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• How do you determine whether a website is a scam [closed]

  - by Tom

  What's the best way to determine if a website is a scam. For example, at first sight (no pun intended) the following website seems to be legitimate. But the price of the product is suspiciously low (all the reviews point to an RRP of approximately £1000). http://www.maxiargos.com/index.php/asus-zenbook-ux31e-dh72-13-3-inch-thin-and-light-ultrabook-silver-aluminum.html Another indication is the lack of SSL for the checkout page, and lack of useful information in the WHOIS record. Registration Service Provided By: TMDHOSTING Contact: +1.8665325635 Domain Name: MAXIARGOS.COM Registrant: PrivacyProtect.org Domain Admin ([email protected]) ID#10760, PO Box 16 Note - All Postal Mails Rejected, visit Privacyprotect.org Nobby Beach null,QLD 4218 AU Tel. +45.36946676 Creation Date: 09-Nov-2011 Expiration Date: 09-Nov-2012 Domain servers in listed order: ns1.tmdhosting410.com ns2.tmdhosting410.com Administrative Contact: PrivacyProtect.org Domain Admin ([email protected]) ID#10760, PO Box 16 Note - All Postal Mails Rejected, visit Privacyprotect.org Nobby Beach null,QLD 4218 AU Tel. +45.36946676 Technical Contact: PrivacyProtect.org Domain Admin ([email protected]) ID#10760, PO Box 16 Note - All Postal Mails Rejected, visit Privacyprotect.org Nobby Beach null,QLD 4218 AU Tel. +45.36946676 Billing Contact: PrivacyProtect.org Domain Admin ([email protected]) ID#10760, PO Box 16 Note - All Postal Mails Rejected, visit Privacyprotect.org Nobby Beach null,QLD 4218 AU Tel. +45.36946676

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• 12.10 upgrade broke brightness keys [closed]

  - by Chris Morgan

  I have been running Ubuntu (64-bit) on my HP 6710b laptop (Core 2 Duo with integrated graphics) for several years, and the backlight brightness keys have always worked. Since I upgraded to Ubuntu 12.10 earlier today, those keys do not work any more. The secondary function keys: Fn+F3: sleep; still works (and considerably faster than ever before!) Fn+F8: battery info; still works Fn+F9: reduce brightness; stopped working in 12.10 Fn+F10: increase brightness; stopped working in 12.10 It may also be worth while mentioning that X does not appear to be receiving the brightness events at all, or at least not sending them out further. (This I detected with a key logger I wrote for a Uni project, which uses X's Record extension; it is informed of the sleep and battery info keystrokes, but doesn't receive the brightness ones at all.) In the mean time, I know that I can use the Brightness & Lock settings screen to alter the brightness. (Wow! I can suddenly make my backlight darker than I could before—I can go right down to turning the backlight off, something I couldn't do before... but this model has a fairly dim screen, so I don't expect to use that much, if ever.) How can I get the brightness keys working again? This question is probably strongly related to I can't control my Brightness in HP Compaq 6710s.

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• Ensure Payroll Success with PeopleSoft Year-End Training for U.S. and Canada

  - by Breanne Cooley

  Year-end payroll processing and reporting is a requirement for your business. If you're responsible for completing these processes in either Canada or the United States using the PeopleSoft Payroll application, and if you're new to PeopleSoft Payroll or to performing these processes, consider enrolling in Oracle University's expert training. Our PeopleSoft Payroll specialists will guide you through the necessary steps to ensure you can smoothly and successfully perform your job. Training is specific to the country for which you are performing the processing and reporting. Training lasts one day and is delivered in our Live Virtual Class Format, which helps you avoid travel during this busy season. Here's the training we recommend: PeopleSoft Year-End Payroll - U.S. This course teaches you how to complete U.S. year-end processing and reporting using PeopleSoft Payroll for North America, step-by-step. Update tax reporting setup tables and update employees' income and tax records. Load each employee's year-end data into a single year-end record for processing and reporting.  Identify reports needed to reconcile the year-end data. Correct tax balances and other data as necessary. Generate final print and online W-2 forms and prepare the electronic file for the Social Security Administration.  Enter corrected W-2 information and print a W-2c form. Report periodic retirement distributions and related tax withholding amounts on form 1099-R.   Please Note: this course is intended for organizations using PeopleSoft release 8.81 or higher. PeopleSoft Year-End Payroll – Canada This course covers the steps necessary to perform Canadian year-end processing using Oracle's PeopleSoft Payroll for North America. Explore adjustments, balances, year-end slip processing, common pitfalls and errors and balancing reports.  Produce accurate year-end reporting results such as T4, T4A, RL-1 and RL-2.  Please Note: this course is intended for organizations using PeopleSoft release 8.81 or higher. See you in class! -Oracle University Marketing Team 

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• What are the hard and fast rules for Cache Control?

  - by Metalshark

  Confession: sites I maintain have different rules for Cache Control mostly based on the default configuration of the server followed up with recommendations from the Page Speed & Y-Slow Firefox plug-ins and the Network Resources view in Google's Speed Tracer. Cache-Control is set to private/public depending on what they say to do, ETag's/Last-Modified headers are only tinkered with if Y-Slow suggests there is something wrong and Vary-Accept-Encoding seems necessary when manually gziping files for Amazon CloudFront. When reading through the material on the different options and what they do there seems to be conflicting information, rules for broken proxies and cargo cult configurations. Any of the official information provided by the analysis tools mentioned above is quite inaccessible as it deals with each topic individually instead of as a unified strategy (so there is no cross-referencing of techniques). For example, it seems to make no sense that the speed analysis tools rate a site with ETag's the same as a site without them if they are meant to help with caching. What are the hard and fast rules for a platform agnostic Cache Control strategy? EDIT: A link through Jeff Atwood's article explains Caching in superb depth. For the record though here are the hard and fast rules: If the file is Compressed using GZIP, etc - use "cache-control: private" as a proxy may return the compressed version to a client that does not support it (the browser cache will hold files marked this way though). Also remember to include a "Vary: Accept-Encoding" to say that it is compressible. Use Last-Modified in conjunction with ETag - belt and braces usage provides both validators, whilst ETag is based on file contents instead of modification time alone, using both covers all bases. NOTE: AOL's PageTest has a carte blanche approach against ETags for some reason. If you are using Apache on more than one server to host the same content then remove the implicitly declared inode from ETags by excluding it from the FileETag directive (i.e. "FileETag MTime Size") unless you are genuinely using the same live filesystem. Use "cache-control: public" wherever you can - this means that proxy servers (and the browser cache) will return your content even if the rest of the page needs HTTP authentication, etc.

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• Help parsing long (3.5mil lines) text file, line by line and storing data, need a strategy

  - by Jarrod

  This is a question about solving a particular problem I am struggling with, I am parsing a long list of text data, line by line for a business app in PHP (cron script on the CLI). The file follows the format: HD: Some text here {text here too} DC: A description here DC: the description continues here DC: and it ends here. DT: 2012-08-01 HD: Next header here {supplemental text} ... this repeats over and over for a few hundred megs I have to read each line, parse out the HD: line and grab the text on this line. I then compare this text against data stored in a database. When a match is found, I want to then record the following DC: lines that succeed the matched HD:. Pseudo code: while ( the_file_pointer_isnt_end_of_file) { line = getCurrentLineFromFile title = parseTitleFrom(line) matched = searchForMatchInDB(line) if ( matched ) { recordTheDCLines // <- Best way to do this? } } My problem is that because I am reading line by line, what is the best way to trigger the script to start saving DC lines, and then when they are finished save them to the database? I have a vague idea, but have yet to properly implement it. I would love to hear the communities ideas\suggestions! Thank you.

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• How to avoid throwing vexing exceptions?

  - by Mike

  Reading Eric Lippert's article on exceptions was definitely an eye opener on how I should approach exceptions, both as the producer and as the consumer. However, I'm still struggling to define a guideline regarding how to avoid throwing vexing exceptions. Specifically: Suppose you have a Save method that can fail because a) Somebody else modified the record before you, or b) The value you're trying to create already exists. These conditions are to be expected and not exceptional, so instead of throwing an exception you decide to create a Try version of your method, TrySave, which returns a boolean indicating if the save succeeded. But if it fails, how will the consumer know what was the problem? Or would it be best to return an enum indicating the result, kind of Ok/RecordAlreadyModified/ValueAlreadyExists? With integer.TryParse this problem doesn't exist, since there's only one reason the method can fail. Is the previous example really a vexing situation? Or would throwing an exception in this case be the preferred way? I know that's how it's done in most libraries and frameworks, including the Entity framework. How do you decide when to create a Try version of your method vs. providing some way to test beforehand if the method will work or not? I'm currently following these guidelines: If there is the chance of a race condition, then create a Try version. This prevents the need for the consumer to catch an exogenous exception. For example, in the Save method described before. If the method to test the condition pretty much would do all that the original method does, then create a Try version. For example, integer.TryParse(). In any other case, create a method to test the condition.

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• Track sales and commission with third-party tool

  - by Andrew

  I have a clothing website where I link to various clothing retailers. I have reached an agreement with one of the retailers whereby they will pay a commission to us for every sale they make from traffic that was referred by our site. I need a mechanism for tracking how much commission should be paid to us, that involves as little work as possible to implement from their side. We both have Google Analytics. Option 1: They record a goal in their GA account whenever someone makes a purchase on their site. They see how many completed goals are marked as referral traffic from our site and calculate commission accordingly. The problem with this is that the whole process of calculating and paying commission will be manual. They will need to frequently check how many sales were generated by referral traffic from our site, and probably we will have to chase them for commission payments. Also - since we won't have access to their GA data - we will need to trust that they report all sales accurately. Option 2: Sign them up to an affiliate network like Commission Junction or Google's Affiliate Network, and connect to them through this network. The problem with this solution is that it seems too heavyweight; ideally we don't want to ask a retailer to go through the whole sign up process just to deal with us and pay us commission. I am assuming that there must be some lightweight service that tracks the number of sales by one site and pays commission accordingly to the other site, where the sign up and installation procedure is simple and fast.

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• invitation: Oracle Endeca Information Discovery Bootcamp

  - by mseika

  The Oracle Endeca Information Discovery (OEID) Boot Camp is designed to give partners an understanding of OEID’s features, and how it complements the existing Oracle Business Intelligence suite. Participants will learn how to develop & implement solutions using a Data Discovery method. Training is in EnglishWhat will be covered?The Oracle Endeca Information Discovery (OEID) Boot Camp is a three-day class with a combination of lecture and hands-on exercises, tailored to make participants aware of the Oracle Endeca Information Discovery platform, and to gain valuable skills for the implementation of projects.The course will follow a combination of lectures and hands-on lab sessions, to allow participants to apply the knowledge they have gained by extracting from sample data sources, and creating an end-user application that will be used to answer several business questions. What You Will Learn Architecture: OEID Components, use of graphs, overview of clustering OEID Installation: Architecture planning, infrastructure requirements, installation process, production hints & tips OEID Administration: Data store management, administrative operations, portal configuration, data sources, system monitoring Indexing: Integration Suite, Data source analysis, Graph (ETL) creation, record design techniques Portlets: Studio portlets, custom portlet development, querying functions Reporting: Studio applications & best practices, visualizations, EQL PrerequisitesYou must bring a laptop with you for the Hands-on labs ENVIRONMENT – LAPTOP REQUIREMENTS For the OEID boot camp, participants will perform the hands-on lab exercises using a virtual machine image. These virtual machines will be provided to participants within a cloud environment, requiring participants to bring a laptop to the Boot Camp that can access a Windows server utilizing Microsoft RDP from their laptop. Participants will not need to install any software onto their laptops, but must ensure that they have the proper software installed for their OS, to connect through RDP to a server. HARDWARE • CPU: Dual-core, x64, 1.8Ghz or higher • RAM: 2GB SOFTWARE • Microsoft Remote Desktop Client • Internet Explorer 7, Firefox, or Google Chrome This boot camp is intended for prospective implementers of Oracle Endeca Information Discovery (OEID), or those in a presales role looking to gain insight into the technical benefits of this new package. Attendees should have experience and familiarity with the basic concepts of business intelligence. Where and When ? Monday, October 15th until wednesday, October 17th included 9:00 - 18:00 Oracle France 15, boulevard Charles de Gaulle 92715 Colombes Access Register Here Limited number of seats !

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• Algorithmic problem - quickly finding all #'s where value %x is some given value

  - by Steve B.

  Problem I'm trying to solve, apologies in advance for the length: Given a large number of stored records, each with a unique (String) field S. I'd like to be able to find through an indexed query all records where Hash(S) % N == K for any arbitrary N, K (e.g. given a million strings, find all strings where HashCode(s) % 17 = 5. Is there some way of memoizing this so that we can quickly answer any question of this form without doing the % on every value? The motivation for this is a system of N distributed nodes, where each record has to be assigned to at least one node. The nodes are numbered 0 - (K-1) , and each node has to load up all of the records that match it's number: If we have 3 nodes Node 0 loads all records where Hash % 3 ==0 Node 1 loads all records where Hash % 3 ==1 Node 2 loads all records where Hash % 3 ==2 adding a 4th node, obviously all the assignments have to be recomputed - Node 0 loads all records where Hash % 4 ==0 ... etc I'd like to easily find these records through an indexed query without having to compute the mod individually. The best I've been able to come up with so far: If we take the prime factors of N (p1 * p2 * ... ) if N % M == I then p % M == I % p for all of N's prime factors e.g. 10 nodes : N % 10 == 6 then N % 2 = 0 == 6 %2 N % 5 = 1 == 6 %5 so storing an array of the "%" of N for the first "reasonable" number of primes for my data set should be helpful. For example in the above example we store the hash and the primes HASH PRIMES (array of %2, %3, %5, %7, ... ]) 16 [0 1 1 2 .. ] so looking for N%10 == 6 is equivalent to looking for all values where array[1]==1 and array[2] == 1. However, this breaks at the first prime larger than the highest number I'm storing in the factor table. Is there a better way?

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• Subdomain still times out after set up a month ago

  - by user8137

  I'm a newbie on this and this has probably been asked already but the subjects online were close but too vague in there answers so I've probably really messed this up. I would really appreciate specific step by step instructions. This is what I'd like to do: use the subdomain www.high-res.domain.com to be accessed by external customers with specific permissions to access the site (like ftp). We use Network Solutions to house domain.com. We recently added a new ip address to point to www.high-res.domain.com. I gave the ip address to the company that hosts our website. I pinged www.high-res.domain.com and it points to the correct ip address but still times out. It’s been a few weeks now and when you ping it, it still times out. C:ping XXX.XXX.X.XXX Pinging XXX.XXX.X.XXX with 32 bytes of data: Request timed out. Request timed out. Request timed out. Request timed out. Ping statistics for XXX.XXX.X.XXX: Packets: Sent = 4, Received = 0, Lost = 4 (100% loss). Tracert times out as well. I even went to DNS tools and a few other sites for checking this and it shows the same thing. I recently went into the DNSmgmt on our server (wink2k3sp1) and created an A record under the DomainDnsZones which translated to a Cname when you look at it. Under the Domain it has two entries one to the subdomain and the other to the website host each with separate ip addresses. Is this correct? The website people are too busy on another project to research it further and my friends haven't gotten back to me. Please help. Thanks KK

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• USB and CD data cannot be read or mounted in 12.10

  - by aravind4j

  I'm using Ubuntu 12.10. I wrote a data disk using Brasero Disk Burner, but the system cannot read the CD. I tried to write the same data into my HP v220w pen drive but now there is an error in that too. It shows the following: Error mounting /dev/sdb at /media/aravind4j/Aravind4j: Command-line `mount -t "ntfs" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000,dmask=0077,fmask=0177" "/dev/sdb" "/media/aravind4j/Aravind4j"' exited with non-zero exit status 13: $MFTMirr does not match $MFT (record 0). Failed to mount '/dev/sdb': Input/output error NTFS is either inconsistent, or there is a hardware fault, or it's a SoftRAID/FakeRAID hardware. In the first case run chkdsk /f on Windows then reboot into Windows twice. The usage of the /f parameter is very important! If the device is a SoftRAID/FakeRAID then first activate it and mount a different device under the /dev/mapper/ directory, (e.g. /dev/mapper/nvidia_eahaabcc1). Please see the 'dmraid' documentation for more details. (udisks-error-quark, 0) I used a NTFS file system for the pen drive as you can recognize from the above statement. I would like to recover the files so please help me recover the files without formatting the drive.

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• Best Architecture for ASP.NET WebForms Application

  - by stack man

  I have written an ASP.NET WebForms portal for a client. The project has kind of evolved rather than being properly planned and structured from the beginning. Consequently, all the code is mashed together within the same project and without any layers. The client is now happy with the functionality, so I would like to refactor the code such that I will be confident about releasing the project. As there seems to be many differing ways to design the architecture, I would like some opinions about the best approach to take. FUNCTIONALITY The portal allows administrators to configure HTML templates. Other associated "partners" will be able to display these templates by adding IFrame code to their site. Within these templates, customers can register and purchase products. An API has been implemented using WCF allowing external companies to interface with the system also. An Admin section allows Administrators to configure various functionality and view reports for each partner. The system sends out invoices and email notifications to customers. CURRENT ARCHITECTURE It is currently using EF4 to read/write to the database. The EF objects are used directly within the aspx files. This has facilitated rapid development while I have been writing the site but it is probably unacceptable to keep it like that as it is tightly coupling the db with the UI. Specific business logic has been added to partial classes of the EF objects. QUESTIONS The goal of refactoring will be to make the site scalable, easily maintainable and secure. 1) What kind of architecture would be best for this? Please describe what should be in each layer, whether I should use DTO's / POCO / Active Record pattern etc. 2) Is there a robust way to auto-generate DTO's / BOs so that any future enhancements will be simple to implement despite the extra layers? 3) Would it be beneficial to convert the project from WebForms to MVC?

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• Turning a problem into a data

  - by Fogmeister

  OK, I have an app that I'm creating but I'm just really not sure about how to approach the problem. The idea is fairly simple. I'm just not sure how to wrap it in a data model (or even if I should). TBH I feel like I'm making it more complicated than it needs to be. How it works. The app will have circles along the top in a row that need to be connected to circles along the bottom in a row. 10 circles at the top. 10 at the bottom. One connection per pair of dots. Anyway, I can get the dots to connect I'm just not sure how to wrap it in a data model so that I can analyse what has been connected and see if it is right or not. The circles will be questions and answers. I can make an array of question objects with a question and answer properties. I can then display these as the dot pairs. I'm just not sure how to record which questions have been connected to which answers. It is valid for a user to connect a wrong answer as they all get checked at the end. I was thinking of using SpriteKit but this isn't a restriction. I could use UIKit or something else. TBH, this question is fairly language free as I'm just after a way of modelling it.

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• Deploy multiple emails to email providers, but without showing favouritism

  - by Ardman

  We are currently developing a new email deployment system. We have the system currently configured so that it reads a record from the database and loads the email content and deploys it to the target. Now we want to move this over to multiple threads. That is easily done, except we then hit the email providers returning SMTP codes referring to "Too many connections", or "Deferred connection". The solution to this is to have a thread open up a connection to the email provider and deploy n emails and then disconnect. We have currently configured the application so that it will support these session based email deployments. The problem is this, the database table has multiple email addresses in and they aren't grouped by email provider because that will show favouritism. We need to be able to retrieve a set number of, i.e. Hotmail, emails (@hotmail.com, @hotmail.co.uk, @live.co.uk) so that we are reducing the number of connections to Hotmail and reducing the risks of getting the "Too many connections" error. We are at the point now where we have gone round and round in circles trying to get a solution, so I thought I'd throw it out there and see if anyone has any ideas? EDIT I would like to stress that this application is not used for spamming purposes.

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• Unit testing and Test Driven Development questions

  - by Theomax

  I'm working on an ASP.NET MVC website which performs relatively complex calculations as one of its functions. This functionality was developed some time ago (before I started working on the website) and defects have occurred whereby the calculations are not being calculated properly (basically these calculations are applied to each user which has certain flags on their record etc). Note; these defects have only been observed by users thus far, and not yet investigated in code while debugging. My questions are: Because the existing unit tests all pass and therefore do not indicate that the defects that have been reported exist; does this suggest the original code that was implemented is incorrect? i.e either the requirements were incorrect and were coded accordingly or just not coded as they were supposed to be coded? If I use the TDD approach, would I disgregard the existing unit tests as they don't show there are any problems with the calculations functionality - and I start by making some failing unit tests which test/prove there are these problems occuring, and then add code to make them pass? Note; if it's simply a bug that is occurring that can be found while debugging the code, do the unit tests need to be updated since they are already passing?

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• How do I understand the partition table? (I want to start over.)

  - by Sammy Black

  I have Ubuntu 10.04 Lucid installed through wubi on my laptop (it came with Windows 7 preinstalled). This was my first foray into Linux, and I'm here to stay. I have no use for Windows, and yet I must manually choose not to boot into it! Should I shrink the Windows partition to something negligible and grow the Linux one using something like gparted or fdisk, and just be content that everything runs? In that case, I need to understand the filesystems. Which is which? Here's the output of $ df -h: Filesystem Size Used Avail Use% Mounted on /dev/loop0 17G 11G 4.5G 71% / none 1.8G 300K 1.8G 1% /dev none 1.8G 376K 1.8G 1% /dev/shm none 1.8G 316K 1.8G 1% /var/run none 1.8G 0 1.8G 0% /var/lock none 1.8G 0 1.8G 0% /lib/init/rw /dev/sda3 290G 50G 240G 18% /host I would prefer to start over with a clean install of 10.10 Maverick, but I fear what I may lose. Certainly, I will backup my home directory tree (gzip?), but what about various pieces of software that I've acquired from the repositories? Can I keep a record of them? By the way, I asked a similar question over on Ubuntu forums.

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• Are the only types of data "sources" static and dynamic?

  - by blunders

  Thinking that there might be others, but not sure -- but before getting into that, let me explain what I mean by static and dynamic data sources. Static (or datastore) - Meaning that the data's state is non-changing, and if was changed, that would be a new state, and the old data would be considered stateless; meaning it no longer is known to exist, or not exist. Another way of possibly looking at a static data source might be that if read and written back without modification, the checksum for before and after should be exactly the same regardless of the duration of time between the reading and rewriting of the data. Examples: Photos, Files, Database Record, Dynamic (or datastream) - Meaning that the data's state is known to be in flux, and never expected to be the same per input. Example: Live video/audio feed, Stock Market feed, First let me say, the above is a very loose mapping of the concepts, and I'd welcome any feedback. Next, onto the core of the question, that being are these the only two types of data sources. My guess, is that yes, they are -- but that there are hybrid versions of the two. That being, streaming data that has a fixed state. For example, the data being streamed has a checksum given and each unique checksum is known to be a single instance of static data. On the flip side, static data could be chained via say a version control system; when played back, each version might be viewed as a segment of a stream; thing is, the very fact that it can be played back makes the data source static. Another type might be that the data source is being organically discovered, and it's simply unknown what the state is. Questions, feedback, requests -- just comment, thanks!!

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• Possible to draw a select portion of a render target? (in XNA)

  - by TheBroodian

  I'm going to try to do this in reverse fashion and skip straight to the punch line, and then give the back story afterward: Is it possible to, after drawing a scene to a RenderTarget2D, only draw a select portion of the RenderTarget2D, if I don't want the entire thing? I'm using xTile to manage world data in my game (it's a great piece of work, colinvella [xTile's author] has made an amazing product), and for the most part it works great. xTile supports parallax effects in its layers to add some wonderful depth to 2d scenes, which was great, until I implemented a dynamic split-screen system into my game. Wanted to make a co-op game that wouldn't require players to be in close proximity to each other, so I made it so that if the players separate too far apart, the singular full-screen viewport 'snaps-apart', and is replaced by two split-screen viewports, which then smoothly transition to their respective player targets. The effect is pretty smooth aside from the part where the parallax backgrounds become skewed once the viewports split, because xTile's ratio for handling parallax effects is dependent upon viewport size. This is unfortunate, because the effect would otherwise be really snazzy, but the backgrounds become pretty heavily affected when the game goes from single-viewport to multi-viewport. So, Colinvella suggests using rendertargets to record the scene at full viewport size, and then only drawing a portion of it. But as far as I can tell, that isn't even possible? That being said, I've never even used render targets before, so I'm still learning, hence the question here.

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• Is there a canonical source supporting "all-surrogates"?

  - by user61852

  Background The "all-PK-must-be-surrogates" approach is not present in Codd's Relational Model or any SQL Standard (ANSI, ISO or other). Canonical books seems to elude this restrictions too. Oracle's own data dictionary scheme uses natural keys in some tables and surrogate keys in other tables. I mention this because these people must know a thing or two about RDBMS design. PPDM (Professional Petroleum Data Management Association) recommend the same canonical books do: Use surrogate keys as primary keys when: There are no natural or business keys Natural or business keys are bad ( change often ) The value of natural or business key is not known at the time of inserting record Multicolumn natural keys ( usually several FK ) exceed three columns, which makes joins too verbose. Also I have not found canonical source that says natural keys need to be immutable. All I find is that they need to be very estable, i.e need to be changed only in very rare ocassions, if ever. I mention PPDM because these people must know a thing or two about RDBMS design too. The origins of the "all-surrogates" approach seems to come from recommendations from some ORM frameworks. It's true that the approach allows for rapid database modeling by not having to do much business analysis, but at the expense of maintainability and readability of the SQL code. Much prevision is made for something that may or may not happen in the future ( the natural PK changed so we will have to use the RDBMS cascade update funtionality ) at the expense of day-to-day task like having to join more tables in every query and having to write code for importing data between databases, an otherwise very strightfoward procedure (due to the need to avoid PK colisions and having to create stage/equivalence tables beforehand ). Other argument is that indexes based on integers are faster, but that has to be supported with benchmarks. Obviously, long, varying varchars are not good for PK. But indexes based on short, fix-length varchar are almost as fast as integers. The questions - Is there any canonical source that supports the "all-PK-must-be-surrogates" approach ? - Has Codd's relational model been superceded by a newer relational model ?

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• What's the proper term for a function inverse to a constructor - to unwrap a value from a data type?

  - by Petr Pudlák

  Edit: I'm rephrasing the question a bit. Apparently I caused some confusion because I didn't realize that the term destructor is used in OOP for something quite different - it's a function invoked when an object is being destroyed. In functional programming we (try to) avoid mutable state so there is no such equivalent to it. (I added the proper tag to the question.) Instead, I've seen that the record field for unwrapping a value (especially for single-valued data types such as newtypes) is sometimes called destructor or perhaps deconstructor. For example, let's have (in Haskell): newtype Wrap = Wrap { unwrap :: Int } Here Wrap is the constructor and unwrap is what? The questions are: How do we call unwrap in functional programming? Deconstructor? Destructor? Or by some other term? And to clarify, is this/other terminology applicable to other functional languages, or is it used just in the Haskell? Perhaps also, is there any terminology for this in general, in non-functional languages? I've seen both terms, for example: ... Most often, one supplies smart constructors and destructors for these to ease working with them. ... at Haskell wiki, or ... The general theme here is to fuse constructor - deconstructor pairs like ... at Haskell wikibook (here it's probably meant in a bit more general sense), or newtype DList a = DL { unDL :: [a] -> [a] } The unDL function is our deconstructor, which removes the DL constructor. ... in The Real World Haskell.

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• Visual Studio 2012 first impressions...no Macros!

  - by bconlon

  Yesterday I installed Microsoft Visual Studio 2012 for the first time (all 8.5GB) and after 20 years of (mostly) happy times using VS they have removed Macros, one of the most handy features.The first thing I wanted to do when I upgraded my VS2010 project was to add a #elseif block to each file. This would usually be simple case of find in files of the previous #elseif and then Ctrl+Shift+R to record a macro which would be: F8 (to select the next file from find list), F3 (to find the correct position in file), Ctrl+V to paste the new code. Then all I would need to do is keep Ctrl+Shift+P (Play Macro) pressed until all the files were processed.But alas Ctrl+Shift+R does nothing! I won’t say that I use Macros every day but it was a very useful feature.To continue my moaning a little more, I also don't like the bland interface. This has been well documented by others, but now I have used it myself, I find it difficult to tell one grey area of screen from another and the lack of colour makes the icons unclear.I also don't see why the menus now need to SHOUT in capital letters?On the plus side, they have now added the ability to see WPF properties in the debugger...a bit of an oversight in Visual Studio 2010. Oh, but you still can't edit and continue on files that contain templated code.Whilst Visual Studio 2012 is not a complete disaster like Windows 8 (why develop a desk top OS to be the same as a Smart device OS), it does not float my boat.Rant over.#

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• Why can't tuxboot and ubuntu play well together?

  - by mmr

  I'm trying to get clonezilla to run off of a usb stick, and it seems that the right way to do that is via tuxboot. Tuxboot is not compilable on ubuntu. I used git to get it from the repository, and then when I run the 'install' script (because building it is apparently not allowed, since the build script just tries to install windows things). Qmake-linux wants my qmake executable to be in the same directory as the stuff I pulled down, and let's just say that if there's a way to do this easily, I ain't seein' it. So then I download the linux file, the most recent of which is tuxboot-linux-25. Try to run it, get a failure that libpng12.so.0 isn't found. OK, then I go to install that via the instructions I found on the web but firefox seems to have already deleted from my history (yay!) Then I add the /usr/local/lib directory to ldconfig via emacs (had to install that too, of course): http://ubuntuforums.org/showthread.php?t=369848 I still get the errors that libpng12.so.0 cannot be opened because 'No such file or directory'. ldconfig -p | grep libpng shows that the library is there, but it still doesn't seem to be findable. What to do next? (for the record, doing this in windows is painless-- download, click, and it's done. But I'm trying to be all linuxy and get away from Windows for this...)

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• Algorithm to match timestamped events from two sources

  - by urza.cc

  I have two different physical devices (one is camera, one is other device) that observe the same scene and mark when a specified event occures. (record timestamp) So they each produce a serie of timestamps "when the event was observed". Theoretically the recorded timestamps should be very well aligned: Visualized ideal situation on two time lines "s" and "r" as recorded from the two devices: but more likely they will not be so nicely aligned and there might be missing events from timeline s or r: I am looking for algorithm to match events from "s" and "r" like this: So that the result will be something like: (s1,null); (s2,r1); (s3,null); (s4,r2); (s5,r3); (null,r4); (s6,r5); Or something similar. Maybe with some "confidence" rating. I have some ideas, but I feel that this might be probably a well known problem, that has some good known solutions, but I don't know the right terminology. I am a little bit out of my element here, this is not my primary area of programming.. Any helps, suggestions etc will be appreciated.

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• Commands in Task-It - Part 1

  Download Source Code NOTE: To run the source code provided your will need to update to the RC (release candidate) versions of Silverlight 4 and VisualStudio 2010. In recent blog posts, like my MVVM post, I used Commands to invoke actions, like Saving a record. In this rather simplistic sample I will talk about the basics of Commands, and in my next post will get deeper into it. What is a Command? I remember the first time a UI designer used the word "command" I wasn't really sure what she was referring to. I later realized that it is just a term that is used to represent some UI control that can invoke an action, like a Button, HyperlinkButton, RadMenuItem, RadRadioButton, etc. Why should we use Commands? I'm sure you're familiar with the code behind approach of handling events. For example, if you had a Button and a RadMenuItem that ...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Thoughts on exception handling.

  - by AndyScott

  Was working on a windows form app (something I haven't done in a while), adding threading and logging so that it would work a little more smoothly and have a record of who did what.  I was just about at the point where I was going to check it into source control when I noticed that the Output window was showing "A first chance exception of type 'System.InvalidCastException' occurred in mscorlib.dll", so I googled it.  In reading some threads about the error, I came across the following comment and it got me thinking: "In addition, while they should be avoided if possible, exceptions are a quite legitimate part of program execution. It's their going unhandled that is a real issue, because that means crashy, crashy." How do you normally use exception handling?  I feel that exceptions are intended to handle errors in code (in my experience generally related to bad data making its way into the system).  Now don't get me wrong, I understand that exceptions happen and should be dealt with, but I feel that they are a "last resort" to keep a program from crashing, but should never be a way to pass data or continue logical processing that could be handled in standard code flow. I mention this, because I have seen it done. What do you think?

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