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  • Real-Time Multi-User Gaming Platform

    - by Victor Engel
    I asked this question at Stack Overflow but was told it's more appropriate here, so I'm posting it again here. I'm considering developing a real-time multi-user game, and I want to gather some information about possibilities before I do some real development. I've thought about how best to ask the question, and for simplicity, the best way that occurred to me was to make an analogy to the field (or playground) game darebase. In the field game of darebase, there are two or more bases. To start, there is one team on each base. The game is a fancy game of tag. When two people meet out in the field, the person who left his base most recently timewise captures the other person. They then return to that person's base. Play continues until everyone is part of the same team. So, analogizing this to an online computer game, let's suppose there are an indefinite number of bases. When a person starts up the game, he has a team that is located at, for example, his current GPS coordinates. It could be a virtual world, but for sake of argument, let's suppose the virtual world corresponds to the player's actual GPS coordinates. The game software then consults the database to see where the closest other base is that is online, and the two teams play their game of virtual tag. Note that the user of the other base could have a different base than the one run by the current user as the closest base to him, in which case, he would be in two simultaneous battles, one with each base. When they go offline, the state of their players is saved on a server somewhere. Game logic calls for the players to have some automaton-logic of some sort, so they can fend for themselves in a limited way using basic rules, until their user goes online again. The user doesn't control the players' movements directly, but issues general directives that influence the players' movement logic. I think this analogy is good enough to frame my question. What sort of platforms are available to develop this sort of game? I've been looking at smartfoxserver, but I'm not convinced yet that it is the best option or even that it will work at all. One possibility, of course, would be to roll out my own web server, but I'd rather not do that if there is an existing service out there already that I could tap into. I will be developing for iOS devices at first. So any suggestions would be greatly appreciated. I think I need to establish the architecture first before proceeding with this project. Note that darbase is not the game I intend to implement, but, upon reflection, that might not be a bad idea either.

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  • Cyber Stalking Victims May Know Their Offenders

    Not every victim of cyber stalking is accosted by a stranger. In a surprisingly large number of cases the person being victimized may know the person who is harassing them. Many times this unwanted a... [Author: Ed Opperman - Computers and Internet - May 25, 2010]

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  • SEO - The Best Means to Have Visitors!

    Keywords are the words relevant to the subject of your site searching which, any person can land on to your site. They could be any word pertaining to the product or service provided by your portal. Related words are said for, if a person reaches your site searching for something not offered by your site, it would be a waste. Search engines are the websites where any internet user, not knowing of the sites providing a product or service, gets to know all the available sites.

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  • Getting a virus is *very* annoying

    - by bconlon
    I spent most of yesterday removing an annoying virus from my PC. I feel slightly foolish for getting one in the first place, but after so many years I guess I was always going to eventually succumb. I was also a little surprised at the failure of various tools at removing it. The virus would redirect the browser to websites including ‘licosearch’, ‘hugosearch’ and ‘facebook’, and the disk would be thrashing away infecting dlls in some way. I had the full up to date version of McAfee installed. This identified that there was an issue in some dlls on the system and was able to ‘fix’ them. But they kept getting re-infected. So I installed Microsoft Security Essentials and this too was able to identify and ‘fix’ the infected dlls. The system scans take forever and I really expected better results. I also tried Malwarebytes, Hitman Pro, AVG and Sophos to no avail. Eventually I thought I’d investigate myself. It turned out that on reboot, the virus would start 3 instances of Firefox.exe which I’m guessing would do bad things including infecting as many dlls on the system as possible. I removed Firefox and the virus cleverly then launched 3 instances of Chrome! So I uninstalled Chrome and yes, it then started to launch 3 instances of iexplore.exe. If I’m honest, by this stage I was just seeing if it would be able to use any of the browsers! As it was starting these on reboot, I looked in my User Startup folder and there was a <randomly named>.exe and several log files. I deleted these and rebooted. When I looked they had been recreated. So I then looked in the registry Run and RunOnce entries: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run. Sure enough there were entries to run a file in C:\Program Files\<random name folder>\<random name file>.exe. I deleted this and rebooted and it was fixed. I also looked in the event log and found a warning that Winlogon had failed to start the file C:\Program Files\<random name folder>\<random name file>.exe So I also checked HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon and this entry had also been changed. Finally I ran a full system scan to clean up any infected dlls. I hope it’s gone for good!  #

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  • Is it OK to repeat code for unit tests?

    - by Pete
    I wrote some sorting algorithms for a class assignment and I also wrote a few tests to make sure the algorithms were implemented correctly. My tests are only like 10 lines long and there are 3 of them but only 1 line changes between the 3 so there is a lot of repeated code. Is it better to refactor this code into another method that is then called from each test? Wouldn't I then need to write another test to test the refactoring? Some of the variables can even be moved up to the class level. Should testing classes and methods follow the same rules as regular classes/methods? Here's an example: [TestMethod] public void MergeSortAssertArrayIsSorted() { int[] a = new int[1000]; Random rand = new Random(DateTime.Now.Millisecond); for(int i = 0; i < a.Length; i++) { a[i] = rand.Next(Int16.MaxValue); } int[] b = new int[1000]; a.CopyTo(b, 0); List<int> temp = b.ToList(); temp.Sort(); b = temp.ToArray(); MergeSort merge = new MergeSort(); merge.mergeSort(a, 0, a.Length - 1); CollectionAssert.AreEqual(a, b); } [TestMethod] public void InsertionSortAssertArrayIsSorted() { int[] a = new int[1000]; Random rand = new Random(DateTime.Now.Millisecond); for (int i = 0; i < a.Length; i++) { a[i] = rand.Next(Int16.MaxValue); } int[] b = new int[1000]; a.CopyTo(b, 0); List<int> temp = b.ToList(); temp.Sort(); b = temp.ToArray(); InsertionSort merge = new InsertionSort(); merge.insertionSort(a); CollectionAssert.AreEqual(a, b); }

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  • Setting uniform value of a vertex shader for different sprites in a SpriteBatch

    - by midasmax
    I'm using libGDX and currently have a simple shader that does a passthrough, except for randomly shifting the vertex positions. This shift is a vec2 uniform that I set within my code's render() loop. It's declared in my vertex shader as uniform vec2 u_random. I have two different kind of Sprites -- let's called them SpriteA and SpriteB. Both are drawn within the same SpriteBatch's begin()/end() calls. Prior to drawing each sprite in my scene, I check the type of the sprite. If sprite instance of SpriteA: I set the uniform u_random value to Vector2.Zero, meaning that I don't want any vertex changes for it. If sprite instance of SpriteB, I set the uniform u_random to Vector2(MathUtils.random(), MathUtils.random(). The expected behavior was that all the SpriteA objects in my scene won't experience any jittering, while all SpriteB objects would be jittering about their positions. However, what I'm experiencing is that both SpriteA and SpriteB are jittering, leading me to believe that the u_random uniform is not actually being set per Sprite, and being applied to all sprites. What is the reason for this? And how can I fix this such that the vertex shader correctly accepts the uniform value set to affect each sprite individually? passthrough.vsh attribute vec4 a_color; attribute vec3 a_position; attribute vec2 a_texCoord0; uniform mat4 u_projTrans; uniform vec2 u_random; varying vec4 v_color; varying vec2 v_texCoord; void main() { v_color = a_color; v_texCoord = a_texCoord0; vec3 temp_position = vec3( a_position.x + u_random.x, a_position.y + u_random.y, a_position.z); gl_Position = u_projTrans * vec4(temp_position, 1.0); } Java Code this.batch.begin(); this.batch.setShader(shader); for (Sprite sprite : sprites) { Vector2 v = Vector2.Zero; if (sprite instanceof SpriteB) { v.x = MathUtils.random(-1, 1); v.y = MathUtils.random(-1, 1); } shader.setUniformf("u_random", v); sprite.draw(this.batch); } this.batch.end();

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  • Ubuntu 12.04 partial freeze

    - by user1550594
    While working on the system suddenly if i open a random file or start browsing and on other random moments the system starts hanging or start responding slowly. In this situation, i can able to open the virtual console using the Ctrl + Alt + F1-F6 and type the top and list the processes. Due to urgency, i will kill the long running processes or the over memory utilizing process to recover the screen back. Can anyone give me a permanent fix.!

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  • Do functional generics exist and what is the correct name for them if they do?

    - by voroninp
    Consider the following generic class: public class EntityChangeInfo<EntityType,TEntityKey> { ChangeTypeEnum ChangeType {get;} TEntityKeyType EntityKey {get;} } Here EntityType unambiguously defines TEntityKeyType. So it would be nice to have some kind of types' map: public class EntityChangeInfo<EntityType,TEntityKey> with map < [ EntityType : Person -> TEntityKeyType : int] [ EntityType : Car -> TEntityKeyType : CarIdType ]> { ChangeTypeEnum ChangeType {get;} TEntityKeyType EntityKey {get;} } Another one example is: public class Foo<TIn> with map < [TIn : Person -> TOut1 : string, TOut2 : int, ..., TOutN : double ] [TIn : Car -> TOut1 : int, TOut2 :int, ..., TOutN : Price ] > { TOut1 Prop1 {get;set;} TOut2 Prop2 {get;set;} ... TOutN PropN {get;set;} } The reasonable question: how can this be interpreted by the compiler? Well, for me it is just the shortcut for two structurally similar classes: public sealed class Foo<Person> { string Prop1 {get;set;} int Prop2 {get;set;} ... double PropN {get;set;} } public sealed class Foo<Car> { int Prop1 {get;set;} int Prop2 {get;set;} ... Price PropN {get;set;} } But besides this we could imaging some update of the Foo<>: public class Foo<TIn> with map < [TIn : Person -> TOut1 : string, TOut2 : int, ..., TOutN : double ] [TIn : Car -> TOut1 : int, TOut2 :int, ..., TOutN : Price ] > { TOut1 Prop1 {get;set;} TOut2 Prop2 {get;set;} ... TOutN PropN {get;set;} public override string ToString() { return string.Format("prop1={0}, prop2={1},...propN={N-1}, Prop1, Prop2,...,PropN); } } This all can seem quite superficial but the idea came when I was designing the messages for our system. The very first class. Many messages with the same structure should be discriminated by the EntityType. So the question is whether such construct exists in any programming language?

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  • Do functional generics exist or what is the correct name for them if they do?

    - by voroninp
    Consider the following generic class public class EntityChangeInfo<EntityType,TEntityKey> { ChangeTypeEnum ChangeType {get;} TEntityKeyType EntityKey {get;} } Here EntityType unambiguously defines TEntityKeyType. So it would be nice to have some kind of types' map public class EntityChangeInfo<EntityType,TEntityKey> with map < [ EntityType : Person -> TEntityKeyType : int] [ EntityType : Car -> TEntityKeyType : CarIdType ]> { ChangeTypeEnum ChangeType {get;} TEntityKeyType EntityKey {get;} } Another one example is: public class Foo<TIn> with map < [TIn : Person -> TOut1 : string, TOut2 : int, ..., TOutN : double ] [TIn : Car -> TOut1 : int, TOut2 :int, ..., TOutN : Price ] > { TOut1 Prop1 {get;set;} TOut2 Prop2 {get;set;} ... TOutN PropN {get;set;} } The reasonable question how this can be interpreted by the compiler? Well, for me it is just the sortcut for two structurally similar classes: public sealed class Foo<Person> { string Prop1 {get;set;} int Prop2 {get;set;} ... double PropN {get;set;} } public sealed class Foo<Car> { int Prop1 {get;set;} int Prop2 {get;set;} ... Price PropN {get;set;} } But besides this we could imaging some update of the Foo<: public class Foo<TIn> with map < [TIn : Person -> TOut1 : string, TOut2 : int, ..., TOutN : double ] [TIn : Car -> TOut1 : int, TOut2 :int, ..., TOutN : Price ] > { TOut1 Prop1 {get;set;} TOut2 Prop2 {get;set;} ... TOutN PropN {get;set;} public override string ToString() { return string.Format("prop1={0}, prop2={1},...propN={N-1}, Prop1, Prop2,...,PropN); } } This all can seem quite superficial but the idea came when I was designing the messages for our system. The very first class. Many messages with the same structrue should be discriminated by the EntityType. So the question is whether such construct exist in any programming language?

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  • Ten Things You Should Avoid Having on Your Website

    Website layouts can actually show to the audience what type of person you are. If you come across a nice and simple website, it goes to show that you?re a neat and tidy person. It also let the audien... [Author: Amelia Foo - Web Design and Development - April 28, 2010]

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  • Relevance of Performance Based SEO Services

    It was an interesting conversation between a Search Engine Optimization (SEO) business development person and a prospective customer. The prospective customer had scoffed at the SEO person's sales pitch about them offering "Performance Based SEO Services", saying Performance Based Services of any kind in life is not a luxury but a fundamental requirement.

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  • Connection reset by peer: mod_fcgid: error reading data from FastCGI server Issues

    - by user145857
    Help is greatly needed for our server. We are experiencing random "Connection reset by peer: mod_fcgid: error reading data from FastCGI server" errors which cause a 500 internal server error. If the page is then reloaded it loads normally as it should. We are running MPM Worker with mod FCGID to handle PHP. We had APC cache enabled but disabled it recently to see if it would fix the problem, but the random mod FCGID errors are still continuing. No other opcode cache is active now. Our settings are below: <IfModule worker.c> MinSpareThreads 25 MaxSpareThreads 150 ThreadsPerChild 25 ThreadLimit 100 ServerLimit 700 MaxClients 700 MaxRequestsPerChild 0 </IfModule> <IfModule mod_fcgid.c> FcgidMaxRequestLen 1073741824 FcgidMaxRequestsPerProcess 2000 FcgidMaxProcessesPerClass 100 FcgidMinProcessesPerClass 0 FcgidConnectTimeout 300 FcgidIOTimeout 900 FcgidFixPathinfo 1 FcgidIdleTimeout 300 FcgidIdleScanInterval 120 FcgidBusyTimeout 300 FcgidBusyScanInterval 120 FcgidErrorScanInterval 12 FcgidZombieScanInterval 12 FcgidProcessLifeTime 3600 </IfModule> The server is a 64 core 2.1 GHZ 94 GB RAM so it has some power. Some of the fcgid timeout settings are higher because we run large reports which take up to 15 minutes. Any help is greatly appreciated! Just to clarify, the random fcgid errors are occurring when a user clicks a page on our site and the 500 error page loads instantly. This is random and occurrs less than 1% of the time but it is still an issue.

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  • Windows XP seemingly out of resources but plenty of free RAM and swap available

    - by Artem Russakovskii
    This one has been bothering me for years and so far I couldn't find an adequate solution. The problem occurs on pretty much every XP install I've done. After opening a variety of programs or the system running existing programs for a while, Windows seemingly runs out of resources, without telling me. There's ALWAYS free RAM. For example, it just happened to me and I had over a gig of free RAM. There are no viruses, spyware, or other nonsense - it is a Windows resource problem, but the question is which resource is it running out of, how does one pinpoint it, and how does one prevent it? Sometimes, this happens after running specific programs - for example, today it happened when I started Photoshop CS4 and Flash CS4 at the same time. I also noticed that restarting The Bat (email client by Ritlabs) seems to get rid of this problem for a while but again, this happens on machines that don't even have The Bat installed. So what does exactly happen? The symptoms are: pressing alt-tab doesn't bring up the list anymore - it just jumps to the next window instantly, very similar to the way Alt-Esc works, however in this case, it's due to not having enough resources to bring up the alt-tab menu random programs would randomly crash, citing random errors, out of memory errors, system resources, inabilities to do system calls, etc. random programs would start missing random parts - for example, Firefox top menus might disappear, pull up partial selections, or not pull up anymore altogether. IE might lose a few of its toolbars. Some programs might fail to redraw or would just plain go gray where the UI used to be. Windows itself never complains about running out of RAM, virtual memory, or anything at all, yet it's running out of something. The only clue I was able to find and apply the fix today was this Desktop Heap Limitation. I haven't confirmed the fix working as not enough time passed. In the meantime, what are everyone's thoughts?

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  • Falsification of an email sent from lotus notes

    - by thejumper
    I needed from a person an important email with an attachment (I give the person a fictious name here: Name familyname) . The person sent me an email in the format below (I changed the content but respected the format). In the email he sent me there is two parts, first below the email he sent, and after that above the answer he received. I told the person that he didn't give me the true information because the first part of the email is falsified. Please tell me what you think. Thanks a lot. From: abc efg To: Name familyname Date: 2012-03-09 12:14 AM Subject: Lorem ipsum dolor Nam dictum feugiat neque, euismod convallis mi euismod ut. Mauris at vulputate enim. Nunc posuere tortor vitae justo volutpat luctus. Sed ut ligula id magna dictum blandit id vitae erat. Nunc dignissim eleifend vulputate. 2012/3/4 Name familyname Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce aliquam ligula in elit blandit porta. Vestibulum facilisis, elit ut aliquam euismod, erat elit tempor mi, et pulvinar velit neque ac nibh. Nullam fringilla viverra erat sed laoreet. Aenean elementum enim ac elit ultricies luctus. Name Adress. Tel. Thanks for your help.

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  • Pivot Table grand total across columns

    - by Jon
    I'm using Excel 2010 and Power Pivot. I'm trying to calculate confidence and velocity for a development team. I'm extracting some information from our time and defect system each day and building a data set. What I need to do with Excel is do the calculations. So each day I add to my data set 1 row per task in the current project, estimate for that task and the time spent on that task. What I want to calculate is the estimate/actual for each task but also for each person. The trouble is that each day the actual is cumulative so I need to pick out the maximum value for each task. The estimate should remain unchanged. I can make this work at the task level with a calculated measure (=MAX(worked)/MAX(estimate)) but I don't know how to total this up for a person. I need the sum of the max worked for each task. So a dataset might look like: Name Task Estimate Worked N1 T1 3 1 N2 T2 3 1 N3 T3 4 1 N1 T1 3 2 N2 T4 5 1 N3 T3 4 2 N1 T5 1 2 N2 T6 2 3 N3 T7 3 2 What I want to see is for task T1 2 days were worked against an estimate of 3 days - so 2/3. For person N1 I want to see that they worked a total of 4 days against an estimate of 4 days so 4/4. For person N2 they worked 5 days for an estimate of 10 days. Any ideas on how I can achieve this?

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  • Can a website see/know my MAC address even if I use a VPN?

    - by ilhan
    I have searched other results and read many of them but I could not get an enough information. My question is that can a website see my MAC address or can they have an information about that I'm the same person under these conditions: I am using a VPN and I use two IPs: first one is normal one, the second one is the VPN's IP. I use two browsers to hide behind browser fingerprinting. I use both browsers with Incognito Mode. I always use one for normal IP, one for the VPN IP. I do not know that if the website uses cookies or not. But can they collect an enough information to prove that these two identities belong to same person? Is there any other way for them to see that I am the same person? I use different IPs, different browsers and I use both browsers in incognito mode. I even changed one of browsers language to only English. So even if they collect my info from browser, they will see two browsers using different languages. (Addition after edit): So I have changed my IP and browser information and the website can not reach this information anymore to prove that I am the same person using two accounts. Then let's come to the title: Can they see my MAC address? Because I think that it is the last way that they can identify me and my main question is that. I wrote the information above to mention that I changed IPs and I have some precautions to avoid browser fingerprinting (btw my VPN provider already has a service about blocking it). I wrote them because I read similar advices in some related questions but my question is that can they see my MAC address (or anything else that can make me detected) despite all these precautions. And lastly, Is there an extra way to be anonymized that I can do? For example, can my system clock or anything else give an information? Thanks in advance.

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  • SQLAuthority News – Job Interviewing the Right Way (and for the Right Reasons) – Guest Post by Feodor Georgiev

    - by pinaldave
    Feodor Georgiev is a SQL Server database specialist with extensive experience of thinking both within and outside the box. He has wide experience of different systems and solutions in the fields of architecture, scalability, performance, etc. Feodor has experience with SQL Server 2000 and later versions, and is certified in SQL Server 2008. Feodor has written excellent article on Job Interviewing the Right Way. Here is his article in his own language. A while back I was thinking to start a blog post series on interviewing and employing IT personnel. At that time I had just read the ‘Smart and gets things done’ book (http://www.joelonsoftware.com/items/2007/06/05.html) and I was hyped up on some debatable topics regarding finding and employing the best people in the branch. I have no problem with hiring the best of the best; it’s just the definition of ‘the best of the best’ that makes things a bit more complicated. One of the fundamental books one can read on the topic of interviewing is the one mentioned above. If you have not read it, then you must do so; not because it contains the ultimate truth, and not because it gives the answers to most questions on the subject, but because the book contains an extensive set of questions about interviewing and employing people. Of course, a big part of these questions have different answers, depending on location, culture, available funds and so on. (What works in the US may not necessarily work in the Nordic countries or India, or it may work in a different way). The only thing that is valid regardless of any external factor is this: curiosity. In my belief there are two kinds of people – curious and not-so-curious; regardless of profession. Think about it – professional success is directly proportional to the individual’s curiosity + time of active experience in the field. (I say ‘active experience’ because vacations and any distractions do not count as experience :)  ) So, curiosity is the factor which will distinguish a good employee from the not-so-good one. But let’s shift our attention to something else for now: a few tips and tricks for successful interviews. Tip and trick #1: get your priorities straight. Your status usually dictates your priorities; for example, if the person looking for a job has just relocated to a new country, they might tend to ignore some of their priorities and overload others. In other words, setting priorities straight means to define the personal criteria by which the interview process is lead. For example, similar to the following questions can help define the criteria for someone looking for a job: How badly do I need a (any) job? Is it more important to work in a clean and quiet environment or is it important to get paid well (or both, if possible)? And so on… Furthermore, before going to the interview, the candidate should have a list of priorities, sorted by the most importance: e.g. I want a quiet environment, x amount of money, great helping boss, a desk next to a window and so on. Also it is a good idea to be prepared and know which factors can be compromised and to what extent. Tip and trick #2: the interview is a two-way street. A job candidate should not forget that the interview process is not a one-way street. What I mean by this is that while the employer is interviewing the potential candidate, the job seeker should not miss the chance to interview the employer. Usually, the employer and the candidate will meet for an interview and talk about a variety of topics. In a quality interview the candidate will be presented to key members of the team and will have the opportunity to ask them questions. By asking the right questions both parties will define their opinion about each other. For example, if the candidate talks to one of the potential bosses during the interview process and they notice that the potential manager has a hard time formulating a question, then it is up to the candidate to decide whether working with such person is a red flag for them. There are as many interview processes out there as there are companies and each one is different. Some bigger companies and corporates can afford pre-selection processes, 3 or even 4 stages of interviews, small companies usually settle with one interview. Some companies even give cognitive tests on the interview. Why not? In his book Joel suggests that a good candidate should be pampered and spoiled beyond belief with a week-long vacation in New York, fancy hotels, food and who knows what. For all I can imagine, an interview might even take place at the top of the Eifel tower (right, Mr. Joel, right?) I doubt, however, that this is the optimal way to capture the attention of a good employee. The ‘curiosity’ topic What I have learned so far in my professional experience is that opinions can be subjective. Plus, opinions on technology subjects can also be subjective. According to Joel, only hiring the best of the best is worth it. If you ask me, there is no such thing as best of the best, simply because human nature (well, aside from some physical limitations, like putting your pants on through your head :) ) has no boundaries. And why would it have boundaries? I have seen many curious and interesting people, naturally good at technology, though uninterested in it as one  can possibly be; I have also seen plenty of people interested in technology, who (in an ideal world) should have stayed far from it. At any rate, all of this sums up at the end to the ‘supply and demand’ factor. The interview process big-bang boils down to this: If there is a mutual benefit for both the employer and the potential employee to work together, then it all sorts out nicely. If there is no benefit, then it is much harder to get to a common place. Tip and trick #3: word-of-mouth is worth a thousand words Here I would just mention that the best thing a job candidate can get during the interview process is access to future team members or other employees of the new company. Nowadays the world has become quite small and everyone knows everyone. Look at LinkedIn, look at other professional networks and you will realize how small the world really is. Knowing people is a good way to become more approachable and to approach them. Tip and trick #4: Be confident. It is true that for some people confidence is as natural as breathing and others have to work hard to express it. Confidence is, however, a key factor in convincing the other side (potential employer or employee) that there is a great chance for success by working together. But it cannot get you very far if it’s not backed up by talent, curiosity and knowledge. Tip and trick #5: The right reasons What really bothers me in Sweden (and I am sure that there are similar situations in other countries) is that there is a tendency to fill quotas and to filter out candidates by criteria different from their skill and knowledge. In job ads I see quite often the phrases ‘positive thinker’, ‘team player’ and many similar hints about personality features. So my guess here is that discrimination has evolved to a new level. Let me clear up the definition of discrimination: ‘unfair treatment of a person or group on the basis of prejudice’. And prejudice is the ‘partiality that prevents objective consideration of an issue or situation’. In other words, there is not much difference whether a job candidate is filtered out by race, gender or by personality features – it is all a bad habit. And in reality, there is no proven correlation between the technology knowledge paired with skills and the personal features (gender, race, age, optimism). It is true that a significantly greater number of Darwin awards were given to men than to women, but I am sure that somewhere there is a paper or theory explaining the genetics behind this. J This topic actually brings to mind one of my favorite work related stories. A while back I was working for a big company with many teams involved in their processes. One of the teams was occupying 2 rooms – one had the team members and was full of light, colorful posters, chit-chats and giggles, whereas the other room was dark, lighted only by a single monitor with a quiet person in front of it. Later on I realized that the ‘dark room’ person was the guru and the ultimate problem-solving-brain who did not like the chats and giggles and hence was in a separate room. In reality, all severe problems which the chatty and cheerful team members could not solve and all emergencies were directed to ‘the dark room’. And thus all worked out well. The moral of the story: Personality has nothing to do with technology knowledge and skills. End of story. Summary: I’d like to stress the fact that there is no ultimately perfect candidate for a job, and there is no such thing as ‘best-of-the-best’. From my personal experience, the main criteria by which I measure people (co-workers and bosses) is the curiosity factor; I know from experience that the more curious and inventive a person is, the better chances there are for great achievements in their field. Related stories: (for extra credit) 1) Get your priorities straight. A while back as a consultant I was working for a few days at a time at different offices and for different clients, and so I was able to compare and analyze the work environments. There were two different places which I compared and recently I asked a friend of mine the following question: “Which one would you prefer as a work environment: a noisy office full of people, or a quiet office full of faulty smells because the office is rarely cleaned?” My friend was puzzled for a while, thought about it and said: “Hmm, you are talking about two different kinds of pollution… I will probably choose the second, since I can clean the workplace myself a bit…” 2) The interview is a two-way street. One time, during a job interview, I met a potential boss that had a hard time phrasing a question. At that particular time it was clear to me that I would not have liked to work under this person. According to my work religion, the properly asked question contains at least half of the answer. And if I work with someone who cannot ask a question… then I’d be doing double or triple work. At another interview, after the technical part with the team leader of the department, I was introduced to one of the team members and we were left alone for 5 minutes. I immediately jumped on the occasion and asked the blunt question: ‘What have you learned here for the past year and how do you like your job?’ The team member looked at me and said ‘Nothing really. I like playing with my cats at home, so I am out of here at 5pm and I don’t have time for much.’ I was disappointed at the time and I did not take the job offer. I wasn’t that shocked a few months later when the company went bankrupt. 3) The right reasons to take a job: personality check. A while back I was asked to serve as a job reference for a coworker. I agreed, and after some weeks I got a phone call from the company where my colleague was applying for a job. The conversation started with the manager’s question about my colleague’s personality and about their social skills. (You can probably guess what my internal reaction was… J ) So, after 30 minutes of pouring common sense into the interviewer’s head, we finally agreed on the fact that a shy or quiet personality has nothing to do with work skills and knowledge. Some years down the road my former colleague is taking the manager’s position as the manager is demoted to a different department. Reference: Feodor Georgiev, Pinal Dave (http://blog.SQLAuthority.com) Filed under: PostADay, Readers Contribution, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Computer Networks UNISA - Chap 12 &ndash; Networking Security

    - by MarkPearl
    After reading this section you should be able to Identify security risks in LANs and WANs and design security policies that minimize risks Explain how physical security contributes to network security Discuss hardware and design based security techniques Understand methods of encryption such as SSL and IPSec, that can secure data in storage and in transit Describe how popular authentication protocols such as RADIUS< TACACS,Kerberos, PAP, CHAP, and MS-CHAP function Use network operating system techniques to provide basic security Understand wireless security protocols such as WEP, WPA and 802.11i Security Audits Before spending time and money on network security, examine your networks security risks – rate and prioritize risks. Different organizations have different levels of network security requirements. Security Risks Not all security breaches result from a manipulation of network technology – there are human factors that can play a role as well. The following categories are areas of considerations… Risks associated with People Risks associated with Transmission and Hardware Risks associated with Protocols and Software Risks associated with Internet Access An effective security policy A security policy identifies your security goals, risks, levels of authority, designated security coordinator and team members, responsibilities for each team member, and responsibilities for each employee. In addition it specifies how to address security breaches. It should not state exactly which hardware, software, architecture, or protocols will be used to ensure security, nor how hardware or software will be installed and configured. A security policy must address an organizations specific risks. to understand your risks, you should conduct a security audit that identifies vulnerabilities and rates both the severity of each threat and its likelihood of occurring. Security Policy Content Security policy content should… Policies for each category of security Explain to users what they can and cannot do and how these measures protect the networks security Should define what confidential means to the organization Response Policy A security policy should provide for a planned response in the event of a security breach. The response policy should identify the members of a response team, all of whom should clearly understand the the security policy, risks, and measures in place. Some of the roles concerned could include… Dispatcher – the person on call who first notices the breach Manager – the person who coordinates the resources necessary to solve the problem Technical Support Specialist – the person who focuses on solving the problem Public relations specialist – the person who acts as the official spokesperson for the organization Physical Security An important element in network security is restricting physical access to its components. There are various techniques for this including locking doors, security people at access points etc. You should identify the following… Which rooms contain critical systems or data and must be secured Through what means might intruders gain access to these rooms How and to what extent are authorized personnel granted access to these rooms Are authentication methods such as ID cards easy to forge etc. Security in Network Design The optimal way to prevent external security breaches from affecting you LAN is not to connect your LAN to the outside world at all. The next best protection is to restrict access at every point where your LAN connects to the rest of the world. Router Access List – can be used to filter or decline access to a portion of a network for certain devices. Intrusion Detection and Prevention While denying someone access to a section of the network is good, it is better to be able to detect when an attempt has been made and notify security personnel. This can be done using IDS (intrusion detection system) software. One drawback of IDS software is it can detect false positives – i.e. an authorized person who has forgotten his password attempts to logon. Firewalls A firewall is a specialized device, or a computer installed with specialized software, that selectively filters or blocks traffic between networks. A firewall typically involves a combination of hardware and software and may reside between two interconnected private networks. The simplest form of a firewall is a packet filtering firewall, which is a router that examines the header of every packet of data it receives to determine whether that type of packet is authorized to continue to its destination or not. Firewalls can block traffic in and out of a LAN. NOS (Network Operating System) Security Regardless of the operating system, generally every network administrator can implement basic security by restricting what users are authorized to do on a network. Some of the restrictions include things related to Logons – place, time of day, total time logged in, etc Passwords – length, characters used, etc Encryption Encryption is the use of an algorithm to scramble data into a format that can be read only by reversing the algorithm. The purpose of encryption is to keep information private. Many forms of encryption exist and new ways of cracking encryption are continually being invented. The following are some categories of encryption… Key Encryption PGP (Pretty Good Privacy) SSL (Secure Sockets Layer) SSH (Secure Shell) SCP (Secure CoPy) SFTP (Secure File Transfer Protocol) IPSec (Internet Protocol Security) For a detailed explanation on each section refer to pages 596 to 604 of textbook Authentication Protocols Authentication protocols are the rules that computers follow to accomplish authentication. Several types exist and the following are some of the common authentication protocols… RADIUS and TACACS PAP (Password Authentication Protocol) CHAP and MS-CHAP EAP (Extensible Authentication Protocol) 802.1x (EAPoL) Kerberos Wireless Network Security Wireless transmissions are particularly susceptible to eavesdropping. The following are two wireless network security protocols WEP WPA

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  • Get and Set property accessors are ‘actually’ methods

    - by nmarun
    Well, they are ‘special’ methods, but they indeed are methods. See the class below: 1: public class Person 2: { 3: private string _name; 4:  5: public string Name 6: { 7: get 8: { 9: return _name; 10: } 11: set 12: { 13: if (value == "aaa") 14: { 15: throw new ArgumentException("Invalid Name"); 16: } 17: _name = value; 18: } 19: } 20:  21: public void Save() 22: { 23: Console.WriteLine("Saving..."); 24: } 25: } Ok, so a class with a field, a property with the get and set accessors and a method. Now my calling code says: 1: static void Main() 2: { 3: try 4: { 5: Person person1 = new Person 6: { 7: Name = "aaa", 8: }; 9:  10: } 11: catch (Exception ex) 12: { 13: Console.WriteLine(ex.Message); 14: Console.WriteLine(ex.StackTrace); 15: Console.WriteLine("--------------------"); 16: } 17: } When the code is run, you’ll get the following exception message displayed: Now, you see the first line of the stack trace where it says that the exception was thrown in the method set_Name(String value). Wait a minute, we have not declared any method with that name in our Person class. Oh no, we actually have. When you create a property, this is what happens behind the screen. The CLR creates two methods for each get and set property accessor. Let’s look at the signature once again: set_Name(String value) This also tells you where the ‘value’ keyword comes from in our set property accessor. You’re actually wiring up a method parameter to a field. 1: set 2: { 3: if (value == "aaa") 4: { 5: throw new ArgumentException("Invalid Name"); 6: } 7: _name = value; 8: } Digging deeper on this, I ran the ILDasm tool and this is what I see: We see the ‘free’ constructor (named .ctor) that the compiler gives us, the _name field, the Name property and the Save method. We also see the get_Name and set_Name methods. In order to compare the Save and the set_Name methods, I double-clicked on the two methods and this is what I see: The ‘.method’ keyword tells that both Save and set_Name are both methods (no guessing there!). Seeing the set_Name method as a public method did kinda surprise me. So I said, why can’t I do a person1.set_Name(“abc”) since it is declared as public. This cannot be done because the get_Name and set_Name methods have an extra attribute called ‘specialname’. This attribute is used to identify an IL (Intermediate Language) token that can be treated with special care by the .net language. So the thumb-rule is that any method with the ‘specialname’ attribute cannot be generally called / invoked by the user (a simple test using intellisense proves this). Their functionality is exposed through other ways. In our case, this is done through the property itself. The same concept gets extended to constructors as well making them special methods too. These so-called ‘special’ methods can be identified through reflection. 1: static void ReflectOnPerson() 2: { 3: Type personType = typeof(Person); 4:  5: MethodInfo[] methods = personType.GetMethods(); 6:  7: for (int i = 0; i < methods.Length; i++) 8: { 9: Console.Write("Method: {0}", methods[i].Name); 10: // Determine whether or not each method is a special name. 11: if (methods[i].IsSpecialName) 12: { 13: Console.Write(" has 'SpecialName' attribute"); 14: } 15: Console.WriteLine(); 16: } 17: } Line 11 shows the ‘IsSpecialName’ boolean property. So a method with a ‘specialname’ attribute gets mapped to the IsSpecialName property. The output is displayed as: Wuhuuu! There they are.. our special guests / methods. Verdict: Getting to know the internals… helps!

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  • How do I prove or disprove "god" objects are wrong?

    - by honestduane
    Problem Summary: Long story short, I inherited a code base and an development team I am not allowed to replace and the use of God Objects is a big issue. Going forward, I want to have us re-factor things but I am getting push-back from the teams who want to do everything with God Objects "because its easier" and this means I would not be allowed to re-factor. I pushed back citing my years of dev experience, that I'm the new boss who was hired to know these things, etc, and so did the third party offshore companies account sales rep, and this is now at the executive level and my meeting is tomorrow and I want to go in with a lot of technical ammo to advocate best practices because I feel it will be cheaper in the long run (And I personally feel that is what the third party is worried about) for the company. My issue is from a technical level, I know its good long term but I'm having trouble with the ultra short term and 6 months term, and while its something I "know" I cant prove it with references and cited resources outside of one person (Robert C. Martin, aka Uncle Bob), as that is what I am being asked to do as I have been told having data from one person and only one person (Robert C Martin) is not good enough of an argument. Question: What are some resources I can cite directly (Title, year published, page number, quote) by well known experts in the field that explicitly say this use of "God" Objects/Classes/Systems is bad (or good, since we are looking for the most technically valid solution)? Research I have already done: I have a number of books here and I have searched their indexes for the use of the words "god object" and "god class". I found that oddly its almost never used and the copy of the GoF book I have for example, never uses it (At least according to the index in front of me) but I have found it in 2 books per the below, but I want more I can use. I checked the Wikipedia page for "God Object" and its currently a stub with little reference links so although I personally agree with that it says, It doesn't have much I can use in an environment where personal experience is not considered valid. The book cited is also considered too old to be valid by the people I am debating these technical points with as the argument they are making is that "it was once thought to be bad but nobody could prove it, and now modern software says "god" objects are good to use". I personally believe that this statement is incorrect, but I want to prove the truth, whatever it is. In Robert C Martin's "Agile Principles, Patterns, and Practices in C#" (ISBN: 0-13-185725-8, hardcover) where on page 266 it states "Everybody knows that god classes are a bad idea. We don't want to concentrate all the intelligence of a system into a single object or a single function. One of the goals of OOD is the partitioning and distribution of behavior into many classes and many function." -- And then goes on to say sometimes its better to use God Classes anyway sometimes (Citing micro-controllers as an example). In Robert C Martin's "Clean Code: A Handbook of Agile Software Craftsmanship" page 136 (And only this page) talks about the "God class" and calls it out as a prime example of a violation of the "classes should be small" rule he uses to promote the Single Responsibility Principle" starting on on page 138. The problem I have is all my references and citations come from the same person (Robert C. Martin), and am from the same single person/source. I am being told that because he is just one guy, my desire to not use "God Classes" is invalid and not accepted as a standard best practice in the software industry. Is this true? Am I doing things wrong from a technical perspective by trying to keep to the teaching of Uncle Bob? God Objects and Object Oriented Programming and Design: The more I think of this the more I think this is more something you learn when you study OOP and its never explicitly called out; Its implicit to good design is my thinking (Feel free to correct me, please, as I want to learn), The problem is I "know" this, but but not everybody does, so in this case its not considered a valid argument because I am effectively calling it out as universal truth when in fact most people are statistically ignorant of it since statistically most people are not programmers. Conclusion: I am at a loss on what to search for to get the best additional results to cite, since they are making a technical claim and I want to know the truth and be able to prove it with citations like a real engineer/scientist, even if I am biased against god objects due to my personal experience with code that used them. Any assistance or citations would be deeply appreciated.

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  • Microsoft TechEd 2010 - Day 2 @ Bangalore

    - by sathya
    Microsoft TechEd 2010 - Day 2 @ Bangalore Today is the day 2 @ Microsoft TechEd 2010. We had lot of technical sessions as usual there were many tracks going on side by side and I was attending the Web simplified track, Which comprised of the following sessions :   Developing a scalable Media Application using ASP.NET MVC - This was a kind of little advanced stuff. Anyways I couldn't understand much because this was not my piece of cake and I havent worked on this before ASP.Net MVC Unplugged - This was really great because this session covered from the basics of MVC showing what is Model,View and Controller and how it worked and the speaker went into the details of the same. Building RESTful Applications with the Open Data Protocol - There were some concepts explained about this from the basics on how to build RESTful Services and it went on till some advanced configurations of the same. Developing Scalable Web Applications with AppFabric Caching - This session showed about the integration of AppFabric with the .Net Web Applications. Instead of using Inproc Sessions, we can use this AppFabric as a substitute for Caching and outofProc Session Storage without writing code and doing a little bit of configurations which brings in High Scalability, performance to our applications. (But unfortunately there were no demos for this session ) Deep Dive : WCF RIA Services - This session was also an interactive one, in this the speaker presented from the basics of WCF and took a Book Store Application as a sample and explained all details concepts on linking with RIA Services   Apart from these sessions, in between there happened some small events in the breaks like Some discussions about Technology, Innovations Music Jokes Mimicry, etc. And on doing all these things, the developers were given some kool gifts / goodies like USBs, T-Shirts, etc. And today I got a chance to do the following certification : (70-562) Microsoft Certified Technology Specialist in .NET 3.5 Web Applications Since I already have an MCTS in .NET 2.0, I wanted to do an MCPD and for doing the same I was required to do an update to my MCTS with the .NET 3.5 framework and I did the same I cleared it and now am an MCTS in .NET 3.5 Web Apps And on doing this I got a T-Shirt and they gave something called Learning $ of worth 30$. And in various stalls for attending each quiz or some game or some referrals we got some Learning $ which we can redeem later based on our Total Learning $. I got 105 $ which i was able to redeem and got a Microsoft Learning BagPack, 1 free Microsoft certification offer, a laptop light and an e-learning content activated. And after all these sessions and small events, we had something called Demo Extravaganza like I mentioned yesterday. This was a great funfilled event with lot of goodies for the attendees. There were some lucky draw which enabled 2 attendees to get Netbooks (Sponsored by Intel) and 1 attendee to get X-box (Sponsored by Citrix). After Choosing the raffle in the lucky draw they kept it on a device called Microsoft Surface which is a kind of big touch screen device and on putting the raffle on that it detected the code of the attendee and said intelligently how many sessions that person has attended and if he has attended more than 5 he got a Netbook and this was coded by a guy called Imran. Apart from they showed demos on : Research by 2 Tamilnadu students from Krishna Arts and Science college, taken 1200 photographs of their college from different angles and put that up in Bing maps using silverlight and linked with Photosynth, which showed a 3d view of their college based on the photos they uploaded Reasearch by Microsoft on Panaramic HD views of the images. One young guy from Microsoft Research showed a demo of this on Srivilliputhur Andal Temple, in Tamil Nadu and its history with a panoramic view of the temple and the near by places with narration of the historical information on the same and with the videos embedded in it with high definition images which we can zoom to a very detailed level. Some Demo on a business app with Silverlight, Business Intelligence (BI) and maps integrated. It showed the sales of a particular product across locations. Some kool demos by 2 geeks who used Robots to show their development talents. 2 Robots fought with each other 2 Robots danced in sync for the A.R. Rehman song Humma Humma... A dream home project by Raman. He is currently using the same in his home too. Robots are controlling his home currently. They showed a video on this. Here are the list of activities that Robot does for him When he reads a book, robot automatically scans that and shows that image of that person in the screen (TV or comp) in front of him. It shows a wikipedia about that person. It says that person is not in linked in. do you want to add him If he sees an IPL Match news in the book and smiles it understands he is interested in that and opens a website related to that and shows the current game and the scorecard. It cooks for him It cleans the room for him whenever he leaves the house when he is doing something if some intruder comes inside his house his computer automatically switches his screen showing the video of the person coming inside. When he wakes up it automatically opens up the system, loads his mails and the news by the side, etc. Some Demos on Microsoft Pivot. This was there in livelabs but it is now available in getpivot.com its a pivoting of the pictorial data based on some categories and filters on the searches that we do. And finally on filling up some feedback forms we got T-Shirts and Microsoft Visual Studio 2010 Training Kit CDs. Whats more on TechEd??? Stay tuned!!! Will update you soon on the other happenings!! PS : I typed a lot of content for more than a hour but I pressed a backspace and it went to the previous page and all my content were lost and I was not able to retrieve the same and I typed everything again.

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  • Is the salt contained in a phpass hash or do you need to salt its input?

    - by Exception e
    phpass is a widely used hashing 'framework'. Is it good practice to salt the plain password before giving it to PasswordHash (v0.2), like so?: $dynamicSalt = $record['salt']; $staticSalt = 'i5ininsfj5lt4hbfduk54fjbhoxc80sdf'; $plainPassword = $_POST['password']; $password = $plainPassword . $dynamicSalt . $staticSalt; $passwordHash = new PasswordHash(8, false); $storedPassword = $passwordHash->HashPassword($password); For reference the phpsalt class: # Portable PHP password hashing framework. # # Version 0.2 / genuine. # # Written by Solar Designer <solar at openwall.com> in 2004-2006 and placed in # the public domain. # # # class PasswordHash { var $itoa64; var $iteration_count_log2; var $portable_hashes; var $random_state; function PasswordHash($iteration_count_log2, $portable_hashes) { $this->itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'; if ($iteration_count_log2 < 4 || $iteration_count_log2 > 31) $iteration_count_log2 = 8; $this->iteration_count_log2 = $iteration_count_log2; $this->portable_hashes = $portable_hashes; $this->random_state = microtime() . getmypid(); } function get_random_bytes($count) { $output = ''; if (is_readable('/dev/urandom') && ($fh = @fopen('/dev/urandom', 'rb'))) { $output = fread($fh, $count); fclose($fh); } if (strlen($output) < $count) { $output = ''; for ($i = 0; $i < $count; $i += 16) { $this->random_state = md5(microtime() . $this->random_state); $output .= pack('H*', md5($this->random_state)); } $output = substr($output, 0, $count); } return $output; } function encode64($input, $count) { $output = ''; $i = 0; do { $value = ord($input[$i++]); $output .= $this->itoa64[$value & 0x3f]; if ($i < $count) $value |= ord($input[$i]) << 8; $output .= $this->itoa64[($value >> 6) & 0x3f]; if ($i++ >= $count) break; if ($i < $count) $value |= ord($input[$i]) << 16; $output .= $this->itoa64[($value >> 12) & 0x3f]; if ($i++ >= $count) break; $output .= $this->itoa64[($value >> 18) & 0x3f]; } while ($i < $count); return $output; } function gensalt_private($input) { $output = '$P$'; $output .= $this->itoa64[min($this->iteration_count_log2 + ((PHP_VERSION >= '5') ? 5 : 3), 30)]; $output .= $this->encode64($input, 6); return $output; } function crypt_private($password, $setting) { $output = '*0'; if (substr($setting, 0, 2) == $output) $output = '*1'; if (substr($setting, 0, 3) != '$P$') return $output; $count_log2 = strpos($this->itoa64, $setting[3]); if ($count_log2 < 7 || $count_log2 > 30) return $output; $count = 1 << $count_log2; $salt = substr($setting, 4, 8); if (strlen($salt) != 8) return $output; # We're kind of forced to use MD5 here since it's the only # cryptographic primitive available in all versions of PHP # currently in use. To implement our own low-level crypto # in PHP would result in much worse performance and # consequently in lower iteration counts and hashes that are # quicker to crack (by non-PHP code). if (PHP_VERSION >= '5') { $hash = md5($salt . $password, TRUE); do { $hash = md5($hash . $password, TRUE); } while (--$count); } else { $hash = pack('H*', md5($salt . $password)); do { $hash = pack('H*', md5($hash . $password)); } while (--$count); } $output = substr($setting, 0, 12); $output .= $this->encode64($hash, 16); return $output; } function gensalt_extended($input) { $count_log2 = min($this->iteration_count_log2 + 8, 24); # This should be odd to not reveal weak DES keys, and the # maximum valid value is (2**24 - 1) which is odd anyway. $count = (1 << $count_log2) - 1; $output = '_'; $output .= $this->itoa64[$count & 0x3f]; $output .= $this->itoa64[($count >> 6) & 0x3f]; $output .= $this->itoa64[($count >> 12) & 0x3f]; $output .= $this->itoa64[($count >> 18) & 0x3f]; $output .= $this->encode64($input, 3); return $output; } function gensalt_blowfish($input) { # This one needs to use a different order of characters and a # different encoding scheme from the one in encode64() above. # We care because the last character in our encoded string will # only represent 2 bits. While two known implementations of # bcrypt will happily accept and correct a salt string which # has the 4 unused bits set to non-zero, we do not want to take # chances and we also do not want to waste an additional byte # of entropy. $itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'; $output = '$2a$'; $output .= chr(ord('0') + $this->iteration_count_log2 / 10); $output .= chr(ord('0') + $this->iteration_count_log2 % 10); $output .= '$'; $i = 0; do { $c1 = ord($input[$i++]); $output .= $itoa64[$c1 >> 2]; $c1 = ($c1 & 0x03) << 4; if ($i >= 16) { $output .= $itoa64[$c1]; break; } $c2 = ord($input[$i++]); $c1 |= $c2 >> 4; $output .= $itoa64[$c1]; $c1 = ($c2 & 0x0f) << 2; $c2 = ord($input[$i++]); $c1 |= $c2 >> 6; $output .= $itoa64[$c1]; $output .= $itoa64[$c2 & 0x3f]; } while (1); return $output; } function HashPassword($password) { $random = ''; if (CRYPT_BLOWFISH == 1 && !$this->portable_hashes) { $random = $this->get_random_bytes(16); $hash = crypt($password, $this->gensalt_blowfish($random)); if (strlen($hash) == 60) return $hash; } if (CRYPT_EXT_DES == 1 && !$this->portable_hashes) { if (strlen($random) < 3) $random = $this->get_random_bytes(3); $hash = crypt($password, $this->gensalt_extended($random)); if (strlen($hash) == 20) return $hash; } if (strlen($random) < 6) $random = $this->get_random_bytes(6); $hash = $this->crypt_private($password, $this->gensalt_private($random)); if (strlen($hash) == 34) return $hash; # Returning '*' on error is safe here, but would _not_ be safe # in a crypt(3)-like function used _both_ for generating new # hashes and for validating passwords against existing hashes. return '*'; } function CheckPassword($password, $stored_hash) { $hash = $this->crypt_private($password, $stored_hash); if ($hash[0] == '*') $hash = crypt($password, $stored_hash); return $hash == $stored_hash; } }

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  • How can * be a safe hashed password?

    - by Exception e
    phpass is a widely used hashing 'framework'. While evaluating phpass' HashPassword I came across this odd method fragment. function HashPassword($password) { // <snip> trying to generate a hash… # Returning '*' on error is safe here, but would _not_ be safe # in a crypt(3)-like function used _both_ for generating new # hashes and for validating passwords against existing hashes. return '*'; } This is the complete phpsalt class: # Portable PHP password hashing framework. # # Version 0.2 / genuine. # # Written by Solar Designer <solar at openwall.com> in 2004-2006 and placed in # the public domain. # # # class PasswordHash { var $itoa64; var $iteration_count_log2; var $portable_hashes; var $random_state; function PasswordHash($iteration_count_log2, $portable_hashes) { $this->itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'; if ($iteration_count_log2 < 4 || $iteration_count_log2 > 31) $iteration_count_log2 = 8; $this->iteration_count_log2 = $iteration_count_log2; $this->portable_hashes = $portable_hashes; $this->random_state = microtime() . getmypid(); } function get_random_bytes($count) { $output = ''; if (is_readable('/dev/urandom') && ($fh = @fopen('/dev/urandom', 'rb'))) { $output = fread($fh, $count); fclose($fh); } if (strlen($output) < $count) { $output = ''; for ($i = 0; $i < $count; $i += 16) { $this->random_state = md5(microtime() . $this->random_state); $output .= pack('H*', md5($this->random_state)); } $output = substr($output, 0, $count); } return $output; } function encode64($input, $count) { $output = ''; $i = 0; do { $value = ord($input[$i++]); $output .= $this->itoa64[$value & 0x3f]; if ($i < $count) $value |= ord($input[$i]) << 8; $output .= $this->itoa64[($value >> 6) & 0x3f]; if ($i++ >= $count) break; if ($i < $count) $value |= ord($input[$i]) << 16; $output .= $this->itoa64[($value >> 12) & 0x3f]; if ($i++ >= $count) break; $output .= $this->itoa64[($value >> 18) & 0x3f]; } while ($i < $count); return $output; } function gensalt_private($input) { $output = '$P$'; $output .= $this->itoa64[min($this->iteration_count_log2 + ((PHP_VERSION >= '5') ? 5 : 3), 30)]; $output .= $this->encode64($input, 6); return $output; } function crypt_private($password, $setting) { $output = '*0'; if (substr($setting, 0, 2) == $output) $output = '*1'; if (substr($setting, 0, 3) != '$P$') return $output; $count_log2 = strpos($this->itoa64, $setting[3]); if ($count_log2 < 7 || $count_log2 > 30) return $output; $count = 1 << $count_log2; $salt = substr($setting, 4, 8); if (strlen($salt) != 8) return $output; # We're kind of forced to use MD5 here since it's the only # cryptographic primitive available in all versions of PHP # currently in use. To implement our own low-level crypto # in PHP would result in much worse performance and # consequently in lower iteration counts and hashes that are # quicker to crack (by non-PHP code). if (PHP_VERSION >= '5') { $hash = md5($salt . $password, TRUE); do { $hash = md5($hash . $password, TRUE); } while (--$count); } else { $hash = pack('H*', md5($salt . $password)); do { $hash = pack('H*', md5($hash . $password)); } while (--$count); } $output = substr($setting, 0, 12); $output .= $this->encode64($hash, 16); return $output; } function gensalt_extended($input) { $count_log2 = min($this->iteration_count_log2 + 8, 24); # This should be odd to not reveal weak DES keys, and the # maximum valid value is (2**24 - 1) which is odd anyway. $count = (1 << $count_log2) - 1; $output = '_'; $output .= $this->itoa64[$count & 0x3f]; $output .= $this->itoa64[($count >> 6) & 0x3f]; $output .= $this->itoa64[($count >> 12) & 0x3f]; $output .= $this->itoa64[($count >> 18) & 0x3f]; $output .= $this->encode64($input, 3); return $output; } function gensalt_blowfish($input) { # This one needs to use a different order of characters and a # different encoding scheme from the one in encode64() above. # We care because the last character in our encoded string will # only represent 2 bits. While two known implementations of # bcrypt will happily accept and correct a salt string which # has the 4 unused bits set to non-zero, we do not want to take # chances and we also do not want to waste an additional byte # of entropy. $itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'; $output = '$2a$'; $output .= chr(ord('0') + $this->iteration_count_log2 / 10); $output .= chr(ord('0') + $this->iteration_count_log2 % 10); $output .= '$'; $i = 0; do { $c1 = ord($input[$i++]); $output .= $itoa64[$c1 >> 2]; $c1 = ($c1 & 0x03) << 4; if ($i >= 16) { $output .= $itoa64[$c1]; break; } $c2 = ord($input[$i++]); $c1 |= $c2 >> 4; $output .= $itoa64[$c1]; $c1 = ($c2 & 0x0f) << 2; $c2 = ord($input[$i++]); $c1 |= $c2 >> 6; $output .= $itoa64[$c1]; $output .= $itoa64[$c2 & 0x3f]; } while (1); return $output; } function HashPassword($password) { $random = ''; if (CRYPT_BLOWFISH == 1 && !$this->portable_hashes) { $random = $this->get_random_bytes(16); $hash = crypt($password, $this->gensalt_blowfish($random)); if (strlen($hash) == 60) return $hash; } if (CRYPT_EXT_DES == 1 && !$this->portable_hashes) { if (strlen($random) < 3) $random = $this->get_random_bytes(3); $hash = crypt($password, $this->gensalt_extended($random)); if (strlen($hash) == 20) return $hash; } if (strlen($random) < 6) $random = $this->get_random_bytes(6); $hash = $this->crypt_private($password, $this->gensalt_private($random)); if (strlen($hash) == 34) return $hash; # Returning '*' on error is safe here, but would _not_ be safe # in a crypt(3)-like function used _both_ for generating new # hashes and for validating passwords against existing hashes. return '*'; } function CheckPassword($password, $stored_hash) { $hash = $this->crypt_private($password, $stored_hash); if ($hash[0] == '*') $hash = crypt($password, $stored_hash); return $hash == $stored_hash; } }

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  • Example: Controlling randomizer using code contracts

    - by DigiMortal
    One cool addition to Visual Studio 2010 is support for code contracts. Code contracts make sure that all conditions under what method is supposed to run correctly are met. Those who are familiar with unit tests will find code contracts easy to use. In this posting I will show you simple example about static contract checking (example solution is included). To try out code contracts you need at least Visual Studio 2010 Standard Edition. Also you need code contracts package. You can download package from DevLabs Code Contracts page. NB! Speakers, you can use the example solution in your presentations as long as you mention me and this blog in your sessions. Solution has readme.txt file that gives you steps to go through when presenting solution in sessions. This blog posting is companion posting for Visual Studio solution referred below. As an example let’s look at the following class. public class Randomizer {     public static int GetRandomFromRange(int min, int max)     {         var rnd = new Random();         return rnd.Next(min, max);     }       public static int GetRandomFromRangeContracted(int min, int max)     {         Contract.Requires(min < max, "Min must be less than max");           var rnd = new Random();         return rnd.Next(min, max);     } } GetRandomFromRange() method returns results without any checking. GetRandomFromRangeContracted() uses one code contract that makes sure that minimum value is less than maximum value. Now let’s run the following code. class Program {     static void Main(string[] args)     {         var random1 = Randomizer.GetRandomFromRange(0, 9);         Console.WriteLine("Random 1: " + random1);           var random2 = Randomizer.GetRandomFromRange(1, 1);         Console.WriteLine("Random 2: " + random2);           var random3 = Randomizer.GetRandomFromRangeContracted(5, 5);         Console.WriteLine("Random 3: " + random3);           Console.WriteLine(" ");         Console.WriteLine("Press any key to exit ...");         Console.ReadKey();     } } As we have not turned on support for code contracts the code runs without any problems and we get no warnings by Visual Studio that something is wrong. Now let’s turn on static checking for code contracts. As you can see then code still compiles without any errors but Visual Studio warns you about possible problems with contracts. Click on image to see it at original size.  When we open Error list and run our application we get the following output to errors list. Note that these messages are not shown immediately. There is little delay between application starting and appearance of these messages. So wait couple of seconds before going out of your mind. Click on image to see it at original size.  If you look at these warnings you can see that warnings show you illegal calls and also contracts against what they are going. Third warning points to GetRandomFromRange() method and shows that there should be also problem that can be detected by contract. Download Code Contracts example VS2010 solution | 30KB

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  • NetLogo 4.1 - implementation of a motorway ( Problem creating collision of cars )

    - by user206019
    Hi there, I am trying to create a simulation of motorway and the behaviour of the drivers in NetLogo. I have some questions that I m struggling to solve. Here is my code: globals [ selected-car ;; the currently selected car average-speed ;; average speed of all the cars look-ahead ] turtles-own [ speed ;; the current speed of the car speed-limit ;; the maximum speed of the car (different for all cars) lane ;; the current lane of the car target-lane ;; the desired lane of the car change? ;; true if the car wants to change lanes patience ;; the driver's current patience max-patience ;; the driver's maximum patience ] to setup ca import-drawing "my_road3.png" set-default-shape turtles "car" crt number_of_cars [ setup-cars ] end to setup-cars set color blue set size .9 set lane (random 3) set target-lane (lane + 1) setxy round random-xcor (lane + 1) set heading 90 set speed 0.1 + random 9.9 set speed-limit (((random 11) / 10) + 1) set change? false set max-patience ((random 50) + 10) set patience (max-patience - (random 10)) ;; make sure no two cars are on the same patch loop [ ifelse any? other turtles-here [ fd 1 ] [ stop ] ;if count turtles-here > 1 ; fd 0.1 ;if ; ;ifelse (any? turtles-on neighbors) or (count turtles-here > 1) ;[ ; ifelse (count turtles-here = 1) ; [ if any? turtles-on neighbors ; [ ; if distance min-one-of turtles-on neighbors [distance myself] > 0.9 ; [stop] ; ] ; ] ; [ fd 0.1 ] ;] ;[ stop ] ] end to go drive end to drive ;; first determine average speed of the cars set average-speed ((sum [speed] of turtles) / number_of_cars) ;set-current-plot "Car Speeds" ;set-current-plot-pen "average" ;plot average-speed ;set-current-plot-pen "max" ;plot (max [speed] of turtles) ;set-current-plot-pen "min" ;plot (abs (min [speed] of turtles) ) ;set-current-plot-pen "selected-car" ;plot ([speed] of selected-car) ask turtles [ ifelse (any? turtles-at 1 0) [ set speed ([speed] of (one-of (turtles-at 1 0))) decelerate ] [ ifelse (look-ahead = 2) [ ifelse (any? turtles-at 2 0) [ set speed ([speed] of (one-of turtles-at 2 0)) decelerate ] [ accelerate if count turtles-at 0 1 = 0 and ycor < 2.5 [lt 90 fd 1 rt 90] ] ] [accelerate if count turtles-at 0 1 = 0 and ycor < 2.5 [lt 90 fd 1 rt 90] ] ] if (speed < 0.01) [ set speed 0.01 ] if (speed > speed-limit) [ set speed speed-limit ] ifelse (change? = false) [ signal ] [ change-lanes ] ;; Control for making sure no one crashes. ifelse (any? turtles-at 1 0) and (xcor != min-pxcor - .5) [ set speed [speed] of (one-of turtles-at 1 0) ] [ ifelse ((any? turtles-at 2 0) and (speed > 1.0)) [ set speed ([speed] of (one-of turtles-at 2 0)) fd 1 ] [jump speed] ] ] tick end ;; increase speed of cars to accelerate ;; turtle procedure set speed (speed + (speed-up / 1000)) end ;; reduce speed of cars to decelerate ;; turtle procedure set speed (speed - (slow-down / 1000)) end to signal ifelse (any? turtles-at 1 0) [ if ([speed] of (one-of (turtles-at 1 0))) < (speed) [ set change? true ] ] [ set change? false ] end ;; undergoes search algorithms to change-lanes ;; turtle procedure show ycor ifelse (patience <= 0) [ ifelse (max-patience <= 1) [ set max-patience (random 10) + 1 ] [ set max-patience (max-patience - (random 5)) ] set patience max-patience ifelse (target-lane = 0) [ set target-lane 1 set lane 0 ] [ set target-lane 0 set lane 1 ] ] [ set patience (patience - 1) ] ifelse (target-lane = lane) [ ifelse (target-lane = 0) [ set target-lane 1 set change? false ] [ set target-lane 0 set change? false ] ] [ ifelse (target-lane = 1) [ ifelse (pycor = 2) [ set lane 1 set change? false ] [ ifelse (not any? turtles-at 0 1) [ set ycor (ycor + 1) ] [ ifelse (not any? turtles-at 1 0) [ set xcor (xcor + 1) ] [ decelerate if (speed <= 0) [ set speed 0.1 ] ] ] ] ] [ ifelse (pycor = -2) [ set lane 0 set change? false ] [ ifelse (not any? turtles-at 0 -1) [ set ycor (ycor - 1) ] [ ifelse (not any? turtles-at 1 0) [ set xcor (xcor + 1) ] [ decelerate if (speed <= 0) [ set speed 0.1 ] ] ] ] ] ] end I know its a bit messy because I am using code from other models from the library. I want to know how to create the collision of the cars. I can't think of any idea. As you notice my agent has almost the same size as the patch (I set it to 0.9 so that you can distinguish the space between 2 cars when they are set next to each other and I round the coordinates so that they are set to the centre of the patch). In my accelerate procedure I set my agent to turn left, move 1, turn right in a loop. I want to know if there's a command that lets me make the agent jump from one lane to the other (to the patch next to it on its left) without making it turn and move. And last, if you notice the code i created the car checks the patch that is next to it on the lane on its left and the patch in front of it and the back of it. So if the 3 patches on its left are empty then it can change lane. The fuzzy part is that when i run the setup and I press Go sometimes (not always) the car goes out of the 3 basic lanes. To understand this I have 7 lanes. The middle one which I don't use which is lane 0. Then there are 3 lanes on top of lane 0 and 3 below it. So the code I am using refers to the upper 3 lanes where I set the cars but for some reason some of the cars change lane and go to lane -3 then -2 and so forth. If someone can give me a tip I would really appreciate it. Thank you in advance. Tip: if you want to try this code in netlogo keep in mind that on interface tab I have 2 buttons one setup and one go as well as 3 sliders with names: number_of_cars , speed-up , slow-down.

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