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• New computer hangs on shutdown/reboot, how to troubleshoot?

  - by Torben Gundtofte-Bruun

  My system is working perfectly but it freezes during shutdown/reboot/suspend/hibernate: All windows and the menu bar disappear but the desktop wallpaper remains. It doesn't even show the shutdown screen (the one with the animated dots) where I could hit ESC and watch the shutdown console text. The system is brand-new and fully updated using Update Manager. How can I determine what is causing the freeze? Is there a log I can investigate? How can I fix this? I see no obvious cause of the freeze. The only USB attachment is a mouse/keyboard; I don't have any external storage attached; and I don't have any programs running (the machine freezes even when doing shutdown right from the login screen). What I've tried so far: Based on other questions (this, this, and this) that suggest some ACPI settings, I've tried sudo shutdown -h now to see whether the shutdown console text display offers any hints, but the system doesn't even get that far - it still freezes while the screen shown the desktop background image, without any toolbars. Only sudo shutdown --force works, but that's not a solution. Editing the grub menu to add acpi=off to the kernel didn't help. I guess there's not much point in trying the other (lesser) ACPI suggestions? Adding noapic to the grub entry had no discernible effect. Adding nolapic instead did something (I had removed the quiet option) - the system managed to continue further with the shutdown, right until the line Checking for running unattended-upgrades: which were the last characters on the screen. I've also checked the system BIOS, especially regarding power options, but didn't see anything out of the ordinary. Switching the BIOS standby setting from S3 to S1 didn't help. The standby setting can't be disabled, and there are no other ACPI-related settings AFAIK. BIOS reset didn't help. Not surprised; hadn't changed anything. I tried going to a virtual console (CtrlAltF1) as suggested by djeikyb and from there did a shutdown -h now and it froze there too, after this console output. I didn't try killing processes one at a time because I'm still too newbie to figure out how to do that. Booting with kernel 2.6.35.22 rather than 2.6.35.25 didn't help. Disabling the Nvidia drivers didn't help. Booting from Live CD (USB stick in fact) didn't help; it freezes the same way. Booting from Live CD, with acpi=off noapic nolapic didn't help either. Neither did just nolapic. So evidently this is not some custom setting in my install, but some sort of basic issue. MemTest competed in 1 hour without errors.

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• Running a program on boot without login, using the screen

  - by configurator

  Preface: I have a server running on an old laptop. The screen is always on with a login prompt, but because its keyboard is in pretty bad shape, I use it exclusively via ssh. The screen is in a good position, though; I want to use it to display a clock and some stats about what my server is doing. I have scripts to display all those things, but I want to always show them on the monitor screen. My question is, how do I get my script (called HUD) to run on /dev/tty1, instead of the login prompt. Hopefully, it should be possible to accept keyboard input as well as display its output, so that it can use the keyboard to show more info where needed in a future version. I'd also like tty2 etc. to remain active as login screens, in face I actually do need to login locally. For a start, I tried creating a script that I can run from ssh to start the HUD. It goes something like this: ( flock -n 9 watch --interval 0.2 --precise --color --notitle --exec /path/to/script & disown ) 9> /var/lock/hud > /dev/tty1 2> /dev/tty1 < /dev/tty1 (I had to use & disown instead of nohup because nohup recognized the tty and redirects output to nohup.out instead.) This sort-of works. However, it has a few issues: It doesn't steal the terminal's keyboard input, so you can't ctrl+c to get out of it (nor change the script to actually use the keyboard input), and if you press enter it show it and scrolls the display, never refreshing it correctly afterwards. Oddly, if I disconnect the ssh session which created it, it stops working and shows a message: exec: No such file or directory. If I reconnect to ssh, it resumes functioning properly. It feels hackish. Is there a better way to do this? How?

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• Ubuntu doesn't "see" external USB Hard Disk

  - by Mina Michael

  It's NTFS. It's USB2. I'm using Ubuntu 13.04. It works perfectly fine on Windows (which excludes cable and hardware problems). I have two Ubuntu computers and it's not detected on either. It's about 500 GB. Edits: Following the first link, I input sudo lsusb in a terminal; before and after connecting the HDD. The difference was Bus 001 Device 012: ID 14cd:6116 Super Top M6116 SATA Bridge. There it is! ("sata bridge" used to appear in a windows notification when I plugged in the HDD in!). ...This means that Ubuntu detects it but is it not mounting it? I tried this: sudo mount /dev/sdb1 /mnt But gives this: mount: special device /dev/sdb1 does not exist I also tried: sudo mount /dev/sdc1 /mnt but it stays with no output forever. I left it in background for about 30 min.s. sudo fdisk -l gives out this: Disk /dev/sda: 160.0 GB, 160041885696 bytes 255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xa42d04a3 Device Boot Start End Blocks Id System /dev/sda1 63 80324 40131 de Dell Utility /dev/sda2 * 80325 102481919 51200797+ 7 HPFS/NTFS/exFAT /dev/sda3 263874558 312580095 24352769 5 Extended /dev/sda4 102481920 263872511 80695296 7 HPFS/NTFS/exFAT /dev/sda5 263874560 310505471 23315456 83 Linux /dev/sda6 310507520 312580095 1036288 82 Linux swap / Solaris Partition table entries are not in disk order Disk /dev/sdc: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x5822aaea Device Boot Start End Blocks Id System /dev/sdc1 2048 976769023 488383488 7 HPFS/NTFS/exFAT The part below "Partition table entries are not in disk order" takes about 5 minutes to appear. The outputs of ls /dev/ | grep sd before and after connecting the HDD: before: sda sda1 sda2 sda3 sda4 sda5 sda6 ,after: sda sda1 sda2 sda3 sda4 sda5 sda6 sdd sdd1 The second output has the lines sdd and sdd1 different from the first one. IT SHOWED THE FILES!! The command sudo mount /dev/sdd1 /mnt worked after I typed in sudo fdisk -l!!! Thanks a million!! :) :)

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• 2D Collision in Canvas - Balls Overlapping When Velocity is High

  - by kushsolitary

  I am doing a simple experiment in canvas using Javascript in which some balls will be thrown on the screen with some initial velocity and then they will bounce on colliding with each other or with the walls. I managed to do the collision with walls perfectly but now the problem is with the collision with other balls. I am using the following code for it: //Check collision between two bodies function collides(b1, b2) { //Find the distance between their mid-points var dx = b1.x - b2.x, dy = b1.y - b2.y, dist = Math.round(Math.sqrt(dx*dx + dy*dy)); //Check if it is a collision if(dist <= (b1.r + b2.r)) { //Calculate the angles var angle = Math.atan2(dy, dx), sin = Math.sin(angle), cos = Math.cos(angle); //Calculate the old velocity components var v1x = b1.vx * cos, v2x = b2.vx * cos, v1y = b1.vy * sin, v2y = b2.vy * sin; //Calculate the new velocity components var vel1x = ((b1.m - b2.m) / (b1.m + b2.m)) * v1x + (2 * b2.m / (b1.m + b2.m)) * v2x, vel2x = (2 * b1.m / (b1.m + b2.m)) * v1x + ((b2.m - b1.m) / (b2.m + b1.m)) * v2x, vel1y = v1y, vel2y = v2y; //Set the new velocities b1.vx = vel1x; b2.vx = vel2x; b1.vy = vel1y; b2.vy = vel2y; } } You can see the experiment here. The problem is, some balls overlap each other and stick together while some of them rebound perfectly. I don't know what is causing this issue. Here's my balls object if that matters: function Ball() { //Random Positions this.x = 50 + Math.random() * W; this.y = 50 + Math.random() * H; //Random radii this.r = 15 + Math.random() * 30; this.m = this.r; //Random velocity components this.vx = 1 + Math.random() * 4; this.vy = 1 + Math.random() * 4; //Random shade of grey color this.c = Math.round(Math.random() * 200); this.draw = function() { ctx.beginPath(); ctx.fillStyle = "rgb(" + this.c + ", " + this.c + ", " + this.c + ")"; ctx.arc(this.x, this.y, this.r, 0, Math.PI*2, false); ctx.fill(); ctx.closePath(); } }

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• Are they asking too much of me?

  - by Tesserex

  Or am I just whining? Background: I work for a "startup," which I put in air quotes because the company has been around for 4 years. We have about 40 employees in three offices, 9 here plus some part time. We have a good amount of investment and bring in about 75% of what we spend (so not profitable just yet.) Standard work week is supposed to be about 60 hours, but they justify that as we have to be online when our international (Taiwan and Vietnam) offices are awake. When I started the job 6 months ago, I spent about a month prototyping an iphone app and did really well on my own. They also found out about my facebook applications and how many users they got. Putting 2 and 2 together (and winding up at -7) they realized 1. I'm independent and innovative (because I was able to use stackoverflow to answer my iOS questions instead of bugging my superiors) and 2. I must have an eye for marketing (since my fb apps grew totally organically without me doing any advertising), and assigned me to a project optimizing adwords campaigns. Today I got reviewed, and then chewed out, by our CEO for not totally rocking this project. Now I thought I was doing ok, but the CEO said the project is stagnant and they're expecting more from me. But since it's a startup, they play loose with job roles and I've had plenty of other things to do in the past three months. Every time I ask what's most important, I get conflicting responses depending who I ask, and the end result is that almost everything has equal priority - high. I could go on about how I don't think adwords is worthwhile for us since our profit margin is so slim, and how we should be trying to improve our website first, but that's not the point. I also have explained to the office director (who originally assigned me the project, not the CEO) that I don't actually know anything about marketing, I'm just a decent programmer, but they think my general smarts will prove capable of tackling this challenge. The CEO also clarified that he wants a more technical and algorithmic approach to the problem. So is there something I can do to address this? Combined with my existing and confusing workload, should I be raising an issue? Or should I do the grown up thing and give it my all, asking for help when I need it and hoping for the best? Sorry if this is very rant-ish.

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• Nails vs Screws (C# List vs Dictionary)

  - by MarkPearl

  General This may sound like a typical noob statement, but I’m finding out in a very real way that just because you have a solution to a problem, doesn’t necessarily mean it is the best solution. This was reiterated to me when a friend of mine suggested I look at using Dictionaries instead of Lists for a particular problem – he was right, I have always just assumed that because lists solved my problem I did not need to look elsewhere. So my new manifesto to counter this ageless problem is as follows… Look for a solution that will logically work Once you have a solution look for possible alternatives Decide why your current solution is the best approach compared to the alternatives If it is.. use it till something better comes along, if it isnt…. change What’s the difference between Lists & Dictionaries Both lists and dictionaries are used to store collections of data. Assume we had the following declarations… var dic = new Dictionary<string, long>(); var lst = new List<long>(); long data;   With a list, you simply add the item to the list and it will add the item to the end of the list. lst.Add(data); With a dictionary, you need to specify some sort of key and the data you want to add so that it can be uniquely identified. dic.Add(uniquekey, data);   Because with a dictionary you now have unique identifier, in the background they provide all sort’s of optimized algorithms to find your associated data. What this means is that if you are wanting to access your data it is a lot faster than a List. So when is it appropriate to use either class? For me, if I can guarantee that each item in my collection will have a unique identifier, then I will use Dictionaries instead of Lists as there is a considerable performance benefit when accessing each data item. If I cannot make this sort of guarantee, then by default I will use a list. I know this is all really basic, and I hope I haven’t missed some fundamental principle… If anyone would like to add their 2 cents, please feel free to do so…

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• How to appear very professional on my first freelance project?

  - by iamserious

  I need some help on appearing very professional on my first freelance project. How / What should you do to achieve this? Background: I started as a full time web developer 18 months ago, two promotions later I am now a senior software engineer. I've never had any problems with designing / developing / coding a complicated system. I thought I could use some help for Christmas and I started bidding for a project and now I have one - from a very reputable lawyers association in London. I have no problem dealing with the actual implementation of the system, but I have no idea how to appear professional throughout the whole process. About the project: This lawyers association are starting a distant training courses and in addition to having a website to show off all their clients etc, they want a students area where their students would log in, download course materials allocated to them etc.. and an admin section where they assign courses to students / create new ones / upload materials etc.. Questions breakdown: 1) How should I start with the requirement gathering? Is using scrum a good idea, or should I use something like Volere Template - and what should I do with it? should I submit a copy to the client etc.. 2) How often should I meet the client? Would once a fortnight would be good? 3) What are the processes / protocols that I need to follow so that they would be satisfied with me and think that I am very professional 4) How much should I charge for the product? 5) How should I get a quote / contract / receipt for the whole project? 6) What are the steps that professional freelancers go through, during the life cycle of a project? My Research so far Looking at How much should I charge doesn't help.. I live in London, zone 1, though I have no idea how much a project of this size would cost. Help on this would be appreciated. How to be professional articles talks about the work / time management etc and not the actual process, what would real people do etc.. it's like academia theory, but not practical. If this needs revising, please let me know, do not close it because of whatever reason, I will edit the question or details to fit the needs. Thanks for reading a lengthy question.

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• Reasons to Use a VM For Development

  - by George Stocker

  Background: I work at a start-up company, where one team uses Virtual Machines to connect to a remote server to do their development, and another team (the team I'm on) uses local IIS/SQL Server 2005/Visual Studio installations to conduct work. Team VM is located about 1000 miles from Team Non-VM, and the servers the VMs run off of are located near Team VM (Latency, for those that are wondering, is about 50ms). A person high in the company is pushing for Team Non-VM to use virtual machines for programming, development, and testing. The latter point we agree on -- we want Virtual Machines to test configurations and various aspects of the web application in a 'clean' state. The Problem: What we don't agree on is having developers using RDP to connect to a desktop remotely that contains Visual Studio, SQL Server, and IIS to do the same development we could do locally on our laptops. I've tried the VM set-up, and besides the color issue, there is a latency issue that is rather noticeable, not to mention that since we're a start-up, a good number of employees work from home on occasion with our work laptops, and this move would cut off the laptops. They'd be turned in. Reasons to Use Remote VMs for Development (Not Testing!): Here are the stated reasons that this person wants us to use VMs: They work for TeamVM. They keep the source code "safe". If we want to work from home, we could just use our home PCs. Licenses (I don't know what the argument is, only that it's been used). Reasons not to use Remote VMs for Development: Here are the stated reasons why we don't want to use VMs: We like working from home. We get a lot done on our own time. We're not going to use our Home PCs to do work related stuff. The Latency is noticeable. Support for the VMs (if they go down, or if we need a new VM) takes a while. We don't have administrative privileges on the VM, and are unable to change settings as needed. What I'm looking for from the community is this: What reasons would you give for not using VMs for development? Keep in mind these are remote VMs -- this isn't a VM running on a local desktop. It's using the laptop (or a desktop) as a thin client for a remote VM. Also, on the other side of the coin: Is there something we're missing that makes VMs more palatable for development? Edit: I think 'safe' is used in term of corporate espionage, or more correctly if the Laptop gets stolen, the person who stole would have access to our source code. The former (as we've pointed out, is always going to be a possibility -- companies stop that with litigation, there isn't a technical solution (so far as I can see)). The latter point is ( though I don't know its usefulness in a corporate scenario) mitigated by Truecrypt'ing the entire volume.

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• PBCS Hyperion Planning in the Cloud Implementation Workshop

  - by Mike.Hallett(at)Oracle-BI&EPM

  Normal 0 false false false EN-GB X-NONE X-NONE MicrosoftInternetExplorer4 Oracle Planning and Budgeting Cloud Service (PBCS) opens up opportunities for organizations of all sizes to streamline planning and forecasting, accelerate deployment, and reduce costs. This one-day in-person workshop is delivered by Oracle Development (free to OPN member partners), and will cover the handoff from selling-to-implementing of PBCS. Although the basic building blocks are the same as with on-premises Planning, there is a paradigm shift when it comes to selling and implementing a Cloud Service solution. The value proposition behind Oracle Planning and Budgeting Cloud Service is all about the deployment model, how it’s sold and how it gets implemented – simplicity, fast adoption and flexible deployment, without sacrificing first-class functionality. To be successful, the entire cycle from sales to implementation should consistently support this value proposition to your clients. This training event is for OPN member partners whose business roles involve presales, implementation consulting, and support. This workshop briefly reviews the sales approach, as background, with emphasis on partner sales support. The main objective is to learn what is needed to successfully implement Oracle Planning and Budgeting Cloud Service once the sales hand off is made – how to leverage your current Hyperion Planning knowledge and use the features designed specifically to build out a Cloud Service solution. This Workshop is being offered at three locations for partners from all countries in EMEA: June 24, 2014: Kista, Sweden June 26, 2014: Reading, United Kingdom June 29-30, 2014 (split days): Dubaï, United Arab Emirates To get more information, to check pre-requisites, and to register, click here. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

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• If most of team can't follow the architecture, what do you do?

  - by Chris

  Hi all, I'm working on a greenfields project with two other developers. We're all contractors, and myself and one other just started working on the project while the orginal one has been doing most of the basic framework coding. In the past month, my fellow programmer and I have been just frustrated by the design descisions done by our co-worker. Here's a little background information: The application at face value appeared to be your standard n-layered web application using C# on the 3.5 framework. We have a data layer, business layer and a web interface. But as we got deeper into the project we found some very interesting things that have caused us some troubles. There is a custom data access sqlHelper type base which only accepts dictionary key/valued entries and returns only data tables. There are no entity objects, but there are some massive objects which do everything and then are tossed into session for persitance. The general idea is that the pages (.aspx) don't do anything, while the controls (.ascx) do everything. The general flow is that a client clicks on a button, which goes to a user control base which passes a process request to the 'BLL' class which goes to the page processor, which then goes to a getControlProcessor, which at last actually processes the request. The request itself is made up of a dictionary which is passing a string valued method name, stored procedure name, a control name and possibly a value. All switching of the processing is done by comparing the string values of the control names and method names. Pages are linked together via a common header control that uses a combination of javascript and tables to create a hyperlink effect. And as I found out yesterday, a simple hyperlink between one page and another does not work because of the need to have quite a bit of information in session to determine which control to display on a page. My fellow programmer and I both believe that this is a strange and uncommon approach to web application development. Both of us have been in this business for over five years and neither of us have seen this approach. My question is this, how would we approach our co-worker and voice our concerns and what should we do if he does not want to accept the criteic? We both do not want to insult the work that has been done, but feel that going forward will create a nightmare for development. Thanks for your comments.

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• What HTML and CSS markup is best for SEO for a list of questions (like on Stack Exchange sites)

  - by Oleg9

  On the StackOverflow a question block (in the q-list on the index page and so on) represented by the following html code: <div class="question-summary narrow tagged-interesting" id="question-summary-19832613"> <div onclick="window.location.href='/questions/19832613/how-to-display-only-transit-routesfor-trains-in-google-maps-api'" class="cp"> <div class="votes"> <div class="mini-counts">0</div> <div>votes</div> </div> <div class="status unanswered"> <div class="mini-counts">0</div> <div>answers</div> </div> <div class="views"> <div class="mini-counts">3</div> <div>views</div> </div> </div> <div class="summary"> <h3>...</h3> <div class="tags t-javascript t-google-maps t-google t-google-maps-api-3"> </div> <div class="started"> <a href="/questions/19832613/how-to-display-only-transit-routesfor-trains-in-google-maps-api" class="started-link"><span title="2013-11-07 09:52:29Z" class="relativetime">1 min ago</span></a> <a href="/users/1309392/shirish">Shirish</a> <span class="reputation-score" title="reputation score " dir="ltr">189</span> </div> </div> </div> It uses float positioning. My questions is: Would use of css styled tables be a better choice? (It's a table, isn't it?) Or it just depends on what are you prefer to use and doesn't affect the technical side (search engines or something)? The background information (such as number of views, votes etc.) comes first in the code. And I know that search engines have a limit at viewing each page. So would it better to place div's depending on their importance and then markup them on the page using css methods (like negative margins and absolute positioning)? Or it isn't so important in this instance?

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• Android - Force Close - Null Pointer on Canvas?

  - by user22241

  Please bear with me. I have a very odd problem. Basically, my app so far, has 3 activities (a main splash screen, an 'options/menu' screen and the main app). If I follow the very specific steps oulined below, I get a 'null pointer exception' in the 2nd activity) and the app force closes...... Here are the steps: Start the app (a game based on Surfaceview), tap through to the third activity so the game is running, then hit the home key so the game is paused and put to the background, the activity/app is ended through DDMS in the SDK then restarted on the device (all OK so far), now if I hit the back key on the device twice in quick succession, it happens. All other sequence of events is fine, even to the point of pressing the back key, waiting for the previous activity to show, then hitting back again - all OK. Only when the back key is pressed twice in quick succession following all the above steps does the problem occur. I'm assuming that the canvas isn't ready as it's showing as 'null' when this happens, but I'm not sure why this is happening as surely it's happening when I'm trying to go back to activity 1, but the logcat shows the error in activity 2. if I stop the activity running my 'doDraw' method (which referenced the canvas), then all is OK - so I can safely assume it is the canvas causing the problem. Also, if I skip my first activity (which is a very basic full-screen button which just displays a splashscreen and waits for the user to tap the screen), and make my 2nd activity the launch activity, again, it is OK. this is the part of the code that I think is probably relevant: @Override public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) { vheight = this.getHeight(); vwidth = this.getWidth(); } @Override public void surfaceCreated(SurfaceHolder holder) { vheight = this.getHeight(); vwidth = this.getWidth(); this.viewWidth = vwidth; this.viewHeight = vheight; if (runthread==false){ if (preThread.getState()==Thread.State.TERMINATED){ preThread = new OptionsThread(thisholder, thiscontext, thishandler); } preThread.setRunning(true); preThread.start();} } @Override public void surfaceDestroyed(SurfaceHolder holder) { preThread.setRunning(false); //Stop the loop boolean retry = true; //Stop the thread while (retry) { try { preThread.join(); retry = false; } catch (InterruptedException e) { } } Thank you all for any help you can offer

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• Getting started with object detection - Image segmentation algorithm

  - by Dev Kanchen

  Just getting started on a hobby object-detection project. My aim is to understand the underlying algorithms and to this end the overall accuracy of the results is (currently) more important than actual run-time. I'm starting with trying to find a good image segmentation algorithm that provide a good jump-off point for the object detection phase. The target images would be "real-world" scenes. I found two techniques which mirrored my thoughts on how to go about this: Graph-based Image Segmentation: http://www.cs.cornell.edu/~dph/papers/seg-ijcv.pdf Contour and Texture Analysis for Image Segmentation: http://www.eng.utah.edu/~bresee/compvision/files/MalikBLS.pdf The first one was really intuitive to understand and seems simple enough to implement, while the second was closer to my initial thoughts on how to go about this (combine color/intensity and texture information to find regions). But it's an order of magnitude more complex (at least for me). My question is - are there any other algorithms I should be looking at that provide the kind of results that these two, specific papers have arrived at. Are there updated versions of these techniques already floating around. Like I mentioned earlier, the goal is relative accuracy of image segmentation (with an eventual aim to achieve a degree of accuracy of object detection) over runtime, with the algorithm being able to segment an image into "naturally" or perceptually important components, as these two algorithms do (each to varying extents). Thanks! P.S.1: I found these two papers after a couple of days of refining my search terms and learning new ones relevant to the exact kind of techniques I was looking for. :) I have just about reached the end of my personal Google creativity, which is why I am finally here! Thanks for the help. P.S.2: I couldn't find good tags for this question. If some relevant ones exist, @mods please add them. P.S.3: I do not know if this is a better fit for cstheory.stackexchange (or even cs.stackexchange). I looked but cstheory seems more appropriate for intricate algorithmic discussions than a broad question like this. Also, I couldn't find any relevant tags there either! But please do move if appropriate.

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• Trying to use stencils in 2D while retaining layer depth

  - by Steve

  This is a screen of what's going on just so you can get a frame of reference. http://i935.photobucket.com/albums/ad199/fobwashed/tilefloors.png The problem I'm running into is that my game is slowing down due to the amount of texture swapping I'm doing during my draw call. Since walls, characters, floors, and all objects are on their respective sprite sheet containing those types, per tile draw, the loaded texture is swapping no less than 3 to 5+ times as it cycles and draws the sprites in order to layer properly. Now, I've tried throwing all common objects together into their respective lists, and then using layerDepth drawing them that way which makes things a lot better, but the new problem I'm running into has to do with the way my doors/windows are drawn on walls. Namely, I was using stencils to clear out a block on the walls that are drawn in the shape of the door/window so that when the wall would draw, it would have a door/window sized hole in it. This is the way my draw was set up for walls when I was going tile by tile rather than grouped up common objects. first it would check to see if a door/window was on this wall. If not, it'd skip all the steps and just draw normally. Otherwise end the current spriteBatch Clear the buffers with a transparent color to preserve what was already drawn start a new spritebatch with stencil settings draw the door area end the spriteBatch start a new spritebatch that takes into account the previously set stencil draw the wall which will now be drawn with a hole in it end that spritebatch start a new spritebatch with the normal settings to continue drawing tiles In the tile by tile draw, clearing the depth/stencil buffers didn't matter since I wasn't using any layerDepth to organize what draws on top of what. Now that I'm drawing from lists of common objects rather than tile by tile, it has sped up my draw call considerably but I can't seem to figure out a way to keep the stencil system to mask out the area a door or window will be drawn into a wall. The root of the problem is that when I end a spriteBatch to change the DepthStencilState, it flattens the current RenderTarget and there is no longer any depth sorting for anything drawn further down the line. This means walls always get drawn on top of everything regardless of depth or positioning in the game world and even on top of each other as the stencil has to happen once for every wall that has a door or window. Does anyone know of a way to get around this? To boil it down, I need a way to draw having things sorted by layer depth while also being able to stencil/mask out portions of specific sprites.

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• How can we unify business goals and technical goals?

  - by BAM

  Some background I work at a small startup: 4 devs, 1 designer, and 2 non-technical co-founders, one who provides funding, and the other who handles day-to-day management and sales. Our company produces mobile apps for target industries, and we've gotten a lot of lucky breaks lately. The outlook is good, and we're confident we can make this thing work. One reason is our product development team. Everyone on the team is passionate, driven, and has a great sense of what makes an awesome product. As a result, we've built some beautiful applications that we're all proud of. The other reason is the co-founders. Both have a brilliant business sense (one actually founded a multi-million dollar company already), and they have close ties in many of the industries we're trying to penetrate. Consequently, they've brought in some great business and continue to keep jobs in the pipeline. The problem The problem we can't seem to shake is how to bring these two awesome advantages together. On the business side, there is a huge pressure to deliver as fast as possible as much as possible, whereas on the development side there is pressure to take your time, come up with the right solution, and pay attention to all the details. Lately these two sides have been butting heads a lot. Developers are demanding quality while managers are demanding quantity. How can we handle this? Both sides are correct. We can't survive as a company if we build terrible applications, but we also can't survive if we don't sell enough. So how should we go about making compromises? Things we've done with little or no success: Work more (well, it did result in better quality and faster delivery, but the dev team has never been more stressed out before) Charge more (as a startup, we don't yet have the credibility to justify higher prices, so no one is willing to pay) Extend deadlines (if we charge the same, but take longer, we'll end up losing money) Things we've done with some success: Sacrifice pay to cut costs (everyone, from devs to management, is paid less than they could be making elsewhere. In return, however, we all have creative input and more flexibility and freedom, a typical startup trade off) Standardize project management (we recently started adhering to agile/scrum principles so we can base deadlines on actual velocity, not just arbitrary guesses) Hire more people (we used to have 2 developers and no designers, which really limited our bandwidth. However, as a startup we can only afford to hire a few extra people.) Is there anything we're missing or doing wrong? How is this handled at successful companies? Thanks in advance for any feedback :)

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• Why are MVC & TDD not employed more in game architecture?

  - by secoif

  I will preface this by saying I haven't looked a huge amount of game source, nor built much in the way of games. But coming from trying to employ 'enterprise' coding practices in web apps, looking at game source code seriously hurts my head: "What is this view logic doing in with business logic? this needs refactoring... so does this, refactor, refactorrr" This worries me as I'm about to start a game project, and I'm not sure whether trying to mvc/tdd the dev process is going to hinder us or help us, as I don't see many game examples that use this or much push for better architectural practices it in the community. The following is an extract from a great article on prototyping games, though to me it seemed exactly the attitude many game devs seem to use when writing production game code: Mistake #4: Building a system, not a game ...if you ever find yourself working on something that isn’t directly moving your forward, stop right there. As programmers, we have a tendency to try to generalize our code, and make it elegant and be able to handle every situation. We find that an itch terribly hard not scratch, but we need to learn how. It took me many years to realize that it’s not about the code, it’s about the game you ship in the end. Don’t write an elegant game component system, skip the editor completely and hardwire the state in code, avoid the data-driven, self-parsing, XML craziness, and just code the damned thing. ... Just get stuff on the screen as quickly as you can. And don’t ever, ever, use the argument “if we take some extra time and do this the right way, we can reuse it in the game”. EVER. is it because games are (mostly) visually oriented so it makes sense that the code will be weighted heavily in the view, thus any benefits from moving stuff out to models/controllers, is fairly minimal, so why bother? I've heard the argument that MVC introduces a performance overhead, but this seems to me to be a premature optimisation, and that there'd more important performance issues to tackle before you worry about MVC overheads (eg render pipeline, AI algorithms, datastructure traversal, etc). Same thing regarding TDD. It's not often I see games employing test cases, but perhaps this is due to the design issues above (mixed view/business) and the fact that it's difficult to test visual components, or components that rely on probablistic results (eg operate within physics simulations). Perhaps I'm just looking at the wrong source code, but why do we not see more of these 'enterprise' practices employed in game design? Are games really so different in their requirements, or is a people/culture issue (ie game devs come from a different background and thus have different coding habits)?

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• How are OpenGL ES 1 framebuffers and textures sized?

  - by jens

  I am trying to draw to a texture using a framebuffer using OpenGL ES 1.1 on Android, Java. Afterwords I want to overlay this texture full-screen over my game. In theory, this works like a charm, but somehow the coordinates are off. For testing I drew something at (0,0) with width and height 200, and it partly is off-screen. This is how I create the framebuffer: fb = new int[1]; depthRb = new int[1]; renderTex = new int[1]; gl11ep.glGenFramebuffersOES(1, fb, 0); gl11ep.glGenRenderbuffersOES(1, depthRb, 0); // the depth buffer gl.glGenTextures(1, renderTex, 0);// generate texture gl.glBindTexture(GL10.GL_TEXTURE_2D, renderTex[0]); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_LINEAR); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_S, GL10.GL_REPEAT); gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_WRAP_T, GL10.GL_REPEAT); texBuffer = ByteBuffer.allocateDirect(buf.length*4).order(ByteOrder.nativeOrder()).asIntBuffer(); gl.glTexImage2D(GL10.GL_TEXTURE_2D, 0, GL10.GL_LUMINANCE, texW, texH, 0, GL10.GL_LUMINANCE, GL10.GL_UNSIGNED_BYTE, texBuffer); gl11ep.glBindRenderbufferOES(GL11ExtensionPack.GL_RENDERBUFFER_OES, depthRb[0]); gl11ep.glRenderbufferStorageOES(GL11ExtensionPack.GL_RENDERBUFFER_OES, GL11ExtensionPack.GL_DEPTH_COMPONENT16, texW, texH); Before I draw, I do this: gl11ep.glBindFramebufferOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES, fb[0]); gl.glClearColor(0f, 0f, 0f, 0f); // specify texture as color attachment gl11ep.glFramebufferTexture2DOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES, GL11ExtensionPack.GL_COLOR_ATTACHMENT0_OES, GL10.GL_TEXTURE_2D, renderTex[0], 0); // attach render buffer as depth buffer gl11ep.glFramebufferRenderbufferOES(GL11ExtensionPack.GL_FRAMEBUFFER_OES, GL11ExtensionPack.GL_DEPTH_ATTACHMENT_OES, GL11ExtensionPack.GL_RENDERBUFFER_OES, depthRb[0]); I set texW = 1024 and texH = 512. When rendering this texture fullscreen, with a lightmask (size 200x200) placed at (0, 0) and (texW/2, texH/2). You can see that it seems like the coordinate system doesnt start at (0,0) as that light overlaps the screen and the images are not drawn as squares (my lightcone-texture is a circle, not an ellipse). So, how is the coordinate system of this offscreen-drawn texture defined? Thanks

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• Why occlusion is failing sometimes?

  - by cad

  I am rendering two cubes in the space using XNA 4.0 and occlusion only works from certain angles. Here is what I see from the front angle (everything ok) Here is what I see from behind This is my draw method. Cubes are drawn by serverManager and serverManager1 protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); switch (_gameStateFSM.State) { case GameFSMState.GameStateFSM.INTROSCREEN: spriteBatch.Begin(); introscreen.Draw(spriteBatch); spriteBatch.End(); break; case GameFSMState.GameStateFSM.GAME: spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend); // Text screenMessagesManager.Draw(spriteBatch, firstPersonCamera.cameraPosition, fpsHelper.framesPerSecond); // Camera firstPersonCamera.Draw(); // Servers serverManager.Draw(GraphicsDevice, firstPersonCamera.viewMatrix, firstPersonCamera.projMatrix); serverManager1.Draw(GraphicsDevice, firstPersonCamera.viewMatrix, firstPersonCamera.projMatrix); // Room //roomManager.Draw(GraphicsDevice, firstPersonCamera.viewMatrix); spriteBatch.End(); break; case GameFSMState.GameStateFSM.EXITGAME: break; default: break; } base.Draw(gameTime); fpsHelper.IncrementFrameCounter(); } serverManager and serverManager1 are instances of the same class ServerManager that draws a cube. The draw method for ServerManager is: public void Draw(GraphicsDevice graphicsDevice, Matrix viewMatrix, Matrix projectionMatrix) { cubeEffect.World = Matrix.CreateTranslation(modelPosition); // Set the World matrix which defines the position of the cube cubeEffect.View = viewMatrix; // Set the View matrix which defines the camera and what it's looking at cubeEffect.Projection = projectionMatrix; // Enable textures on the Cube Effect. this is necessary to texture the model cubeEffect.TextureEnabled = true; cubeEffect.Texture = cubeTexture; // Enable some pretty lights cubeEffect.EnableDefaultLighting(); // apply the effect and render the cube foreach (EffectPass pass in cubeEffect.CurrentTechnique.Passes) { pass.Apply(); cubeToDraw.RenderToDevice(graphicsDevice); } } Obviously there is something I am doing wrong. Any hint of where to look? (Maybe z-buffer or occlusion tests?)

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• iPhone app development pricing [closed]

  - by AlexMorley-Finch

  I currently manage a website design and development company that integrates itself with print work too. I've been co manager for a couple of months now, however business is slow at the moment. I got an email today from a potential client asking if we do iPhone app development. Obviously we do not. But, seeing as there aren't many other project on the go at the moment, why not give it a go? Searching Google was my first option. I did a bit of background scrubbing. Discovered that I need certain developer tools etc. This can be arranged easily enough. The reason I came to Stack Exchange is for answers to these questions. I am a competant programmer and have had experience in Java, PHP, JavaScript, C++ and C#. So how long would it take me to come to grips with Objective-C? Assuming an 8 hour working day. Not only the language but also the iPhone interface libraries (if any exist) and other native libraries? The potential client said the app will be a catalogue. So I'm assuming either the data will be pulled online or in some kind of local database. I know the requirements are vague but does anyone have any idea of how mug time this would take? To learn the language, design the architecture and code? 40 Hours? 80 Hours? My final question kind of depends on the first two. But obviously the potential client wants a quote. And I have got no idea how much an app costs. I did some research and found a huge range in differences. The majority of the cost would cone from the time to develops the app! So to summarise. How long would it take me to be comfortable coding Objective-C, taking into consideration my past knowledge? I'm assuming a day or two to fully understand but you really don't know. How long would it take me to develop an app? How much should I charge (approx) for the development of this app?

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• Can Anything be Done to Make Improv (a 1993 Win 3.1 App) handle larger Files?

  - by user75185

  My very favorite spradsheet is Improv, a 1993 Windows 3.1 application. It still puts Excel to shame for building spreadsheets and writing formulas. The only problem is because Improv was written when 1 Meg of RAM was state of the art, it becomes unstable when working with larger spreadsheets and often crashes and/or corrupts the data file. I am working on a project that greatly exceeds Improv's limits. Although it will ultimately require more robust databasing capability, I could save a lot of critical time if I could delay that headache and continue working in Improv for now. To that end, I moved to the only product I could find that comes close, Quantrix, which is nothing more than Improv updated to handle large spreadsheets and utilize today's technologies. The problems with Quantrix are its speed (significantly slower than Improv) and its $1000 price (which I cannot afford). I have already had 3 15 day extensions after the initial 30 day trial, so my time to use Quantrix as a bridge is at its end. Searches for Improv over the years have gotten me nowhere and, not surprisingly after reading some posts on this site, I got nothing for the money and time invested to find a programmer to write code to "fix" this problem. Improv is freely available as "abandonware" at http://vetusware.com/download/LotusImprov2.1/?id=5797 , and the best background info can be found on Wikipedia and at "Moose's Greatest Software Products of All Time - Lotus Improv" http://moosevalley.fhost.com.au/mooses_review_page_lotus_improv.html It is critically urgent for me to focus on analyzing the data asap. Working in a stable Improv would, without question, be the fastest route. To that end, I am looking for answers to the following questions and anything else that might be helpful: 1) Is it lawful to hire someone to fix Improv for my own use? If so, 2) About how much should it cost? 3) About how long should it take? 4) What skills should I be looking for &/or how should a post be worded? 5) Is there a niche site where it should it be posted? 6) What questions can I ask to quickly screen candidates? Since I am not a programmer, I need questions the answers to which leave no room to confuse me, whether intentional or not. For example, what tools or players should someone with an acceptable competency level have knowledge of?

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• password incorrect 3 times + suspected failed update

  - by Cheese

  I have been lurking your site for the past few hours, and have found myself in a bit of a pickle. Visiting my parents, I discover that neither computer, nor laptop work. Long story short, I've got the laptop working, but have completely fudged up the computer. I am a n00b, but I was at least willing to give it a go. The comp originally had ubuntu 11.10 installed, later updated to 12.04. We have cds for both. I do not understand what the initial problem was for my parents, but somehow when I turned on the computer, it worked for me. Soon after, I was nagged to install the latest updates. So, I spent the next half an hour wondering why the updates kept on asking for 11.04 cdroms, until I realised that you could turn off the cdrom necessity. After doing this via console, I installed some of the smaller updates, before being told to do a partial update. This failed a few times, and ended up freezing whilst reinstalling drivers. After a hard restart I continued to type whatever I could find on the forum into the console. At some point, the console started saying that I had 3 incorrect password inputs, and sudo commands stopped altogether. I found another thread discussing this; but people kept on suggesting changing passwords (which I did to no avail) or other things that made use of sudo (which I am locked out of, although I am technically the admin) I found myself somehow on the Ctrl+Alt+F1 console, and after being utterly confused (and Ctrl+AltF5 failing for me), another hard reset occurred. Somewhere along the way I created a USB start up for 14.04, (but this does not seem to work) Now I am left with an admin (and guest) account that log in but have blank screens (with only the desktop background showing) and I can't do anything in the console because I'm locked out. Interestingly, the console now says that I am running 14.04 although all updates said they had failed. Aside from the obvious lessons I have learnt (don't fiddle about in the console when you have no idea what you're doing "Dog wearing safety glasses "I have no idea what I am doing" GIF would be inserted here ) Is there any way I can redeem this almighty muck up? A million thanks for any help!

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• Send raw data to USB parallel port after upgrading to 11.10 oneiric

  - by zaphod

  I have a laser cutter connected via a generic USB to parallel adapter. The laser cutter speaks HPGL, as it happens, but since this is a laser cutter and not a plotter, I usually want to generate the HPGL myself, since I care about the ordering, speed, and direction of cuts and so on. In previous versions of Ubuntu, I was able to print to the cutter by copying an HPGL file directly to the corresponding USB "lp" device. For example: cp foo.plt /dev/usblp1 Well, I just upgraded to Ubuntu 11.10 oneiric, and I can't find any "lp" devices in /dev anymore. D'oh! What's the preferred way to send raw data to a parallel port in Ubuntu? I've tried System Settings Printing + Add, hoping that I might be able to associate my device with some kind of "raw printer" driver and print to it with a command like lp -d LaserCutter foo.plt But my USB to parallel adapter doesn't seem to show up in the list. What I do see are my HP Color LaserJet, two USB-to-serial adapters, "Enter URI", and "Network Printer". Meanwhile, over in /dev, I do see /dev/ttyUSB0 and /dev/ttyUSB1 devices for the 2 USB-to-serial adapters. I don't see anything obvious corresponding to the HP printer (which was /dev/usblp0 prior to the upgrade), except for generic USB stuff. For example, sudo find /dev | grep lp produces no output. I do seem to be able to print to the HP printer just fine, though. The printer setup GUI gives it a device URI starting with "hp:" which isn't much help for the parallel adapter. The CUPS administrator's guide makes it sound like I might need to feed it a device URI of the form parallel:/dev/SOMETHING, but of course if I had a /dev/SOMETHING I'd probably just go on writing to it directly. Here's what dmesg says after I disconnect and reconnect the device from the USB port: [ 924.722906] usb 1-1.1.4: USB disconnect, device number 7 [ 959.993002] usb 1-1.1.4: new full speed USB device number 8 using ehci_hcd And here's how it shows up in lsusb -v: Bus 001 Device 008: ID 1a86:7584 QinHeng Electronics CH340S Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 0 (Defined at Interface level) bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 8 idVendor 0x1a86 QinHeng Electronics idProduct 0x7584 CH340S bcdDevice 2.52 iManufacturer 0 iProduct 2 USB2.0-Print iSerial 0 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 32 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0x80 (Bus Powered) MaxPower 96mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 2 bInterfaceClass 7 Printer bInterfaceSubClass 1 Printer bInterfaceProtocol 2 Bidirectional iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x82 EP 2 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0020 1x 32 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x02 EP 2 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0020 1x 32 bytes bInterval 0 Device Status: 0x0000 (Bus Powered)

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• C Programming arrays, I dont understand how I would go about making this program, If anyone can just guide me through the basic outline please :) [on hold]

  - by Rashmi Kohli

  Problem The temperature of a car engine has been measured, from real-world experiments, as shown in the table and graph below: Time (min) Temperature (oC) 0 20 1 36 2 61 3 68 4 77 5 110 Use linear regression to find the engine’s temperature at 1.5 minutes, 4.3 minutes, and any other time specified by the user. Background In engineering, many times we measure several data points in an experiment, but then we need to predict a value that we have not measured which lies between two measured values, such as the problem statement above. If the relation between the measured parameters seems to be roughly linear, then we can use linear regression to find the relationship between those parameters. In the graph of the problem statement above, the relation seems to be roughly linear. Hence, we can apply linear regression to the above problem. Assuming y {y0, y1, …yn-1} has a linear relation with x {x0, x1, … xn-1}, we can say that: y = mx+b where m and b can be found with linear regression as follows: For the problem in this lab, using linear regression gives us the following line (in blue) compared to the measured curve (in red). As you can see, there is usually a difference between the measured values and the estimated (predicted) values. What linear regression does is to minimize those differences and still give us a straight line (blue). Other methods, such as non-linear regression, are also possible to achieve higher accuracy and better curve fitting. Requirements Your program should first print the table of the temperatures similar to the way it’s printed in the problem statement. It should then calculate the temperature at minute 1.5 and 4.3 and show the answers to the user. Next, it should prompt the user to enter a time in minutes (or -1 to quit), and after reading the user’s specified time it should give the value of the engine’s temperature at that time. It should then go back to the prompt. Hints •Use a one dimensional array to store the temperature values given in the problem statement. •Use functions to separate tasks such as calculating m, calculating b, calculating the temperature at a given time, printing the prompt, etc. You can then give your algorithm as well as you pseudo code per function, as opposed to one large algorithm diagram or one large sequence of pseudo code.

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• Storing a looong lookup table

  - by inquisitive

  Background The product i am working on has a very long lookup-table. the table contains static data and cannot be auto generated. there are about 500 rows and 10 columns. columns have mostly integers and strings. to complicate the matters, there are actually two such tables. every row in table-1 maps to zero-or-more rows in table-2. we use an SQLite database with two tables. the product installer places the SQLite file in the installation directory. the application is written in dot-net and we use ADO to load the data once on startup. now, the lookup table grows. in each release a month, we add about 10 new entries existing entries are adjusted. every release we fine tune existing entries. The problem a team of (10) developers work on the lookup table. Code goes in the SVN, but the little devil the SQLite does not. this prevents multiple developers to work on it. we do take regular backups of the file, but proper versioning is not possible. we never know who did the breaking change. the worse thing is we dont know if there is any change at all. diff'ing databases is tedious if not impossible. the tables are expected to grow quite large in years to come and we would need developers to work in parallel on it. the data is business critical. we need to be able to audit changes made to it. Question What would be a solution for the problems outlines above? one idea was to transform the whole thing to XML and treat it like just another source file. that way SVN can do the versioning and we can work in parallel. but the data shows relational behavior. with XML we loose the unique and foreign-key constraints. also we cant query it with sql like ease. any help here will be appreciated.

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• Encapsulating code in F# (Part 1)

  - by MarkPearl

  I have been looking at F# for a while now and seem a few really interesting samples and snippets on howto’s. This has been great to see the basic outline of the language and the possibilities, however a nagging question in the back of my mind has been what does an F# project look like? How do I code group code in F# so that it can be modularized and brought in and out of a project easily? My Expert F# book has an entire chapter (7) dedicated to this and after browsing the other chapters of the book I decided that this topic was something I really wanted to know more about now! Because of my C# background I keep trying to think in F# of objects. So to try and get a clearer idea of how to do things the F# way I am first going to take a very simplified C# example and try to “translate” it. using System; namespace ConsoleApplication1 { namespace ExampleOfEncapsulationInCSharp { class Program { static void EncapsulatedVariableInAMethod() { int count = 10; Console.WriteLine(count); } static void Main(string[] args) { EncapsulatedVariableInAMethod(); Console.ReadLine(); } } } } From the above example the count integer is encapsulated within EncapsulatedVariableInAMethod method. You couldn’t access the count variable from outside the scope of its parent method but have full access to it within the method. Lets look at my F# equivalent… open System let EncapsulatedVariableInAMethod = let count = 10 Console.WriteLine(count) () EncapsulatedVariableInAMethod Console.ReadLine()   Now, when I first attempted to write the F# code I got stuck… I didn’t have the Console.WriteLine calls but had the following… open System let EncapsulatedVariableInAMethod = let count = 10 EncapsulatedVariableInAMethod Console.ReadLine()   The compiler didn’t like the let before the count = 10. This is because every F# expression must evaluate to a value. If I did not want to make the Console call, I would still need to evaluate the expression to something – and for this reason the Unit Type is provided. I could have done something like…. open System let EncapsulatedVariableInAMethod = let count = 10 () EncapsulatedVariableInAMethod Console.ReadLine()   Which the compiler would be happy with…

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