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  • Software to report internet traffic for home user

    - by Mehper C. Palavuzlar
    I need a freeware to monitor my internet activity, especially upload and download amounts over time. For instance, I like to see a graph or table that shows the downloaded and uploaded amounts per day, week or month and in total for a selected period. OS: Windows XP, Vista, 7 Edit: I don't need to see the traffic program by program. I'm not interested in which program accesses the internet, but I'm interested in monitoring my incoming and outgoing data amounts using a light-weight freeware.

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  • Removing a device in "removed" state from Linux software RAID array

    - by Sahasranaman MS
    My workstation has two disks(/dev/sd[ab]), both with similar partitioning. /dev/sdb failed, and cat /proc/mdstat stopped showing the second sdb partition. I ran mdadm --fail and mdadm --remove for all partitions from the failed disk on the arrays that use them, although all such commands failed with mdadm: set device faulty failed for /dev/sdb2: No such device mdadm: hot remove failed for /dev/sdb2: No such device or address Then I hot swapped the failed disk, partitioned the new disk and added the partitions to the respective arrays. All arrays got rebuilt properly except one, because in /dev/md2, the failed disk doesn't seem to have been removed from the array properly. Because of this, the new partition keeps getting added as a spare to the partition, and its status remains degraded. Here's what mdadm --detail /dev/md2 shows: [root@ldmohanr ~]# mdadm --detail /dev/md2 /dev/md2: Version : 1.1 Creation Time : Tue Dec 27 22:55:14 2011 Raid Level : raid1 Array Size : 52427708 (50.00 GiB 53.69 GB) Used Dev Size : 52427708 (50.00 GiB 53.69 GB) Raid Devices : 2 Total Devices : 2 Persistence : Superblock is persistent Intent Bitmap : Internal Update Time : Fri Nov 23 14:59:56 2012 State : active, degraded Active Devices : 1 Working Devices : 2 Failed Devices : 0 Spare Devices : 1 Name : ldmohanr.net:2 (local to host ldmohanr.net) UUID : 4483f95d:e485207a:b43c9af2:c37c6df1 Events : 5912611 Number Major Minor RaidDevice State 0 8 2 0 active sync /dev/sda2 1 0 0 1 removed 2 8 18 - spare /dev/sdb2 To remove a disk, mdadm needs a device filename, which was /dev/sdb2 originally, but that no longer refers to device number 1. I need help with removing device number 1 with 'removed' status and making /dev/sdb2 active.

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  • Software to hold battery at 50% charge level

    - by Mehper C. Palavuzlar
    My Sony Vaio laptop has a built-in program called "Sony Battery Care" which provides a functionality to hold battery at certain levels of charge while operating. For example, I've set it to 50% and the battery is always kept at that level while on AC power. This mode prevents battery degradation and is more effective as I usually use my laptop with AC power. I'm looking for a similar program to use with other laptops with Windows OS; preferably a free one.

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  • Software raid 0 with six disks performance

    - by user134880
    I have some problems with disk performance. I have 6 x WD 500Gb RE4 disks. Each disk gives 135Mb/sec throughput. All measurements are made with hdparm with options "-tT" (I know that it is just synthetic test, but I need some start point to make measurements). I have controller with Sil3124 x 4 ports PCI Express 1x So... RAID0 on controller with 2 disks gives 200Mb/s - ok, pcie limit. RAID0 on motherboard with 2 disks gives 270Mb/s - niceeee :) RAID0 on contorller with 4 disks gives 200Mb/s - ok, pcie limit. RAID0 on controller with 4 disks + 1 disks on motherboard = 340Mb/s ... :( RAID0 on controller with 4 disks + 2 disks on motherboard = 300Mb/s .... why? Any ideas? Maybe need more cpu power? Now there is Pentium D Dual core 2.8Ghz, 4Gb RAM. It is dedicated box for storage.. no other activity.

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  • Assembling Software RAID in Live CD for data recovery

    - by Maletor
    I need help recovering some data that's on my RAID which is on a LVM on my server running Ubuntu. What happened was I deleted the logical volume that controlled my swap space which was on a partition on drives sda2, sdb2, sdc2, and sdd2 in RAID1. This foobared my whole system for one reason or another. Booting leave me with grub rescue and an error saying that it is an unknown filesystem. When I boot to a live cd I can see my RAID arrays and I can even start them up. However, it doesn't appear to mount them anywhere so I can't see the data. I am in the live cd now and I have done sudo apt-get install mdadm lvm2 so it should be mounting them correctly. I just can't see why it wouldn't. Please any help is appreciated here. Here is some output. By the way, there are 3 RAIDs, 1) /boot 100mb RAID1, 2) swap 10gb RAID1, 3) root 990GB RAID5 ubuntu@ubuntu:~$ df -h Filesystem Size Used Avail Use% Mounted on aufs 124M 101M 18M 86% / none 2.0G 324K 2.0G 1% /dev /dev/sde1 2.0G 826M 1.2G 42% /cdrom /dev/loop0 667M 667M 0 100% /rofs none 2.0G 164K 2.0G 1% /dev/shm tmpfs 2.0G 28K 2.0G 1% /tmp none 2.0G 92K 2.0G 1% /var/run none 2.0G 0 2.0G 0% /var/lock none 2.0G 0 2.0G 0% /lib/init/rw /dev/md1 91M 73M 15M 84% /media/5ac3dbf1-a6c5-409c-96ae-edc6e27992c7 ubuntu@ubuntu:~$ cat /etc/fstab aufs / aufs rw 0 0 tmpfs /tmp tmpfs nosuid,nodev 0 0 /dev/sda2 swap swap defaults 0 0 /dev/sdb2 swap swap defaults 0 0 /dev/sdc2 swap swap defaults 0 0 /dev/sdd2 swap swap defaults 0 0

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  • Virtualization software for windows 7

    - by user23950
    I've been using Shadow User and Deep freeze for windows xp. But I don't think its compatible with windows 7. Do you know of any application that can achieve the same thing? Please don't tell me to use Returnil virtual system because I've had a really bad experience with it when I'm using xp. The system just restarted over and over. And I have just reformatted by that time.

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  • Professional Scrum Developer (.NET) Training in London

    - by Martin Hinshelwood
    On the 26th - 30th July in Microsoft’s offices in London Adam Cogan from SSW will be presenting the first Professional Scrum Developer course in the UK. I will be teaching this course along side Adam and it is a fantastic experience. You are split into teams and go head-to-head to deliver units of potentially shippable work in four two hour sprints. The Professional Scrum Developer course is the only course endorsed by both Microsoft and Ken Schwaber and they have worked together very effectively in brining this course to fruition. This course is the brain child of Richard Hundhausen, a Microsoft Regional Director, and both Adam and I attending the Trainer Prep in Sydney when he was there earlier this year. He is a fantastic trainer and no matter where you do this course you can be safe in the knowledge that he has trained and vetted all of the teachers. A tools version of Ken if you will Find a course and register Download this syllabus Download the Scrum Guide What is the Professional Scrum Developer course all about? Professional Scrum Developer course is a unique and intensive five-day experience for software developers. The course guides teams on how to turn product requirements into potentially shippable increments of software using the Scrum framework, Visual Studio 2010, and modern software engineering practices. Attendees will work in self-organizing, self-managing teams using a common instance of Team Foundation Server 2010. Who should attend this course? This course is suitable for any member of a software development team – architect, programmer, database developer, tester, etc. Entire teams are encouraged to attend and experience the course together, but individuals are welcome too. Attendees will self-organize to form cross-functional Scrum teams. These teams require an aggregate of skills specific to the selected case study. Please see the last page of this document for specific details. Product Owners, ScrumMasters, and other stakeholders are welcome too, but keep in mind that everyone who attends will be expected to commit to work and pull their weight on a Scrum team. What should you know by the end of the course? Scrum will be experienced through a combination of lecture, demonstration, discussion, and hands-on exercises. Attendees will learn how to do Scrum correctly while being coached and critiqued by the instructor, in the following topic areas: Form effective teams Explore and understand legacy “Brownfield” architecture Define quality attributes, acceptance criteria, and “done” Create automated builds How to handle software hotfixes Verify that bugs are identified and eliminated Plan releases and sprints Estimate product backlog items Create and manage a sprint backlog Hold an effective sprint review Improve your process by using retrospectives Use emergent architecture to avoid technical debt Use Test Driven Development as a design tool Setup and leverage continuous integration Use Test Impact Analysis to decrease testing times Manage SQL Server development in an Agile way Use .NET and T-SQL refactoring effectively Build, deploy, and test SQL Server databases Create and manage test plans and cases Create, run, record, and play back manual tests Setup a branching strategy and branch code Write more maintainable code Identify and eliminate people and process dysfunctions Inspect and improve your team’s software development process What does the week look like? This course is a mix of lecture, demonstration, group discussion, simulation, and hands-on software development. The bulk of the course will be spent working as a team on a case study application delivering increments of new functionality in mini-sprints. Here is the week at a glance: Monday morning and most of the day Friday will be spent with the computers powered off, so you can focus on sharpening your game of Scrum and avoiding the common pitfalls when implementing it. The Sprints Timeboxing is a critical concept in Scrum as well as in this course. We expect each team and student to understand and obey all of the timeboxes. The timebox duration will always be clearly displayed during each activity. Expect the instructor to enforce it. Each of the ½ day sprints will roughly follow this schedule: Component Description Minutes Instruction Presentation and demonstration of new and relevant tools & practices 60 Sprint planning meeting Product owner presents backlog; each team commits to delivering functionality 10 Sprint planning meeting Each team determines how to build the functionality 10 The Sprint The team self-organizes and self-manages to complete their tasks 120 Sprint Review meeting Each team will present their increment of functionality to the other teams = 30 Sprint Retrospective A group retrospective meeting will be held to inspect and adapt 10 Each team is expected to self-organize and manage their own work during the sprint. Pairing is highly encouraged. The instructor/product owner will be available if there are questions or impediments, but will be hands-off by default. You should be prepared to communicate and work with your team members in order to achieve your sprint goal. If you have development-related questions or get stuck, your partner or team should be your first level of support. Module 1: INTRODUCTION This module provides a chance for the attendees to get to know the instructors as well as each other. The Professional Scrum Developer program, as well as the day by day agenda, will be explained. Finally, the Scrum team will be selected and assembled so that the forming, storming, norming, and performing can begin. Trainer and student introductions Professional Scrum Developer program Agenda Logistics Team formation Retrospective Module 2: SCRUMDAMENTALS This module provides a level-setting understanding of the Scrum framework including the roles, timeboxes, and artifacts. The team will then experience Scrum firsthand by simulating a multi-day sprint of product development, including planning, review, and retrospective meetings. Scrum overview Scrum roles Scrum timeboxes (ceremonies) Scrum artifacts Simulation Retrospective It’s required that you read Ken Schwaber’s Scrum Guide in preparation for this module and course. MODULE 3: IMPLEMENTING SCRUM IN VISUAL STUDIO 2010 This module demonstrates how to implement Scrum in Visual Studio 2010 using a Scrum process template*. The team will learn the mapping between the Scrum concepts and how they are implemented in the tool. After connecting to the shared Team Foundation Server, the team members will then return to the simulation – this time using Visual Studio to manage their product development. Mapping Scrum to Visual Studio 2010 User Story work items Task work items Bug work items Demonstration Simulation Retrospective Module 4: THE CASE STUDY In this module the team is introduced to their problem domain for the week. A kickoff meeting by the Product Owner (the instructor) will set the stage for the why and what that will take during the upcoming sprints. The team will then define the quality attributes of the project and their definition of “done.” The legacy application code will be downloaded, built, and explored, so that any bugs can be discovered and reported. Introduction to the case study Download the source code, build, and explore the application Define the quality attributes for the project Define “done” How to file effective bugs in Visual Studio 2010 Retrospective Module 5: HOTFIX This module drops the team directly into a Brownfield (legacy) experience by forcing them to analyze the existing application’s architecture and code in order to locate and fix the Product Owner’s high-priority bug(s). The team will learn best practices around finding, testing, fixing, validating, and closing a bug. How to use Architecture Explorer to visualize and explore Create a unit test to validate the existence of a bug Find and fix the bug Validate and close the bug Retrospective Module 6: PLANNING This short module introduces the team to release and sprint planning within Visual Studio 2010. The team will define and capture their goals as well as other important planning information. Release vs. Sprint planning Release planning and the Product Backlog Product Backlog prioritization Acceptance criteria and tests Sprint planning and the Sprint Backlog Creating and linking Sprint tasks Retrospective At this point the team will have the knowledge of Scrum, Visual Studio 2010, and the case study application to begin developing increments of potentially shippable functionality that meet their definition of done. Module 7: EMERGENT ARCHITECTURE This module introduces the architectural practices and tools a team can use to develop a valid design on which to develop new functionality. The teams will learn how Scrum supports good architecture and design practices. After the discussion, the teams will be presented with the product owner’s prioritized backlog so that they may select and commit to the functionality they can deliver in this sprint. Architecture and Scrum Emergent architecture Principles, patterns, and practices Visual Studio 2010 modeling tools UML and layer diagrams SPRINT 1 Retrospective Module 8: TEST DRIVEN DEVELOPMENT This module introduces Test Driven Development as a design tool and how to implement it using Visual Studio 2010. To maximize productivity and quality, a Scrum team should setup Continuous Integration to regularly build every team member’s code changes and run regression tests. Refactoring will also be defined and demonstrated in combination with Visual Studio’s Test Impact Analysis to efficiently re-run just those tests which were impacted by refactoring. Continuous integration Team Foundation Build Test Driven Development (TDD) Refactoring Test Impact Analysis SPRINT 2 Retrospective Module 9: AGILE DATABASE DEVELOPMENT This module lets the SQL Server database developers in on a little secret – they can be agile too. By using the database projects in Visual Studio 2010, the database developers can join the rest of the team. The students will see how to apply Agile database techniques within Visual Studio to support the SQL Server 2005/2008/2008R2 development lifecycle. Agile database development Visual Studio database projects Importing schema and scripts Building and deploying Generating data Unit testing SPRINT 3 Retrospective Module 10: SHIP IT Teams need to know that just because they like the functionality doesn’t mean the Product Owner will. This module revisits acceptance criteria as it pertains to acceptance testing. By refining acceptance criteria into manual test steps, team members can execute the tests, recording the results and reporting bugs in a number of ways. Manual tests will be defined and executed using the Microsoft Test Manager tool. As the Sprint completes and an increment of functionality is delivered, the team will also learn why and when they should create a branch of the codeline. Acceptance criteria Testing in Visual Studio 2010 Microsoft Test Manager Writing and running manual tests Branching SPRINT 4 Retrospective Module 11: OVERCOMING DYSFUNCTION This module introduces the many types of people, process, and tool dysfunctions that teams face in the real world. Many dysfunctions and scenarios will be identified, along with ideas and discussion for how a team might mitigate them. This module will enable you and your team to move toward independence and improve your game of Scrum when you depart class. Scrum-butts and flaccid Scrum Best practices working as a team Team challenges ScrumMaster challenges Product Owner challenges Stakeholder challenges Course Retrospective What will be expected of you and you team? This is a unique course in that it’s technically-focused, team-based, and employs timeboxes. It demands that the members of the teams self-organize and self-manage their own work to collaboratively develop increments of software. All attendees must commit to: Pay attention to all lectures and demonstrations Participate in team and group discussions Work collaboratively with other team members Obey the timebox for each activity Commit to work and do your best to deliver All teams should have these skills: Understanding of Scrum Familiarity with Visual Studio 201 C#, .NET 4.0 & ASP.NET 4.0 experience*  SQL Server 2008 development experience Software testing experience * Check with the instructor ahead of time for the exact technologies Self-organising teams Another unique attribute of this course is that it’s a technical training class being delivered to teams of developers, not pairs, and not individuals. Ideally, your actual software development team will attend the training to ensure that all necessary skills are covered. However, if you wish to attend an open enrolment course alone or with just a couple of colleagues, realize that you may be placed on a team with other attendees. The instructor will do his or her best to ensure that each team is cross-functional to tackle the case study, but there are no guarantees. You may be required to try a new role, learn a new skill, or pair with somebody unfamiliar to you. This is just good Scrum! Who should NOT take this course? Because of the nature of this course, as explained above, certain types of people should probably not attend this course: Students requiring command and control style instruction – there are no prescriptive/step-by-step (think traditional Microsoft Learning) labs in this course Students who are unwilling to work within a timebox Students who are unwilling to work collaboratively on a team Students who don’t have any skill in any of the software development disciplines Students who are unable to commit fully to their team – not only will this diminish the student’s learning experience, but it will also impact their team’s learning experience Find a course and register Download this syllabus Download the Scrum Guide Technorati Tags: Scrum,SSW,Pro Scrum Dev

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  • How does the PPA fit into the scenario of publishing an application to the Ubuntu Software Center?

    - by Mridang Agarwalla
    I've been going through docs for the past couple of hours but I haven't understood what the PPA is? I have a cross-platform Java application that I'd like to publish to the Ubuntu Software Center. My application is open-source and I'm using Github. Apparently, publishing applications to the store isn't as simple as uploading a deb package - am I right? I need to create an account on Launchpad and put all my code there. I don't intend to move from Git to Bzr merely for the sake of publishing to the app store but luckily, one is able to set up source-code mirroring from Github to Launchpad. Since my application is still very premature, it'll have updates fairly often. When I build my application on my machine, do I simply go my Ubuntu App Developer page and upload the new DEB package or do they build my application from source? What exactly is the PPA for? I don't think I'll need too many of the Launchpad features so I'd like to stick to Github if possible. (Publishing for Ubuntu really isn't trivial. I can see why there are so many developers out there who haven't published their applications to the Ubuntu Software Center. Publishing an Android applications has been the easiest so far.)

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  • Differences between software testing processes and techniques?

    - by Aptos
    I get confused between these terms. For examples, should Unit testing be listed as a software testing process or technique? I think unit testing is a software testing technique. And how about Test driven development? Can you give me some examples for software testing processes and techniques? In my opinion, software testing process is a part of the software development life cycle. For example, if we use V-Model, the software testing process will be System test, Acceptance test, Integration Test... Thank you.

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  • Access to the Technology Software

    - by rituchhibber
    The Technology Program software is available to Oracle partners, free of charge, for demonstration and development purposes according to the terms of the OPN Agreement. Instructions for Ordering Software: Download software via the Oracle Software Delivery Cloud website. Downloads are available in most countries. To determine if downloads are available within your country click on the Download software link. Request a physical shipment of the software by downloading and completing the Development and Demonstration Ordering Document (XLS). Should you have additional questions or need assistance in completing the ordering document, please contact your local Partner Business Center. Incomplete orders will not be processed.

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  • How is a "Software Developer" different from a "Software Consultant"? What makes a consultant?

    - by Kumar
    I have seen a lot of people claiming themselves to be a "software consultant". These consultants do what a normal software developer does, write code, estimate tasks, fix bugs and attend meetings etc. The only difference being the financials, consultants end up earning more. Then how is a software developer different from a "consultant"? In addition to the main question, I would like to know how can a software developer become a consultant? Are there any specific guidelines for a consultant? Do they need to amass certifications and write up research papers? Please do not confuse the software consultant with a management consultant. Software consultants I have seen are not managers.

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  • Started wrong with a project. Should I start over?

    - by solidsnake
    I'm a beginner web developer (one year of experience). A couple of weeks after graduating, I got offered a job to build a web application for a company whose owner is not much of a tech guy. He recruited me to avoid theft of his idea, the high cost of development charged by a service company, and to have someone young he can trust onboard to maintain the project for the long run (I came to these conclusions by myself long after being hired). Cocky as I was back then, with a diploma in computer science, I accepted the offer thinking I can build anything. I was calling the shots. After some research I settled on PHP, and started with plain PHP, no objects, just ugly procedural code. Two months later, everything was getting messy, and it was hard to make any progress. The web application is huge. So I decided to check out an MVC framework that would make my life easier. That's where I stumbled upon the cool kid in the PHP community: Laravel. I loved it, it was easy to learn, and I started coding right away. My code looked cleaner, more organized. It looked very good. But again the web application was huge. The company was pressuring me to deliver the first version, which they wanted to deploy, obviously, and start seeking customers. Because Laravel was fun to work with, it made me remember why I chose this industry in the first place - something I forgot while stuck in the shitty education system. So I started working on small projects at night, reading about methodologies and best practice. I revisited OOP, moved on to object-oriented design and analysis, and read Uncle Bob's book Clean Code. This helped me realize that I really knew nothing. I did not know how to build software THE RIGHT WAY. But at this point it was too late, and now I'm almost done. My code is not clean at all, just spaghetti code, a real pain to fix a bug, all the logic is in the controllers, and there is little object oriented design. I'm having this persistent thought that I have to rewrite the whole project. However, I can't do it... They keep asking when is it going to be all done. I can not imagine this code deployed on a server. Plus I still know nothing about code efficiency and the web application's performance. On one hand, the company is waiting for the product and can not wait anymore. On the other hand I can't see myself going any further with the actual code. I could finish up, wrap it up and deploy, but god only knows what might happen when people start using it. What do you think I should do?

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  • Open Source Projects for Beginning Coders?

    - by MattDMo
    After working as a molecular biologist at the bench for many years, I lost my job last year and am thinking about a career change. I've been using open-source software and doing Linux system administration since the mid 90s, and have written/improved some small shell/Perl/PHP scripts, and am very comfortable building from source, but never progressed to creating non-trivial programs de novo. I want to move to actually learning real programming skills and contributing back to the community, with the possible eventual goal of getting into bioinformatics as a career in the future. I'm a stay-at-home dad now, so I have some time on my hands. I've done a lot of research on languages, and have settled on Python as my major focus for now. I'm set up on GitHub, but haven't forked anything yet. I've looked around OpenHatch some, but nothing really grabbed me. I've heard the advice to work on what you use/love, but that category is so broad that I'm having trouble finding any one thing to get started on. What are your suggestions for getting started? How do you pick a project that will welcome your (possibly amateurish) help? With a fairly limited skill set, how do you find a request that you can handle? What are common newbie mistakes to avoid? Any other advice?

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  • Can I use my prepaid phone balance (in pesos) to buy from the Software Centre?

    - by obetus
    Using local network broadband, we can use it to buy games and applications from load balance. Is there any possible ways to use it also in Ubuntu software Center? additional: I'm using mobile broadband for the internet connection,this broadband has a sim card and account number where you can download money from buying a prepaid card worth 100 pesos,300 pesos or 500 pesos, provided by our local network. We use this mobile broadband when there is no wifi connection. There are two kinds of mobile broadband, one is postpaid account and the other is prepaid account. I use prepaid account, this kind of account can load a money for transaction like data plans, from 10 pesos for 30 minutes internet connection or 200 pesos for 5 days internet connection., and this prepaid account can load 5 pesos up to thousands of pesos. Now, if this prepaid mobile broadband can provide money in pesos and has internet connection, I think it can also use it for buying goods or applications or games via internet. i think its only need a software that can detect the sim card number and the money balance for transactions. Sorry for my bad english but I hope you got my point.

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  • How to create browser based software?

    - by erkant
    I have recently used some software, which come as a regular setup file, where you install your software, and then when you run it, opens the browser, uses the localhost with some specific port number to connect to the software, and runs it from there. I find it quite useful and interesting. But I even don't know whether this kind of software and programming methodology have a name or not. Therefore, I would like to learn which programming languages, APIs, and frameworks are specifically designed for this purpose? One example to this is Metasploit. You can download its setup file, and install it casually like any other software, then when everything finishes, and you want to use the software. It will open the browser and connect to, http://localhost:3790/ where Metasploit will load and start.

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  • Ubuntu Software Centre is gone! How can I get it back?

    - by Mochan
    Right. I am having MAJOR issues. (It would be much appreciated if you would solve them for me! Check my profile for open questions...) Following an answerer... who sorry to say... didn't give a great answer because it was just a graphical way of doing what I had already done - suggested I purge a library. Turns out that library controlled the Advanced Packaging Tool (apt), Ubuntu Software Centre and the repositories. Not a great tool to mess with. While trying to purge the library, it came up with 'Removing MyUnity.. Removing x... Removing x... Removing Ubuntu Software Centre... Removing X... Removing apt..." I quickly recognized and force shut-down my system. But I guess it was too late. So... well, plainly put - how do I get it back?!

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  • The case of the phantom ADF developer (and other yarns)

    - by Chris Muir
    A few years of ADF experience means I see common mistakes made by different developers, some I regularly make myself.  This post is designed to assist beginners to Oracle JDeveloper Application Development Framework (ADF) avoid a common ADF pitfall, the case of the phantom ADF developer [add Scooby-Doo music here]. ADF Business Components - triggers, default table values and instead of views. Oracle's JDeveloper tutorials help with the A-B-Cs of ADF development, typically built on the nice 'n safe demo schema provided by with the Oracle database such as the HR demo schema. However it's not too long until ADF beginners, having built up some confidence from learning with the tutorials and vanilla demo schemas, start building ADF Business Components based upon their own existing database schema objects.  This is where unexpected problems can sneak in. The crime Developers may encounter a surprising error at runtime when editing a record they just created or updated and committed to the database, based on their own existing tables, namely the error: JBO-25014: Another user has changed the row with primary key oracle.jbo.Key[x] ...where X is the primary key value of the row at hand.  In a production environment with multiple users this error may be legit, one of the other users has updated the row since you queried it.  Yet in a development environment this error is just plain confusing.  If developers are isolated in their own database, creating and editing records they know other users can't possibly be working with, or all the other developers have gone home for the day, how is this error possible? There are no other users?  It must be the phantom ADF developer! [insert dramatic music here] The following picture is what you'll see in the Business Component Browser, and you'll receive a similar error message via an ADF Faces page: A false conclusion What can possibly cause this issue if it isn't our phantom ADF developer?  Doesn't ADF BC implement record locking, locking database records when the row is modified in the ADF middle-tier by a user?  How can our phantom ADF developer even take out a lock if this is the case?  Maybe ADF has a bug, maybe ADF isn't implementing record locking at all?  Shouldn't we see the error "JBO-26030: Failed to lock the record, another user holds the lock" as we attempt to modify the record, why do we see JBO-25014? : Let's verify that ADF is in fact issuing the correct SQL LOCK-FOR-UPDATE statement to the database. First we need to verify ADF's locking strategy.  It is determined by the Application Module's jbo.locking.mode property.  The default (as of JDev 11.1.1.4.0 if memory serves me correct) and recommended value is optimistic, and the other valid value is pessimistic. Next we need a mechanism to check that ADF is issuing the LOCK statements to the database.  We could ask DBAs to monitor locks with OEM, but optimally we'd rather not involve overworked DBAs in this process, so instead we can use the ADF runtime setting –Djbo.debugoutput=console.  At runtime this options turns on instrumentation within the ADF BC layer, which among a lot of extra detail displayed in the log window, will show the actual SQL statement issued to the database, including the LOCK statement we're looking to confirm. Setting our locking mode to pessimistic, opening the Business Components Browser of a JSF page allowing us to edit a record, say the CHARGEABLE field within a BOOKINGS record where BOOKING_NO = 1206, upon editing the record see among others the following log entries: [421] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[422] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[423] Where binding param 1: 1206  As can be seen on line 422, in fact a LOCK-FOR-UPDATE is indeed issued to the database.  Later when we commit the record we see: [441] OracleSQLBuilder: SAVEPOINT 'BO_SP'[442] OracleSQLBuilder Executing, Lock 1 DML on: BOOKINGS (Update)[443] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[444] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[445] Update binding param 1: N[446] Where binding param 2: 1206[447] BookingsView1 notify COMMIT ... [448] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [449] EntityCache close prepared statement ....and as a result the changes are saved to the database, and the lock is released. Let's see what happens when we use the optimistic locking mode, this time to change the same BOOKINGS record CHARGEABLE column again.  As soon as we edit the record we see little activity in the logs, nothing to indicate any SQL statement, let alone a LOCK has been taken out on the row. However when we save our records by issuing a commit, the following is recorded in the logs: [509] OracleSQLBuilder: SAVEPOINT 'BO_SP'[510] OracleSQLBuilder Executing doEntitySelect on: BOOKINGS (true)[511] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[512] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[513] Where binding param 1: 1205[514] OracleSQLBuilder Executing, Lock 2 DML on: BOOKINGS (Update)[515] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[516] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[517] Update binding param 1: Y[518] Where binding param 2: 1205[519] BookingsView1 notify COMMIT ... [520] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [521] EntityCache close prepared statement Again even though we're seeing the midtier delay the LOCK statement until commit time, it is in fact occurring on line 412, and released as part of the commit issued on line 419.  Therefore with either optimistic or pessimistic locking a lock is indeed issued. Our conclusion at this point must be, unless there's the unlikely cause the LOCK statement is never really hitting the database, or the even less likely cause the database has a bug, then ADF does in fact take out a lock on the record before allowing the current user to update it.  So there's no way our phantom ADF developer could even modify the record if he tried without at least someone receiving a lock error. Hmm, we can only conclude the locking mode is a red herring and not the true cause of our problem.  Who is the phantom? At this point we'll need to conclude that the error message "JBO-25014: Another user has changed" is somehow legit, even though we don't understand yet what's causing it. This leads onto two further questions, how does ADF know another user has changed the row, and what's been changed anyway? To answer the first question, how does ADF know another user has changed the row, the Fusion Guide's section 4.10.11 How to Protect Against Losing Simultaneous Updated Data , that details the Entity Object Change-Indicator property, gives us the answer: At runtime the framework provides automatic "lost update" detection for entity objects to ensure that a user cannot unknowingly modify data that another user has updated and committed in the meantime. Typically, this check is performed by comparing the original values of each persistent entity attribute against the corresponding current column values in the database at the time the underlying row is locked. Before updating a row, the entity object verifies that the row to be updated is still consistent with the current state of the database.  The guide further suggests to make this solution more efficient: You can make the lost update detection more efficient by identifying any attributes of your entity whose values you know will be updated whenever the entity is modified. Typical candidates include a version number column or an updated date column in the row.....To detect whether the row has been modified since the user queried it in the most efficient way, select the Change Indicator option to compare only the change-indicator attribute values. We now know that ADF BC doesn't use the locking mechanism at all to protect the current user against updates, but rather it keeps a copy of the original record fetched, separate to the user changed version of the record, and it compares the original record against the one in the database when the lock is taken out.  If values don't match, be it the default compare-all-columns behaviour, or the more efficient Change Indicator mechanism, ADF BC will throw the JBO-25014 error. This leaves one last question.  Now we know the mechanism under which ADF identifies a changed row, what we don't know is what's changed and who changed it? The real culprit What's changed?  We know the record in the mid-tier has been changed by the user, however ADF doesn't use the changed record in the mid-tier to compare to the database record, but rather a copy of the original record before it was changed.  This leaves us to conclude the database record has changed, but how and by who? There are three potential causes: Database triggers The database trigger among other uses, can be configured to fire PLSQL code on a database table insert, update or delete.  In particular in an insert or update the trigger can override the value assigned to a particular column.  The trigger execution is actioned by the database on behalf of the user initiating the insert or update action. Why this causes the issue specific to our ADF use, is when we insert or update a record in the database via ADF, ADF keeps a copy of the record written to the database.  However the cached record is instantly out of date as the database triggers have modified the record that was actually written to the database.  Thus when we update the record we just inserted or updated for a second time to the database, ADF compares its original copy of the record to that in the database, and it detects the record has been changed – giving us JBO-25014. This is probably the most common cause of this problem. Default values A second reason this issue can occur is another database feature, default column values.  When creating a database table the schema designer can define default values for specific columns.  For example a CREATED_BY column could be set to SYSDATE, or a flag column to Y or N.  Default values are only used by the database when a user inserts a new record and the specific column is assigned NULL.  The database in this case will overwrite the column with the default value. As per the database trigger section, it then becomes apparent why ADF chokes on this feature, though it can only specifically occur in an insert-commit-update-commit scenario, not the update-commit-update-commit scenario. Instead of trigger views I must admit I haven't double checked this scenario but it seems plausible, that of the Oracle database's instead of trigger view (sometimes referred to as instead of views).  A view in the database is based on a query, and dependent on the queries complexity, may support insert, update and delete functionality to a limited degree.  In order to support fully insertable, updateable and deletable views, Oracle introduced the instead of view, that gives the view designer the ability to not only define the view query, but a set of programmatic PLSQL triggers where the developer can define their own logic for inserts, updates and deletes. While this provides the database programmer a very powerful feature, it can cause issues for our ADF application.  On inserting or updating a record in the instead of view, the record and it's data that goes in is not necessarily the data that comes out when ADF compares the records, as the view developer has the option to practically do anything with the incoming data, including throwing it away or pushing it to tables which aren't used by the view underlying query for fetching the data. Readers are at this point reminded that this article is specifically about how the JBO-25014 error occurs in the context of 1 developer on an isolated database.  The article is not considering how the error occurs in a production environment where there are multiple users who can cause this error in a legitimate fashion.  Assuming none of the above features are the cause of the problem, and optimistic locking is turned on (this error is not possible if pessimistic locking is the default mode *and* none of the previous causes are possible), JBO-25014 is quite feasible in a production ADF application if 2 users modify the same record. At this point under project timelines pressure, the obvious fix for developers is to drop both database triggers and default values from the underlying tables.  However we must be careful that these legacy constructs aren't used and assumed to be in place by other legacy systems.  Dropping the database triggers or default value that the existing Oracle Forms  applications assumes and requires to be in place could cause unexpected behaviour and bugs in the Forms application.  Proficient software engineers would recognize such a change may require a partial or full regression test of the existing legacy system, a potentially costly and timely exercise, not ideal. Solving the mystery once and for all Luckily ADF has built in functionality to deal with this issue, though it's not a surprise, as Oracle as the author of ADF also built the database, and are fully aware of the Oracle database's feature set.  At the Entity Object attribute level, the Refresh After Insert and Refresh After Update properties.  Simply selecting these instructs ADF BC after inserting or updating a record to the database, to expect the database to modify the said attributes, and read a copy of the changed attributes back into its cached mid-tier record.  Thus next time the developer modifies the current record, the comparison between the mid-tier record and the database record match, and JBO-25014: Another user has changed" is no longer an issue. [Post edit - as per the comment from Oracle's Steven Davelaar below, as he correctly points out the above solution will not work for instead-of-triggers views as it relies on SQL RETURNING clause which is incompatible with this type of view] Alternatively you can set the Change Indicator on one of the attributes.  This will work as long as the relating column for the attribute in the database itself isn't inadvertently updated.  In turn you're possibly just masking the issue rather than solving it, because if another developer turns the Change Indicator back on the original issue will return.

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  • Determing software estimates and tracking past estimates

    - by Casey
    I know that this probably has as many answers as users here on SO, but software estimation always seemed like an esoteric science. Software developers don't have a magic book to refer to as exist in many other industries. I've been spending the last couple of days working on putting together some estimates for a bit of work that I am proposing for a freelance project that I am working on and am having trouble getting it down. I'm not experienced with any real software estimation practices and am trying to go from the gut based on my experience but also trying to be a little loose (not too loose though) on the estimates to leave me a bit of room to work. I read this blog entry http://blogs.popart.com/2007/07/what-scotty-from-star-trek-can-teach-us-about-managing-expectations/ that was linked to from SO and would like to start tracking my estimates at work as well even though I'm not really required to create estimates there. What tools or techniques would you recommend? Also, how much padding do you usually add in to a time estimate?

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