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  • Is bonding mode=5 a solution against MAC flapping?

    - by Yuri
    There is two are interconnected Cisco WS-2950T. By the one GBIC port on first switch connected a first NIC of bonding interface, and by the one GBIC port on second switch connected a second NIC of bonding interface. Of course the both switches sees the bonding MAC-address only on one interface (eg it is GBIC on first switch) and all incoming traffic for bonding interface passes through this GBIC. But in "mode=5" all outgoing traffic are distributed between the all interfaces that make bond. In this case, the packets will be dropped from the second switch and anyway will going through the first switch? Or the division will be working?

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  • Flash Technology Can Revolutionize your IT Infrastructure

    - by kimberly.billings
    A recent article in the Data Center Journal written by Mark Teter outlines how flash is becoming a disruptive technology in the data center and how it will soon replace HDDs in the storage hierarchy. As Teter explains, the drivers behind this trend are lower cost/performance and power savings; flash is over 100x faster for reads than the fastest HDD, and while it is expensive, it can produce dramatic reductions in the cost of performance as measured in Input/Outputs per second (IOPS). What's more, flash consumes 1/5th the power of HDD, so it's faster AND greener. Teter writes, "when appropriately used, flash turns the current economics of IT performance on its head. That's disruptive." Exadata Smart Flash Cache in the Sun Oracle Database Machine makes intelligent use of flash storage to deliver extreme performance for OLTP and mixed workloads. It intelligently caches data from the Oracle Database replacing slow mechanical I/O operations to disk with very rapid flash memory operations. Exadata Smart Flash Cache is the fundamental technology of the Sun Oracle Database Machine that enables the processing of up to 1 million random I/O operations per second (IOPS), and the scanning of data within Exadata storage at up to 50 GB/second. Are you incorporating flash into your storage strategy? Let us know! Read more: "Flash technology can revolutionize your IT infrastructure", The Data Center Journal, March 30, 2010. Exadata Smart Flash Cache and the Sun Oracle Database Machine white paper var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); try { var pageTracker = _gat._getTracker("UA-13185312-1"); pageTracker._trackPageview(); } catch(err) {}

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  • SQL SERVER – Three Methods to Insert Multiple Rows into Single Table – SQL in Sixty Seconds #024 – Video

    - by pinaldave
    One of the biggest ask I have always received from developers is that if there is any way to insert multiple rows into a single table in a single statement. Currently when developers have to insert any value into the table they have to write multiple insert statements. First of all this is not only boring it is also very much time consuming as well. Additionally, one has to repeat the same syntax so many times that the word boring becomes an understatement. In the following quick video we have demonstrated three different methods to insert multiple values into a single table. -- Insert Multiple Values into SQL Server CREATE TABLE #SQLAuthority (ID INT, Value VARCHAR(100)); Method 1: Traditional Method of INSERT…VALUE -- Method 1 - Traditional Insert INSERT INTO #SQLAuthority (ID, Value) VALUES (1, 'First'); INSERT INTO #SQLAuthority (ID, Value) VALUES (2, 'Second'); INSERT INTO #SQLAuthority (ID, Value) VALUES (3, 'Third'); Clean up -- Clean up TRUNCATE TABLE #SQLAuthority; Method 2: INSERT…SELECT -- Method 2 - Select Union Insert INSERT INTO #SQLAuthority (ID, Value) SELECT 1, 'First' UNION ALL SELECT 2, 'Second' UNION ALL SELECT 3, 'Third'; Clean up -- Clean up TRUNCATE TABLE #SQLAuthority; Method 3: SQL Server 2008+ Row Construction -- Method 3 - SQL Server 2008+ Row Construction INSERT INTO #SQLAuthority (ID, Value) VALUES (1, 'First'), (2, 'Second'), (3, 'Third'); Clean up -- Clean up DROP TABLE #SQLAuthority; Related Tips in SQL in Sixty Seconds: SQL SERVER – Insert Multiple Records Using One Insert Statement – Use of UNION ALL SQL SERVER – 2008 – Insert Multiple Records Using One Insert Statement – Use of Row Constructor I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. If we like your idea we promise to share with you educational material. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology, Video

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  • SQL SERVER – DATEDIFF – Accuracy of Various Dateparts

    - by pinaldave
    I recently received the following question through email and I found it very interesting so I want to share it with you. “Hi Pinal, In SQL statement below the time difference between two given dates is 3 sec, but when checked in terms of Min it says 1 Min (whereas the actual min is 0.05Min) SELECT DATEDIFF(MI,'2011-10-14 02:18:58' , '2011-10-14 02:19:01') AS MIN_DIFF Is this is a BUG in SQL Server ?” Answer is NO. It is not a bug; it is a feature that works like that. Let us understand that in a bit more detail. When you instruct SQL Server to find the time difference in minutes, it just looks at the minute section only and completely ignores hour, second, millisecond, etc. So in terms of difference in minutes, it is indeed 1. The following will also clear how DATEDIFF works: SELECT DATEDIFF(YEAR,'2011-12-31 23:59:59' , '2012-01-01 00:00:00') AS YEAR_DIFF The difference between the above dates is just 1 second, but in terms of year difference it shows 1. If you want to have accuracy in seconds, you need to use a different approach. In the first example, the accurate method is to find the number of seconds first and then divide it by 60 to convert it to minutes. SELECT DATEDIFF(second,'2011-10-14 02:18:58' , '2011-10-14 02:19:01')/60.0 AS MIN_DIFF Even though the concept is very simple it is always a good idea to refresh it. Please share your related experience with me through your comments. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DateTime, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Unity 3D (with Nvidia driver) becomes very slow and laggy

    - by Graham
    How can I prevent my Unity 3D desktop from becoming slow after a while, given that I have an Nvidia Quadro NVS 290 graphics in TwinView mode? The desktop starts out fast on login, but becomes slow / lagging / hesitant / high latency after a while, symptoms being spikes in CPU usage by /usr/bin/X whenever I cause any graphical activity with the mouse or keyboard (e.g. typing, changing tabs, dragging windows). The desktop remains slow even with all windows (except htop in Terminal) and extraneous processes killed. Detail: Changing tabs in Terminal takes about a second, and X spikes to 76% CPU. As I type into Firefox, X spikes to 95% CPU. Dragging Termiinal window, X goes to 70% CPU. Basically, every graphical action sends CPU usage of X through the roof. Device: Nvidia Quadro NVS 290 Driver package: binary driver nvidia-current-updates (280.13-0ubuntu5) Dual Monitors: Pair of DELL UltraSharp 1908FP in TwinView (X screen 2560x1024) OS: Fresh install of Ubuntu 11.10 amd64 Desktop with all updates. Hardware: Dell Precision T5400 Workstation Pastebin of Xorg.0.log Pastebin of xorg.conf Pastebin of nvidia-xconfig -t output (easier to read than xorg.conf) Output of /usr/lib/nux/unity_support_test -p: To obtain the following htop screenshow I typed "asdf" several times in in this text box, alt-tabbed to Terminal and took a screenshot of the high X CPU usage. This also happens when firefox is not running: Quadro NVS 290 has "No" thermal sensor according to sensors-detect: Next adapter: NVIDIA i2c adapter 0 at 2:00.0 (i2c-0) Do you want to scan it? (YES/no/selectively): Client found at address 0x50 Probing for `Analog Devices ADM1033'... No Probing for `Analog Devices ADM1034'... No P robing for `SPD EEPROM'... No Probing for `EDID EEPROM'... Yes (confidence 8, not a hardware monitoring chip) I tried the nouveau driver by disabling the nvidia-current-updates under Additional Drivers, but Ubuntu and xrandr -q fail to detect the second monitor. This may be issue 737349. Funniest thing is that Nouveau wiki says that XRandR 1.2 dual-monitor is supported so it should work with a second monitor.

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  • Find The Bug

    - by Alois Kraus
    What does this code print and why?             HashSet<int> set = new HashSet<int>();             int[] data = new int[] { 1, 2, 1, 2 };             var unique = from i in data                          where set.Add(i)                          select i;   // Compiles to: var unique = Enumerable.Where(data, (i) => set.Add(i));             foreach (var i in unique)             {                 Console.WriteLine("First: {0}", i);             }               foreach (var i in unique)             {                 Console.WriteLine("Second: {0}", i);             }   The output is: First: 1 First: 2 Why is there no output of the second loop? The reason is that LINQ does not cache the results of the collection but it does recalculate the contents for every new enumeration again. Since I have used state (the Hashset does decide which entries are part of the output) I do arrive with an empty sequence since Add of the Hashset will return false for all values I have already passed in leaving nothing to return a second time. The solution is quite simple: Use the Distinct extension method or cache the results by calling .ToList() or ToArray() for the result of the LINQ query. Lession Learned: Do never forget to think about state in Where clauses!

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  • Update to 13.10: blank screen and repeated suspend on resume from suspend

    - by user208026
    On my Asus x201e, after updating from 13.04 to 13.10, intermittently when awaking from suspend, my screen will blink to a black screen a few times, offers a lock screen, and then go back to suspend unexpectedly (during this it is possible to quickly login to the desktop before the system suspends again). This will repeat each time I subsequently awake it from suspend. Only a restart will escape the suspend loop. The problem only occurs when suspending by closing lid, not by manual (pm-suspend) or menu suspend. Opening the lid after a manual or menu-initiated suspend works as expected. When an external monitor is attached, the black screen and second lock screen still appear twice upon wake, but the system does not fall back into suspend (though networking is disabled and needs to be restarted). This issue arose in tandem with the already raised issue regarding networking not restarting on wake from suspend, though appears to be distinct from that issue and persists after a fix is applied for the networking issue. This issue only occurs on waking from suspend, never upon booting. And only on the second suspend cycle after reboot. This question duplicates the second, unanswered question included in this closed question and seems to correspond with this reported bug. Any ideas for a workaround?

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  • Tip 13 : Kill a process using C#, from local to remote

    - by StanleyGu
    1. My first choice is always to try System.Diagnostics to kill a process 2. The first choice works very well in killing local processes. I thought the first choice should work for killing remote process too because process.kill() method is overloaded with second argument of machine name. I pass process name plus remote machine name and call the process.kill() method 3. Unfortunately, it gives me error message of "Feature is not supported for remote machines.". Apparently, you can query but not kill a remote process using Process class in System.Diagnostics. The MSDN library document explicitly states that about Process class: Provides access to local and remote processes and enables you to start and stop local system processes. 4. I try my second choice: using System.Management to kill a process running on a remote machine. Make sure add references to System.Management.dll and System.Management.Instrumentation.dll 5. The second choice works very well in killing a remote process. Just need to make sure the account running your program must be configured to have permission to kill a process running on the remote machine.  

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  • iWork '09 Keynote: is there is straightforward way to 'dim' and 'highlight' each item in a bullet li

    - by doug
    I have a bullet list on a slide: first item second item third item What I want to do is show those three bulleted items in a sequence like this: first bullet appears first bullet dims second bullet appears second bullet dims third bullet appears third bullet dims In other words, only one bullet is shown at a time (the one i am current discussing) to reduce audience distraction by what comes next or what i just finished discussing (the prior bullet). This is such a common thing to do, there's got to be a simple, reliable way to do it. The only way I know of is to configure the items individually (using "Build In" and "Action" on each bullet item, which is not only slow but doesn't work well). Another way i've found--which, again is very slow--is to create my bullet list not by selecting a bullet list, but to build the list manually with text boxes (one bullet item per text box) then line them up as a list. This way it's easier to manipulate them independently--again though, takes way too long to do one slide this way.

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  • SQL SERVER – DMV sys.dm_exec_describe_first_result_set_for_object – Describes the First Result Metadata for the Module

    - by pinaldave
    Here is another interesting follow up blog post of SQL SERVER – sp_describe_first_result_set New System Stored Procedure in SQL Server 2012. While I was writing earlier blog post I had come across DMV sys.dm_exec_describe_first_result_set_for_object as well. I found that SQL Server 2012 is providing all this quick and new features which quite often we miss  to learn it and when in future someone demonstrates the same to us, we express our surprise on the subject. DMV sys.dm_exec_describe_first_result_set_for_object returns result set which describes the columns used in the stored procedure. Here is the quick example. Let us first create stored procedure. USE [AdventureWorks] GO ALTER PROCEDURE [dbo].[CompSP] AS SELECT [DepartmentID] id ,[Name] n ,[GroupName] gn FROM [HumanResources].[Department] GO Now let us run following two DMV which gives us meta data description of the stored procedure passed as a parameter. Option1: Pass second parameter @include_browse_information as a 0. SELECT * FROM sys.dm_exec_describe_first_result_set_for_object ( OBJECT_ID('[dbo].[CompSP]'),0) AS Table1 GO Option2: Pass second parameter @include_browse_information as a 1. SELECT * FROM sys.dm_exec_describe_first_result_set_for_object ( OBJECT_ID('[dbo].[CompSP]'),1) AS Table1 GO Here is the result of Option1 and Option2. If you see the result, there is absolutely no difference between the results. Both of the resultset are returning column names which are aliased in the stored procedure. Let us scroll on the right side and you will notice that there is clear difference in some columns. You will see in second resultset source_database, Source_schema as well few other columns are reporting original table instead of NULL values. When @include_browse_information result is set to 1 it will provide the columns details of the underlying table. I have just discovered this DMV, I have yet to use it in production code and find out where exactly I will use this DMV. Do you have any idea? Does any thing comes up to your mind where this DMV can be helpful. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Keeping multiple root directories in a single partition

    - by intuited
    I'm working out a partition scheme for a new install. I'd like to keep the root filesystem fairly small and static, so that I can use LVM snapshots to do backups without having to allocate a ton of space for the snapshot. However, I'd also like to keep the number of total partitions small. Even with LVM, there's inevitably some wasted space and it's still annoying and vaguely dangerous to allocate more. So there seem to be a couple of different options: Have the partition that will contain bulky, variable files, like /srv, /var, and /home, be the root partition, and arrange for the core system state — /etc, /usr, /lib, etc. — to live in a second partition. These files can (I think) be backed up using a different backup scheme, and I don't think LVM snapshots will be necessary for them. The opposite: putting the big variable directories on the second partition, and having the essential system directories live on the root FS. Either of these options require that certain directories be pointers of some variety to subdirectories of a second partition. I'm aware of two different ways to do this: symlinks and bind-mounts. Is one better than the other for this purpose? Is there another option? Do any of the various Ubuntu installation media/strategies support this style of partition layout?

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  • Failures when copying between two external drives on the same controller

    - by Krzysztof Kosinski
    I'm encountering a weird problem which is present both on Ubuntu 9.10 and 10.04, on two different machines. When trying to copy between two external drives connected to the same USB controller, the transfer will randomly hang at some random time (after copying 300MB, 1GB, 10GB - it doesn't appear to depend on the dataset being copied). The hang appears to happen faster in 10.04. It appears to happen slower if both drives are connected to a hub. If the drives are connected to 2 distinct physical ports on the machine, the hang will be very fast. Hangs cannot be reproduced if: Data is copied from the first external drive to an internal drive, then to the second external drive Drives are connected to different USB controllers, for example the first one is connected to the built-in controller and the second one via an external PCMCIA controller. lspci says the first machine has an Intel ICH9 USB controller, the second an Intel ICH4. Is this a hardware problem, a kernel problem or a software issue? I used Nautilus when copying the files.

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  • Numbered list with subclauses

    - by Barry Clearwater
    I'm trying to create a legal document with decimal numbered subclauses, then alpha and roman subsub and subsubsub clauses. (whew!) `1. MAIN HEADING 1.1 This is an example of a sub-clause and you can see that even though the words continue on to the right, it would be best if it wrapped around and formed a block to the right of the decimal number 1.2 In doing so the normal second clause should also wrap around but the second subsequent clause should hang in from the left and be in a block. See below for the remaining clauses (a) this list is completely for demonstration and should not be construed as legal language in any way, nor should make sense in that (b) should the indentation take more than: i) this many lines it would be overly big 11) legal numbering continues in the sub-sub clauses with the use of lower roman lettering and should flow below in a block iii) and continue the formatting on to the next line but be underneath the body of the the text and not begin directly below the number itself. In this example the text carries out to the right but I need it to wrap around underneath. Sorry its so wordy, need this to show the example. 2. Second Clause Heading 2.1 and so it continues thus I've found the examples for decimal numbering but they do not create a block out to the right of the number, and they carry on with multiple decimals rather than alpha and roman sub clauses.

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  • Adding Vertices to a dynamic mesh via Method Call

    - by Raven Dreamer
    I have a C# Struct with a static method, "Get Shape" which populates a List with the vertices of a polyhedron. Method Signature: public static void GetShape(Block b, int x, int y, int z, List<Vector3> vertices, List<int> triangles, List<Vector2> uvs, List<Vector2> uv2s) Adding directly to the vertices list (via vertices.Add(vector3) ), the code works as expected, and the new polyhedron appears when I trigger the method. However, I want to do some processing on the vertices I'm adding (a rotation), and the most sensible way I can think to do that is by creating a separate list of Vector3s, and then combining the lists when I'm done. However, vertices.AddRange(newVerts) does not add the shape to the mesh, nor does a foreach loop with verts.Add(vertices[i]). And this is before I've added in any of the processing! I have a feeling this might stem from passing the list of vertices in as a parameter, rather than returning a list and then adding to the vertices in the calling object, but since I'm filling 4 lists, I was trying to avoid having to create a data struct to return all four at once. Any ideas? The working version of the method is reprinted below, in full: public static void GetShape(Block b, int x, int y, int z, List<Vector3> vertices, List<int> triangles, List<Vector2> uvs, List<Vector2> uv2s) { //List<Vector3> vertices = new List<Vector3>(); int l_blockShape = b.blockShape; int l_blockType = b.blockType; //CheckFace checks if the block is empty //if this block is empty, don't draw anything. int vertexIndex; //only y faces need to be hidden. //if((l_blockShape & BlockShape.NegZFace) == BlockShape.NegZFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.2f, y + 1, z+.2f)); vertices.Add(new Vector3(x+.8f, y + 1, z+.2f)); vertices.Add(new Vector3(x+.8f, y , z+.2f)); vertices.Add(new Vector3(x+.2f, y , z+.2f)); // first triangle for the face triangles.Add(vertexIndex); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+3); // second triangle for the face triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+3); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } //XY Z+1 face //if((l_blockShape & BlockShape.PosZFace) == BlockShape.PosZFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.8f, y + 1, z+.8f)); vertices.Add(new Vector3(x+.2f, y + 1, z+.8f)); vertices.Add(new Vector3(x+.2f, y , z+.8f)); vertices.Add(new Vector3(x+.8f, y , z+.8f)); // first triangle for the face triangles.Add(vertexIndex); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+3); // second triangle for the face triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+3); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } //ZY face //if((l_blockShape & BlockShape.NegXFace) == BlockShape.NegXFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.2f, y + 1, z+.8f)); vertices.Add(new Vector3(x+.2f, y + 1, z+.2f)); vertices.Add(new Vector3(x+.2f, y , z+.2f)); vertices.Add(new Vector3(x+.2f, y , z+.8f)); // first triangle for the face triangles.Add(vertexIndex); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+3); // second triangle for the face triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+3); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } //ZY X+1 face // if((l_blockShape & BlockShape.PosXFace) == BlockShape.PosXFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.8f, y + 1, z+.2f)); vertices.Add(new Vector3(x+.8f, y + 1, z+.8f)); vertices.Add(new Vector3(x+.8f, y , z+.8f)); vertices.Add(new Vector3(x+.8f, y , z+.2f)); // first triangle for the face triangles.Add(vertexIndex); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+3); // second triangle for the face triangles.Add(vertexIndex+1); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+3); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } //ZX face if((l_blockShape & BlockShape.NegYFace) == BlockShape.NegYFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.8f, y , z+.8f)); vertices.Add(new Vector3(x+.8f, y , z+.2f)); vertices.Add(new Vector3(x+.2f, y , z+.2f)); vertices.Add(new Vector3(x+.2f, y , z+.8f)); // first triangle for the face triangles.Add(vertexIndex+3); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex); // second triangle for the face triangles.Add(vertexIndex+3); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+1); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } //ZX + 1 face if((l_blockShape & BlockShape.PosYFace) == BlockShape.PosYFace) { vertexIndex = vertices.Count; //top left, top right, bottom right, bottom left vertices.Add(new Vector3(x+.8f, y+1 , z+.2f)); vertices.Add(new Vector3(x+.8f, y+1 , z+.8f)); vertices.Add(new Vector3(x+.2f, y+1 , z+.8f)); vertices.Add(new Vector3(x+.2f, y+1 , z+.2f)); // first triangle for the face triangles.Add(vertexIndex+3); triangles.Add(vertexIndex+1); triangles.Add(vertexIndex); // second triangle for the face triangles.Add(vertexIndex+3); triangles.Add(vertexIndex+2); triangles.Add(vertexIndex+1); //UVs for the face uvs.Add( new Vector2(0,1)); uvs.Add( new Vector2(1,1)); uvs.Add( new Vector2(1,0)); uvs.Add( new Vector2(0,0)); //UV2s (lightmapping?) uv2s.Add( new Vector2(0,1)); uv2s.Add( new Vector2(1,1)); uv2s.Add( new Vector2(1,0)); uv2s.Add( new Vector2(0,0)); } }

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  • What is the correct configuration for multiple apache2 vhosts and multiple php5-fpm pools?

    - by farinspace
    I have a group of sites (group A) which I would like to run using one php5-fpm pool and a second group of sites (group B) which I would like to run using a second php5-fpm pool. I can effectively define/create the pool in the fpm.conf file and I confirmed that it is running with the different user/group I've defined. However I am unclear as to how to setup the apache virtual host config. I've tried a few apache2 configurations but I seem to not be able to add the second pool. If you've done this please help.

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  • C#: Handling Notifications: inheritance, events, or delegates?

    - by James Michael Hare
    Often times as developers we have to design a class where we get notification when certain things happen. In older object-oriented code this would often be implemented by overriding methods -- with events, delegates, and interfaces, however, we have far more elegant options. So, when should you use each of these methods and what are their strengths and weaknesses? Now, for the purposes of this article when I say notification, I'm just talking about ways for a class to let a user know that something has occurred. This can be through any programmatic means such as inheritance, events, delegates, etc. So let's build some context. I'm sitting here thinking about a provider neutral messaging layer for the place I work, and I got to the point where I needed to design the message subscriber which will receive messages from the message bus. Basically, what we want is to be able to create a message listener and have it be called whenever a new message arrives. Now, back before the flood we would have done this via inheritance and an abstract class: 1:  2: // using inheritance - omitting argument null checks and halt logic 3: public abstract class MessageListener 4: { 5: private ISubscriber _subscriber; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber) 11: { 12: _subscriber = subscriber; 13: _messageThread = new Thread(MessageLoop); 14: _messageThread.Start(); 15: } 16:  17: // user will override this to process their messages 18: protected abstract void OnMessageReceived(Message msg); 19:  20: // handle the looping in the thread 21: private void MessageLoop() 22: { 23: while(!_isHalted) 24: { 25: // as long as processing, wait 1 second for message 26: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 27: if(msg != null) 28: { 29: OnMessageReceived(msg); 30: } 31: } 32: } 33: ... 34: } It seems so odd to write this kind of code now. Does it feel odd to you? Maybe it's just because I've gotten so used to delegation that I really don't like the feel of this. To me it is akin to saying that if I want to drive my car I need to derive a new instance of it just to put myself in the driver's seat. And yet, unquestionably, five years ago I would have probably written the code as you see above. To me, inheritance is a flawed approach for notifications due to several reasons: Inheritance is one of the HIGHEST forms of coupling. You can't seal the listener class because it depends on sub-classing to work. Because C# does not allow multiple-inheritance, I've spent my one inheritance implementing this class. Every time you need to listen to a bus, you have to derive a class which leads to lots of trivial sub-classes. The act of consuming a message should be a separate responsibility than the act of listening for a message (SRP). Inheritance is such a strong statement (this IS-A that) that it should only be used in building type hierarchies and not for overriding use-specific behaviors and notifications. Chances are, if a class needs to be inherited to be used, it most likely is not designed as well as it could be in today's modern programming languages. So lets look at the other tools available to us for getting notified instead. Here's a few other choices to consider. Have the listener expose a MessageReceived event. Have the listener accept a new IMessageHandler interface instance. Have the listener accept an Action<Message> delegate. Really, all of these are different forms of delegation. Now, .NET events are a bit heavier than the other types of delegates in terms of run-time execution, but they are a great way to allow others using your class to subscribe to your events: 1: // using event - ommiting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private bool _isHalted = false; 6: private Thread _messageThread; 7:  8: // assign the subscriber and start the messaging loop 9: public MessageListener(ISubscriber subscriber) 10: { 11: _subscriber = subscriber; 12: _messageThread = new Thread(MessageLoop); 13: _messageThread.Start(); 14: } 15:  16: // user will override this to process their messages 17: public event Action<Message> MessageReceived; 18:  19: // handle the looping in the thread 20: private void MessageLoop() 21: { 22: while(!_isHalted) 23: { 24: // as long as processing, wait 1 second for message 25: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 26: if(msg != null && MessageReceived != null) 27: { 28: MessageReceived(msg); 29: } 30: } 31: } 32: } Note, now we can seal the class to avoid changes and the user just needs to provide a message handling method: 1: theListener.MessageReceived += CustomReceiveMethod; However, personally I don't think events hold up as well in this case because events are largely optional. To me, what is the point of a listener if you create one with no event listeners? So in my mind, use events when handling the notification is optional. So how about the delegation via interface? I personally like this method quite a bit. Basically what it does is similar to inheritance method mentioned first, but better because it makes it easy to split the part of the class that doesn't change (the base listener behavior) from the part that does change (the user-specified action after receiving a message). So assuming we had an interface like: 1: public interface IMessageHandler 2: { 3: void OnMessageReceived(Message receivedMessage); 4: } Our listener would look like this: 1: // using delegation via interface - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private IMessageHandler _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler.OnMessageReceived(msg); 28: } 29: } 30: } 31: } And they would call it by creating a class that implements IMessageHandler and pass that instance into the constructor of the listener. I like that this alleviates the issues of inheritance and essentially forces you to provide a handler (as opposed to events) on construction. Well, this is good, but personally I think we could go one step further. While I like this better than events or inheritance, it still forces you to implement a specific method name. What if that name collides? Furthermore if you have lots of these you end up either with large classes inheriting multiple interfaces to implement one method, or lots of small classes. Also, if you had one class that wanted to manage messages from two different subscribers differently, it wouldn't be able to because the interface can't be overloaded. This brings me to using delegates directly. In general, every time I think about creating an interface for something, and if that interface contains only one method, I start thinking a delegate is a better approach. Now, that said delegates don't accomplish everything an interface can. Obviously having the interface allows you to refer to the classes that implement the interface which can be very handy. In this case, though, really all you want is a method to handle the messages. So let's look at a method delegate: 1: // using delegation via delegate - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler(msg); 28: } 29: } 30: } 31: } Here the MessageListener now takes an Action<Message>.  For those of you unfamiliar with the pre-defined delegate types in .NET, that is a method with the signature: void SomeMethodName(Message). The great thing about delegates is it gives you a lot of power. You could create an anonymous delegate, a lambda, or specify any other method as long as it satisfies the Action<Message> signature. This way, you don't need to define an arbitrary helper class or name the method a specific thing. Incidentally, we could combine both the interface and delegate approach to allow maximum flexibility. Doing this, the user could either pass in a delegate, or specify a delegate interface: 1: // using delegation - give users choice of interface or delegate 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // passes the interface method as a delegate using method group 19: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 20: : this(subscriber, handler.OnMessageReceived) 21: { 22: } 23:  24: // handle the looping in the thread 25: private void MessageLoop() 26: { 27: while(!_isHalted) 28: { 29: // as long as processing, wait 1 second for message 30: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 31: if(msg != null) 32: { 33: _handler(msg); 34: } 35: } 36: } 37: } } This is the method I tend to prefer because it allows the user of the class to choose which method works best for them. You may be curious about the actual performance of these different methods. 1: Enter iterations: 2: 1000000 3:  4: Inheritance took 4 ms. 5: Events took 7 ms. 6: Interface delegation took 4 ms. 7: Lambda delegate took 5 ms. Before you get too caught up in the numbers, however, keep in mind that this is performance over over 1,000,000 iterations. Since they are all < 10 ms which boils down to fractions of a micro-second per iteration so really any of them are a fine choice performance wise. As such, I think the choice of what to do really boils down to what you're trying to do. Here's my guidelines: Inheritance should be used only when defining a collection of related types with implementation specific behaviors, it should not be used as a hook for users to add their own functionality. Events should be used when subscription is optional or multi-cast is desired. Interface delegation should be used when you wish to refer to implementing classes by the interface type or if the type requires several methods to be implemented. Delegate method delegation should be used when you only need to provide one method and do not need to refer to implementers by the interface name.

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  • External monitor is blank if I boot with the monitor plugged in

    - by Ronald
    Ubuntu 12.04 has problem with Intel GM45 Chipset, featuring the the Mobile Intel® Graphics Media Accelerator (GMA) 4500MHD I have a COMPAQ Presario CQ70 laptop with an Intel GM45 chipset that features the Mobile Intel® Graphics Media Accelerator (GMA) 4500MHD. I was using the second HDMI video port to drive both a projector or a second monitor. Everything was working fine under Ubuntu 8.04, 9.04, 10.04 and 11.04, however, when I upgraded to 12.04 the second monitor stopped working. What I mean when I say stopped working is: boot with monitor plugged in. Blank screen! Power off, unplug monitor and power on everything works. Plug in monitor (only mode that works in Mirror mode) two monitors that look same. Close laptop lid. screen goes blank only option for useful system is power off and unplug monitor. If I attempt to Adjust the monitor to maximum resolution that the monitor will handle and turn off mirror mode nothing can be moved onto that screen. This all worked fine with earlier versions of Ubuntu, is there a notes about the changes to the graphics management system in 12.04, like there is for the resolver change?

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  • Does command/query separation apply to a method that creates an object and returns its ID?

    - by Gilles
    Let's pretend we have a service that calls a business process. This process will call on the data layer to create an object of type A in the database. Afterwards we need to call again on another class of the data layer to create an instance of type B in the database. We need to pass some information about A for a foreign key. In the first method we create an object (modify state) and return it's ID (query) in a single method. In the second method we have two methods, one (createA) for the save and the other (getId) for the query. public void FirstMethod(Info info) { var id = firstRepository.createA(info); secondRepository.createB(id); } public void SecondMethod(Info info) { firstRepository.createA(info); var key = firstRepository.getID(info); secondRepository.createB(key); } From my understanding the second method follows command query separation more fully. But I find it wasteful and counter-intuitive to query the database to get the object we have just created. How do you reconcile CQS with such a scenario? Does only the second method follow CQS and if so is it preferable to use it in this case?

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  • Use linefeed or carriage return in Subversion commit message from the command line

    - by Scott
    I am using Subversion 1.6.6 on Ubuntu 10.04. I would like to insert a carriage return, or linefeed, or newline into my commit message so that when reading the log, the comments are formatted appropriately. It works fine when I use the system editor, or specify a file for the commit comment, but what I really want is to be able to do something like the following: svn ci -m "This is the first line\nThis is the second line" and have the comment presented as: This is the first line This is the second line My example does not work, it produces output: This is the first line\nThis is the second line So, is there a way to do this? If so, how?

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  • BizTalk: History of one project architecture

    - by Leonid Ganeline
    "In the beginning God made heaven and earth. Then he started to integrate." At the very start was the requirement: integrate two working systems. Small digging up: It was one system. It was good but IT guys want to change it to the new one, much better, chipper, more flexible, and more progressive in technologies, more suitable for the future, for the faster world and hungry competitors. One thing. One small, little thing. We cannot turn off the old system (call it A, because it was the first), turn on the new one (call it B, because it is second but not the last one). The A has a hundreds users all across a country, they must study B. A still has a lot nice custom features, home-made features that cannot disappear. These features have to be moved to the B and it is a long process, months and months of redevelopment. So, the decision was simple. Let’s move not jump, let’s both systems working side-by-side several months. In this time we could teach the users and move all custom A’s special functionality to B. That automatically means both systems should work side-by-side all these months and use the same data. Data in A and B must be in sync. That’s how the integration projects get birth. Moreover, the specific of the user tasks requires the both systems must be in sync in real-time. Nightly synchronization is not working, absolutely.   First draft The first draft seems simple. Both systems keep data in SQL databases. When data changes, the Create, Update, Delete operations performed on the data, and the sync process could be started. The obvious decision is to use triggers on tables. When we are talking about data, we are talking about several entities. For example, Orders and Items [in Orders]. We decided to use the BizTalk Server to synchronize systems. Why it was chosen is another story. Second draft   Let’s take an example how it works in more details. 1.       User creates a new entity in the A system. This fires an insert trigger on the entity table. Trigger has to pass the message “Entity created”. This message includes all attributes of the new entity, but I focused on the Id of this entity in the A system. Notation for this message is id.A. System A sends id.A to the BizTalk Server. 2.       BizTalk transforms id.A to the format of the system B. This is easiest part and I will not focus on this kind of transformations in the following text. The message on the picture is still id.A but it is in slightly different format, that’s why it is changing in color. BizTalk sends id.A to the system B. 3.       The system B creates the entity on its side. But it uses different id-s for entities, these id-s are id.B. System B saves id.A+id.B. System B sends the message id.A+id.B back to the BizTalk. 4.       BizTalk sends the message id.A+id.B to the system A. 5.       System A saves id.A+id.B. Why both id-s should be saved on both systems? It was one of the next requirements. Users of both systems have to know the systems are in sync or not in sync. Users working with the entity on the system A can see the id.B and use it to switch to the system B and work there with the copy of the same entity. The decision was to store the pairs of entity id-s on both sides. If there is only one id, the entities are not in sync yet (for the Create operation). Third draft Next problem was the reliability of the synchronization. The synchronizing process can be interrupted on each step, when message goes through the wires. It can be communication problem, timeout, temporary shutdown one of the systems, the second system cannot be synchronized by some internal reason. There were several potential problems that prevented from enclosing the whole synchronization process in one transaction. Decision was to restart the whole sync process if it was not finished (in case of the error). For this purpose was created an additional service. Let’s call it the Resync service. We still keep the id pairs in both systems, but only for the fast access not for the synchronization process. For the synchronizing these id-s now are kept in one main place, in the Resync service database. The Resync service keeps record as: ·       Id.A ·       Id.B ·       Entity.Type ·       Operation (Create, Update, Delete) ·       IsSyncStarted (true/false) ·       IsSyncFinished (true/false0 The example now looks like: 1.       System A creates id.A. id.A is saved on the A. Id.A is sent to the BizTalk. 2.       BizTalk sends id.A to the Resync and to the B. id.A is saved on the Resync. 3.       System B creates id.B. id.A+id.B are saved on the B. id.A+id.B are sent to the BizTalk. 4.       BizTalk sends id.A+id.B to the Resync and to the A. id.A+id.B are saved on the Resync. 5.       id.A+id.B are saved on the B. Resync changes the IsSyncStarted and IsSyncFinished flags accordingly. The Resync service implements three main methods: ·       Save (id.A, Entity.Type, Operation) ·       Save (id.A, id.B, Entity.Type, Operation) ·       Resync () Two Save() are used to save id-s to the service storage. See in the above example, in 2 and 4 steps. What about the Resync()? It is the method that finishes the interrupted synchronization processes. If Save() is started by the trigger event, the Resync() is working as an independent process. It periodically scans the Resync storage to find out “unfinished” records. Then it restarts the synchronization processes. It tries to synchronize them several times then gives up.     One more thing, both systems A and B must tolerate duplicates of one synchronizing process. Say on the step 3 the system B was not able to send id.A+id.B back. The Resync service must restart the synchronization process that will send the id.A to B second time. In this case system B must just send back again also created id.A+id.B pair without errors. That means “tolerate duplicates”. Fourth draft Next draft was created only because of the aesthetics. As it always happens, aesthetics gave significant performance gain to the whole system. First was the stupid question. Why do we need this additional service with special database? Can we just master the BizTalk to do something like this Resync() does? So the Resync orchestration is doing the same thing as the Resync service. It is started by the Id.A and finished by the id.A+id.B message. The first works as a Start message, the second works as a Finish message.     Here is a diagram the whole process without errors. It is pretty straightforward. The Resync orchestration is waiting for the Finish message specific period of time then resubmits the Id.A message. It resubmits the Id.A message specific number of times then gives up and gets suspended. It can be resubmitted then it starts the whole process again: waiting [, resubmitting [, get suspended]], finishing. Tuning up The Resync orchestration resubmits the id.A message with special “Resubmitted” flag. The subscription filter on the Resync orchestration includes predicate as (Resubmit_Flag != “Resubmitted”). That means only the first Sync orchestration starts the Resync orchestration. Other Sync orchestration instantiated by the resubmitting can finish this Resync orchestration but cannot start another instance of the Resync   Here is a diagram where system B was inaccessible for some period of time. The Resync orchestration resubmitted the id.A two times. Then system B got the response the id.A+id.B and this finished the Resync service execution. What is interesting about this, there were submitted several identical id.A messages and only one id.A+id.B message. Because of this, the system B and the Resync must tolerate the duplicate messages. We also told about this requirement for the system B. Now the same requirement is for the Resunc. Let’s assume the system B was very slow in the first response and the Resync service had time to resubmit two id.A messages. System B responded not, as it was in previous case, with one id.A+id.B but with two id.A+id.B messages. First of them finished the Resync execution for the id.A. What about the second id.A+id.B? Where it goes? So, we have to add one more internal requirement. The whole solution must tolerate many identical id.A+id.B messages. It is easy task with the BizTalk. I added the “SinkExtraMessages” subscriber (orchestration with one receive shape), that just get these messages and do nothing. Real design Real architecture is much more complex and interesting. In reality each system can submit several id.A almost simultaneously and completely unordered. There are not only the “Create entity” operation but the Update and Delete operations. And these operations relate each other. Say the Update operation after Delete means not the same as Update after Create. In reality there are entities related each other. Say the Order and Order Items. Change on one of it could start the series of the operations on another. Moreover, the system internals are the “black boxes” and we cannot predict the exact content and order of the operation series. It worth to say, I had to spend a time to manage the zombie message problems. The zombies are still here, but this is not a problem now. And this is another story. What is interesting in the last design? One orchestration works to help another to be more reliable. Why two orchestration design is more reliable, isn’t it something strange? The Synch orchestration takes all the message exchange between systems, here is the area where most of the errors could happen. The Resync orchestration sends and receives messages only within the BizTalk server. Is there another design? Sure. All Resync functionality could be implemented inside the Sync orchestration. Hey guys, some other ideas?

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  • tcp flags in iptables: What's the difference between RST SYN and RST and SYN RST ? When to use ALL?

    - by Kris
    I'm working on a firewall for a virtual dedicated server and one of the things I'm looking into is port scanners. TCP flags are used for protection. I have 2 questions. The rule: -p tcp --tcp-flags SYN,ACK,FIN,RST SYN -j DROP First argument says check packets with flag SYN Second argument says make sure the flags ACK,FIN,RST SYN are set And when that's the case (there's a match), drop the tcp packet First question: I understand the meaning of RST and RST/ACK but in the second argument RST SYN is being used. What's the difference between RST SYN and RST and SYN RST ? Is there a "SYN RST" flag in a 3 way handshake ? Second question is about the difference between -p tcp --tcp-flags SYN,ACK,FIN,RST SYN -j DROP and -p tcp --tcp-flags ALL SYN,ACK,FIN,RST SYN -j DROP When should ALL be used ? When I use ALL, does that mean if the tcp packet with the syn flag doesn't have the ACK "and" the FIN "and" the RST SYN flags set, there will be no match ?

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  • What is the best way to code the XNA Game Server for FPS game?

    - by AgentFire
    I'm writing a FPS XNA game. It gonna be multiplayer so I came up with following: I'm making two different assemblies — one for the game logic and the second for drawing it and the game irrelevant stuff (like rocket trails). The type of the connection is client-server (not peer-to-peer), so every client at first connects to the server and then the game begins. I'm completly decided to use XNA.Framework.Game class for the clients to run their game in window (or fullscreen) and the GameComponent/DrawableGameComponent classes to store the game objects and update&draw them on each frame. Next, I want to get the answer to the question: What should I do on the server side? I got few options: Create my own Game class on the server, which will process all the game logic (only, no graphics). The reason why I am not using the standart Game class is when I call Game.Run() the white window appears and I cant figure out how to get rid of it. Use somehow the original XNA's Game class, which is already has the GameComponent collection and Update event (60 times per second, just what I need). UPDATE: I got more questions: First, what socket mode should I use? TCP or UDP? And how to actually let the client know that this packet is meant to be processed after that one? Second, if I is going to use exacly GameComponent class for the game objects which is stored and process on the server, how to make them to be drawn on the client? Inherit them (while they are combined to an assembly)? Something else?

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  • cygwin GNU make .net program piping inconsistent behavior

    - by Codism
    This question may sound like a superuser question but I feel there is something related to programming. Anyway, my computer had a fresh installation of Win 7 64 and cygwin recently. Now I observed some problem with pipe handling in gnu make file. The following is the Makefile I use to reproduce the issue: all: fsutil | cat my-dotnet-console.exe | cat The problem is: for the first command line, the piping works every time but for the second command line, the piping barely works - I got no result for the second command for most cases, regardless of the environment (cmd or bash) in which the make file is invoked. However, if I copy paste the second command line into cmd (or bash), the pipe works every time. The following is my .net program: static void Main(string[] args) { Console.WriteLine(new string('a', 40)); Console.Out.Flush(); } The make version is 3.82.90 but the same problem was observed in a previous version (because of the windows path handling problem in 3.82.9, I replaced make.exe with a previous version). I don't know the exact cygwin version I have installed but the current version on cygwin.com is 1.7.11-1. Currently, my work around is to redirect the output to a temporary file but it would be great if I can avoid the temporary file. Thanks

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  • Caching DNS server (bind9.2) CPU usage is so so so high.

    - by Gk
    Hi, I have a caching-only dns server which get ~3k queries per second. Here is specs: Xeon dual-core 2,8GHz 4GB of RAM Centos 5x (kernel 2.6.18-164.15.1.el5PAE) bind 9.4.2 rndc status: recursive clients: 666/4900/5000 About 300 new queries (not in cache) per second. Bind always uses 100% on one core on single-thread config. After I recompiled it to multi-thread, it uses nearly 200% on two core :( No iowait, only sys and user. I searched around but didn't see any info about how bind use CPU. Why does it become bottleneck? One more thing, here is RAM usage: cat /proc/meminfo MemTotal: 4147876 kB MemFree: 1863972 kB Buffers: 143632 kB Cached: 372792 kB SwapCached: 0 kB Active: 1916804 kB Inactive: 276056 kB I've set max-cache-size to 0 to make sure bind can use as much RAM as it want, but it always stop at ~2GB. Since every second we got not cached queries so theoretically RAM must be exhausted but it wasn't. Do you have any idea? TIA, -Gk

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  • if/else statements or exceptions

    - by Thaven
    I don't know, that this question fit better on this board, or stackoverflow, but because my question is connected rather to practices, that some specified problem. So, consider an object that does something. And this something can (but should not!) can go wrong. So, this situation can be resolved in two way: first, with exceptions: DoSomethingClass exampleObject = new DoSomethingClass(); try { exampleObject.DoSomething(); } catch (ThisCanGoWrongException ex) { [...] } And second, with if statement: DoSomethingClass exampleObject = new DoSomethingClass(); if(!exampleObject.DoSomething()) { [...] } Second case in more sophisticated way: DoSomethingClass exampleObject = new DoSomethingClass(); ErrorHandler error = exampleObject.DoSomething(); if (error.HasError) { if(error.ErrorType == ErrorType.DivideByPotato) { [...] } } which way is better? In one hand, I heard that exception should be used only for real unexpected situations, and if programist know, that something may happen, he should used if/else. In second hand, Robert C. Martin in his book Clean Code Wrote, that exception are far more object oriented, and more simple to keep clean.

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