logical operator - Page 50

Data classes: getters and setters or different method design

- by Frog

I've been trying to design an interface for a data class I'm writing. This class stores styles for characters, for example whether the character is bold, italic or underlined. But also the font-size and the font-family. So it has different types of member variables. The easiest way to implement this would be to add getters and setters for every member variable, but this just feels wrong to me. It feels way more logical (and more OOP) to call style.format(BOLD, true) instead of style.setBold(true). So to use logical methods insteads of getters/setters. But I am facing two problems while implementing these methods: I would need a big switch statement with all member variables, since you can't access a variable by the contents of a string in C++. Moreover, you can't overload by return type, which means you can't write one getter like style.getFormatting(BOLD) (I know there are some tricks to do this, but these don't allow for parameters, which I would obviously need). However, if I would implement getters and setters, there are also issues. I would have to duplicate quite some code because styles can also have a parent styles, which means the getters have to look not only at the member variables of this style, but also at the variables of the parent styles. Because I wasn't able to figure out how to do this, I decided to ask a question a couple of weeks ago. See Object Oriented Programming: getters/setters or logical names. But in that question I didn't stress it would be just a data object and that I'm not making a text rendering engine, which was the reason one of the people that answered suggested I ask another question while making that clear (because his solution, the decorator pattern, isn't suitable for my problem). So please note that I'm not creating my own text rendering engine, I just use these classes to store data. Because I still haven't been able to find a solution to this problem I'd like to ask this question again: how would you design a styles class like this? And why would you do that? Thanks on forehand!

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What should I do when my team leader is unfair for no reason? [closed]

- by crucified soul

I'm a new software developer and this is my first job. It's a startup and the CEO and the working environment is just great. I work really hard and I believe that I also do my job well. But recently, I have felt like my team leader is being unfair to me for no reason. It appears that he is nice to my co-workers, but not me. I figure he is mad at me, but I didn't bother to find out why. I really love this company and I really love working there. But if my team leader continues to be unfair then I have no option other than leaving. How can I fix this? EDIT: The other day he called me into his office and wanted to see my work in the afternoon (Yes, in my country, at summer season after 5PM is afternoon. My office begins at 8AM. And I'm not saying I've problems to work after 5PM). At the time I was facing a weird runtime error and I was pretty tired. I explained the situation to him. Then he found a small logical error in my code and asked me why I didn't fix this. I told him I was trying to resolve this runtime error and that I was sure that this logical error had nothing to do with the runtime error. He then proceeded to yell at me. After fixing the logical error that runtime error was still there. This is not the only occasion he has been unfair to me. I'm saying is being unfair because he doesn't do this kind of thing to other developers when they do really silly mistakes.

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Unable to mount USBDRIVE Error creating moint point: Permission denied

- by steve

Whenever I plug a usb into my computer a window pops up and says Unable to mount [Name of USB] Error creating moint point: Permission denied steve@goliath:/$ uname -a Linux goliath 3.2.0-32-generic #51-Ubuntu SMP Wed Sep 26 21:33:09 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux steve@goliath:/$ sudo fdisk -l WARNING: GPT (GUID Partition Table) detected on '/dev/sda'! The util fdisk doesn't support GPT. Use GNU Parted. Disk /dev/sda: 120.0 GB, 120034123776 bytes 255 heads, 63 sectors/track, 14593 cylinders, total 234441648 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0f716ee1 Device Boot Start End Blocks Id System /dev/sda1 1 234441647 117220823+ ee GPT WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted. Disk /dev/sdb: 1500.3 GB, 1500301910016 bytes 255 heads, 63 sectors/track, 182401 cylinders, total 2930277168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0f710ee1 Device Boot Start End Blocks Id System /dev/sdb1 1 2930277167 1465138583+ ee GPT Disk /dev/sdc: 16.0 GB, 16005464064 bytes 74 heads, 10 sectors/track, 42244 cylinders, total 31260672 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xc3072e18 Device Boot Start End Blocks Id System /dev/sdc1 8064 31260671 15626304 c W95 FAT32 (LBA) steve@goliath:/$ sudo mkdir /media/external mkdir: cannot create directory `/media/external': Permission denied steve@goliath:/$ sudo mkdir /media/usb0 mkdir: cannot create directory `/media/usb0': Permission denied steve@goliath:/$ sudo ls -l / | grep media drwxr-xr-x 3 root root 4096 Oct 3 22:48 media steve@goliath:/$ ls /media/ -a . .. MediaShare MediaShare is the the directory on my server that has all my movies and music. If there is any information I left out please let me know.

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Using visitor pattern with large object hierarchy

- by T. Fabre

Context I've been using with a hierarchy of objects (an expression tree) a "pseudo" visitor pattern (pseudo, as in it does not use double dispatch) : public interface MyInterface { void Accept(SomeClass operationClass); } public class MyImpl : MyInterface { public void Accept(SomeClass operationClass) { operationClass.DoSomething(); operationClass.DoSomethingElse(); // ... and so on ... } } This design was, however questionnable, pretty comfortable since the number of implementations of MyInterface is significant (~50 or more) and I didn't need to add extra operations. Each implementation is unique (it's a different expression or operator), and some are composites (ie, operator nodes that will contain other operator/leaf nodes). Traversal is currently performed by calling the Accept operation on the root node of the tree, which in turns calls Accept on each of its child nodes, which in turn... and so on... But the time has come where I need to add a new operation, such as pretty printing : public class MyImpl : MyInterface { // Property does not come from MyInterface public string SomeProperty { get; set; } public void Accept(SomeClass operationClass) { operationClass.DoSomething(); operationClass.DoSomethingElse(); // ... and so on ... } public void Accept(SomePrettyPrinter printer) { printer.PrettyPrint(this.SomeProperty); } } I basically see two options : Keep the same design, adding a new method for my operation to each derived class, at the expense of maintainibility (not an option, IMHO) Use the "true" Visitor pattern, at the expense of extensibility (not an option, as I expect to have more implementations coming along the way...), with about 50+ overloads of the Visit method, each one matching a specific implementation ? Question Would you recommand using the Visitor pattern ? Is there any other pattern that could help solve this issue ?

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Win7 no longer available after installing 12.04

- by Michael

I have installed Ubuntu 12.04 but my Windows 7 partition seems to have been lost. It is in sda2. Can anyone help me how to get this Windows 7 partition back without having to reinstall Windows 7? Disk /dev/sda: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xd45cd45c Device Boot Start End Blocks Id System /dev/sda1 2048 61433855 30715904 83 Linux /dev/sda2 * 61433856 122873855 30720000 7 HPFS/NTFS/exFAT /dev/sda3 122873856 976769023 426947584 7 HPFS/NTFS/exFAT Disk /dev/sdb: 203.9 GB, 203928109056 bytes 255 heads, 63 sectors/track, 24792 cylinders, total 398297088 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x03ee03ee Device Boot Start End Blocks Id System /dev/sdb1 * 63 20482874 10241406 c W95 FAT32 (LBA) /dev/sdb2 20482875 40965749 10241437+ 1c Hidden W95 FAT32 (LBA) /dev/sdb3 40965750 398283479 178658865 f W95 Ext'd (LBA) /dev/sdb5 40965813 76694309 17864248+ 7 HPFS/NTFS/exFAT /dev/sdb6 76694373 108856439 16081033+ 7 HPFS/NTFS/exFAT /dev/sdb7 108856503 398283479 144713488+ 7 HPFS/NTFS/exFAT Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes 240 heads, 63 sectors/track, 129201 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000001 Device Boot Start End Blocks Id System /dev/sdc1 * 63 20480543 10240240+ 82 Linux swap / Solaris /dev/sdc2 20480605 1953519119 966519257+ f W95 Ext'd (LBA) /dev/sdc5 20480607 1953519119 966519256+ 7 HPFS/NTFS/exFAT

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Dual Boot Windows 8 and Ubuntu

- by Nick

My laptop has two hard drives, one 320GB HDD and a 30GB SSD. I installed Windows 8 on the HDD and Ubuntu on the SSD. However, after I installed Ubuntu, Windows 8 did not appear on the boot list. I tried boot-repair, but this didn't help.Here is the output of my fdisk -l: Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x6cd9314a Device Boot Start End Blocks Id System /dev/sda1 * 2048 625139711 312568832 7 HPFS/NTFS/exFAT Disk /dev/sdb: 30.0 GB, 30016659456 bytes 255 heads, 63 sectors/track, 3649 cylinders, total 58626288 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x6cd93132 Device Boot Start End Blocks Id System /dev/sdb1 * 2048 207126 102539+ 83 Linux /dev/sdb2 208894 58626047 29208577 5 Extended /dev/sdb5 208896 4112383 1951744 82 Linux swap / Solaris /dev/sdb6 4114432 58626047 27255808 83 Linux Disk /dev/mmcblk0: 3965 MB, 3965190144 bytes 49 heads, 48 sectors/track, 3292 cylinders, total 7744512 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0009c694 Device Boot Start End Blocks Id System /dev/mmcblk0p1 * 8192 7744511 3868160 b W95 FAT32 I also tried sudo grub-update, but that also did nothing.

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Lenovo v570 ubuntu 12.04 wireless hard blocked even when ext. switch is on

- by user100987

When I run iwconfig it say's lo and eth0 have no wireless extensions, but wlan0 it says IEEE 802.11bgn ESSID:off/any Mode:Managed Access Point: Not-Associated Tx-Power=off Retry long limit:7 RTS the:off Fragment the:off Power Management:off and I believe that's my problem, I just don't know how to turn it back on Any help? When I ran lspci | grep Network it gave me this 02:00.0 Network controller: Intell Corporation Centrino Wireless -N + WiMAX 6150 (rev 67) How I know that my wireless is hard blocked because when I run sudo rfkill list all I get 0: Ideapad_wlan: Wireless LAN Soft blocked: no Hard blocked: no 1: phy0: Wireless LAN Soft blocked: no Hard blocked: yes when I run lshw -c network I get. *-network DISABLED description: Wireless interface product: Centrino Wireless-N + WiMAX 6150 vendor: Intel Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: mon1 version: 67 serial: 40:25:c2:d2:96:2c width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list logical wireless ethernet physical configuration: broadcast=yes driver=iwlwifi driverversion=3.2.0-32-generic-pae firmware=41.28.5.1 build 33926 latency=0 link=no multicast=yes wireless=IEEE 802.11bgn resources: irq:43 memory:d0500000-d0501fff *-network description: Ethernet interface product: RTL8111/8168B PCI Express Gigabit Ethernet controller vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:03:00.0 logical name: eth0 version: 06 serial: f0:de:f1:d7:a0:4d size: 100Mbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl_nic/rtl8168e-2.fw ip=192.168.0.65 latency=0 link=yes multicast=yes port=MII speed=100Mbit/s resources: irq:41 ioport:2000(size=256) memory:d0404000-d0404fff memory:d0400000-d0403fff

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trying to setup multiple primary partitions on ubuntu linux

- by JohnMerlino

I currently have ubuntu desktop installed on a harddrive. I want to partition the harddrive so that I can reserve 30 gigs for ubuntu server and 30 gigs for ubuntu desktop. The drive has 300 gigs available. Right now I am booting from dvd drive and installing ubuntu server. I selected "Guided partitioning" and created a 30 gig primary partition of Ext4 journaling filesystem, set "yes, format it" for format partition and set bootable flag to on. I intend to use this 30 gig partition to hold ubuntu server and allow me to boot from it. Now I have two other partitions. They are both set to "logical", one is currently using 285.8 gigs and is using ext4 (when I try to set bootable flag to true, it gives a warning "You are trying to set the bootable flag on a logical partition. The bootable flag is only useful on the primary partitions"). More alarming it says "No existing file system was detected in this partition". Actually, Im thinking that this is the parittion that is supposed to be holding my current Ubuntu Desktop. And of course I want this to be bootable and be a primary partition, so I could dual boot from this and the server partition. Now the third partition is also set to logical and it is being used as swap area. My question is regarding that second partition. Its supposed to be a primary partition thats holding my existing ubuntu desktop edition. How do I switch it to primary and to make sure that its pointing to my existing desktop installation?

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Poor performance after reinstalling to a USB drive

- by anonymous

I am currently running Ubuntu 11.10 off of a SanDisk 16GB USB. I installed it using a Live USB with the following partition configuration: 6GB Primary /dos FAT32 5GB Logical / ext4 5GB Logical /home ext4 I don't have a hard disk, and don't see myself getting one anytime soon. I rely solely on this 16GB, and two other 4GB USBs, one of which I used as the LiveUSB. I bring the USBs around, and even use the install at work. I previously used an install that used a swap file. It functioned fine for the most part, save for a few slow moments, but I came across this post, and it got me thinking about my USB's life, so I reinstalled with the current config. My problem now is that it is slower. Applications like Firefox would hang more often. In my previous setup (the automatically partitioned setup), Firefox would start hanging if I was running an unzip or install task on the same partition as /. Now however, it would hang if I had another window open i.e. the system settings window. My guess is that it may have something to do with the swap file or the install being on a Logical partition rather than a Primary partition, but I don't know. Any insight as to why it has slowed down?

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Using ASP.NET MVC, Linq To SQL, and StructureMap causing DataContext to cache data

- by Dragn1821

I'll start by telling my project setup: ASP.NET MVC 1.0 StructureMap 2.6.1 VB I've created a bootstrapper class shown here: Imports StructureMap Imports DCS.Data Imports DCS.Services Public Class BootStrapper Public Shared Sub ConfigureStructureMap() ObjectFactory.Initialize(AddressOf StructureMapRegistry) End Sub Private Shared Sub StructureMapRegistry(ByVal x As IInitializationExpression) x.AddRegistry(New MainRegistry()) x.AddRegistry(New DataRegistry()) x.AddRegistry(New ServiceRegistry()) x.Scan(AddressOf StructureMapScanner) End Sub Private Shared Sub StructureMapScanner(ByVal scanner As StructureMap.Graph.IAssemblyScanner) scanner.Assembly("DCS") scanner.Assembly("DCS.Data") scanner.Assembly("DCS.Services") scanner.WithDefaultConventions() End Sub End Class I've created a controller factory shown here: Imports System.Web.Mvc Imports StructureMap Public Class StructureMapControllerFactory Inherits DefaultControllerFactory Protected Overrides Function GetControllerInstance(ByVal controllerType As System.Type) As System.Web.Mvc.IController Return ObjectFactory.GetInstance(controllerType) End Function End Class I've modified the Global.asax.vb as shown here: ... Sub Application_Start() RegisterRoutes(RouteTable.Routes) 'StructureMap BootStrapper.ConfigureStructureMap() ControllerBuilder.Current.SetControllerFactory(New StructureMapControllerFactory()) End Sub ... I've added a Structure Map registry file to each of my three projects: DCS, DCS.Data, and DCS.Services. Here is the DCS.Data registry: Imports StructureMap.Configuration.DSL Public Class DataRegistry Inherits Registry Public Sub New() 'Data Connections. [For](Of DCSDataContext)() _ .HybridHttpOrThreadLocalScoped _ .Use(New DCSDataContext()) 'Repositories. [For](Of IShiftRepository)() _ .Use(Of ShiftRepository)() [For](Of IMachineRepository)() _ .Use(Of MachineRepository)() [For](Of IShiftSummaryRepository)() _ .Use(Of ShiftSummaryRepository)() [For](Of IOperatorRepository)() _ .Use(Of OperatorRepository)() [For](Of IShiftSummaryJobRepository)() _ .Use(Of ShiftSummaryJobRepository)() End Sub End Class Everything works great as far as loading the dependecies, but I'm having problems with the DCSDataContext class that was genereated by Linq2SQL Classes. I have a form that posts to a details page (/Summary/Details), which loads in some data from SQL. I then have a button that opens a dialog box in JQuery, which populates the dialog from a request to (/Operator/Modify). On the dialog box, the form has a combo box and an OK button that lets the user change the operator's name. Upon clicking OK, the form is posted to (/Operator/Modify) and sent through the service and repository layers of my program and updates the record in the database. Then, the RedirectToAction is called to send the user back to the details page (/Summary/Details) where there is a call to pull the data from SQL again, updating the details view. Everything works great, except the details view does not show the new operator that was selected. I can step through the code and see the DCSDataContext class being accessed to update the operator (which does actually change the database record), but when the DCSDataContext is accessed to reload the details objects, it pulls in the old value. I'm guessing that StructureMap is causing not only the DCSDataContext class but also the data to be cached? I have also tried adding the following to the Global.asax, but it just ends up crashing the program telling me the DCSDataContext has been disposed... Private Sub MvcApplication_EndRequest(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.EndRequest StructureMap.ObjectFactory.ReleaseAndDisposeAllHttpScopedObjects() End Sub Can someone please help?

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Problem with combination boost::exception and boost::variant

- by Rick

Hello all, I have strange problem with two-level variant struct when boost::exception is included. I have following code snippet: #include <boost/variant.hpp> #include <boost/exception/all.hpp> typedef boost::variant< int > StoredValue; typedef boost::variant< StoredValue > ExpressionItem; inline std::ostream& operator << ( std::ostream & os, const StoredValue& stvalue ) { return os;} inline std::ostream& operator << ( std::ostream & os, const ExpressionItem& stvalue ) { return os; } When I try to compile it, I have following error: boost/exception/detail/is_output_streamable.hpp(45): error C2593: 'operator <<' is ambiguous test.cpp(11): could be 'std::ostream &operator <<(std::ostream &,const ExpressionItem &)' [found using argument-dependent lookup] test.cpp(8): or 'std::ostream &operator <<(std::ostream &,const StoredValue &)' [found using argument-dependent lookup] 1> while trying to match the argument list '(std::basic_ostream<_Elem,_Traits>, const boost::error_info<Tag,T>)' 1> with 1> [ 1> _Elem=char, 1> _Traits=std::char_traits<char> 1> ] 1> and 1> [ 1> Tag=boost::tag_original_exception_type, 1> T=const type_info * 1> ] Code snippet is simplified as much as possible, in the real code are structures much more complicated and each variant has five sub-types. When i remove #include and try following test snippet, program is compiled correctly: void TestVariant() { ExpressionItem test; std::stringstream str; str << test; } Could someone please advise me how to define operators << in order to function even when using boost::Exception ? Thanks and regards Rick

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Is it ok to dynamic cast "this" as a return value?

- by Panayiotis Karabassis

This is more of a design question. I have a template class, and I want to add extra methods to it depending on the template type. To practice the DRY principle, I have come up with this pattern (definitions intentionally omitted): template <class T> class BaseVector: public boost::array<T, 3> { protected: BaseVector<T>(const T x, const T y, const T z); public: bool operator == (const Vector<T> &other) const; Vector<T> operator + (const Vector<T> &other) const; Vector<T> operator - (const Vector<T> &other) const; Vector<T> &operator += (const Vector<T> &other) { (*this)[0] += other[0]; (*this)[1] += other[1]; (*this)[2] += other[2]; return *dynamic_cast<Vector<T> * const>(this); } } template <class T> class Vector : public BaseVector<T> { public: Vector<T>(const T x, const T y, const T z) : BaseVector<T>(x, y, z) { } }; template <> class Vector<double> : public BaseVector<double> { public: Vector<double>(const double x, const double y, const double z); Vector<double>(const Vector<int> &other); double norm() const; }; I intend BaseVector to be nothing more than an implementation detail. This works, but I am concerned about operator+=. My question is: is the dynamic cast of the this pointer a code smell? Is there a better way to achieve what I am trying to do (avoid code duplication, and unnecessary casts in the user code)? Or am I safe since, the BaseVector constructor is private?

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Are there known problems with >= and <= and the eval function in JS?

- by Augier

I am currently writing a JS rules engine which at one point needs to evaluate boolean expressions using the eval() function. Firstly I construct an equation as such: var equation = "relation.relatedTrigger.previousValue" + " " + relation.operator + " " + "relation.value"; relation.relatedTrigger.previousValue is the value I want to compare. relation.operator is the operator (either "==", "!=", <=, "<", "", ="). relation.value is the value I want to compare with. I then simply pass this string to the eval function and it returns true or false as such: return eval(equation); This works absolutely fine (with words and numbers) or all of the operators except for = and <=. E.g. When evaluating the equation: relation.relatedTrigger.previousValue <= 100 It returns true when previousValue = 0,1,10,100 & all negative numbers but false for everything in between. I would greatly appreciate the help of anyone to either answer my question or to help me find an alternative solution. Regards, Augier. P.S. I don't need a speech on the insecurities of the eval() function. Any value given to relation.relatedTrigger.previousValue is predefined. edit: Here is the full function: function evaluateRelation(relation) { console.log("Evaluating relation") var currentValue; //if multiple values if(relation.value.indexOf(";") != -1) { var values = relation.value.split(";"); for (x in values) { var equation = "relation.relatedTrigger.previousValue" + " " + relation.operator + " " + "values[x]"; currentValue = eval(equation); if (currentValue) return true; } return false; } //if single value else { //Evaluate the relation and get boolean var equation = "relation.relatedTrigger.previousValue" + " " + relation.operator + " " + "relation.value"; console.log("relation.relatedTrigger.previousValue " + relation.relatedTrigger.previousValue); console.log(equation); return eval(equation); } } Answer: Provided by KennyTM below. A string comparison doesn't work. Converting to a numerical was needed.

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How to pass operators as parameters

- by Rodion Ingles

I have to load an array of doubles from a file, multiply each element by a value in a table (different values for different elements), do some work on it, invert the multiplication (that is, divide) and then save the data back to file. Currently I implement the multiplication and division process in two separate methods. Now there is some extra work behind the scenes but apart from the specific statements where the multiplication/division occurs, the rest of the code is identical. As you can imagine, with this approach you have to be very careful making any changes. The surrounding code is not trivial, so its either a case of manually editing each method or copying changes from one method to the other and remembering to change the * and / operators. After too many close calls I am fed up of this and would like to make a common function which implements the common logic and two wrapper functions which pass which operator to use as a parameter. My initial approach was to use function pointers: MultiplyData(double data) { TransformData(data, &(operator *)); } DivideData(double data) { TransformData(data, &(operator /)); } TransformData(double data, double (*func)(double op1, double op2)) { /* Do stuff here... */ } However, I can't pass the operators as pointers (is this because it is an operator on a native type?), so I tried to use function objects. Initially I thought that multiplies and divides functors in <functional> would be ideal: MultiplyData(double data) { std::multiplies<double> multFunct; TransformData(data, &multFunct); } DivideData(double data) { std::divides<double> divFunct; TransformData(data, &divFunct); } TransformData(double data, std::binary_function<double, double, double> *funct) { /* Do stuff here... */ } As you can see I was trying to use a base class pointer to pass the functor polymorphically. The problem is that std::binary_function does not declare an operator() member for the child classes to implement. Is there something I am missing, or is the solution to implement my own functor heirarchy (which really seems more trouble than it is worth)?

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Understanding C++ dynamic allocation

- by kiokko89

Consider the following code: class CString { private: char* buff; size_t len; public: CString(const char* p):len(0), buff(nullptr) { cout << "Constructor called!"<<endl; if (p!=nullptr) { len= strlen(p); if (len>0) { buff= new char[len+1]; strcpy_s(buff, len+1, p); } } } CString (const CString& s) { cout << "Copy constructor called!"<<endl; len= s.len; buff= new char[len+1]; strcpy_s(buff, len+1, s.buff); } CString& operator = (const CString& rhs) { cout << "Assignment operator called!"<<endl; if (this != &rhs) { len= rhs.len; delete[] buff; buff= new char[len+1]; strcpy_s(buff, len+1, rhs.buff); } return *this; } CString operator + (const CString& rhs) const { cout << "Addition operator called!"<<endl; size_t lenght= len+rhs.len+1; char* tmp = new char[lenght]; strcpy_s(tmp, lenght, buff); strcat_s(tmp, lenght, rhs.buff); return CString(tmp); } ~CString() { cout << "Destructor called!"<<endl; delete[] buff; } }; int main() { CString s1("Hello"); CString s2("World"); CString s3 = s1+s2; } My problem is that I don't know how to delete the memory allocated in the addition operator function(char* tmp = new char[length]). I couldn't do this in the constructor(I tried delete[] p) because it is also called from the main function with arrays of chars as parameters which are not allocated on the heap...How can I get around this? (Sorry for my bad English...)

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Implementing default constructors

- by James

Implement the default constructor, the constructors with one and two int parameters. The one-parameter constructor should initialize the first member of the pair, the second member of the pair is to be 0. Overload binary operator + to add the pairs as follows: (a, b) + (c, d) = (a + c, b + d); Overload the - analogously. Overload the * on pairs ant int as follows: (a, b) * c = (a * c, b * c). Write a program to test all the member functions and overloaded operators in your class definition. You will also need to write accessor (get) functions for each member. The definition of the class Pairs: class Pairs { public: Pairs(); Pairs(int first, int second); Pairs(int first); // other members and friends friend istream& operator>> (istream&, Pair&); friend ostream& operator<< (ostream&, const Pair&); private: int f; int s; }; Self-Test Exercise #17: istream& operator (istream& ins, Pair& second) { char ch; ins ch; // discard init '(' ins second.f; ins ch; // discard comma ',' ins second.s; ins ch; // discard final '(' return ins; } ostream& operator<< (ostream& outs, const Pair& second) { outs << '('; outs << second.f; outs << ", " ;// I followed the Author's suggestion here. outs << second.s; outs << ")"; return outs; }

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Copy constructor bug

- by user168715

I'm writing a simple nD-vector class, but am encountering a strange bug. I've stripped out the class to the bare minimum that still reproduces the bug: #include <iostream> using namespace std; template<unsigned int size> class nvector { public: nvector() {data_ = new double[size];} ~nvector() {delete[] data_;} template<unsigned int size2> nvector(const nvector<size2> &other) { data_ = new double[size]; int i=0; for(; i<size && i < size2; i++) data_[i] = other[i]; for(; i<size; i++) data_[i] = 0; } double &operator[](int i) {return data_[i];} const double&operator[](int i) const {return data_[i];} private: const nvector<size> &operator=(const nvector<size> &other); //Intentionally unimplemented for now double *data_; }; int main() { nvector<2> vector2d; vector2d[0] = 1; vector2d[1] = 2; nvector<3> vector3d(vector2d); for(int i=0; i<3; i++) cout << vector3d[i] << " "; cout << endl; //Prints 1 2 0 nvector<3> other3d(vector3d); for(int i=0; i<3; i++) cout << other3d[i] << " "; cout << endl; //Prints 1 2 0 } //Segfault??? On the surface this seems to work fine, and both tests print out the correct values. However, at the end of main the program crashes with a segfault, which I've traced to nvector's destructor. At first I thought the (incorrect) default assignment operator was somehow being called, which is why I added the (currently) unimplemented explicit assignment operator to rule this possibility out. So my copy constructor must be buggy, but I'm having one of those days where I'm staring at extremely simple code and just can't see it. Do you guys have any ideas?

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Can't insert a number into a C++ custom streambuf/ostream

- by 0xbe5077ed

I have written a custom std::basic_streambuf and std::basic_ostream because I want an output stream that I can get a JNI string from in a manner similar to how you can call std::ostringstream::str(). These classes are quite simple. namespace myns { class jni_utf16_streambuf : public std::basic_streambuf<char16_t> { JNIEnv * d_env; std::vector<char16_t> d_buf; virtual int_type overflow(int_type); public: jni_utf16_streambuf(JNIEnv *); jstring jstr() const; }; typedef std::basic_ostream<char16_t, std::char_traits<char16_t>> utf16_ostream; class jni_utf16_ostream : public utf16_ostream { jni_utf16_streambuf d_buf; public: jni_utf16_ostream(JNIEnv *); jstring jstr() const; }; // ... } // namespace myns In addition, I have made four overloads of operator<<, all in the same namespace: namespace myns { // ... utf16_ostream& operator<<(utf16_ostream&, jstring) throw(std::bad_cast); utf16_ostream& operator<<(utf16_ostream&, const char *); utf16_ostream& operator<<(utf16_ostream&, const jni_utf16_string_region&); jni_utf16_ostream& operator<<(jni_utf16_ostream&, jstring); // ... } // namespace myns The implementation of jni_utf16_streambuf::overflow(int_type) is trivial. It just doubles the buffer width, puts the requested character, and sets the base, put, and end pointers correctly. It is tested and I am quite sure it works. The jni_utf16_ostream works fine inserting unicode characters. For example, this works fine and results in the stream containing "hello, world": myns::jni_utf16_ostream o(env); o << u"hello, wor" << u'l' << u'd'; My problem is as soon as I try to insert an integer value, the stream's bad bit gets set, for example: myns::jni_utf16_ostream o(env); if (o.badbit()) throw "bad bit before"; // does not throw int32_t x(5); o << x; if (o.badbit()) throw "bad bit after"; // throws :( I don't understand why this is happening! Is there some other method on std::basic_streambuf I need to be implementing????

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Ubuntu missing from the Grub menu

- by varevarao

Recently I've had some audio issues with Ubuntu (using precise), and in the process of trying to resolve that I ran a dist-upgrade. Everything went just fine, and the sound seemed good, until I rebooted my machine for the first time since the dist-upgrade. All I see now in the Grub menu at startup is memtest86+, another memtest variant, and Windows 7. It's not showing any of the linux kernels that Ubuntu is running on. I am attaching my bootinfoscript: Boot Info Script 0.61.full + Boot-Repair extra info [Boot-Info November 20th 2012] ============================= Boot Info Summary: =============================== => Grub2 (v1.99) is installed in the MBR of /dev/sda and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks for (,msdos6)/boot/grub on this drive. sda1: __________________________________________________________________________ File system: vfat Boot sector type: Dell Utility: FAT16 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: sda2: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: sda3: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files: sda4: __________________________________________________________________________ File system: Extended Partition Boot sector type: Unknown Boot sector info: sda5: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: According to the info in the boot sector, sda5 starts at sector 2048. Operating System: Boot files: sda6: __________________________________________________________________________ File system: ext4 Boot sector type: Grub2 (v1.99-2.00) Boot sector info: Grub2 (v1.99) is installed in the boot sector of sda6 and looks at sector 220046240 of the same hard drive for core.img. core.img is at this location and looks for (,msdos6)/boot/grub on this drive. Operating System: Ubuntu 12.04.1 LTS Boot files: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img sda7: __________________________________________________________________________ File system: swap Boot sector type: - Boot sector info: ============================ Drive/Partition Info: ============================= Drive: sda _____________________________________________________________________ Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sda1 63 273,104 273,042 de Dell Utility /dev/sda2 * 274,432 19,406,847 19,132,416 7 NTFS / exFAT / HPFS /dev/sda3 19,406,848 218,274,364 198,867,517 7 NTFS / exFAT / HPFS /dev/sda4 218,275,838 625,139,711 406,863,874 f W95 Extended (LBA) /dev/sda5 328,630,272 625,139,711 296,509,440 7 NTFS / exFAT / HPFS /dev/sda6 218,275,840 324,030,463 105,754,624 83 Linux /dev/sda7 324,032,512 328,626,175 4,593,664 82 Linux swap / Solaris "blkid" output: ________________________________________________________________ Device UUID TYPE LABEL /dev/loop0 squashfs /dev/sda1 07DA-0512 vfat DellUtility /dev/sda2 8834146034145392 ntfs RECOVERY /dev/sda3 48E2189DE21890F4 ntfs OS /dev/sda5 BC2A44C02A447982 ntfs Varshneya /dev/sda6 34731459-4b0f-46ac-a9bf-cb360a2c947c ext4 /dev/sda7 dcb9ce9b-799a-4c65-b008-887b01775670 swap /dev/sr0 iso9660 Ubuntu 12.04.1 LTS i386 ================================ Mount points: ================================= Device Mount_Point Type Options /dev/loop0 /rofs squashfs (ro,noatime) /dev/sda6 /mnt ext4 (rw) /dev/sr0 /cdrom iso9660 (ro,noatime) =========================== sda6/boot/grub/grub.cfg: =========================== -------------------------------------------------------------------------------- # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c if loadfont /boot/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c set locale_dir=($root)/boot/grub/locale set lang=en_US insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${1}" if [ "${1}" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ "${recordfail}" != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "${linux_gfx_mode}" != "text" ]; then load_video; fi ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Windows 7 (loader) (on /dev/sda2)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd0,msdos2)' search --no-floppy --fs-uuid --set=root 8834146034145392 chainloader +1 } ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### -------------------------------------------------------------------------------- =============================== sda6/etc/fstab: ================================ -------------------------------------------------------------------------------- # /etc/fstab: static file system information. # # Use 'blkid -o value -s UUID' to print the universally unique identifier # for a device; this may be used with UUID= as a more robust way to name # devices that works even if disks are added and removed. See fstab(5). # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc nodev,noexec,nosuid 0 0 # / was on /dev/sda6 during installation UUID=34731459-4b0f-46ac-a9bf-cb360a2c947c / ext4 errors=remount-ro,user_xattr 0 1 # swap was on /dev/sda7 during installation UUID=dcb9ce9b-799a-4c65-b008-887b01775670 none swap sw 0 0 -------------------------------------------------------------------------------- =================== sda6: Location of files loaded by Grub: ==================== GiB - GB File Fragment(s) 104.851909637 = 112.583880704 boot/grub/core.img 1 121.191410065 = 130.128285696 boot/grub/grub.cfg 1 ======================== Unknown MBRs/Boot Sectors/etc: ======================== Unknown BootLoader on sda4 00000000 eb 0f 2a 5d f4 b7 75 f2 e9 56 12 b8 50 b4 79 ec |..*]..u..V..P.y.| 00000010 89 91 ca c3 16 40 31 d0 ae c4 53 3d c7 dd d7 98 |[email protected]=....| 00000020 bd a4 f2 a4 e8 ab fc ea 36 30 1b 34 cf 8a 28 30 |........60.4..(0| 00000030 43 95 6c 31 3e 76 93 58 84 37 99 c3 ae 3a 88 a3 |C.l1>v.X.7...:..| 00000040 c2 a6 36 2a f8 e0 e1 03 91 8d a1 50 cd ad b0 b5 |..6*.......P....| 00000050 ad 69 3a 49 63 1f 4a 33 97 6e 0c 71 bf 7d bd 35 |.i:Ic.J3.n.q.}.5| 00000060 86 c5 17 93 b4 9f e5 af e0 c4 6f f4 6f f9 4b dd |..........o.o.K.| 00000070 14 39 e2 9e b9 36 ca b1 56 5b d9 b1 66 2c 05 b2 |.9...6..V[..f,..| 00000080 5d 5b 99 c0 db e6 81 27 ab c2 e1 55 00 ac 0b 2c |][.....'...U...,| 00000090 24 d3 8e 54 b0 3d ab 58 e4 23 fc 3a 79 93 fb 5e |$..T.=.X.#.:y..^| 000000a0 94 5a 3a c2 16 4e 56 cb 1b 7f 7e b3 4c 38 ca 5b |.Z:..NV...~.L8.[| 000000b0 ca ab c1 2c 2a 64 e7 77 fe 2a ba ee 08 33 b5 9b |...,*d.w.*...3..| 000000c0 d0 c2 b4 a8 fc 73 4f 01 fd 03 61 75 eb 6d 1a 74 |.....sO...au.m.t| 000000d0 5f 79 31 7f ed e6 f5 99 21 36 16 ed 25 d9 6d 2b |_y1.....!6..%.m+| 000000e0 5f f4 42 b8 9d 01 89 10 fe df a4 98 e7 ab ab ea |_.B.............| 000000f0 1d 1c 44 e1 49 d9 19 c9 ab f5 41 eb 4a 32 c2 39 |..D.I.....A.J2.9| 00000100 87 57 f6 f6 f3 b5 4d 17 72 f2 b1 16 19 aa ec 24 |.W....M.r......$| 00000110 39 bd e3 b1 68 b3 b0 7f fa 2a 3a 2e 99 ed db 8a |9...h....*:.....| 00000120 f8 61 b4 ef 9d 7d 85 95 ed ad eb 9e 71 f4 27 d3 |.a...}......q.'.| 00000130 f3 04 8b 8a 69 98 02 72 df e1 f9 83 27 5b 01 4c |....i..r....'[.L| 00000140 d4 9a b9 3b db ca 1e 40 35 db 6f c1 52 c0 7f 27 |...;[email protected]..'| 00000150 8a 1d bc 34 89 24 b6 e3 fd ec a1 2a e5 9e d1 8f |...4.$.....*....| 00000160 77 e0 d5 52 c0 4c c4 38 38 3c 28 19 bf 20 f0 03 |w..R.L.88<(.. ..| 00000170 38 a4 b1 b5 ed 6a b8 f7 a9 7b 65 b1 7b 64 4a 33 |8....j...{e.{dJ3| 00000180 66 1a 60 29 38 1d 5b 52 40 31 de a5 0c 0f cc 6f |f.`)8.[[email protected]| 00000190 dd 31 6d 3d f0 2a 32 85 67 66 ca 4f 02 aa 0d 30 |.1m=.*2.gf.O...0| 000001a0 66 c9 b2 33 c2 4b 8a fa 3c 7b 52 02 00 88 8e cf |f..3.K..<{R.....| 000001b0 67 1e d4 20 49 1d 1a b8 71 ad c2 d4 37 9d 00 fe |g.. I...q...7...| 000001c0 ff ff 07 fe ff ff 02 e0 93 06 00 60 ac 11 00 fe |...........`....| 000001d0 ff ff 05 fe ff ff 01 00 00 00 01 b0 4d 06 00 00 |............M...| 000001e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| 000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00000200 ADDITIONAL INFORMATION : =================== log of boot-repair 2012-11-24__09h45 =================== boot-repair version : 3.195~ppa2~precise boot-sav version : 3.195~ppa2~precise glade2script version : 3.2.2~ppa45~precise boot-sav-extra version : 3.195~ppa2~precise boot-repair is executed in live-session (Ubuntu 12.04.1 LTS, precise, Ubuntu, i686) CPU op-mode(s): 32-bit, 64-bit file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash -- =================== os-prober: /dev/sda2:Windows 7 (loader):Windows:chain /dev/sda6:Ubuntu 12.04.1 LTS (12.04):Ubuntu:linux =================== blkid: /dev/sda1: SEC_TYPE="msdos" LABEL="DellUtility" UUID="07DA-0512" TYPE="vfat" /dev/sda2: LABEL="RECOVERY" UUID="8834146034145392" TYPE="ntfs" /dev/sda3: LABEL="OS" UUID="48E2189DE21890F4" TYPE="ntfs" /dev/sda5: LABEL="Varshneya" UUID="BC2A44C02A447982" TYPE="ntfs" /dev/loop0: TYPE="squashfs" /dev/sda6: UUID="34731459-4b0f-46ac-a9bf-cb360a2c947c" TYPE="ext4" /dev/sda7: UUID="dcb9ce9b-799a-4c65-b008-887b01775670" TYPE="swap" /dev/sr0: LABEL="Ubuntu 12.04.1 LTS i386" TYPE="iso9660" 1 disks with OS, 2 OS : 1 Linux, 0 MacOS, 1 Windows, 0 unknown type OS. Windows not detected by os-prober on sda3. Warning: extended partition does not start at a cylinder boundary. DOS and Linux will interpret the contents differently. =================== /mnt/etc/default/grub : # If you change this file, run 'update-grub' afterwards to update # /boot/grub/grub.cfg. # For full documentation of the options in this file, see: # info -f grub -n 'Simple configuration' GRUB_DEFAULT=0 GRUB_HIDDEN_TIMEOUT=0 GRUB_HIDDEN_TIMEOUT_QUIET=true GRUB_TIMEOUT=10 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX="" # Uncomment to enable BadRAM filtering, modify to suit your needs # This works with Linux (no patch required) and with any kernel that obtains # the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...) #GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef" # Uncomment to disable graphical terminal (grub-pc only) #GRUB_TERMINAL=console # The resolution used on graphical terminal # note that you can use only modes which your graphic card supports via VBE # you can see them in real GRUB with the command `vbeinfo' #GRUB_GFXMODE=640x480 # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux #GRUB_DISABLE_LINUX_UUID=true # Uncomment to disable generation of recovery mode menu entries #GRUB_DISABLE_RECOVERY="true" # Uncomment to get a beep at grub start #GRUB_INIT_TUNE="480 440 1" =================== /mnt/etc/grub.d/ : drwxr-xr-x 2 root root 4096 Nov 22 16:15 grub.d total 56 -rwxr-xr-x 1 root root 6743 Sep 12 20:19 00_header -rwxr-xr-x 1 root root 5522 Sep 12 20:05 05_debian_theme -rwxr-xr-x 1 root root 7407 Sep 12 20:19 10_linux -rwxr-xr-x 1 root root 6335 Sep 12 20:19 20_linux_xen -rwxr-xr-x 1 root root 1588 Sep 24 2010 20_memtest86+ -rwxr-xr-x 1 root root 7603 Sep 12 20:19 30_os-prober -rwxr-xr-x 1 root root 214 Sep 12 20:19 40_custom -rwxr-xr-x 1 root root 95 Sep 12 20:19 41_custom -rw-r--r-- 1 root root 483 Sep 12 20:19 README =================== No kernel in /mnt/boot: grub memtest86+.bin memtest86+_multiboot.bin =================== UEFI/Legacy mode: This live-session is not EFI-compatible. SecureBoot maybe enabled. =================== PARTITIONS & DISKS: sda1 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, no-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, not-far, /mnt/boot-sav/sda1. sda2 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, is-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, bootmgr, is-winboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, not-far, /mnt/boot-sav/sda2. sda3 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, is-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, haswinload, no-recov-nor-hid, no-bmgr, notwinboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, farbios, /mnt/boot-sav/sda3. sda5 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, no-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, farbios, /mnt/boot-sav/sda5. sda6 : sda, not-sepboot, grubenv-ok grub2, grub-pc, update-grub, 64, no-kernel, is-os, not--efi--part, fstab-without-boot, fstab-without-efi, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, apt-get, grub-install, with--usr, fstab-without-usr, not-sep-usr, standard, farbios, /mnt. sda : not-GPT, BIOSboot-not-needed, has-no-EFIpart, not-usb, has-os, 63 sectors * 512 bytes =================== parted -l: Model: ATA ST9320423AS (scsi) Disk /dev/sda: 320GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 140MB 140MB primary fat16 diag 2 141MB 9936MB 9796MB primary ntfs boot 3 9936MB 112GB 102GB primary ntfs 4 112GB 320GB 208GB extended lba 6 112GB 166GB 54.1GB logical ext4 7 166GB 168GB 2352MB logical linux-swap(v1) 5 168GB 320GB 152GB logical ntfs Model: HL-DT-ST DVD+-RW GA31N (scsi) Disk /dev/sr0: 4700MB Sector size (logical/physical): 2048B/2048B Partition Table: msdos Number Start End Size Type File system Flags 1 131kB 2916MB 2916MB primary boot, hidden =================== parted -lm: BYT; /dev/sda:320GB:scsi:512:512:msdos:ATA ST9320423AS; 1:32.3kB:140MB:140MB:fat16::diag; 2:141MB:9936MB:9796MB:ntfs::boot; 3:9936MB:112GB:102GB:ntfs::; 4:112GB:320GB:208GB:::lba; 6:112GB:166GB:54.1GB:ext4::; 7:166GB:168GB:2352MB:linux-swap(v1)::; 5:168GB:320GB:152GB:ntfs::; BYT; /dev/sr0:4700MB:scsi:2048:2048:msdos:HL-DT-ST DVD+-RW GA31N; 1:131kB:2916MB:2916MB:::boot, hidden; =================== mount: /cow on / type overlayfs (rw) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) udev on /dev type devtmpfs (rw,mode=0755) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755) /dev/sr0 on /cdrom type iso9660 (ro,noatime) /dev/loop0 on /rofs type squashfs (ro,noatime) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) tmpfs on /tmp type tmpfs (rw,nosuid,nodev) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) gvfs-fuse-daemon on /home/ubuntu/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=ubuntu) /dev/sda6 on /mnt type ext4 (rw) /dev on /mnt/dev type none (rw,bind) /proc on /mnt/proc type none (rw,bind) /sys on /mnt/sys type none (rw,bind) /usr on /mnt/usr type none (rw,bind) /dev/sda1 on /mnt/boot-sav/sda1 type vfat (rw) /dev/sda2 on /mnt/boot-sav/sda2 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) /dev/sda3 on /mnt/boot-sav/sda3 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) /dev/sda5 on /mnt/boot-sav/sda5 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) =================== ls: /sys/block/sda (filtered): alignment_offset bdi capability dev device discard_alignment events events_async events_poll_msecs ext_range holders inflight power queue range removable ro sda1 sda2 sda3 sda4 sda5 sda6 sda7 size slaves stat subsystem trace uevent /sys/block/sr0 (filtered): alignment_offset bdi capability dev device discard_alignment events events_async events_poll_msecs ext_range holders inflight power queue range removable ro size slaves stat subsystem trace uevent /dev (filtered): autofs block bsg btrfs-control bus cdrom cdrw char console core cpu cpu_dma_latency disk dri dvd dvdrw ecryptfs fb0 fd full fuse fw0 hidraw0 hpet input kmsg log mapper mcelog mei mem net network_latency network_throughput null oldmem port ppp psaux ptmx pts random rfkill rtc rtc0 sda sda1 sda2 sda3 sda4 sda5 sda6 sda7 sg0 sg1 shm snapshot snd sr0 stderr stdin stdout uinput urandom usbmon0 usbmon1 usbmon2 v4l vga_arbiter video0 zero ls /dev/mapper: control =================== df -Th: Filesystem Type Size Used Avail Use% Mounted on /cow overlayfs 1.9G 113M 1.8G 6% / udev devtmpfs 1.9G 12K 1.9G 1% /dev tmpfs tmpfs 777M 872K 776M 1% /run /dev/sr0 iso9660 696M 696M 0 100% /cdrom /dev/loop0 squashfs 667M 667M 0 100% /rofs tmpfs tmpfs 1.9G 20K 1.9G 1% /tmp none tmpfs 5.0M 0 5.0M 0% /run/lock none tmpfs 1.9G 176K 1.9G 1% /run/shm /dev/sda6 ext4 51G 27G 22G 56% /mnt /dev/sda1 vfat 134M 9.1M 125M 7% /mnt/boot-sav/sda1 /dev/sda2 fuseblk 9.2G 5.6G 3.6G 61% /mnt/boot-sav/sda2 /dev/sda3 fuseblk 95G 80G 16G 84% /mnt/boot-sav/sda3 /dev/sda5 fuseblk 142G 130G 12G 92% /mnt/boot-sav/sda5 =================== fdisk -l: Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xb8000000 Device Boot Start End Blocks Id System /dev/sda1 63 273104 136521 de Dell Utility /dev/sda2 * 274432 19406847 9566208 7 HPFS/NTFS/exFAT /dev/sda3 19406848 218274364 99433758+ 7 HPFS/NTFS/exFAT /dev/sda4 218275838 625139711 203431937 f W95 Ext'd (LBA) /dev/sda5 328630272 625139711 148254720 7 HPFS/NTFS/exFAT /dev/sda6 218275840 324030463 52877312 83 Linux /dev/sda7 324032512 328626175 2296832 82 Linux swap / Solaris Partition table entries are not in disk order =================== Repair blockers 64bits detected. Please use this software in a 64bits session. (Please use Ubuntu-Secure-Remix-64bits (www.sourceforge.net/p/ubuntu-secured) which contains a 64bits-compatible version of this software.) This will enable this feature. =================== Final advice in case of recommended repair The boot files of [Ubuntu 12.04.1 LTS] are far from the start of the disk. Your BIOS may not detect them. You may want to retry after creating a /boot partition (EXT4, >200MB, start of the disk). This can be performed via tools such as gParted. Then select this partition via the [Separate /boot partition:] option of [Boot Repair]. (https://help.ubuntu.com/community/BootPartition) =================== Default settings Recommended-Repair This setting would reinstall the grub2 of sda6 into the MBR of sda, using the following options: kernel-purge Additional repair would be performed: unhide-bootmenu-10s fix-windows-boot =================== Settings chosen by the user Boot-Info This setting will not act on the MBR. No change has been performed on your computer. See you soon! pastebinit packages needed dpkg-preconfigure: unable to re-open stdin: No such file or directory pastebin.com ko (), using paste.ubuntu Please report this message to [email protected] Any help would be great, I'm really missing Ubuntu (hate being stuck in the Windows world).

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SQL SERVER – Merge Operations – Insert, Update, Delete in Single Execution

- by pinaldave

This blog post is written in response to T-SQL Tuesday hosted by Jorge Segarra (aka SQLChicken). I have been very active using these Merge operations in my development. However, I have found out from my consultancy work and friends that these amazing operations are not utilized by them most of the time. Here is my attempt to bring the necessity of using the Merge Operation to surface one more time. MERGE is a new feature that provides an efficient way to do multiple DML operations. In earlier versions of SQL Server, we had to write separate statements to INSERT, UPDATE, or DELETE data based on certain conditions; however, at present, by using the MERGE statement, we can include the logic of such data changes in one statement that even checks when the data is matched and then just update it, and similarly, when the data is unmatched, it is inserted. One of the most important advantages of MERGE statement is that the entire data are read and processed only once. In earlier versions, three different statements had to be written to process three different activities (INSERT, UPDATE or DELETE); however, by using MERGE statement, all the update activities can be done in one pass of database table. I have written about these Merge Operations earlier in my blog post over here SQL SERVER – 2008 – Introduction to Merge Statement – One Statement for INSERT, UPDATE, DELETE. I was asked by one of the readers that how do we know that this operator was doing everything in single pass and was not calling this Merge Operator multiple times. Let us run the same example which I have used earlier; I am listing the same here again for convenience. --Let’s create Student Details and StudentTotalMarks and inserted some records. USE tempdb GO CREATE TABLE StudentDetails ( StudentID INTEGER PRIMARY KEY, StudentName VARCHAR(15) ) GO INSERT INTO StudentDetails VALUES(1,'SMITH') INSERT INTO StudentDetails VALUES(2,'ALLEN') INSERT INTO StudentDetails VALUES(3,'JONES') INSERT INTO StudentDetails VALUES(4,'MARTIN') INSERT INTO StudentDetails VALUES(5,'JAMES') GO CREATE TABLE StudentTotalMarks ( StudentID INTEGER REFERENCES StudentDetails, StudentMarks INTEGER ) GO INSERT INTO StudentTotalMarks VALUES(1,230) INSERT INTO StudentTotalMarks VALUES(2,255) INSERT INTO StudentTotalMarks VALUES(3,200) GO -- Select from Table SELECT * FROM StudentDetails GO SELECT * FROM StudentTotalMarks GO -- Merge Statement MERGE StudentTotalMarks AS stm USING (SELECT StudentID,StudentName FROM StudentDetails) AS sd ON stm.StudentID = sd.StudentID WHEN MATCHED AND stm.StudentMarks > 250 THEN DELETE WHEN MATCHED THEN UPDATE SET stm.StudentMarks = stm.StudentMarks + 25 WHEN NOT MATCHED THEN INSERT(StudentID,StudentMarks) VALUES(sd.StudentID,25); GO -- Select from Table SELECT * FROM StudentDetails GO SELECT * FROM StudentTotalMarks GO -- Clean up DROP TABLE StudentDetails GO DROP TABLE StudentTotalMarks GO The Merge Join performs very well and the following result is obtained. Let us check the execution plan for the merge operator. You can click on following image to enlarge it. Let us evaluate the execution plan for the Table Merge Operator only. We can clearly see that the Number of Executions property suggests value 1. Which is quite clear that in a single PASS, the Merge Operation completes the operations of Insert, Update and Delete. I strongly suggest you all to use this operation, if possible, in your development. I have seen this operation implemented in many data warehousing applications. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Joins, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Merge

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ODI 11g – Insight to the SDK

- by David Allan

This post is a useful index into the ODI SDK that cross references the type names from the user interface with the SDK class and also the finder for how to get a handle on the object or objects. The volume of content in the SDK might seem a little ominous, there is a lot there, but there is a general pattern to the SDK that I will describe here. Also I will illustrate some basic CRUD operations so you can see how the SDK usage pattern works. The examples are written in groovy, you can simply run from the groovy console in ODI 11.1.1.6. Entry to the Platform Object Finder SDK odiInstance odiInstance (groovy variable for console) OdiInstance Topology Objects Object Finder SDK Technology IOdiTechnologyFinder OdiTechnology Context IOdiContextFinder OdiContext Logical Schema IOdiLogicalSchemaFinder OdiLogicalSchema Data Server IOdiDataServerFinder OdiDataServer Physical Schema IOdiPhysicalSchemaFinder OdiPhysicalSchema Logical Schema to Physical Mapping IOdiContextualSchemaMappingFinder OdiContextualSchemaMapping Logical Agent IOdiLogicalAgentFinder OdiLogicalAgent Physical Agent IOdiPhysicalAgentFinder OdiPhysicalAgent Logical Agent to Physical Mapping IOdiContextualAgentMappingFinder OdiContextualAgentMapping Master Repository IOdiMasterRepositoryInfoFinder OdiMasterRepositoryInfo Work Repository IOdiWorkRepositoryInfoFinder OdiWorkRepositoryInfo Project Objects Object Finder SDK Project IOdiProjectFinder OdiProject Folder IOdiFolderFinder OdiFolder Interface IOdiInterfaceFinder OdiInterface Package IOdiPackageFinder OdiPackage Procedure IOdiUserProcedureFinder OdiUserProcedure User Function IOdiUserFunctionFinder OdiUserFunction Variable IOdiVariableFinder OdiVariable Sequence IOdiSequenceFinder OdiSequence KM IOdiKMFinder OdiKM Load Plans and Scenarios Object Finder SDK Load Plan IOdiLoadPlanFinder OdiLoadPlan Load Plan and Scenario Folder IOdiScenarioFolderFinder OdiScenarioFolder Model Objects Object Finder SDK Model IOdiModelFinder OdiModel Sub Model IOdiSubModel OdiSubModel DataStore IOdiDataStoreFinder OdiDataStore Column IOdiColumnFinder OdiColumn Key IOdiKeyFinder OdiKey Condition IOdiConditionFinder OdiCondition Operator Objects Object Finder SDK Session Folder IOdiSessionFolderFinder OdiSessionFolder Session IOdiSessionFinder OdiSession Schedule OdiSchedule How to Create an Object? Here is a simple example to create a project, it uses IOdiEntityManager.persist to persist the object. import oracle.odi.domain.project.OdiProject; import oracle.odi.core.persistence.transaction.support.DefaultTransactionDefinition; txnDef = new DefaultTransactionDefinition(); tm = odiInstance.getTransactionManager() txnStatus = tm.getTransaction(txnDef) project = new OdiProject("Project For Demo", "PROJECT_DEMO") odiInstance.getTransactionalEntityManager().persist(project) tm.commit(txnStatus) How to Update an Object? This update example uses the methods on the OdiProject object to change the project’s name that was created above, it is then persisted. import oracle.odi.domain.project.OdiProject; import oracle.odi.domain.project.finder.IOdiProjectFinder; import oracle.odi.core.persistence.transaction.support.DefaultTransactionDefinition; txnDef = new DefaultTransactionDefinition(); tm = odiInstance.getTransactionManager() txnStatus = tm.getTransaction(txnDef) prjFinder = (IOdiProjectFinder)odiInstance.getTransactionalEntityManager().getFinder(OdiProject.class); project = prjFinder.findByCode("PROJECT_DEMO"); project.setName("A Demo Project"); odiInstance.getTransactionalEntityManager().persist(project) tm.commit(txnStatus) How to Delete an Object? Here is a simple example to delete all of the sessions, it uses IOdiEntityManager.remove to delete the object. import oracle.odi.domain.runtime.session.finder.IOdiSessionFinder; import oracle.odi.domain.runtime.session.OdiSession; import oracle.odi.core.persistence.transaction.support.DefaultTransactionDefinition; txnDef = new DefaultTransactionDefinition(); tm = odiInstance.getTransactionManager() txnStatus = tm.getTransaction(txnDef) sessFinder = (IOdiSessionFinder)odiInstance.getTransactionalEntityManager().getFinder(OdiSession.class); sessc = sessFinder.findAll(); sessItr = sessc.iterator() while (sessItr.hasNext()) { sess = (OdiSession) sessItr.next() odiInstance.getTransactionalEntityManager().remove(sess) } tm.commit(txnStatus) This isn't an all encompassing summary of the SDK, but covers a lot of the content to give you a good handle on the objects and how they work. For details of how specific complex objects are created via the SDK, its best to look at postings such as the interface builder posting here. Have fun, happy coding!

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Best Practices - Core allocation

- by jsavit

This post is one of a series of "best practices" notes for Oracle VM Server for SPARC (also called Logical Domains) Introduction SPARC T-series servers currently have up to 4 CPU sockets, each of which has up to 8 or (on SPARC T3) 16 CPU cores, while each CPU core has 8 threads, for a maximum of 512 dispatchable CPUs. The defining feature of Oracle VM Server for SPARC is that each domain is assigned CPU threads or cores for its exclusive use. This avoids the overhead of software-based time-slicing and emulation (or binary rewriting) of system state-changing privileged instructions used in traditional hypervisors. To create a domain, administrators specify either the number of CPU threads or cores that the domain will own, as well as its memory and I/O resources. When CPU resources are assigned at the individual thread level, the logical domains constraint manager attempts to assign threads from the same cores to a domain, and avoid "split core" situations where the same CPU core is used by multiple domains. Sometimes this is unavoidable, especially when domains are allocated and deallocated CPUs in small increments. Why split cores can matter Split core allocations can silenty reduce performance because multiple domains with different address spaces and memory contents are sharing the core's Level 1 cache (L1$). This is called false cache sharing since even identical memory addresses from different domains must point to different locations in RAM. The effect of this is increased contention for the cache, and higher memory latency for each domain using that core. The degree of performance impact can be widely variable. For applications with very small memory working sets, and with I/O bound or low-CPU utilization workloads, it may not matter at all: all machines wait for work at the same speed. If the domains have substantial workloads, or are critical to performance then this can have an important impact: This blog entry was inspired by a customer issue in which one CPU core was split among 3 domains, one of which was the control and service domain. The reported problem was increased I/O latency in guest domains, but the root cause might be higher latency servicing the I/O requests due to the control domain being slowed down. What to do about it Split core situations are easily avoided. In most cases the logical domain constraint manager will avoid it without any administrative action, but it can be entirely prevented by doing one of the several actions: Assign virtual CPUs in multiples of 8 - the number of threads per core. For example: ldm set-vcpu 8 mydomain or ldm add-vcpu 24 mydomain. Each domain will then be allocated on a core boundary. Use the whole core constraint when assigning CPU resources. This allocates CPUs in increments of entire cores instead of virtual CPU threads. The equivalent of the above commands would be ldm set-core 1 mydomain or ldm add-core 3 mydomain. Older syntax does the same thing by adding the -c flag to the add-vcpu, rm-vcpu and set-vcpu commands, but the new syntax is recommended. When whole core allocation is used an attempt to add cores to a domain fails if there aren't enough completely empty cores to satisfy the request. See https://blogs.oracle.com/sharakan/entry/oracle_vm_server_for_sparc4 for an excellent article on this topic by Eric Sharakan. Don't obsess: - if the workloads have minimal CPU requirements and don't need anywhere near a full CPU core, then don't worry about it. If you have low utilization workloads being consolidated from older machines onto a current T-series, then there's no need to worry about this or to assign an entire core to domains that will never use that much capacity. In any case, make sure the most important domains have their own CPU cores, in particular the control domain and any I/O or service domain, and of course any important guests. Summary Split core CPU allocation to domains can potentially have an impact on performance, but the logical domains manager tends to prevent this situation, and it can be completely and simply avoided by allocating virtual CPUs on core boundaries.

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lvm disappeared after disc replacement on raid10

- by user142295

here my problem: I am running ubuntu 12.04 on a raid10 (4 disks), on top of which I installed an lvm with two volume groups (one for /, one for /home). The layout of the disks are as follows: Disk /dev/sda: 1500.3 GB, 1500301910016 bytes 255 heads, 63 sectors/track, 182401 cylinders, total 2930277168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0003f3b6 Device Boot Start End Blocks Id System /dev/sda1 * 63 481949 240943+ 83 Linux /dev/sda2 481950 2910640634 1455079342+ fd Linux raid autodetect /dev/sda3 2910640635 2930272064 9815715 82 Linux swap / Solaris Disk /dev/sdb: 1500.3 GB, 1500301910016 bytes 255 heads, 63 sectors/track, 182401 cylinders, total 2930277168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00069785 Device Boot Start End Blocks Id System /dev/sdb1 63 2910158684 1455079311 fd Linux raid autodetect /dev/sdb2 2910158685 2930272064 10056690 82 Linux swap / Solaris Disk /dev/sdc: 1500.3 GB, 1500301910016 bytes 255 heads, 63 sectors/track, 182401 cylinders, total 2930277168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdc1 63 2910158684 1455079311 fd Linux raid autodetect /dev/sdc2 2910158685 2930272064 10056690 82 Linux swap / Solaris Disk /dev/sdd: 1500.3 GB, 1500301910016 bytes 255 heads, 63 sectors/track, 182401 cylinders, total 2930277168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000f14de Device Boot Start End Blocks Id System /dev/sdd1 63 2910158684 1455079311 fd Linux raid autodetect /dev/sdd2 2910158685 2930272064 10056690 82 Linux swap / Solaris The first disk (/dev/sda) contains the /boot partition on /dev/sda1. I use grub2 to boot the system off this partition. On top of this raid10 I installed two volume groups, one for /, one for /home. This system worked well, I even exchanged two disks during the last two years. It always worked. But not this time. For the first time, /dev/sda broke. I do not know if this is an issue – I know I would have struggled anyways to overcome the problem with /boot installed on that disk and grub2 installed on the mbr of /dev/sda. Anyways, I did what I always did: start knoppix fire up the raid sudo mdadm --examine -scan which returns ARRAY /dev/md127 UUID=0dbf4558:1a943464:132783e8:19cdff95 start it up sudo mdadm --assemble /dev/md127 fail the failing disk (smart event) sudo mdadm /dev/md127 --fail /dev/sda2 remove the failing disk sudo mdadm /dev/md127 --remove /dev/sda2 stop the raid sudo mdadm -S /dev/md127 take out the disk replace it with a new one create the same partitions as on the failling one add it to the raid sudo mdadm --assemble /dev/md127 sudo mdadm /dev/md127 --add /dev/sda2 wait 4 hours All looks fine: cat /proc/mdstat returns: Personalities : [raid10] md127 : active raid10 sda2[0] sdd1[3] sdc1[2] sdb1[1] 2910158464 blocks 64K chunks 2 near-copies [4/4] [UUUU] unused devices: <none> and sudo mdadm --detail /dev/md127 returns /dev/md127: Version : 0.90 Creation Time : Wed Jun 10 13:08:46 2009 Raid Level : raid10 Array Size : 2910158464 (2775.34 GiB 2980.00 GB) Used Dev Size : 1455079232 (1387.67 GiB 1490.00 GB) Raid Devices : 4 Total Devices : 4 Preferred Minor : 127 Persistence : Superblock is persistent Update Time : Thu Mar 21 16:27:40 2013 State : clean Active Devices : 4 Working Devices : 4 Failed Devices : 0 Spare Devices : 0 Layout : near=2 Chunk Size : 64K UUID : 0dbf4558:1a943464:132783e8:19cdff95 (local to host Microknoppix) Events : 0.4824680 Number Major Minor RaidDevice State 0 8 2 0 active sync /dev/sda2 1 8 17 1 active sync /dev/sdb1 2 8 33 2 active sync /dev/sdc1 3 8 49 3 active sync /dev/sdd1 However, there is no trace of the volume groups. Rebooting into knoppix does not help Restarting the old system (I actually replugged and re-added the failing disk for that – the system begins to start, but then fails to see the / partition – no wonder if the volume group is gone) does not help. sudo vgscan, sudo vgdisplay, sudo lvs, sudo lvdisplay, sudo vgscan –mknodes all returned No volume groups found. I am completely at a loss. Can anyone tell me if and how I can recover my data? Thanks in advance!

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concurrency::extent<N> from amp.h

- by Daniel Moth

Overview We saw in a previous post how index<N> represents a point in N-dimensional space and in this post we'll see how to define the N-dimensional space itself. With C++ AMP, an N-dimensional space can be specified with the template class extent<N> where you define the size of each dimension. From a look and feel perspective, you'd expect the programmatic interface of a point type and size type to be similar (even though the concepts are different). Indeed, exactly like index<N>, extent<N> is essentially a coordinate vector of N integers ordered from most- to least- significant, BUT each integer represents the size for that dimension (and hence cannot be negative). So, if you read the description of index, you won't be surprised with the below description of extent<N> There is the rank field returning the value of N you passed as the template parameter. You can construct one extent from another (via the copy constructor or the assignment operator), you can construct it by passing an integer array, or via convenience constructor overloads for 1- 2- and 3- dimension extents. Note that the parameterless constructor creates an extent of the specified rank with all bounds initialized to 0. You can access the components of the extent through the subscript operator (passing it an integer). You can perform some arithmetic operations between extent objects through operator overloading, i.e. ==, !=, +=, -=, +, -. There are operator overloads so that you can perform operations between an extent and an integer: -- (pre- and post- decrement), ++ (pre- and post- increment), %=, *=, /=, +=, –= and, finally, there are additional overloads for plus and minus (+,-) between extent<N> and index<N> objects, returning a new extent object as the result. In addition to the usual suspects, extent offers a contains function that tests if an index is within the bounds of the extent (assuming an origin of zero). It also has a size function that returns the total linear size of this extent<N> in units of elements. Example code extent<2> e(3, 4); _ASSERT(e.rank == 2); _ASSERT(e.size() == 3 * 4); e += 3; e[1] += 6; e = e + index<2>(3,-4); _ASSERT(e == extent<2>(9, 9)); _ASSERT( e.contains(index<2>(8, 8))); _ASSERT(!e.contains(index<2>(8, 9))); grid<N> Our upcoming pre-release bits also have a similar type to extent, grid<N>. The way you create a grid is by passing it an extent, e.g. extent<3> e(4,2,6); grid<3> g(e); I am not going to dive deeper into grid, suffice for now to think of grid<N> simply as an alias for the extent<N> object, that you create when you encounter a function that expects a grid object instead of an extent object. Usage The extent class on its own simply defines the size of the N-dimensional space. We'll see in future posts that when you create containers (arrays) and wrappers (array_views) for your data, it is an extent<N> object that you'll need to use to create those (and use an index<N> object to index into them). We'll also see that it is a grid<N> object that you pass to the new parallel_for_each function that I'll cover in the next post. Comments about this post by Daniel Moth welcome at the original blog.

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Failed to unmount partitions

- by msknapp

I'm trying to install ubuntu from a pen drive. I have windows 7 installed already and want to keep that installation. I have a 3TB drive that has one 2TB partition on it, so the last 1TB is completely unused, which is where I want to install ubuntu. I started ubuntu in "try ubuntu" mode and then opened gparted, and then deleted the unused partition for the last third of my drive, then tried to install ubuntu. During the install, it asked me if I wanted to unmount the drives I already have The installer has detected that the following disks have mounted partitions: /dev/sda, /dev/sdb Do you want the installer to try to unmount the partitions on these disks before continuing? If you leave them mounted, you will not be able to create, delete, or resize partitions on these disks, but you may be able to install to existing partitions there. No, Yes I said no because I don't want to lose my windows 7 installation, nor any of that data. I wonder, if I had said yes above, would I have lost all the data on those drives? Anyways, I hit no and continued. I chose to install ubuntu alongside windows 7, and hit continue. A few minutes passed when this popup appeared: Failed to unmount partitions The installer needs to commit changes to partition tables, but cannot do so because the partitions on the following mount points could not be unmounted: /media/ubuntu/Three\ Terabyte Drive Terabyte\ DriveDrive Please close any applications using these mount points. Would you like the installer to try to unmount these partitions again? Go Back, Continue Why is this not working? What am I supposed to do? ========== Update: I went ahead and said yes, it can unmount those partitions. It finished installing Ubuntu, but now when i start my machine it just takes me to the grub rescue prompt. Seems like it broke something. What can I do now? =============== Results of fdisk -l: Disk /dev/sda: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00027e14 Device Boot Start End Blocks Id System /dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sda2 206848 976771071 488282112 7 HPFS/NTFS/exFAT WARNING: GPT (GUID Partition Table) detected on '/dev/sdb'! The util fdisk doesn't support GPT. Use GNU Parted. Disk /dev/sdb: 3000.6 GB, 3000592982016 bytes 255 heads, 63 sectors/track, 364801 cylinders, total 5860533168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdb1 1 4294967295 2147483647+ ee GPT Partition 1 does not start on physical sector boundary. Disk /dev/sdc: 16.0 GB, 16008609792 bytes 255 heads, 63 sectors/track, 1946 cylinders, total 31266816 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdc1 * 32 31266815 15633392 c W95 FAT32 (LBA) Disk /dev/sdd: 999.5 GB, 999501594624 bytes 255 heads, 63 sectors/track, 121515 cylinders, total 1952151552 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0002ae3f Device Boot Start End Blocks Id System /dev/sdd1 2048 1952151551 976074752 7 HPFS/NTFS/exFAT

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