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• Insufficient storage available to create shadow copy

  - by Bob.at.SBS

  I have used the "Windows 7 File Recovery" tool under Windows 8 to create system image backups to an external USB hard drive. I built a new Windows 8.1 machine, and I want to create my first system image backup of that machine to the same USB hard drive. The "Windows 7 File Recovery" tool is gone in Windows 8.1, but wbAdmin is alive and well: wbAdmin start backup -backupTarget:\\?\Volume{2a2b...994f} -allCritical -quiet fails with this text displayed: wbadmin 1.0 - Backup command-line tool (C) Copyright 2013 Microsoft Corporation. All rights reserved. Retrieving volume information... This will back up (EFI System Partition),(C:),Recovery (300.00 MB) to \?\Volume {2a2b1255-3a86-11e3-be86-b8ca3a83994f}. The backup operation to F: is starting. Creating a shadow copy of the volumes specified for backup... Summary of the backup operation: The backup operation stopped before completing. The backup operation stopped before completing. Detailed error: ERROR - A Volume Shadow Copy Service operation error has occurred: (0x8004231f) Insufficient storage available to create either the shadow copy storage file or other shadow copy data. The EFI System Partition is 100 MB The Recovery Partition is 300 MB The C partition is 1.72 TB, NTFS, 218 GB used, 1.51 TB free The destination drive is 1.81 TB, NTFS, 678 GB used, 1.15 TB free I've fiddled with vssadmin resize shadowstorage, with no change in the error. vssadmin list shadowstorage displays: Shadow Copy Storage association For volume: (C:)\?\Volume{37a0...263}\ Shadow Copy Storage volume: (C:)\?\Volume{37a0...263}\ Used Shadow Copy Storage space: 2.39 GB (0%) Allocated Shadow Copy Storage space: 2.81 GB (0%) Maximum Shadow Copy Storage space: 531 GB (30%) Shadow Copy Storage association For volume: (F:)\?\Volume{2a2...94f}\ Shadow Copy Storage volume: (F:)\?\Volume{2a2...94f}\ Used Shadow Copy Storage space: 334 GB (17%) Allocated Shadow Copy Storage space: 337 GB (18%) Maximum Shadow Copy Storage space: UNBOUNDED (922154758%) (Yeah, the "percent calculation" for UNBOUNDED is seriously bogus.) I've run SFC /verifyonly and it seems happy. I've verified that the new `Volume Shadow Copy" service starts when I start the backup operation. Any suggestions?

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• Server cost for smartphone app with web service

  - by FrankieA

  Hello, I am working on a smartphone application that will require a backend web service - but I have absolutely clueless to how much it will cost. Web Service will handle: - login of users - cataloging of our user base - holding minimal profile information for users (the only binary data is a display picture which will be < 20k each) - performing some very minor calculation/algorithm before return results - All the above will be communicated to server from a smartphone (iPhone/BlackBerry/Android) Bandwidth Requirements: - We want to handle up to 10k users throughout the day. - I predict 10k * 50 HTTP requests a day = 500,000 requests a day * 30 = 15 million requests a month Space Requirements: - Data will be in SQL database. - I predict 1MB/user * 10k = 10GB + overhead. In other words - space is not a big issue. Software Requirements: (unless someone knows an alternative) - Windows Server 2008 + IIS - MSFT SQL Server Note: This is 100% new to me, so please hit me with all you got. Do I need Windows Server or are there alternative? Is it better to get multiple cheap servers to distribute load? Will Amazon S3 work for me? How about Windows Azure? Thank you!!

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• How to deal with lots of brackets in a formula?

  - by wenlibin02

  Say, I have a formula like this (in LaTeX or Maple or other text system): Result: ((6*(k2+k3))*A123*k2*k3*(A12*A13*k2^2-2*A12*A13*k2*k3+A12*A13*k3^2-A123*k2^2-2*A123*k2*k3-A123*k3^2)*(exp(-k3*(k3^2*t-x)))^2+6*A12*(-k3+k2)*k2*k3*(A12*A13*k2^2-2*A12*A13*k2*k3+A12*A13*k3^2-A123*k2^2-2*A123*k2*k3-A123*k3^2)*exp(-k3*(k3^2*t-x)))*(exp(-k2*(k2^2*t-x)))^2+(-(6*(-k3+k2))*A13*k2*k3*(A12*A13*k2^2-2*A12*A13*k2*k3+A12*A13*k3^2-A123*k2^2-2*A123*k2*k3-A123*k3^2)*(exp(-k3*(k3^2*t-x)))^2-(6*(k2+k3))*k2*k3*(A12*A13*k2^2-2*A12*A13*k2*k3+A12*A13*k3^2-A123*k2^2-2*A123*k2*k3-A123*k3^2)*exp(-k3*(k3^2*t-x)))*exp(-k2*(k2^2*t-x)) Note: the above formula is only one part of the result of a maple calculation, I just can't break them up because there are so many many terms. Apparently, It's very hard to read. What I want to do is to fold the matched brackets level by level. If all the brackets are folded, I can find out clearly how many terms there are. Then I can analyze from the top level to the details of every term. But I just don't know how to realize that. Maybe there are some existed software which can visualize this kind of complex formula. Any idea? P.S. I use Linux system. The open source alternatives are better.

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• 32 core (each physical core) 2.2 GhZ or 12 core (6 physical cores) 3.0GHZ?

  - by Tejaswi Rana

  I am working on a multithreaded application (Forex trading app built on C#) and had the client upgrade from the 12 core 3.0GHZ machine (Intel) to a 32 core 2.2 Ghz machine (AMD). The PassMark benchmark results were significantly higher when using multicores doing Integer, Floating and other calculations while for a single core calculation it was a bit slower than the pack (others that were being compared to with similar config as the 12 core one). Oh it also comes with 64 GB RAM (4 times as the other one) and a much faster SSD. So after configuring and running the application on that machine, not only did it not perform as well, it was significantly slower. We're talking about 30seconds - 1 minute slower on an app that usually completes processing within 5-20 secs. The application uses MAX DEGREE of PARALLELISM (TPL) which I've tried setting to number of cores and also half of that. I've also tried running single threaded and without setting any limits in parallel threading. While it may be the hardware has some issues, I am wondering if the CPU processing speed is the issue. I can overclock to 3.0 GHZ. But is that even a good idea? Server Info - AMD http://www.passmark.com/forum/showthread.php?4013-AMD-Dual-6272-performance-is-60-lower-than-benchmarks Seems that benchmark was wrong to start with - officially. Intel i7 3930k OS (same in both) Windows 7 Professional 64-bit

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• 16TB Volumes and SNMP On Windows

  - by John K

  As volumes larger than 16TB became more common, it was recognized that the 32 bit value used to report disk size and usage within the standard "HOST-RESOURCES" MIB in SNMP was not large enough to report the proper disk size. Net-SNMP seems to have addressed this issue by simply manipulating the value of "AllocationUnits" to maintain a 32 bit value for disk utilization (since total disk size/usage is equal to the 32 bit space value times the allocation unit), to allow for the calculation of a volume larger than 8/16TB. Presuming you don't have any reporting interest in the allocation unit, this seems like a fine solution. https://bugzilla.redhat.com/show_bug.cgi?id=654384 Window's built in SNMP service, however, seems to continue to suffer from this error, simply reporting the modulo of the used/assigned disk space, resulting in inaccurate disk size reporting. Is there a way to enable Windows to correctly report disk usage for volumes over 16TB? We attempted to simply install Net-SNMP 5.5 x64 and disable Windows SNMP service entirely, however this unfortunately did not fix our issue. I've seen people in the Cacti community mention simply scripting out a solution. Unfortunately, we're using Observium for quick and basic systems monitoring. If the issue can't be correct on the Window's side, can Observium be made to report custom MIBs?

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• How to achieve the following RTO & RPO with logshipping only using SQL Server?

  - by Jimmy Chandra

  Trying to come up with viable backup restore & logshipping solution for achieving the following: 15 minutes Recovery Point Objective (no more than 15 minutes data loss at any time) 5 minutes Recovery Time Objective (must be able to get the db up and running back by 5 minutes) Considering using logshipping only (which I think is kind of pushing it, but I want to know if anyone else know how to achieve this). Some other info for consideration: Using 40 Gbit / sec fiber channel between the primary and disaster recovery (DRC) sites The sites are about 600 km apart. At close of business, the amount of data generated is predicted to be about 150 MB/sec. Log backup is planned for every 5 min. Doing some rough calculation I came up w/ the following numbers: 40 Gbit / sec = 5 MB / sec @ 100% network efficiency. 5 MB / sec = 300 MB / min. @ 300 MB / min, the total amount of data that can be transfer considering the 5min RTO is about 1.5GB, but that will left no time for the actual backup and restore, so if we cut it down to 3min logshipping time, which equals to ~900 MB over 3 minutes at 100% network efficiency, that will left about 1 min backup time and 1 minute restore time. Currently don't have any information if the system being used is capable of restoring 900 MB in 1 min, but assume it can. for COB scenario... 150 MB/sec, and considering the 3 min logshipping time, which should equal to about 27 GB of data over 3 mins...??? I think this is where the SLA will break... since there is no way to transfer 27 GB of data over a 40Gbit/sec line in 3 min. Can I get someone else opinion? I am thinking database mirroring might be a better answer for this...

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• Access 2007: How can I make this EXPRESSION less complex?

  - by Mike

  Access is telling me that my new expression is to complex. It used to work when we had 10 service levels, but now we have 19! Great! My expression is checking the COST of our services in the [PriceCharged] field and then assigning the appropriate HOURS [Servicelevel] when I perform a calculation to work out how much REVENUE each colleague has made when working for a client. The [EstimatedTime] field stores the actual hours each colleague has worked. [EstimatedTime]/[ServiceLevel]*[PriceCharged] Great. Below is the breakdown of my COST to HOURS expression. I've put them on different lines to make it easier to read - please do not be put off by the length of this post, it's all the same info in the end. Many thanks,Mike ServiceLevel: IIf([pricecharged]=100(COST),6(HOURS), IIf([pricecharged]=200 Or [pricecharged]=210,12.5, IIf([pricecharged]=300,19, IIf([pricecharged]=400 Or [pricecharged]=410,25, IIf([pricecharged]=500,31, IIf([pricecharged]=600,37.5, IIf([pricecharged]=700,43, IIf([pricecharged]=800 Or [pricecharged]=810,50, IIf([pricecharged]=900,56, IIf([pricecharged]=1000,62.5, IIf([pricecharged]=1100,69, IIf([pricecharged]=1200 Or [pricecharged]=1210,75, IIf([pricecharged]=1300 Or [pricecharged]=1310,100, IIf([pricecharged]=1400,125, IIf([pricecharged]=1500,150, IIf([pricecharged]=1600,175, IIf([pricecharged]=1700,200, IIf([pricecharged]=1800,225, IIf([pricecharged]=1900,250,0)))))))))))))))))))

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• How do I calculate clock speed in multi-core processors?

  - by NReilingh

  Is it correct to say, for example, that a processor with four cores each running at 3GHz is in fact a processor running at 12GHz? I once got into a "Mac vs. PC" argument (which by the way is NOT the focus of this topic... that was back in middle school) with an acquaintance who insisted that Macs were only being advertised as 1Ghz machines because they were dual-processor G4s each running at 500MHz. At the time I knew this to be hogwash for reasons I think are apparent to most people, but I just saw a comment on this website to the effect of "6 cores x 0.2GHz = 1.2Ghz" and that got me thinking again about whether there's a real answer to this. So, this is a more-or-less philosophical/deep technical question about the semantics of clock speed calculation. I see two possibilities: Each core is in fact doing x calculations per second, thus the total number of calculations is x(cores). Clock speed is rather a count of the number of cycles the processor goes through in the space of a second, so as long as all cores are running at the same speed, the speed of each clock cycle stays the same no matter how many cores exist. In other words, Hz = (core1Hz+core2Hz+...)/cores.

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• Turn Excel spreadsheet into a formula

  - by ?????? ??????????

  I have an Excel spreadsheet that has a complex computation that is not trivial to turn into a macro or a single-cell formula. The spreadsheet has a about 10 different inputs (values a human enters in different cells of the spreadsheet) and then it outputs 5 independent calculations (in different 5 cells) based on that input. There calculation is using some pre-entered data in the spreadsheet (about 100 different constants) and doing some look-ups on them. Now I would like to use this whole spreadsheet as a formula on a different spreadsheet to calculate a set of input values and produce the corresponding set of output values. Imagine this as creating different table with 10 columns for the input variables and 5 columns for the outputs, then copying each input into the other spreadsheet and copying back the output in the results table. For instance: - A1, A2, A3,... A10 are cells where someone enters values - through a series of calculations B1, B2, B3, B4 and B5 are updated with some formulas Can I use the whole series of calculations from A1..A10 into B1..B5 without creating one massive huge formula or a VBA macro? I want to have a set of input values in 100 rows from A100, B100, C100,... J100 onward. Then do some Excel magic that will: 1. copy the values from A100...J100 into A1 to A10 2. wait for the result to appear in B1 to B5 3. copy the values from B1 to B5 into K100 to O100 4. repeat steps 1 to 3 for all rows from 100 to 150

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• How does Windows 7 taskbar "color hot-tracking" feature calculate the colour to use?

  - by theyetiman

  This has intrigued me for quite some time. Does anyone know the algorithm Windows 7 Aero uses to determine the colour to use as the hot-tracking hover highlight on taskbar buttons for currently-running apps? It is definitely based on the icon of the app, but I can't see a specific pattern of where it's getting the colour value from. It doesn't seem to be any of the following: An average colour value from the entire icon, otherwise you would get brown all the time with multi-coloured icons like Chrome. The colour used the most in the image, otherwise you'd get yellow for the SQL Server Management Studio icon (6th from left). Also, the Chrome icon used red, green and yellow in equal measure. A colour located at certain pixel coordinates within the icon, because Chrome is red -indicating the top of the icon - and Notepad++ (2nd from right) is green - indicating the bottom of the icon. I asked this question on ux.stackoverflow.com and it got closed as off-topic, but someone answered with the following: As described by Raymond Chen in this MSDN blog article: Some people ask how it's done. It's really nothing special. The code just looks for the predominant color in the icon. (And, since visual designers are sticklers for this sort of thing, black, white, and shades of gray are not considered "colors" for the purpose of this calculation.) However I wasn't really satisfied with that answer because it doesn't explain how the "predominant" colour is calculated. Surely on the SQL Management Studio icon, the predominant colour, to my eyes at least, is yellow. Yet the highlight is green. I want to know, specifically, what the algorithm is.

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• Access 2007: How can I make this EXPRESSION less complex?

  - by Mike

  Access is telling me that my new expression is to complex. It used to work when we had 10 service levels, but now we have 19! Great! My expression is checking the COST of our services in the [PriceCharged] field and then assigning the appropriate HOURS [Servicelevel] when I perform a calculation to work out how much REVENUE each colleague has made when working for a client. The [EstimatedTime] field stores the actual hours each colleague has worked. [EstimatedTime]/[ServiceLevel]*[PriceCharged] Great. Below is the breakdown of my COST to HOURS expression. I've put them on different lines to make it easier to read - please do not be put off by the length of this post, it's all the same info in the end. Many thanks,Mike ServiceLevel: IIf([pricecharged]=100(COST),6(HOURS), IIf([pricecharged]=200 Or [pricecharged]=210,12.5, IIf([pricecharged]=300,19, IIf([pricecharged]=400 Or [pricecharged]=410,25, IIf([pricecharged]=500,31, IIf([pricecharged]=600,37.5, IIf([pricecharged]=700,43, IIf([pricecharged]=800 Or [pricecharged]=810,50, IIf([pricecharged]=900,56, IIf([pricecharged]=1000,62.5, IIf([pricecharged]=1100,69, IIf([pricecharged]=1200 Or [pricecharged]=1210,75, IIf([pricecharged]=1300 Or [pricecharged]=1310,100, IIf([pricecharged]=1400,125, IIf([pricecharged]=1500,150, IIf([pricecharged]=1600,175, IIf([pricecharged]=1700,200, IIf([pricecharged]=1800,225, IIf([pricecharged]=1900,250,0)))))))))))))))))))

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• What is the "in-the-wire" size of a ethernet frame? 1518 or 1542?

  - by chrisapotek

  According to the table here, it says that MTU = 1500 bytes and that the payload part is 1500 - 42 bytes or 1458 bytes (<- this is actually wrong!). Now on top of that you have to add IPv4 and UDP headers, which are 28 bytes (20 IP + 8 UDP). That leaves my maximum possible application message to as 1430 bytes! But by looking for this number in the Internet I see 1472 instead. Am I doing this calculation wrong here? All I want to find out is the maximum application message I can send over the wire without the risk of fragmentation. It is definitely not 1500 because that includes the frame headers. Can someone help? The confusion is the the PAYLOAD can actually be as large as 1500 bytes and that's the MTU. So now what is the size in-the-wire for a payload of 1500? From that table it can be as big as 1542 bytes. So the maximum app messages I can send is 1472 (1500 - 20 (ip) - 8 (udp)) for a maximum in the wire size of 1542. It amazes me how things can get so complicated when they are actually simple. And I have not clue how someone came up with the number 1518 if the table says 1542.

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• SSH & SFTP: Should I assign one port to each user to facilitate bandwidth monitoring?

  - by BertS

  There is no easy way to track real-time per-user bandwidth usage for SSH and SFTP. I think assigning one port to each user may help. Idea of implementation Use case Bob, with UID 1001, shall connect on port 31001. Alice, with UID 1002, shall connect on port 31002. John, with UID 1003, shall connect on port 31003. (I do not want to lauch several sshd instances as proposed in question 247291.) 1. Setup for SFTP: In /etc/ssh/sshd_config: Port 31001 Port 31002 Port 31003 Subsystem sftp /usr/bin/sftp-wrapper.sh The file sftp-wrapper.sh starts the sftp server only if the port is the correct one: #!/bin/sh mandatory_port=3`id -u` current_port=`echo $SSH_CONNECTION | awk '{print $4}'` if [ $mandatory_port -eq $current_port ] then exec /usr/lib/openssh/sftp-server fi 2. Additional setup for SSH: A few lines in /etc/profile prevents the user from connecting on the wrong port: if [ -n "$SSH_CONNECTION" ] then mandatory_port=3`id -u` current_port=`echo $SSH_CONNECTION | awk '{print $4}'` if [ $mandatory_port -ne $current_port ] then echo "Please connect on port $mandatory_port." exit 1 fi fi Benefits Now it should be easy to monitor per-user bandwidth usage. A Rrdtool-based application could produce charts like this: I know this won't be a perfect calculation of the bandwidth usage: for example, if somebody launches a bruteforce attack on port 31001, there will be a lot of traffic on this port although not from Bob. But this is not a problem to me: I do not need an exact computation of per-user bandwidth usage, but an indicator that is approximately correct in standard situations. Questions Is the idea of assigning one port for each user is a good one? Is the proposed setup an reliable one? If I have to open dozens of ports for many users, should I expect a performance drawback? Do you know a rrdtool-based application which could make the chart above?

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• Improved appointment rendering in RadScheduler for ASP.NET AJAX, Q1 2010

  Now that Q1 2010 release is out in the wild, we can sit down and discuss some of the changes we decided to make in the new release. One of them is the new appointment rendering of RadScheduler - a potentially breaking change, but a much needed one. If you have problems with your old custom skins, include the old base stylesheet along with your RadScheduler and set EnableEmbeddedBaseStylesheet=false in your RadScheduler. You can find the said base stylesheet attached to this post.   While trying to improve the performance of RadScheduler, I noticed that the number of resources slows down the rendering and overall performance considerably. This had to be expected - the images to support the appointment rounded corners (and the predefined resources) were quite large. However, I didnt take into account that all browsers keep for performance reasons their images uncompressed in memory and with the color depth of the current desktop. A simple calculation later I discovered that the appointment sprite itself is taking 25MB memory when loaded. Add 5 resources to the fray and you have 150MB memory down with a single blow. As it turns out - a sprite image is not a panacea, if it gets too big - dont be afraid to break it in two. The loading time may suffer, but your browser suffers more while rendering a 25MB monster. First I thought of undertaking the aforementioned solution - breaking the appointment sprite in two and thus reducing the two appointment sprites to mere 2MB uncompressed. Then I thought - the rounded corners are small - I can use borders and backgrounds to simulate rounded appointment borders while still keeping the same HTML structure. The gradients can be done with a single 10x50px image plus we have a gain - border colors and backgrounds can be changed on the fly.  I started with five rendering elements at first, then tried with four and finally I settled on only three elements.  Behold the new appointment rendering (quite simple really):       On the left you can see that the first container has only top and bottom borders and a background. In fact, the background isnt even needed since it will be obscured by the elements on top of it. The whole first container is only needed for the four dots that reside in the four corners of the appointment. On top of this container is another one that holds the left and right borders and slightly lighter background to create the illusion of a second lighter border beside the other two. At last on top of all others is placed the text container that also holds the top and bottom borders and the gradient background. On the right you can see the final result - Im quite happy with it and I hope you will be too. After creating the new rendering we took another step further - we decided to use alpha gradients for the resource rendering, thus supporting any color appointments with rounded corners and gradients. You can see some examples below:We plan on adding BorderColor and BackColor properties  to the ResourceStyles definitions for Q1 SP1. However with the new rendering in Q1 2010 we do support BackColor and BorderColor appointment properties - you only need to set AppointmentStyleMode=Default to keep RadScheduler from switching to Simple appointment rendering. Here is one screenshot of RadScheduler with appointments set to different colors: I hope that you will enjoy working with the new appointments in RadScheduler. RadScheduler base stylesheet 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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• Improved appointment rendering in RadScheduler for ASP.NET AJAX, Q1 2010

  Now that Q1 2010 release is out in the wild, we can sit down and discuss some of the changes we decided to make in the new release. One of them is the new appointment rendering of RadScheduler - a potentially breaking change, but a much needed one. If you have problems with your old custom skins, include the old base stylesheet along with your RadScheduler and set EnableEmbeddedBaseStylesheet=false in your RadScheduler. You can find the said base stylesheet attached to this post.   While trying to improve the performance of RadScheduler, I noticed that the number of resources slows down the rendering and overall performance considerably. This had to be expected - the images to support the appointment rounded corners (and the predefined resources) were quite large. However, I didnt take into account that all browsers keep for performance reasons their images uncompressed in memory and with the color depth of the current desktop. A simple calculation later I discovered that the appointment sprite itself is taking 25MB memory when loaded. Add 5 resources to the fray and you have 150MB memory down with a single blow. As it turns out - a sprite image is not a panacea, if it gets too big - dont be afraid to break it in two. The loading time may suffer, but your browser suffers more while rendering a 25MB monster. First I thought of undertaking the aforementioned solution - breaking the appointment sprite in two and thus reducing the two appointment sprites to mere 2MB uncompressed. Then I thought - the rounded corners are small - I can use borders and backgrounds to simulate rounded appointment borders while still keeping the same HTML structure. The gradients can be done with a single 10x50px image plus we have a gain - border colors and backgrounds can be changed on the fly.  I started with five rendering elements at first, then tried with four and finally I settled on only three elements.  Behold the new appointment rendering (quite simple really):       On the left you can see that the first container has only top and bottom borders and a background. In fact, the background isnt even needed since it will be obscured by the elements on top of it. The whole first container is only needed for the four dots that reside in the four corners of the appointment. On top of this container is another one that holds the left and right borders and slightly lighter background to create the illusion of a second lighter border beside the other two. At last on top of all others is placed the text container that also holds the top and bottom borders and the gradient background. On the right you can see the final result - Im quite happy with it and I hope you will be too. After creating the new rendering we took another step further - we decided to use alpha gradients for the resource rendering, thus supporting any color appointments with rounded corners and gradients. You can see some examples below:We plan on adding BorderColor and BackColor properties  to the ResourceStyles definitions for Q1 SP1. However with the new rendering in Q1 2010 we do support BackColor and BorderColor appointment properties - you only need to set AppointmentStyleMode=Default to keep RadScheduler from switching to Simple appointment rendering. Here is one screenshot of RadScheduler with appointments set to different colors: I hope that you will enjoy working with the new appointments in RadScheduler. RadScheduler base stylesheet 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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• Advanced Data Source Engine coming to Telerik Reporting Q1 2010

  This is the final blog post from the pre-release series. In it we are going to share with you some of the updates coming to our reporting solution in Q1 2010. A new Declarative Data Source Engine will be added to Telerik Reporting, that will allow full control over data management, and deliver significant gains in rendering performance and memory consumption. Some of the engines new features will be: Data source parameters - those parameters will be used to limit data retrieved from the data source to just the data needed for the report. Data source parameters are processed on the data source side, however only queried data is fetched to the reporting engine, rather than the full data source. This leads to lower memory consumption, because data operations are performed on queried data only, rather than on all data. As a result, only the queried data needs to be stored in the memory vs. the whole dataset, which was the case with the old approach Support for stored procedures - they will assist in achieving a consistent implementation of logic across applications, and are especially practical for performing repetitive tasks. A stored procedure stores the SQL statements and logic, which can then be executed in different reports and/or applications. Stored Procedures will not only save development time, but they will also improve performance, because each stored procedure is compiled on the data base server once, and then is reutilized. In Telerik Reporting, the stored procedure will also be parameterized, where elements of the SQL statement will be bound to parameters. These parameterized SQL queries will be handled through the data source parameters, and are evaluated at run time. Using parameterized SQL queries will improve the performance and decrease the memory footprint of your application, because they will be applied directly on the database server and only the necessary data will be downloaded on the middle tier or client machine; Calculated fields through expressions - with the help of the new reporting engine you will be able to use field values in formulas to come up with a calculated field. A calculated field is a user defined field that is computed "on the fly" and does not exist in the data source, but can perform calculations using the data of the data source object it belongs to. Calculated fields are very handy for adding frequently used formulas to your reports; Improved performance and optimized in-memory OLAP engine - the new data source will come with several improvements in how aggregates are calculated, and memory is managed. As a result, you may experience between 30% (for simpler reports) and 400% (for calculation-intensive reports) in rendering performance, and about 50% decrease in memory consumption. Full design time support through wizards - Declarative data sources are a great advance and will save developers countless hours of coding. In Q1 2010, and true to Telerik Reportings essence, using the new data source engine and its features requires little to no coding, because we have extended most of the wizards to support the new functionality. The newly extended wizards are available in VS2005/VS2008/VS2010 design-time. More features will be revealed on the product's what's new page when the new version is officially released in a few days. Also make sure you attend the free webinar on Thursday, March 11th that will be dedicated to the updates in Telerik Reporting Q1 2010. 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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• GPGPU

  WhatGPU obviously stands for Graphics Processing Unit (the silicon powering the display you are using to read this blog post). The extra GP in front of that stands for General Purpose computing.So, altogether GPGPU refers to computing we can perform on GPU for purposes beyond just drawing on the screen. In effect, we can use a GPGPU a bit like we already use a CPU: to perform some calculation (that doesn’t have to have any visual element to it). The attraction is that a GPGPU can be orders of magnitude faster than a CPU.WhyWhen I was at the SuperComputing conference in Portland last November, GPGPUs were all the rage. A quick online search reveals many articles introducing the GPGPU topic. I'll just share 3 here: pcper (ignoring all pages except the first, it is a good consumer perspective), gizmodo (nice take using mostly layman terms) and vizworld (answering the question on "what's the big deal").The GPGPU programming paradigm (from a high level) is simple: in your CPU program you define functions (aka kernels) that take some input, can perform the costly operation and return the output. The kernels are the things that execute on the GPGPU leveraging its power (and hence execute faster than what they could on the CPU) while the host CPU program waits for the results or asynchronously performs other tasks.However, GPGPUs have different characteristics to CPUs which means they are suitable only for certain classes of problem (i.e. data parallel algorithms) and not for others (e.g. algorithms with branching or recursion or other complex flow control). You also pay a high cost for transferring the input data from the CPU to the GPU (and vice versa the results back to the CPU), so the computation itself has to be long enough to justify the overhead transfer costs. If your problem space fits the criteria then you probably want to check out this technology.HowSo where can you get a graphics card to start playing with all this? At the time of writing, the two main vendors ATI (owned by AMD) and NVIDIA are the obvious players in this industry. You can read about GPGPU on this AMD page and also on this NVIDIA page. NVIDIA's website also has a free chapter on the topic from the "GPU Gems" book: A Toolkit for Computation on GPUs.If you followed the links above, then you've already come across some of the choices of programming models that are available today. Essentially, AMD is offering their ATI Stream technology accessible via a language they call Brook+; NVIDIA offers their CUDA platform which is accessible from CUDA C. Choosing either of those locks you into the GPU vendor and hence your code cannot run on systems with cards from the other vendor (e.g. imagine if your CPU code would run on Intel chips but not AMD chips). Having said that, both vendors plan to support a new emerging standard called OpenCL, which theoretically means your kernels can execute on any GPU that supports it. To learn more about all of these there is a website: gpgpu.org. The caveat about that site is that (currently) it completely ignores the Microsoft approach, which I touch on next.On Windows, there is already a cross-GPU-vendor way of programming GPUs and that is the DirectX API. Specifically, on Windows Vista and Windows 7, the DirectX 11 API offers a dedicated subset of the API for GPGPU programming: DirectCompute. You use this API on the CPU side, to set up and execute the kernels that run on the GPU. The kernels are written in a language called HLSL (High Level Shader Language). You can use DirectCompute with HLSL to write a "compute shader", which is the term DirectX uses for what I've been referring to in this post as a "kernel". For a comprehensive collection of links about this (including tutorials, videos and samples) please see my blog post: DirectCompute.Note that there are many efforts to build even higher level languages on top of DirectX that aim to expose GPGPU programming to a wider audience by making it as easy as today's mainstream programming models. I'll mention here just two of those efforts: Accelerator from MSR and Brahma by Ananth. Comments about this post welcome at the original blog.

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• CRMIT’s HIGH VALUE CRM++ PLUGINS FOR CRM On DEMAND

  - by Soumo Das

  Customer satisfaction and experience being the two most considerable factors, these days businesses are on the lookout for automation tools that are world class, agile and keep quality at its core. CRMIT has developed such tools using cutting edge technologies and abstracting industry best practices and R&D.  Self Service Portal  With customers being so meticulous about regular updates and reliable access to their data, administrators just cannot think of walking a thin line. Surviving without a resource that provides a track of customer requirements for services available 24 x 7 can severely affect the productivity. In such a scenario, CRMIT’s Self Service Portal (SSP) is the best solution. This not only tracks the required customer data, but also allows companies to stay in tune with their employees, vendors and stakeholders.   One can directly sign up to become a CRMOD contact and SSP user. One need not use the database, as operations and interactions are d at run time. This is a fully configurable solution that tracks results periodically, thus making it easy for end users. It also offers better security and data visibility that enables users to progress smoothly. Quote and Order Management   When dealing with quotes, contracts and orders becomes complicated, only Quote & Order Management can work as a one-stop solution. CRMIT offers this great tool for managing all this information and for taking care of customer orders and service requirements.  This CRM On Demand plug-in allows one to create a new quote or copy the existing one. Products can be directly added from the product list of CRMOD and the pricing is calculated automatically. Quote can be generated and mailed to the external users in PDF, HTML and XLS formats. This not only allows management of quotes in an enhanced manner, but also supports various billing and tax calculation features that make work effortless.    Report Scheduler  When it comes to analyzing and providing statistics of various business processes currently running in an organization, one cannot depend on manual updates, which sometimes may be inaccurate or even delayed. CRMIT provides a SaaS based powerful solution - Report Scheduler - that allows CRM users to schedule reports as per the frequencies and then receive them as email attachments at the scheduled time.   With this powerful tool, administrators can control the report scheduler for assigning specific reports to specific users. After that, users can login and schedule any assigned report for viewing at particular intervals on monthly, weekly or daily basis. Additionally, users can also copy the mail to external users and can choose the preferred format. The best part is that sharing business data with third party become easy with this and for viewing reports, users need not log into their CRMOD account.  CRM On Demand Offline Solution CRM On-Demand Offline is another great CRM++ extension that allows one to work in both online and offline modes. Synchronizing both the modes is absolutely easy and offers ease while working. CRM OD offline works as an automation tool that not only improves efficiency, but also works as a backup in most cases. It is readily available as a windows application installer and requires users to be online only while validating and synchronizing. The best part is that working in the offline mode also works as a backup. 

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• F# in ASP.NET, mathematics and testing

  - by DigiMortal

  Starting from Visual Studio 2010 F# is full member of .NET Framework languages family. It is functional language with syntax specific to functional languages but I think it is time for us also notice and study functional languages. In this posting I will show you some examples about cool things other people have done using F#. F# and ASP.NET As I am ASP/ASP.NET MVP I am – of course – interested in how people use different languages and technologies with ASP.NET. C# MVP Tomáš Petrícek writes about developing ASP.NET MVC applications using F#. He also shows how to use LINQ To SQL in F# (using F# PowerPack) and provides sample solution and Visual Studio 2010 template for F# MVC web applications. You may also find interesting how you can create controllers in F#. Excellent work, Tomáš! Vladimir Matveev has interesting example about how to use F# and ApplicationHost class to process ASP.NET requests ouside of IIS. This is simple and very straight-forward example and I strongly suggest you to take a look at it. Very cool example is project Strom in Codeplex. Storm is web services testing tool that is fully written on F#. Take a look at this site because Codeplex offers also source code besides binaries. Math Functional languages are strong in fields like mathematics and physics. When I wrote my C# example about BigInteger class I found out that recursive version of Fibonacci algorithm in C# is not performing well. In same time I made same experiment on F# and in F# there were no performance problems with recursive version. You can find F# version of Fibonacci algorithm from Bob Palmer’s blog posting Fibonacci numbers in F#. Although golden spiral is useful for solving many problems I looked for some practical code example and found one. Kean Walmsley published in his Through the Interface blog very interesting posting Creating Fibonacci spirals in AutoCAD using F#. There are also other cool examples you may be interested in. Using numerical components by Extreme Optimization  it is possible to make some numerical integration (quadrature method) using F# (also C# example is available). fsharp.it introduces factorials calculation on F#. Robert Pickering has made very good work on programming The Game of Life in Silverlight and F# – I definitely suggest you to try out this example as it is very illustrative too. Who wants something more complex may take a look at Newton basin fractal example in F# by Jonathan Birge. Testing After some searching and surfing I found out that there is almost everything available for F# to write tests and test your F# code. FsCheck - FsCheck is a port of Haskell's QuickCheck. Important parts of the manual for using FsCheck is almost literally "adapted" from the QuickCheck manual and paper. Any errors and omissions are entirely my responsibility. FsTest - This project is designed to Language Oriented Programming constructs around unit testing and behavior testing in F#. The goal of this project is to create a Domain Specific Language for testing F# code in a way that makes sense for functional programming. FsUnit - FsUnit makes unit-testing with F# more enjoyable. It adds a special syntax to your favorite .NET testing framework. xUnit.NET - xUnit.net is a developer testing framework, built to support Test Driven Development, with a design goal of extreme simplicity and alignment with framework features. It is compatible with .NET Framework 2.0 and later, and offers several runners: console, GUI, MSBuild, and Visual Studio integration via TestDriven.net, CodeRush Test Runner and Resharper. It also offers test project integration for ASP.NET MVC. Getting started Well, as a first thing you need Visual Studio 2010. Then take a look at these resources: F# samples @ MSDN Microsoft F# Developer Center @ MSDN F# Language Reference @ MSDN F# blog F# forums Real World Functional Programming: With Examples in F# and C# (Amazon) Happy F#-ing! :)

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• Algorithm to Find the Aggregate Mass of "Granola Bar"-Like Structures?

  - by Stuart Robbins

  I'm a planetary science researcher and one project I'm working on is N-body simulations of Saturn's rings. The goal of this particular study is to watch as particles clump together under their own self-gravity and measure the aggregate mass of the clumps versus the mean velocity of all particles in the cell. We're trying to figure out if this can explain some observations made by the Cassini spacecraft during the Saturnian summer solstice when large structures were seen casting shadows on the nearly edge-on rings. Below is a screenshot of what any given timestep looks like. (Each particle is 2 m in diameter and the simulation cell itself is around 700 m across.) The code I'm using already spits out the mean velocity at every timestep. What I need to do is figure out a way to determine the mass of particles in the clumps and NOT the stray particles between them. I know every particle's position, mass, size, etc., but I don't know easily that, say, particles 30,000-40,000 along with 102,000-105,000 make up one strand that to the human eye is obvious. So, the algorithm I need to write would need to be a code with as few user-entered parameters as possible (for replicability and objectivity) that would go through all the particle positions, figure out what particles belong to clumps, and then calculate the mass. It would be great if it could do it for "each" clump/strand as opposed to everything over the cell, but I don't think I actually need it to separate them out. The only thing I was thinking of was doing some sort of N2 distance calculation where I'd calculate the distance between every particle and if, say, the closest 100 particles were within a certain distance, then that particle would be considered part of a cluster. But that seems pretty sloppy and I was hoping that you CS folks and programmers might know of a more elegant solution? Edited with My Solution: What I did was to take a sort of nearest-neighbor / cluster approach and do the quick-n-dirty N2 implementation first. So, take every particle, calculate distance to all other particles, and the threshold for in a cluster or not was whether there were N particles within d distance (two parameters that have to be set a priori, unfortunately, but as was said by some responses/comments, I wasn't going to get away with not having some of those). I then sped it up by not sorting distances but simply doing an order N search and increment a counter for the particles within d, and that sped stuff up by a factor of 6. Then I added a "stupid programmer's tree" (because I know next to nothing about tree codes). I divide up the simulation cell into a set number of grids (best results when grid size ˜7 d) where the main grid lines up with the cell, one grid is offset by half in x and y, and the other two are offset by 1/4 in ±x and ±y. The code then divides particles into the grids, then each particle N only has to have distances calculated to the other particles in that cell. Theoretically, if this were a real tree, I should get order N*log(N) as opposed to N2 speeds. I got somewhere between the two, where for a 50,000-particle sub-set I got a 17x increase in speed, and for a 150,000-particle cell, I got a 38x increase in speed. 12 seconds for the first, 53 seconds for the second, 460 seconds for a 500,000-particle cell. Those are comparable speeds to how long the code takes to run the simulation 1 timestep forward, so that's reasonable at this point. Oh -- and it's fully threaded, so it'll take as many processors as I can throw at it.

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• How to develop RPG Damage Formulas?

  - by user127817

  I'm developing a classical 2d RPG (in a similar vein to final fantasy) and I was wondering if anyone had some advice on how to do damage formulas/links to resources/examples? I'll explain my current setup. Hopefully I'm not overdoing it with this question, and I apologize if my questions is too large/broad My Characters stats are composed of the following: enum Stat { HP = 0, MP = 1, SP = 2, Strength = 3, Vitality = 4, Magic = 5, Spirit = 6, Skill = 7, Speed = 8, //Speed/Agility are the same thing Agility = 8, Evasion = 9, MgEvasion = 10, Accuracy = 11, Luck = 12, }; Vitality is basically defense to physical attacks and spirit is defense to magic attacks. All stats have fixed maximums (9999 for HP, 999 for MP/SP and 255 for the rest). With abilities, the maximums can be increased (99999 for HP, 9999 for HP/SP, 999 for the rest) with typical values (at level 100) before/after abilities+equipment+etc will be 8000/20,000 for HP, 800/2000 for SP/MP, 180/350 for other stats Late game Enemy HP will typically be in the lower millions (with a super boss having the maximum of ~12 million). I was wondering how do people actually develop proper damage formulas that scale correctly? For instance, based on this data, using the damage formulas for Final Fantasy X as a base looked very promising. A full reference here http://www.gamefaqs.com/ps2/197344-final-fantasy-x/faqs/31381 but as a quick example: Str = 127, 'Attack' command used, enemy Def = 34. 1. Physical Damage Calculation: Step 1 ------------------------------------- [{(Stat^3 ÷ 32) + 32} x DmCon ÷16] Step 2 ---------------------------------------- [{(127^3 ÷ 32) + 32} x 16 ÷ 16] Step 3 -------------------------------------- [{(2048383 ÷ 32) + 32} x 16 ÷ 16] Step 4 --------------------------------------------------- [{(64011) + 32} x 1] Step 5 -------------------------------------------------------- [{(64043 x 1)}] Step 6 ---------------------------------------------------- Base Damage = 64043 Step 7 ----------------------------------------- [{(Def - 280.4)^2} ÷ 110] + 16 Step 8 ------------------------------------------ [{(34 - 280.4)^2} ÷ 110] + 16 Step 9 ------------------------------------------------- [(-246)^2) ÷ 110] + 16 Step 10 ---------------------------------------------------- [60516 ÷ 110] + 16 Step 11 ------------------------------------------------------------ [550] + 16 Step 12 ---------------------------------------------------------- DefNum = 566 Step 13 ---------------------------------------------- [BaseDmg * DefNum ÷ 730] Step 14 --------------------------------------------------- [64043 * 566 ÷ 730] Step 15 ------------------------------------------------------ [36248338 ÷ 730] Step 16 ------------------------------------------------- Base Damage 2 = 49655 Step 17 ------------ Base Damage 2 * {730 - (Def * 51 - Def^2 ÷ 11) ÷ 10} ÷ 730 Step 18 ---------------------- 49655 * {730 - (34 * 51 - 34^2 ÷ 11) ÷ 10} ÷ 730 Step 19 ------------------------- 49655 * {730 - (1734 - 1156 ÷ 11) ÷ 10} ÷ 730 Step 20 ------------------------------- 49655 * {730 - (1734 - 105) ÷ 10} ÷ 730 Step 21 ------------------------------------- 49655 * {730 - (1629) ÷ 10} ÷ 730 Step 22 --------------------------------------------- 49655 * {730 - 162} ÷ 730 Step 23 ----------------------------------------------------- 49655 * 568 ÷ 730 Step 24 -------------------------------------------------- Final Damage = 38635 I simply modified the dividers to include the attack rating of weapons and the armor rating of armor. Magic Damage is calculated as follows: Mag = 255, Ultima is used, enemy MDef = 1 Step 1 ----------------------------------- [DmCon * ([Stat^2 ÷ 6] + DmCon) ÷ 4] Step 2 ------------------------------------------ [70 * ([255^2 ÷ 6] + 70) ÷ 4] Step 3 ------------------------------------------ [70 * ([65025 ÷ 6] + 70) ÷ 4] Step 4 ------------------------------------------------ [70 * (10837 + 70) ÷ 4] Step 5 ----------------------------------------------------- [70 * (10907) ÷ 4] Step 6 ------------------------------------ Base Damage = 190872 [cut to 99999] Step 7 ---------------------------------------- [{(MDef - 280.4)^2} ÷ 110] + 16 Step 8 ------------------------------------------- [{(1 - 280.4)^2} ÷ 110] + 16 Step 9 ---------------------------------------------- [{(-279.4)^2} ÷ 110] + 16 Step 10 -------------------------------------------------- [(78064) ÷ 110] + 16 Step 11 ------------------------------------------------------------ [709] + 16 Step 12 --------------------------------------------------------- MDefNum = 725 Step 13 --------------------------------------------- [BaseDmg * MDefNum ÷ 730] Step 14 --------------------------------------------------- [99999 * 725 ÷ 730] Step 15 ------------------------------------------------- Base Damage 2 = 99314 Step 16 ---------- Base Damage 2 * {730 - (MDef * 51 - MDef^2 ÷ 11) ÷ 10} ÷ 730 Step 17 ------------------------ 99314 * {730 - (1 * 51 - 1^2 ÷ 11) ÷ 10} ÷ 730 Step 18 ------------------------------ 99314 * {730 - (51 - 1 ÷ 11) ÷ 10} ÷ 730 Step 19 --------------------------------------- 99314 * {730 - (49) ÷ 10} ÷ 730 Step 20 ----------------------------------------------------- 99314 * 725 ÷ 730 Step 21 -------------------------------------------------- Final Damage = 98633 The problem is that the formulas completely fall apart once stats start going above 255. In particular Defense values over 300 or so start generating really strange behavior. High Strength + Defense stats lead to massive negative values for instance. While I might be able to modify the formulas to work correctly for my use case, it'd probably be easier just to use a completely new formula. How do people actually develop damage formulas? I was considering opening excel and trying to build the formula that way (mapping Attack Stats vs. Defense Stats for instance) but I was wondering if there's an easier way? While I can't convey the full game mechanics of my game here, might someone be able to suggest a good starting place for building a damage formula? Thanks

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• Solving Euler Project Problem Number 1 with Microsoft Axum

  - by Jeff Ferguson

  Note: The code below applies to version 0.3 of Microsoft Axum. If you are not using this version of Axum, then your code may differ from that shown here. I have just solved Problem 1 of Project Euler using Microsoft Axum. The problem statement is as follows: If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Find the sum of all the multiples of 3 or 5 below 1000. My Axum-based solution is as follows: namespace EulerProjectProblem1{ // http://projecteuler.net/index.php?section=problems&id=1 // // If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. // The sum of these multiples is 23. // Find the sum of all the multiples of 3 or 5 below 1000. channel SumOfMultiples { input int Multiple1; input int Multiple2; input int UpperBound; output int Sum; } agent SumOfMultiplesAgent : channel SumOfMultiples { public SumOfMultiplesAgent() { int Multiple1 = receive(PrimaryChannel::Multiple1); int Multiple2 = receive(PrimaryChannel::Multiple2); int UpperBound = receive(PrimaryChannel::UpperBound); int Sum = 0; for(int Index = 1; Index < UpperBound; Index++) { if((Index % Multiple1 == 0) || (Index % Multiple2 == 0)) Sum += Index; } PrimaryChannel::Sum <-- Sum; } } agent MainAgent : channel Microsoft.Axum.Application { public MainAgent() { var SumOfMultiples = SumOfMultiplesAgent.CreateInNewDomain(); SumOfMultiples::Multiple1 <-- 3; SumOfMultiples::Multiple2 <-- 5; SumOfMultiples::UpperBound <-- 1000; var Sum = receive(SumOfMultiples::Sum); System.Console.WriteLine(Sum); System.Console.ReadLine(); PrimaryChannel::ExitCode <-- 0; } }} Let’s take a look at the various parts of the code. I begin by setting up a channel called SumOfMultiples that accepts three inputs and one output. The first two of the three inputs will represent the two possible multiples, which are three and five in this case. The third input will represent the upper bound of the problem scope, which is 1000 in this case. The lone output of the channel represents the sum of all of the matching multiples: channel SumOfMultiples{ input int Multiple1; input int Multiple2; input int UpperBound; output int Sum;} I then set up an agent that uses the channel. The agent, called SumOfMultiplesAgent, received the three inputs from the channel sent to the agent, stores the results in local variables, and performs the for loop that iterates from 1 to the received upper bound. The agent keeps track of the sum in a local variable and stores the sum in the output portion of the channel: agent SumOfMultiplesAgent : channel SumOfMultiples{ public SumOfMultiplesAgent() { int Multiple1 = receive(PrimaryChannel::Multiple1); int Multiple2 = receive(PrimaryChannel::Multiple2); int UpperBound = receive(PrimaryChannel::UpperBound); int Sum = 0; for(int Index = 1; Index < UpperBound; Index++) { if((Index % Multiple1 == 0) || (Index % Multiple2 == 0)) Sum += Index; } PrimaryChannel::Sum <-- Sum; }} The application’s main agent, therefore, simply creates a new SumOfMultiplesAgent in a new domain, prepares the channel with the inputs that we need, and then receives the Sum from the output portion of the channel: agent MainAgent : channel Microsoft.Axum.Application{ public MainAgent() { var SumOfMultiples = SumOfMultiplesAgent.CreateInNewDomain(); SumOfMultiples::Multiple1 <-- 3; SumOfMultiples::Multiple2 <-- 5; SumOfMultiples::UpperBound <-- 1000; var Sum = receive(SumOfMultiples::Sum); System.Console.WriteLine(Sum); System.Console.ReadLine(); PrimaryChannel::ExitCode <-- 0; }} The result of the calculation (which, by the way, is 233,168) is sent to the console using good ol’ Console.WriteLine().

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• HSSFS Part 2.1 - Parsing @@VERSION

  - by Most Valuable Yak (Rob Volk)

  For Part 2 of the Handy SQL Server Function Series I decided to tackle parsing useful information from the @@VERSION function, because I am an idiot.  It turns out I was confused about CHARINDEX() vs. PATINDEX() and it pretty much invalidated my original solution.  All is not lost though, this mistake turned out to be informative for me, and hopefully for you. Referring back to the "Version" view in the prelude I started with the following query to extract the version number: SELECT DISTINCT SQLVersion, SUBSTRING(VersionString,PATINDEX('%-%',VersionString)+2, 12) VerNum FROM VERSION I used PATINDEX() to find the first hyphen "-" character in the string, since the version number appears 2 positions after it, and got these results: SQLVersion VerNum ----------- ------------ 2000 8.00.2055 (I 2005 9.00.3080.00 2005 9.00.4053.00 2008 10.50.1600.1 As you can see it was good enough for most of the values, but not for the SQL 2000 @@VERSION.  You'll notice it has only 3 version sections/octets where the others have 4, and the SUBSTRING() grabbed the non-numeric characters after.  To properly parse the version number will require a non-fixed value for the 3rd parameter of SUBSTRING(), which is the number of characters to extract. The best value is the position of the first space to occur after the version number (VN), the trick is to figure out how to find it.  Here's where my confusion about PATINDEX() came about.  The CHARINDEX() function has a handy optional 3rd parameter: CHARINDEX (expression1 ,expression2 [ ,start_location ] ) While PATINDEX(): PATINDEX ('%pattern%',expression ) Does not.  I had expected to use PATINDEX() to start searching for a space AFTER the position of the VN, but it doesn't work that way.  Since there are plenty of spaces before the VN, I thought I'd try PATINDEX() on another character that doesn't appear before, and tried "(": SELECT SQLVersion, SUBSTRING(VersionString,PATINDEX('%-%',VersionString)+2, PATINDEX('%(%',VersionString)) FROM VERSION Unfortunately this messes up the length calculation and yields: SQLVersion VerNum ----------- --------------------------- 2000 8.00.2055 (Intel X86) Dec 16 2008 19:4 2005 9.00.3080.00 (Intel X86) Sep 6 2009 01: 2005 9.00.4053.00 (Intel X86) May 26 2009 14: 2008 10.50.1600.1 (Intel X86) Apr 2008 10.50.1600.1 (X64) Apr 2 20 Yuck.  The problem is that PATINDEX() returns position, and SUBSTRING() needs length, so I have to subtract the VN starting position: SELECT SQLVersion, SUBSTRING(VersionString,PATINDEX('%-%',VersionString)+2, PATINDEX('%(%',VersionString)-PATINDEX('%-%',VersionString)) VerNum FROM VERSION And the results are: SQLVersion VerNum ----------- -------------------------------------------------------- 2000 8.00.2055 (I 2005 9.00.4053.00 (I Msg 537, Level 16, State 2, Line 1 Invalid length parameter passed to the LEFT or SUBSTRING function. Ummmm, whoops.  Turns out SQL Server 2008 R2 includes "(RTM)" before the VN, and that causes the length to turn negative. So now that that blew up, I started to think about matching digit and dot (.) patterns.  Sadly, a quick look at the first set of results will quickly scuttle that idea, since different versions have different digit patterns and lengths. At this point (which took far longer than I wanted) I decided to cut my losses and redo the query using CHARINDEX(), which I'll cover in Part 2.2.  So to do a little post-mortem on this technique: PATINDEX() doesn't have the flexibility to match the digit pattern of the version number; PATINDEX() doesn't have a "start" parameter like CHARINDEX(), that allows us to skip over parts of the string; The SUBSTRING() expression is getting pretty complicated for this relatively simple task! This doesn't mean that PATINDEX() isn't useful, it's just not a good fit for this particular problem.  I'll include a version in the next post that extracts the version number properly. UPDATE: Sorry if you saw the unformatted version of this earlier, I'm on a quest to find blog software that ACTUALLY WORKS.

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• Ongoing confusion about ivars and properties in objective C

  - by Earl Grey

  After almost 8 months being in ios programming, I am again confused about the right approach. Maybe it is not the language but some OOP principle I am confused about. I don't know.. I was trying C# a few years back. There were fields (private variables, private data in an object), there were getters and setters (methods which exposed something to the world) ,and properties which was THE exposed thing. I liked the elegance of the solution, for example there could be a class that would have a property called DailyRevenue...a float...but there was no private variable called dailyRevenue, there was only a field - an array of single transaction revenues...and the getter for DailyRevenue property calculated the revenue transparently. If somehow the internals of daily revenue calculation would change, it would not affect somebody who consumed my DailyRevenue property in any way, since he would be shielded from getter implementation. I understood that sometimes there was , and sometimes there wasn't a 1-1 relationship between fields and properties. depending on the requirements. It seemed ok in my opinion. And that properties are THE way to acces the data in object. I know the difference betweeen private, protected, and public keyword. Now lets get to objectiveC. On what factor should I base my decision about making someting only an ivar or making it as a property? Is the mental model the same as I describe above? I know that ivars are "protected" by default, not "private" asi in c#..But thats ok I think, no big deal for my presnet level of understanding the whole ios development. The point is ivars are not accesible from outside (given i don't make them public..but i won't). The thing that clouds my clear understanding is that I can have IBOutlets from ivars. Why am I seeing internal object data in the UI? *Why is it ok?* On the other hand, if I make an IBOutlet from property, and I do not make it readonly, anybody can change it. Is this ok too? Let's say I have a ParseManager object. This object would use a built in Foundation framework class called NSXMLParser. Obviously my ParseManager will utilize this nsxmlparser's capabilities but will also do some additional work. Now my question is, who should initialize this NSXMLParser object and in which way should I make a reference to it from the ParseManager object, when there is a need to parse something. A) the ParseManager -1) in its default init method (possible here ivar - or - ivar+ppty) -2) with lazyloading in getter (required a ppty here) B) Some other object - who will pass a reference to NSXMLParser object to the ParseManager object. -1) in some custom initializer (initWithParser:(NSXMLPArser *) parser) when creating the ParseManager object.. A1 - the problem is, we create a parser and waste memory while it is not yet needed. However, we can be sure that all methods that are part ot ParserManager object, can use the ivar safely, since it exists. A2 - the problem is, the nsxmlparser is exposed to outside world, although it could be read only. Would we want a parser to be exposed in some scenario? B1 - this could maybe be useful when we would want to use more types of parsers..i dont know... I understand that architectural requirements and and language is not the same. But clearly the two are in relation. How to get out of that mess of my? Please bear with me, I wasn't able to come up with a single ultimate question. And secondly, it's better to not scare me with some superadvanced newspeak that talks about some crazy internals (what the compiler does) and edge cases.

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• Inappropriate Updates?

  - by Tony Davis

  A recent Simple-talk article by Kathi Kellenberger dissected the fastest SQL solution, submitted by Peter Larsson as part of Phil Factor's SQL Speed Phreak challenge, to the classic "running total" problem. In its analysis of the code, the article re-ignited a heated debate regarding the techniques that should, and should not, be deemed acceptable in your search for fast SQL code. Peter's code for running total calculation uses a variation of a somewhat contentious technique, sometimes referred to as a "quirky update": SET @Subscribers = Subscribers = @Subscribers + PeopleJoined - PeopleLeft This form of the UPDATE statement, @variable = column = expression, is documented and it allows you to set a variable to the value returned by the expression. Microsoft does not guarantee the order in which rows are updated in this technique because, in relational theory, a table doesn’t have a natural order to its rows and the UPDATE statement has no means of specifying the order. Traditionally, in cases where a specific order is requires, such as for running aggregate calculations, programmers who used the technique have relied on the fact that the UPDATE statement, without the WHERE clause, is executed in the order imposed by the clustered index, or in heap order, if there isn’t one. Peter wasn’t satisfied with this, and so used the ingenious device of assuring the order of the UPDATE by the use of an "ordered CTE", based on an underlying temporary staging table (a heap). However, in either case, the ordering is still not guaranteed and, in addition, would be broken under conditions of parallelism, or partitioning. Many argue, with validity, that this reliance on a given order where none can ever be guaranteed is an abuse of basic relational principles, and so is a bad practice; perhaps even irresponsible. More importantly, Microsoft doesn't wish to support the technique and offers no guarantee that it will always work. If you put it into production and it breaks in a later version, you can't file a bug. As such, many believe that the technique should never be tolerated in a production system, under any circumstances. Is this attitude justified? After all, both forms of the technique, using a clustered index to guarantee the order or using an ordered CTE, have been tested rigorously and are proven to be robust; although not guaranteed by Microsoft, the ordering is reliable, provided none of the conditions that are known to break it are violated. In Peter's particular case, the technique is being applied to a temporary table, where the developer has full control of the data ordering, and indexing, and knows that the table will never be subject to parallelism or partitioning. It might be argued that, in such circumstances, the technique is not really "quirky" at all and to ban it from your systems would server no real purpose other than to deprive yourself of a reliable technique that has uses that extend well beyond the running total calculations. Of course, it is doubly important that such a technique, including its unsupported status and the assumptions that underpin its success, is fully and clearly documented, preferably even when posting it online in a competition or forum post. Ultimately, however, this technique has been available to programmers throughout the time Sybase and SQL Server has existed, and so cannot be lightly cast aside, even if one sympathises with Microsoft for the awkwardness of maintaining an archaic way of doing updates. After all, a Table hint could easily be devised that, if specified in the WITH (<Table_Hint_Limited>) clause, could be used to request the database engine to do the update in the conventional order. Then perhaps everyone would be satisfied. Cheers, Tony.

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