stop processing e-mail...
  5. Z

    Mathematica Mathematica bug? (Solving PDEs when the initial conditions contain a derivative)

    hello I own mathematica 10.02 it is virtually impossible to solve PDE's ,even with NDSolve,if the initial conditions contain a derivative I write Derivative[1,0] [0,x] == f[x] I mean the first t derivative of u[t,x] for x at t=0 is f[x] I own a book based on Mathematica 10.3 Even if a...
  6. P

    Angular velocity of rod and bug

    I(i)w(i)= I(f)w(f) I(i)= 1.08 x 10-3 kg·m2 w(i)= 0.221 rad/s I(f)= mr^2 + I(i) = (5 x 10^-3)(.138)^2 + (1.08 x 10^-3) (1.08 x 10-3)(.221) = ((1.08 x 10^-3)+9.22 x 10^-5))w(f) w(f) = (2.3868 x 10^-4)/(0.00117522) w(f)= 0.203094 rad/s This is my attempt; however, I cannot seem to get it...
  7. crudux_cruo

    B Bug walking around the perimeter of a lazy susan (hypothetical)

    Given a bug that's walking counterclockwise around on the surface of a lazy susan (which itself is sitting on frictionless bearings), wouldn't the the friction between the bug and the lazy susan (which is needed to be able to walk) apply torque (no matter how negligible) that accelerates the...
  8. Z

    Cprev and Self.C are referring to the same NumPy

    I've encountered this really weird bug in Python. Below is a snippet from a class method. The error occurs where I've placed the two print statements. The update method has absolutely nothing to do with Cprev. The update function changes the value of the attribute self.C. However, the two print...
  9. M

    Lessons From the Millennium Bug

    Twenty years ago, we were waiting to see whether the billions of dollars and thousands of person years spent finding and correcting the Y2K problem (aka Millennium Bug) had been successful. To remind you: there were three major problems (and a few minor ones - for full details see the paper...
  10. DaveC426913

    Win 10 bug: "explorer" folder window spontaneously dies

    This has been going on since I first got this laptop (Acer Aspire 5) with Windoze 10. I open my Explorer window to look through some files, and if I leave it to go to another app, it spontaneously disappears. This happens whether I alt-tab to another full screen window or even if I set it up...
  11. Chris Miller

    Unusual Bug: 40 Years of Programming and a Read() Failure

    Been tracking down the most unusual bug I've seen in 40 years of programming (mostly in assemlber and C). It manifests in the test suite for an object oriented XBase language implementation that's been ported everywhere from Palm Pilot to OS/2 to the Blackberry tablet to Windows to, now, Qnx7...
  12. S

    Modern Computer Bugs, What Is The Cause?

    I would like to know what causes bugs, on the software side. Bug was not at all the term used for software but over time, it has evolved into what I think is the result of carelessness, poor development and lack of knowledge. In modern computing, bugs occur in software all the time. But why does...
  13. R

    Bug on spinning disk -- What distance does the bug fly off?

    Homework Statement A bug crawls outward from the center of a compact disc spinning at 210 revolutions per minute. The coefficient of static friction between the bug's sticky feet and the disc surface is 1.1. Homework Equations (static friction)(Gravity) = (centripetal force) This may be wrong...
  14. C

    Mathematica Is this a bug in Mathematica 11 ?

    I calculated a simple complex function integration using Mathematica 11. As the screenshot shows, the only difference between the two inputs is that I set a = 1 in the second one. However, the two outputs differ by a factor of 2. What's wrong? Is this a bug?
  15. T

    Found a bug in unity2017.1

    Hi, Not sure if here is were i should report the bug. If you make a plane and a sphere with a rigidbody, at some specifics altitudes, the sphere goes trough the plane. To reproduce it easily, i put the sphere 3.5 units higher than the plane and change the sphere scale to (0.2 , 0.2 , 0.2). This...
  16. newjerseyrunner

    B Where is the bug in my math?

    I want to know how fast the space shuttle would have to hit the Earth to unleash the same kinetic energy as the asteroid that killed the dinosaurs. I've already determined that it's relativistic, by showing that Newtonian physics gives a v greater than c But once I plug in the equations, I get...
  17. D

    Bug moving on a turntable rotating with constant omega

    Homework Statement A cockroach crawls with constant speed in a circular path of radius b on a phonograph turntable rotating with constant angular speed omega. The circle path is concentric with the center of the turntable. If the mass of the insect is m and the coefficient of static friction...
  18. H

    MCNPX do not finish a simulation possible bug in the code

    I am testing the MCNPX plugging MCUNED to make calculations with neutron generators. After the compilation many examples to test the installation are provided. But one of them (I attached the code below) starts but it never finish. Just keeps in the first rendezvous. I first though in a problem...
  19. B

    How advanced are spy drones used in the military and law enforcement?

    In this movie Eye in the Sky about drone deployment in the middle east. This is this small electronic beattle which can fly and has built in camera to spy inside houses. Is this technology real? Where can one get it? Should there be none, what is the smallest drone you saw that has good...
  20. G

    Medical Is a bug in FMRI software causing decades of brain research to be invalidated?

    http://www.sciencealert.com/a-bug-in-fmri-software-could-invalidate-decades-of-brain-research-scientists-discover Could this be true?
  21. fluidistic

    MITx edx 6.00.2x python 2 code, need to fix a bug

    Hi people, I've "enrolled" into the edx MITx 6.00.2x course on python and data science, but I don't plan to get a certificate and I started so late that all the problems I'm facing aren't due anymore so I think this gives me the right to seek help here. Basically the task is to simulate some...
  22. Hepth

    Mathematica Another bug? Weird integration results.

    I can't upload the notebook I guess, that would be a nice feature mods! (.nb extension) But here is my code , there seems to be a problem with integrating separately and then combining. $Assumptions = 0 < r < 1 && 0 < z < 1; FUNCTION = Expand[-(Pi*(-1 + r)*(-12*z + r^2*z + r*(-12 +...
  23. Prof. 27

    Program Bug: Programming Class

    Homework Statement So, I'm getting two blocks of zeroes in my console output from this program. After much effort (and stack exchange) I'm still unable to get it working. Could someone point me to a solution? Mod note: Added code tags Homework Equations #include<iostream> #include<iomanip>...
  24. hxtasy

    Type this into word or outlook, bug?

    messed up original post: "Hunter is having a top cover re‑designed" no period. now click the cursor right before the d in designed. hit tab, it will tab a single space. not a full tab. change "Hunter" to "Mike" or any other name, it will do a full Tab. try a word like "re-test" or...
  25. Dishsoap

    How much is it appropriate to bug a prof for a LoR?

    Greetings, I've just been having an issue recently and don't know how to approach it. I did an REU over the summer with a professor and I performed quite well. When I mentioned I might apply for the NSF GRFP this fall, the professor told me that if I wanted him to proofread my application essay...
  26. Ibix

    Odd Quoting Behaviour: One Tag, Two Blocks

    While quoting a post earlier I came across the following interesting behaviour. I pasted a QUOTE tag into a place where the person I was quoting had used large bold text, and accidentally made the QUOTE tag large bold text. This seems to have cause the behaviour below - there is only one QUOTE...
  27. O

    Fortran I can't find a small bug in this Fortran code

    So I'm writing a short subroutine to compute a QR factorization of an (mxn) matrix using the Householder method. To test this, I'm computing the factorization of the matrix 12 -51 4...
  28. S

    Error Analysis of Modern Gram Schmidt Technique -code bug

    Hi all, I am to compute A = QR using the Modified Gram-Schmidt algorithm. I need to find the error using the one norm of : (Q transpose * Q) - I. Here is my code: %Modern Gram Schmidt p=zeros(5,5); e=zeros(5,5); g=zeros(5,5); for k=1:n; p(:,k)=(A(:,k)); end %j=k, i=u, r=g, q=e, v=p for...
  29. fluidistic

    Bug in Maxima or I'm missing something?

    I am clueless. Here's the model I tried to follow: g(a):=a^2-1; f(a,b):=a+g(a)-b; f(a,b); With output −b+a^2+a−1 Which is 1)Define a function in terms of some variable(s). 2)Define another function in terms of some variable(s) and in terms of the function defined in 1). 3)Evaluate the function...
  30. Nathanael

    What is the maximum mass of a bug to not tip the straw?

    Homework Statement "A drinking straw of length 1.5a and mass 2m is placed on a square table of side a parallel to one of its sides such that one third of its length extends beyond the table. An insect of mass \frac{1}{2}m lands on the inner end of the straw (ie, the end which lies on the...
  31. Nathanael

    Bug moving on a rubber band

    Homework Statement "You have a 1 km long rubber band with one end attached to the wall, and the other in your hand. The bug begins to crawl towards you on the rubber band, starting from the wall, at a rate of 1 cm/sec. As he crawls the first centimeter you extend the rubber band 1 km; when he...
  32. Hepth

    Mathematica [Mathematica] Bug in Integrate with derivatives of a delta function

    Integrate[f[qs] DiracDelta'[qs (1 - 1/x)], {qs, -\[Infinity], \[Infinity]}, Assumptions -> 0 < x < 1] Integrate[f[qs] DiracDelta'[qs - qs/x], {qs, -\[Infinity], \[Infinity]}, Assumptions -> 0 < x < 1] This is on Mathematica 8 for windows. The results differ by a sign. They are effective...
  33. D H

    [Heartbleed bug] Have you changed your internet passwords yet?

    If you haven't, you should rethink that thanks to the heartbleed bug. Your passwords on a supposedly secure website most likely are not secure, thanks to this bug. The last two xkcd.com cartoons depict the problem quite nicely:
  34. Saitama

    Bug on a hinged square metal frame

    Homework Statement A square metal frame in the vertical plane is hinged at O at its centre as shown in the figure. A bug moves along the rod PN which is at a distance ##l## from the hinge, such that the whole frame is always stationary, even though the frame is free to rotate in the vertical...
  35. Hepth

    Mathematica Mathematica Bug : Integrate and DiracDelta

    I have found that while these two should be the same, mathematica does not evaluate them equally. Integrate[(a + b el + c el^2) DiracDelta[u], {u, 0, 1}, {el, e1, e2}] Integrate[ Integrate[(a + b el + c el^2) DiracDelta[u], {el, e1, e2}], {u, 0, 1}] I believe the second one is correct...
  36. Borek

    Python bug, or am I misunderstanding something?

    I don't know python, yet I am trying to code something, just for fun. But I have hit some strange obstacle and I don't know if it is a bug in my Python version (dated, it is over a year old, under Raspbian), or is it me misunderstanding something? pattern = re.compile('\[(\d+)\]\[(\d+)\](.*)')...
  37. Hepth

    Mathematica Mathematica : Integrate bug? Generate conditions.

    Please try: Integrate[((x - 1)^2/x) (1 - y), {y, 0, 1}, {x, 0, 1}] Integrate[((x - 1)^2/x) (1 - y), {x, 0, 1}, {y, 0, 1}] on your version. My Options[Integrate] GenerateConditions-> Automatic. In the first case, it gives -3/4, the second is divergent. For some reason when the...
  38. T

    Bug Jumps off a rod; what is the angular velocity of the rod

    Homework Statement A small 13.0g bug stands at one end of a thin uniform bar that is initially at rest on a smooth horizontal table. The other end of the bar pivots about a nail driven into the table and can rotate freely, without friction. The bar has mass 65.0g and is 120cm in length. The...
  39. T

    Conservation of Angular Momentum of Bug Problem

    Homework Statement A small 13.0g bug stands at one end of a thin uniform bar that is initially at rest on a smooth horizontal table. The other end of the bar pivots about a nail driven into the table and can rotate freely, without friction. The bar has mass 65.0g and is 120cm in length. The...
  40. B

    Fortran Fortran bug: rank problem gfortran

    This is my own code, and it won't compile with gfortran. All I want to do is extract the location of the cell with the minimum value in an array. A seemingly simple task but one that does not work with the intrinsic function minloc, for reasons I do not understand. The error message...
  41. I

    The bug is Doing the Jive.

    A .5g insect rests on a compact disc at a distance of 4cm from the centre. If the coeffiecient of static friction is .51 what is the maximum velocity the insect can experience without slipping off? I am lost, can someone help ?
  42. Ackbach

    LaTeX The 50 Character Bug and Its Application to LaTeX on MHB

    A well-known bug in vBulletin (the software of this forum) is the 50-character bug. Try this: Nowisthetimeforallgoodmentocometotheaidoftheircountry. This "word" is just over 50 characters long, and you can see that vBulletin forces a space in-between the n and the t of "country", right at the...
  43. 1

    Skin/hair bug looks like a lobster?

    Years ago I remember watching a "documentary?" on TV about our skin or hair (my best guess is hair). It was about all of the microscopic "bugs" that live on us. And the best I remember, there was one that looked like a lobster. Anyone know the name of this "bug"? (I've tried Google with no...
  44. M

    0 vs 0.0 in numerical integrand- bug?

    Hi All, A slight problem I've had with a function defined by a numerical integral. The definition is f[q_,c_,n_]:=NIntegrate[\[Beta]*BesselJ[0,q*\[Beta]]*(E^(I*c*((\[Beta] BesselK[1,\[Beta]] HypergeometricPFQ[{1},{1+n/2,1+n/2},\[Beta]^2/4]+n BesselK[0,\[Beta]]...
  45. G

    Generators Calculation Bug

    Hi guys, For one more time I need your opinion in a kind of strange issue, which escapes my understanding. Performing a single line to ground short circuit calculations (Low Voltage Side) in a simple Generator power plant using a step up to transformer, we can observe the two following...
  46. QuarkCharmer

    LaTeX LaTeX WYSIWYG Editor Bug: Unintended TEX Tags Inserted with Symbols?

    I'm not sure if this is a bug, or I am just an idiot and using this thing wrong, but when you click something in the LaTeX drop-down thing that appears to the right, for instance, a greek letter or something, the thing automatically inputs it where the cursor is, but includes a free set of itex...
  47. G

    Conceptual: bug masses on a rotating wheel

    Homework Statement Two objects of equal mass are on a turning wheel. Mass 1 is located at the rim of the wheel while mass 2 is located halfway between the rim and the axis of rotation. The wheel is rotating with a non-zero angular acceleration. For each of the following statements select the...
  48. N

    Comp Sci (C++) ubuntu g++ bug: multiple definition of a function. What went wrong?

    Homework Statement I can't understand what's causing this bug. I'm not trying to actually use this program, but it's just something I made up to learn how it works, and understand why things don't work, while I'm learning C++. So my question is, what's causing this program to get this error...
  49. J

    Moment of inertia wheel and bug

    Homework Statement There is a wheel with spokes rotating on a horizontal axis about its center. the Wheel has a w(omega) of 6∏ and a radius of .04meters there is a bug on one of the spokes at exactly 1/2 radius or .02meters. the bug has a mass of .005kg. Homework Equations not really sure...
  50. J

    Fortran Small FORTRAN code for combinations. BUG

    small FORTRAN code for combinations. BUG! PROGRAM test implicit double precision(a-h,o-z) INTEGER :: r=2,n=4,k=1 INTEGER,allocatable :: comb(:) !array to hold a set of combinations allocate(comb(r)) comb(1)=1 CALL iterate(1,n-r+1,1) CONTAINS...