Does ubuntu require antivirus? If yes then please tell me what's the difference between windows virus and ubuntu virus?
I thought that there was no need to scan for viruses either in Ubuntu or any Linux distros until I found virus scanner packages clamtk and klamav in Ubuntu software center yesterday.  This leads to the following questions:   How do viruses differ between Linux and Windows? How do the strategies for protection differ between Linux and Windows? Should a virus scanner package be installed on my system? If so, which would be a better option?
Why is serial data transmission faster than parallel? Intuitively, you would think that parallel data transmission should be faster than serial data transmission; in parallel you are transferring many bits at the same time, whereas in serial you are doing one bit at a time.  So what makes SATA interfaces faster than PATA, PCI-e devices faster than PCI, and serial ports faster than parallel? Can “zealot” have a positive connotation? A zealot is a person who is fanatical and uncompromising in pursuit of their religious, political, or other ideals.  I have never seen this word used with positive connotation, but could it (without causing raised eyebrows)? For example, “Gandhi was a zealot and should be admired by all who believe in non-violence.”  Also, do “zealous” and “zeal” carry the same connotation as “zealot”? PNG figures in black and white I'm trying to include a png figure and it works when I see it in dvi, but the ps comes in black and white.  If I compile directly to pdf there is no problem. However I'm using psTricks for a different figure, so I need to use ps first.  Any suggestions? What is a simple example of an unprovable statement? How to replace all occurrences of a string in JavaScript? Eigenvalues of symmetric matrices are real without (!) complex numbers Is there any proof of the fact that the eigenvalues of symmetric matrices (i.e. $A\in\mathbb{R}^{n\times n}$ with $A^t=A$) are real without the use of the concept of complex numbers? Using QGIS 3 graphical modeler I created a model with a variety of input parameters (> 10). When starting the model, a nice user interface is generated. But the arrangement of the GUI elements is totally confused and apparently unpredictable during creating the model. It does neither seem to depend on the arrangement of input parameters in the graphical modeler nor on the chronological order in which the input parameters are added to the model.   Is there a way that let's me arrange the GUI elements in the order I desire? I want to delete the record type which is default to the some profiles How to use regex in String.contains() method in Java Why is paper more frangible when it is wet? My four-year-old daughter asked me why paper tends to fall apart when wet, and I wasn't sure.  I speculated that the water lubricates the paper fibers so that they can untangle and separate more easily, but I really wasn't sure. Determine the exact date of creation of an Apple ID Is it possible to determine the exact date and time (if possible) of creation of an Apple ID?   Is there any official or unofficial way to establish this if you don't have the initial sign up information recorded? says that a photon of  to $10^{-62}$ kg has been detected:     10×10−62 kg   Mass equivalent of the energy of the lightest photon   detected [citation needed]   This equates ($mc^2=E=hf=h\frac{c}{\lambda}$) to a wavelength of $\lambda=2.2\times 10^{20}$ m (roughly a million ly)! Can anyone provide a citation for this measurement? And how can such a large wavelength/low energy photon be detected?  Edit  Apart from the quotation (true/false un/reliable un/documented ....), I'd like to learn about the lightest photon detected, or about the instrumental limit: what is the lower limit of energy that can be registerd by an intrument (or the greatest wavelength), and how it is done? For example, can you detect a radiowave of 1 Hz? if/then/else man page I would like to know if there is any man page documenting the construction of the most basic script commands like if/then/else, while, for each, and all the relative switches, like -eq, -e, -ge, and so on. Generalizing a sequence. Consider a sequence of the form:  $x[n]=-1,-1...,1,1,...,-1,-1...,1,1... \quad n&gt;0$  One can think of this as a square wave ($\pm1$) with a 50 % duty cycle (coming from EE).  For the simplest case of such a series i.e. $-1,+1,-1,+1,-1...$, a general equation is quite trivial ($x[n]=-1^n$).  Can we have e general equation for the other cases i.e. when there are multiple $-1$'s followed by $+1$'s ? I'm trying to solve the well known Coupon Collector's Problem by explicitly finding the probability distribution (so far all the methods I read involve using some sort of trick). However, I'm not having much luck getting anywhere as combinatorics is not something I'm particularly good at.   The Coupon Collector's Problem is stated as:  There are $m$ different kinds of coupons to be collected from boxes. Assuming each type of coupon is equally likely to be found per box, what's the expected amount of boxes one has to buy to collect all types of coupons?  What I'm attempting:  Let $N$ be the random variable associated with the number of boxes one has to buy to find all coupons. Then $P(N=n)=\frac{|A_n|}{|\Omega _n|}$, where $A_n$ is the set of all outcomes such that all types of coupons are observed in $n$ buys, and $\Omega _n$ is the set of all the possible outcomes in $n$ buys. I think $|\Omega _n| = m^n$, but I'm not even sure about that anymore, as all my attempts so far led to garbage probabilities that either diverged or didn't sum up to 1. What does high credit utilization really mean? If M is a non-orientable closed connected 3 manifold prove H1(M) is an infinite group. Derivation of Frey equation from FLT I understand, on  a layman's level, Fray's motivation to write an elliptic equation corresponding to an assumed solution to FLT. My question is, how technically is Frey's equation derived?   $1.$ FLT : Contradiction. There exist integers $A,B,C,n&gt;2$ such that $A^n + B^n = C^n$  $2.$  Frey: $y^2 = x(x-A^n)(x+B^n)$  $3.$  Elliptic curve $y^2= x^3 + ax + b$    $4.$  The curve is not modular. => not elliptic => FLT  proved.   I need is the algebra to go from 1. to 3. above.  Assume Numbers A,B,C such that A^n + B^n = C^n contradicting FLT.  $y^2 = x^3 + ax + b$ an elliptic curve in Weirstrass form. I am guessing A and B go unchanged into x(x-A^n)(x+B^n)   Is that correct ?  Expanding 2. I get a term in x^2 , there is none in 3. This is my problem.  What does a $2$ dimensional graph of the Frey curve look like ? How can I make my AES encryption identical between Java and Objective-C (iPhone)? After I deleted my Ubuntu partition, I rebooted my computer and I only get a prompt:   grub rescue &gt;   The command ls lists   (hd0) (hd0,msdos5) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1) (hd1) (hd1,msdos1)   I check them one by one:  ls (hd0,msdos5)/ ls (hd0,msdos1)/   But I cannot find the right partition.