# 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. ### How to correctly tap hole by use both drill and tap bit

How to correctly tap hole, i.e. make thread inside it, by use a usual drill with bit having 2 in 1 i.e. both bore/drill and tap bit once as in hole tap the rule is it must always go back and forth full cycle clockwise and half cycle counter-clockwise direction, so how can this rule in the former...
2. ### Comp Sci 8 bit block division -- University Level Intro Course: Networking

What I think I should do: 1 = 0001 7 = 0111 3 = 0011 First block = 00010111 Second Block = 00110000 Now, I do binary division 00010111/11010 = find the answer 00110000/11010 = find the answer This is what I think I should do, but I am not sure if this is correct. Is this basically CRC? Any...
3. ### Comp Sci Binary Encoding for 16 Bit Architecture

In class we were given the example of a 32-bit architecture, so the opcode has 5 bits, register A had four bits, register B had four bits, the destination register had 4 bits and the offset was 15 bits, this was how it was done for "add" instruction. But when I was further reading about it...
4. ### Comp Sci Digital Logic 8 Bit Full Adder Circuit

I am unsure of how to approach this problem, we begin with two 8-bit full adders, is the goal to just combine them in some way so that it becomes one entire circuit while also adding NAND and NOR gates where necessary? By the end will we then have 16 1-bit full adders?
5. ### B QM concept of photon.... still a bit of a mystery today?

Hi PF. I desire deeper understanding of fundamental physics, and quantum mechanics can be a challenge for me (compared to other topics in physics). I read in the intro of the physics textbook chapter that QM explains many phenomena, e.g. why copper conducts electricity and glass does not. In...
6. ### Comp Sci How can a 13 bit number represent 16 bit number?

This is more of a mathematics confusion rather than a computer science confusion, so please treat it like that. I understand the computer science behind it(I hope so) but my confusion lies in the basic math part that is there. I am studying about ipv4 fragmentation. This is ipv4 header. The...
7. ### MHB Why is Fragmentation Offset Multiple of 8? Understanding IPv4 Fragmentation

I am studying about ipv4 fragmentation. This is ipv4 header. The fields of concern here are-: -> identification(16 bit) -> Flags(3 bit) -> fragment offset(13 bit) -> Total length(16 bit)...
8. ### Engineering Digital Communications: Bit Error Rate (BER), C/N, Constellations

Problem Statement: I am not quite sure how to approach this problem and would appreciate the help. I how the C/N is closely related to the SNR (Eb/N0), but the question does not give the bandwidth or data rate for me to use the formula above. From the constellation diagram, my guess is this is...
9. ### A Derivation of recovery channel for bit flip error

In general, if R is the recovery channel of an error channel ε, with state ρ, then and according to these lecture slides, we get the final result highlighted in red for a bit flip error channel. I am simply asking how one reaches this final result. Thank you (a full-ish derivation can be found...
10. ### Is my weight during the night a little bit more than during the day?

During the day, I am between sun and earth. During the night, I am behind the Earth if I'm looking from the sun. So its Day: sun-me-earth night: sun-earth-me So the forces of gravity from sun and Earth add during the night, but during the day, the sun attracts me away from the earth...
11. ### Problem to divide two 16 bit numbers in 8051 series microcontrollers

Hi all, I have a project to code in 8051 series, DS80C320-ECG (data source as reference): "Division of two 16 bit unsigned integers being in the internal memory, quotient and remainder should be stored". I find a way to do it but there is a part of the program that i don't understand, I attach...
12. E

### I A bit confused with this question about the Penrose process

The first two parts to the question were as follows. If a vector field ##\xi## preserves the Maxwell field then ##\mathcal{L}_{\xi} F = 0## so by Cartan's magic formula ##i_{\xi} \mathrm{d}F + \mathrm{d}(i_{\xi} F) = 0##. But since ##\mathrm{d}F = 0## then ##\mathrm{d}(i_{\xi} F) = 0 \implies...
13. ### Do you consider writing this program a bit of a challenge?

Do you consider writing a program that takes 3 integer inputs and orders them in ascending order (accounting for same numbers) difficult? You can only use if statements (if, else if, else). I know there is some thing called "sort" that does the tedious work for you but do you find this simple...
14. E

I came across a derivation of the Noether theorem with a step I don't understand; the transformation of the time and configuration space are written as$$\tau(t,\varepsilon) = t + \varepsilon \delta t, \quad Q^a(q,\varepsilon) = q^a + \varepsilon \delta q^a$$here ##\varepsilon## is an...
15. ### Engineering Building a 2 bit comparator using either....

So I got this question while coming across, and I would like to seek some advice/tips for these types of questions. 1) Assuming I want to try and build using MUXs, I will get the truth table of both a 2 bit comparator and MUXs. In this case: For comparator: And for MUX: So from what I...
16. ### A bit confused about significant figures

Hi. I understand that the number 20, written like this, has 1 significant figure Suppose I took a pile of measures of length: 18, 19, 20, 21, 22, 23, 24, 25 giving a mean of 172/8 = 21.5 on my calculator If I have to give the mean to the lowest number of significant figures then that would...
17. ### Did My Old Mac Pro Die of a Broken Heart Before Its Replacement Arrived?

A few weeks ago I ordered a new 27" iMac with a 2TB SSD instead of the standard hybrid drive. Then the old Mac Pro died a few days before its replacement arrived. Broken heart, maybe? Now I've jumped ahead several versions of MacOS to 10.15 a.k.a. Catalina, and have to get new versions of all...
18. ### Claude Shannon "The Bit Player" movie free screening

This weekend (June 26-28) the IEEE Information Theory Society is showing a free screening of The Bit Player - a movie about Claude Shannon (the "father" of information theory) The website below has the link and password for Vimeo...
19. ### Comp Sci Least significant bit when there is a radix point (trivial)

However when there is a binary point where do I start grouping from? Is the rightmost bit considered the least significant bit even then? The other possibility is to begin grouping from the least significant bit for the integral part and then separately begin grouping from the leftmost digit...
20. ### I Fermi's golden rule derivation a bit hazy

My thought is following: However this would give me w=E_m + E_n instead of E_m-E_n I guess something relating to hermiticity or adjointing something has gnoe wrong in my version. Can someone point me in the right direction please? :) Thank you in advance!
21. ### Engineering Thevenin Theorem seems to not work in this 1 bit RAM RC circuit

I have a problem which consist in 1 bit RAM made of 3 MOSFETs. One of the questions is to calculate the maximum voltage that the memory element can receive. I have obtained the result by inspection (it is 4 Volts) but I'm unable to reach the same by applying the Thevenin Theorem. My...
22. ### Upgrading Win 7 32 bit to Win 10 64 bit

We have a Windows 7 Professional 32-bit desktop running on an Intel core i3 processor which is 64-bit capable. No idea why 32-bit version of OS was installed. I want to upgrade it, as stated above. I will be doing this for the first time, so there are some unanswered questions. I will be using...
23. ### Comp Sci Calculate the two's complement of a given 16 bit number

I'm working on an assignment for a computer science course. The professor did not give very good instruction, and I can't find very much information about the subject online. We are supposed to use this http://www.anne-gert.nl/projects/simpsim/ program to perform various operations including...
24. ### OS and Choice of 32- or 64- bit for VMWare

Hi All, I am setting up a WMWare15 Virtual Machine (VMWare Workstation 15 Player, more accurately). It requires the use of an OS. I have a copy of Win7 Pro which I already used successfully _except_ that it was a 32-bit version. Someone who knows more than I told me that it is possible for...
25. ### I How to use a quantum bit, or several

Its all in the summary.
26. ### I "It from Bit" and the multiverse?

Did physicist John Archibald Wheeler propose the existence of multiple universes through his "It from Bit" or "Participatory Universe Principle" or "Law without Law and Pregeometry"? Is the multiverse related to Wheeler's ideas? I've been told that It can produce multiple universes, obviously...
27. ### A Is the Wheeler-DeWitt equation related to Wheeler's It from Bit?

In this article: https://arxiv.org/pdf/hep-th/0211048.pdf by physicist Andrei Linde, it mentions Wheeler-DeWitt equation and he relates it to Wheeler's Participatory Universe model. Also, I found other sources that seem to establish a connection between Wheeler-DeWitt equation and Wheeler's It...
28. ### Cone drill bit with threads to drill in hard rock formations?

i designed a cone drill bit with right hand thread to give friction and grab inside to give pulling force. my question is can this type of cone drill bit drill hard rock formations like normal tricone drill bits with teeth or the cone drill bit will be weak to penetrate hard rock formations .
29. ### I need a bit of help (thesis submitted, lack of publications)

Hi all, I will try not to extend too much, but basically I have been in a horrible situation for the last months and I am starting to get a bit desperate/anxious. I submitted my PhD thesis on Theoretical Physics in December 2017, and since then, I have been unable to find a position anywhere...
30. ### Anyone else a bit concerned with autonomized weapons?

Saw this video today on facebook. I wonder how soon it will be before one of these is fitted with a machine gun. What if one of these was built or stolen for use in terrorism? In a densely populated city, how long could one of these roam freely gunning people down before police or military...
31. ### A A bit of clarification on the domain of a composite function

Recently when I reviewed something about the composite function for my calculus exam, I remembered I had been thinking a question for quite a long time (maybe I was going into a dead end) since I was in high school. I was thinking whether f(x)=1/(1/x) and g(x)=x are the same function or not. It...
32. ### A Bit Of Humor - Heaviest Element Yet Known

A friend knowing I have an interest in science sent me this amusing story - hope you find it as funny as me Scientists at CERN in Geneva have announced the discovery of the HEAVIEST element yet known to science. It was discovered in Australia, which is now the leading producer, but other...
33. ### Has Theoretical Physics met a bit of a roadblock?

I personally am undecided on the issue but it goes without saying that physicists have been stuck on the same problems for years. Sure they recently proved gravitational waves, but one could say that we knew they were they existed anyway with near certainty, if they weren' t there it would be a...
34. ### MHB Fast Exponentiation: Time Complexity and Number of Bit Operations

Hello! (Wave) It is stated in my notes that the calculation of $a^{n-1} \pmod{n}$ by fast exponentiation takes $O(\log{n})$ arithmetic operations and $O((\log{n})^3)$ bit operations.By using fast exponentiation, in order to calculate $a^{n-1} \pmod{n}$ we write $n-1$ as \$n-1=n_0+2 n_1+ \dots+...
35. ### General Question on 32- and 64- bit systems

Hi All, Just curious on pros/cons of installing software designed for 32- bit systems in a 64-bit machine (Windows 8.1*)? * I have never been able to tell the difference, if any, between Win 8 and Win 8.1 .
36. M

### Need help with a mod-6 counter using JK flip flops w/ control bit

Homework Statement [/B] I am currently working on an assignment in which I create a six-state up/down counter. The purpose is to understand the functionality of flip-flops within a circuit among other things. There are 3 input bits (Q2,Q1, Q0), and a 4th control bit (C) which determines the...
37. ### I Why Is There No SI Unit For Information?

Why is the quantity "information" missing from the SI system? Also, if they did add it, do you think it would be added as a base unit or dimensionless derived unit?
38. ### How to calculate this 4 bit DAC

< Mentor Note -- thread moved to HH from the technical forums, so no Homework Help Template is shown > please can somebody help me, how to calculate this 4 bit dac, i know this one if input 1.1.1.1 5/2, 5/4 5/8 5/16 voltage i don't understand nothing i search on the internet but i don't find...
39. ### B Need a bit more clarification on W=F.ds

I was a bit confused about the work energy theorem. I perfectly understood it's applications for point sized particles but I'm a bit confused about its application on extended bodies both rigid and non rigid. Case 1 {for rigid bodies} :- Consider a rod of definite mass hinged at the top. It's...
40. ### Uncertainty of the function? My answer is a bit different

Homework Statement Homework EquationsThe Attempt at a Solution The answer is different though,
41. ### Extended or bit based Reed-Solomon error correction

I am trying to find or develop an algorithm that can take a 1024 (lets assume random) bit array (so 128 bytes) and, by adding some redundancy (making the final code more than 1024 bits long), make it capable of decoding the data with up to n random bits flipped. Important point is that it has...
42. ### How does one decode a 6 bit binary to 2 7 segment display?

So a 3 bit 2 input multiplier has a maximum of 6 bits and the max integer product is 49. Problem is I have no idea displaying it in 2 seven segment displays since the 74LS48 decoder only has 4 inputs and 7 output, only good for a single 7 seg. And we are required only to use ICs which is rather...
43. ### Having trouble forming an equation on 2 bit subtractor

Homework Statement We are asked to make a subtractor circuit which has a 2 bit, 2 input data. Homework Equations A1A0 _ B1B0 _________________________________The Attempt at a Solution I would have a 3 bit output with one borrow. The problem is I am stuck at this point and am having...
44. ### Downsampling a 23 bit number to 8 bits

I'm trying to build a system that receives coefficients and performs a Fourier approximation, I need to write the system in VHDL so I'm using tables to simulate sin functions, they output an 8 bit number which is the sin of the input, then I need to multiply each sin with it's given coefficient...
45. ### B Is the Heisenberg Uncertainty Principle Equivalent to One Bit of Information?

In information theory, one bit is typically defined as the uncertainty of a binary random variable that is 0 or 1 with equal probability,[4] or the information that is gained when the value of such a variable becomes known.[5] https://en.wikipedia.org/wiki/Bit That sounds a lot like...
46. ### I need a bit of direction....thermodynamics & kilns

I'm trying to build a heat treating oven/kiln and I'm having a difficult time identifying equations to assist in sizing and insulation. I have info on sizing a heating element based on available power and I have and equation to quantify heat transfer through the walls and insulation but I'm...
47. ### Insights Why Study Physics? A Bit Goes a Long Way - Comments

anorlunda submitted a new PF Insights post Why Study Physics? A Bit Goes a Long Way! Continue reading the Original PF Insights Post.
48. ### B The universe is shrunk a little bit more than we thought

http://www.iflscience.com/space/the-edge-of-the-universe-is-closer-than-scientists-previously-thought/ Hey, guys! I'm new in this forum and I found this interesting article. Damian
49. ### I Casimir effect and vacuum energy and a bit of relativity....

Hi all, Silly question perhaps: I had understood that the energy density of the vacuum is constant throughout spacetime. But, with the Casimir effect, for example, the geometry of (real) matter (i.e., parallel plates), changes the vacuum energy density in between the plates - is this correct...
50. ### How fast can hackers crack 128 bit file encryption?

I got a freeware encryption software with only 128 bit. How fast it is for hackers to crack 128 bit file encryption?