What is Bit: Definition and 398 Discussions

The bit is the most basic unit of information in computing and digital communications. The name is a contraction of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented as either "1"or"0", but other representations such as true/false, yes/no, +/−, or on/off are commonly used.
The correspondence between these values and the physical states of the underlying storage or device is a matter of convention, and different assignments may be used even within the same device or program. It may be physically implemented with a two-state device.
The symbol for the binary digit is either "bit" per recommendation by the IEC 80000-13:2008 standard, or the lowercase character "b", as recommended by the IEEE 1541-2002 standard.
A contiguous group of binary digits is commonly called a bit string, a bit vector, or a single-dimensional (or multi-dimensional) bit array.
A group of eight binary digits is called one byte, but historically the size of the byte is not strictly defined. Frequently, half, full, double and quadruple words consist of a number of bytes which is a low power of two.
In information theory, one bit is the information entropy of a binary random variable that is 0 or 1 with equal probability, or the information that is gained when the value of such a variable becomes known. As a unit of information, the bit is also known as a shannon, named after Claude E. Shannon.

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  1. K

    Re: MIPS - Making a 64 bit number when you only have 32 bit register support

    Hey guys I've been working on this program for just over a week now and I just can't seem to find any way around my problem. The problem I'm having is: I'm trying to add 32 bit numbers together and if there is an overflow then I'd like to find a way to output the result as a 64 bit number. I...
  2. J

    How to Compile PROPEP for 32 Bit Systems?

    I am trying to compile PROPEP for 32 bit systems. (Martin-Marietta FORTRAN program for chemical equilibrium) It was originally written for IBM professional FORTRAN version 1.00 I can compile with the IBM 1.00, so I know my source code is valid. I have tried G77 with loads of errors...
  3. K

    MIPS - Making a 64 bit number when you only have 32 bit register support

    Hey guys I've been working on this program for just over a week now and I just can't seem to find any way around my problem. The problem I'm having is: I'm trying to add 32 bit numbers together and if there is an overflow then I'd like to find a way to output the result as a 64 bit number...
  4. DHF

    Upgrading Windows 7 (32 bit to 64)

    Greetings, I currently have a laptop with Windows Home 7 32 bit. I would like to move to 64 bit so I can upgrade the RAM but I would rather not start from scratch. is there a way to load the 64 bit version onto my laptop without wiping out my current programs and settings? any info you...
  5. bohm2

    What is the relationship between matter and information?

    "It from bit" or "Bit from it" I've always had some difficulties understanding the whole concept of information: Is matter really just information? Does one mean just our information about matter? Isn't all information embodied in some more basic "physical" stuff? Doesn't information...
  6. Whovian

    Efficient Factorial Calculation in Python: Recursive vs. Iterative Methods

    I tried the following code: def factorial(n): if (n == 0): return 1 else: return n*factorial(n-1) def ncr(n,r): return ((factorial(n))/(factorial(r)*factorial(n-r))) number = 0 for n in range(100): for r in range(100): print ncr(n,r)...
  7. P

    Every decision I make makes my life a little bit worse and I don’t wish to live anymo

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  8. B

    Fourier Transform help (bit )

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  9. C

    Bit of confusion with coils and electromagnetic induction

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  10. H

    I need a bit of help rearranging this equation

    1. The equation is : y = 50 ( 5 - 0.67 ^ x) 2. Just basic rearranging, I need to isolate x. 3. So far I have.. y = 50 ( 5 - 0.67 ^ x) y - 50=( 5 - 0.67 ^ x) y - 55 = - 0.67 ^ x) Now is the bit where I am stuck, seeing it is raised as a power? I know it's simple, I just can't...
  11. C

    How Can Mechanics and Sound Be Tied into a School Project on Stars?

    Hello all, new here, so I hope this would be the best forum for it to go into. Anyway, for school we have to do a project on any subject we want, and tie it into what we've been studying in physics. I selected stars, and I'm having a bit of trouble tying it into everything. What we've done so...
  12. S

    Still a bit confused about electron orbitals?

    Hey Everyone, If you have an electron with the various energy levels: -14 eV, -30 eV, -52 eV, -80 eV. And that the electron can only move between these levels. How do I go about finding the photo energy that is emitted? Do I just subtract the various levels? Ex. 14 - 30 = -16 etc?
  13. P

    I'm a bit confused about rotation and reflection matrices

    Homework Statement I have a final coming up and I am a bit fuzzy on how to create a matrix that represents a rotation or reflection about a certain plane (in R3). Say we are given a rotation/reflection about either a plane or a line through two points T(v)=Av and we are told to find A. Do we...
  14. B

    A bit of help with a capacitor problem

    1. The problem: In the capacitor circuit shown below C1 = 4␣F, C2 = 12␣F, C3 = 12␣F, and C4 = 3␣F. The switch (S) between A and B is closed and the energy stored in C3 is 1.35x10-3 J. If the switch is now opened calculate the change in the charge on C2. Assume the potential difference between C...
  15. 9

    Find points of inflection from f''(x) = 12x + 18? A bit confused

    Homework Statement In my book it specifically asks to "find the points of inflection" of f (x) = 2x^3 + 9x^2 - 24x - 10. Homework Equations f (x) = 2x^3 + 9x^2 - 24x - 10 f'(x) = 6x^2 + 18x - 24 f''(x) = 12x + 18. The Attempt at a Solution What I don't get is why it asks for pointS...
  16. I

    Work, Power, Frictional Force - seems a bit tricky for me

    Homework Statement A highway goes up a hill, rising at a constant rate of 1.00 m for every 48 m along the road. A truck climbs this hill at constant speed vup = 19 m/s, against a resisting force (friction) f equal to 1/24 of the weight of the truck. Now the truck comes down the same hill...
  17. N

    A bit of a problem with the liberal arts department

    I've went above and beyond in my philosophy class and wrote an outstanding (at least compared to other students) essay, or in my opinion at least. I had very good sentence structure, coherence and flow, vocab and ideas, good progression of logic, I had original insight into the topic, and...
  18. turbo

    Need to get a bit more fuel for the furnace.

    Well, we really don't need to, but it's nice to have around in case a family emergency requires us to be away from home a bit in the winter. When we bought this place 6 years ago, we bought a tank-full of #2 heating oil. I have supplanted that with 911 fuel-stabilizer a couple of times, and...
  19. G

    How Is Field Strength Equal to Potential Gradient in Electric Fields?

    I was checking my syllabus to see if my coursebook was missing out on any of the syllabus statements, and it mostly isn't. But for this one statement the explanation in the book isn't good enough and I don't understand what it's trying to say. The chapter is Electric Fields, and the...
  20. H

    Find the bit string for the following sets.

    Homework Statement The a universal set: u = {1,2,3,4,5,6,7,8,9,10} 1) Find the bit string for b = {4,3,3,5,2,3,3,} 2) Find the bit string for the union of two sets. Homework Equations 1)Would I first begin this problem by realizing that set b is the same as {2,3,4,5}? The...
  21. H

    How can I compare bits and perform bit shifts in SystemVerilog?

    Hi, i am trying to do a bit shift in systemverilog and compare the bit. For example: i give a input A=011. Then the input will compare with another digital that i have already setup in fsm like 010. Now it will do the compare, 0 to 0---> bitmatch=1 1 to 1 ---> bitmatch=1 1 to 0 ---> bitmatch=0...
  22. R

    Courses Is Computer Science the course for me (sorry, a bit extensive)?

    Hi, I'm new to Physics Forums and in dire need of your help. Please bear with me, here it goes: Though I'm sure this goes through every person's head who wants to go through University, I really have no good idea of which courses I want to take. I thought maybe computer science would be the...
  23. P

    Can Structural Induction Prove Bit String Relationships?

    Homework Statement Prove that in a bit string, the string 01 occurs at most one more time than the string 10. 2. The attempt at a solution I wish to use structural induction for this proof. Let \Sigma^* be the set of all strings over the alphabet \Sigma={0,1}. Let P(w) be the...
  24. A

    4 Bit Synchronous Counter to use as 4 Bit ADC

    Hello Im really struggling with this question I've been given: ---------------------------------------------------------------------------------------- Construct a four bit synchronous counter, then use as a guide to crate a four bit ADC which will: When output 0 to 3 light should immuminate...
  25. C

    Gates or IC to use to convert 1x 4 bit 2x 4 bit

    example 1111 = 15 is there a circuit to separate output binaries 0001(1) and 0101(5) in input 1111(15)?
  26. K

    Is a Lack of Math Skill a Barrier to a Career in Astrophysics?

    Hello all, I am new to these forums, and I look forward to plumbing the depths of this interesting site. Anywho, I come to you with a bit of a potentially difficult question. I have always been immensely interested in Astronomy and Physics, and I decided long ago to pursue a career in either...
  27. B

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    This really isn't one specific problem per se as it is more of a conceptual issue, so I apologize for breaking away from the given format. I've worked through three problems involving a circuit where a thevenin equivalence circuit is required between two points, and all sources are dependent...
  28. M

    A bit of a fun project - The claw

    Hey guys, I got an idea in my head to have a bit of fun with a project idea. I want to make one of those claw games that they use to pick up toys, or chocolate bars etc. However there are so many ways to do it. Ideally i would like to make a small c program and put it on a PIC and use that...
  29. C

    Solving Trigonometric Identities (A bit Hard)

    Alright, well I am having a difficult time getting these equations to equal out! I keep hitting trouble and have hit a road block. Here is the problem... csc(x)+cot(x) = cot(x)csc(x) tan(x)+sin(x) I am just going to work on the LEFT PART of the equation. 1 + cos(x) sin(x)...
  30. K

    Engineering 2 bit by 1 bit multiplier circuit

    Homework Statement What is the truth table for a 2 bit number multiplied by a 1 bit number? Also, draw the circuit (AKA, the logic gates that give you the truth table). Homework Equations Not really any relavent equations... The Attempt at a Solution so I made the truth table, it...
  31. S

    A little bit of help rearranging and equation

    Hello, Hopefully someone can help me rearrange this equation for x2. The equation is CB = Co e(-x2/4Dt) It is changing the e into a log that is throwing me. Thanks. Seán
  32. A

    Creating a 4 Bit Calculator: Add, Subtract, Multiply & Divide

    Hi! This is a great forum and I've been using it for help for a while so thought I would finally sign up. Anyway my group is making a 4 bit binary calculator for a course in my second semester and we're am having a few issues. The main restriction is that we can only use basic gates to...
  33. C

    Most significant bit (MSB) in ASCII code

    Hello You know that the MSB in each byte is always zero in ASCII code (e.g. text file). If I cut the text file by byte, then there will be 0 (which is MSB) that might reveal some information... So, are there any stochastic rules that I make the strings random in ASCII code? It will be...
  34. G

    Typical Surface Finish of Twist Drill Bit

    Dear All, I am looking for the typical surface finish (surface roughness) of a 5 mm hole made by a twist drill bit. Thankssssss GLO
  35. F

    Libsvm problem in make function with windows7 (64 bit)

    i tried to run libsvm several times but i failed, I've visualc++ i do this mex -setup Welcome to mex -setup. This utility will help you set up a default compiler. For a list of supported compilers, see http://www.mathworks.com/support/compilers/R2011a/win64.html Please choose your compiler...
  36. Pengwuino

    I'm crying and suicidal. and a bit hungry

    So I began grading my students first lab assignment. It was a 175 question math review going all the way from basic addition to logarithms and basic algebra and they had a week to do it. First person was decent enough. This second person makes me cry. MY STUDENTS CANT DO ARITHMETIC...
  37. M

    Where to go from learning precalc and a bit of calculus?

    Hi, This isn't so much a coursework question, but a 'where to go from here' question. But because I'm not in college, I figured it doesn't really belong in the academic guidance forum. But anyways, on to my question. Currently, I'm finishing up a 5-week precalculus course at a local...
  38. Y

    Velocity of proton following a helical path? need a bit of help

    velocity of proton following a helical path?? need a bit of help Homework Statement A proton with an initial velocity given by (4.0 + 3.0 + 3.0)(105 m/s) enters a magnetic field given by (0.62 T). Describe the motion of the proton. The proton will follow a helical path with a velocity of...
  39. G

    Studying Is studying a little bit of statistics worth it?

    I'm going to be a senior in high school next year, and I'm thinking about self-studying AP Statistics. I want to be some sort of mathematician or physicist, and I am thinking that having the equivalent of a first-year course in college statistics will significantly broaden my career choices and...
  40. James889

    Bandwidth vs Bit Rate: What's the Difference?

    Hi, I never really understood this. What are the differences between bandwidth and bit rate ? I understand that they describe the same thing, yet are completely different. How are these related?
  41. T

    Bit rate, symbol rate and sampling in LTE

    Hi guys, I have a problem in understanding LTE. LTE is the long term evolution 4G technology. The LTE requirement is 100 Mbps with 1.3, 2.5, 5, 10, 15 and 20 MHz for 128, 256, 512, 1024, 1536 and 2048 subcarriers. Each bandwidth corresponds to each number of subcarriers. My problem here...
  42. B. Elliott

    Welcome Back! Reflecting on Deployment and the Joy of Homeport

    I haven't been on PF in quite a while now and after reading through some of the threads in the Astronomy and Computing sections, I feel as though I've been missing out, er, a bit guilty. I was out on a couple of deployments for quite some time (got to see some beautiful countries), and finally...
  43. J

    I am a bit confused at orthonormal tetrad in General Relativity

    I am a bit confused at "orthonormal tetrad" in General Relativity... I think orthonormal tetrad should be a set of vectors like e0= (1,0,0,0) e1= (0,1,0,0) e2= (0,0,1,0) e3= (0,0,0,1) However, in my book, it is written as e0= (-1,0,0,0) e1= (0,1,0,0) e2= (0,0,1,0) e3= (0,0,0,1)...
  44. H

    8 bit adder/sub with 4 bit ripple adder and muxes only

    Hi I'm having trouble with coming up with a minimal solution to this problem: create a 8 bit adder/sub using only one 4 bit ripple carry adder and muxes. This is what I'm thinking but I don't know how to make it any bit simpler: We can calculate the sum of first 4 bits using the ripple carry...
  45. B

    128 bit and 256 bit encryption

    Can anyone please explain me what's 128-bit and 256-bit encryption in layman's word (but bit in detail please). (I am a mechanical Engg. and have least knowledge on security aspects of IT). Thnx.
  46. MathematicalPhysicist

    Tinkering a little bit with Vpython.

    I thought to write a naive simulation of an inflated ball, I am not sure how to implement this by Vpython. I mean I want to see it gradually inflating minute by minute. This is the code I wrote but I don't know how to add to it a timer. from visual import *...
  47. B

    Bit confused about the geometric series

    I'm confused about the sum of the geometric series: \sum ar^{n-1} = \frac{a}{1-r} when |r|<1 but if you have a series like: \sum (1/4)^{n-1} the sum is: \frac{1/4}{1-(1/4)} should't it be \frac{1}{1-(1/4)} because there is no a value?
  48. K

    How Do You Solve Lagrange Multipliers with Complex Constraints?

    1. Use the method of Lagrange multipliers to nd the minimum value of the function: f(x,y,z) = xy + 2xz + 2yz subject to the constraint xyz = 32. I understand the method how Lagranges Multipliers is donw done but seem to have got stuck solving the Simultaneous Equations involving the...
  49. J

    Just stuck on the last bit integral

    i need to work out the integral on a complex curve: i am just stuck with the integral: int[0,2pi]((ie^it)/(e^it +1+i))dt ps. how do you insert latex text? thank you!
  50. M

    What is the Kinetic Energy of a 3000lb Car Traveling at 60mph?

    Homework Statement what is the kinetic energy of a 3000lb car traveling at a 60mph (pounds are not units of mass) Homework Equations KE=1/2* mass * velocity ^2 The Attempt at a Solution pounds are the units of force but to calculate the mass I am missing some data unless I'm...
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