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  • error of pdf2djvu: "Bogus memory allocation size"

    - by Tim
    I am using pdf2djvu to convert a pdf file into a djvu file, but got this error while trying to convert to either bundled or indirect multi-page djvu file: $ pdf2djvu 1.pdf -o 1.djvu 1.pdf: - page #1 -> #1 Bogus memory allocation size $ pdf2djvu 1.pdf -i 1.djvu 1.pdf: - page #1 -> #1 Bogus memory allocation size I was wondering what is wrong here and how I shall fix the problem? You can suggest another application other than pdf2djvu. My pdf file can be downloaded from here , in case that you may wonder what is special about it. Thanks and regards!

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  • How can I switch between fglrx and ati drivers?

    - by Santa Maradona
    Hi there, How can I switch between fglrx and ati (open source) drivers without uninstalling fglrx? The thing is I'm using FGLRX on a daily basis, because it's better for movies--OS driver displays annoying horizontal line while playing movies. FGLRX also does this, but it's less visible. That's only disadvantage of OS driver. When I want to plug in external monitor with different resolution than my laptop's LCD I have to use open source driver, because FGLRX can't display two different resolutions at the same time. I can uninstall FGLRX, but it's rather inconvenient to do this all the time. I've noticed that when I'm using FGLRX there is xorg.conf file and when I uninstall it, then the file is missing. So my question is how to switch between them? It'll be perfect if I could do this without restarting my computer either. I'm using Ubuntu 10.10, laptop/netbook MSI U250.

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  • Resources for up-to-date Delphi programming

    - by Dan Kelly
    I'm a developer in a small department and have been using Delphi for the last 10 years. Whilst I've tried to keep up-to-date with movements there are a lot of changes that have occurred between Delphi 7 and (current for us) 2010. Stack Exchange and here have been great for answering the "how do you" questions, but what I'd like is a resource that shows great examples of larger scale programming. For example is there anywhere that hosts examples of well written, multi form applications? Something that can be looked at as a whole to illustrate why things should be done a certain way?

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  • How to hide Thinking at Work so that the Non-Programmers don't suspect Slacking?

    - by stesch
    Better programmers than me can write in essays about walking around with a coffee mug and call it programming. And it's perfectly accepted at a place that knows the business. Or see what Gregory House (TV show "House M.D.") does when he is thinking. But what about the other places where you are the only programmer? If you don't stare at boring stuff on the monitor for 8 hours straight, co-workers suspect you being a slacker. Yes, not the managers who see the output. Only the co-workers who see the process and can't relate to this kind of work. Yesterday I had to explain to a trainee of some other profession that software development is like flying. The explanation from the Hitchhiker's Guide to the Galaxy. I don't think she bought it.

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  • HSSFS Part 3: SQL Saturday is Awesome! And DEFAULT_DOMAIN(), and how I found it

    - by Most Valuable Yak (Rob Volk)
    Just a quick post I should've done yesterday but I was recovering from SQL Saturday #48 in Columbia, SC, where I went to some really excellent sessions by some very smart experts.  If you have not yet attended a SQL Saturday, or its been more than 1 month since you last did, SIGN UP NOW! While searching the OBJECT_DEFINITION() of SQL Server system procedures I stumbled across the DEFAULT_DOMAIN() function in xp_grantlogin and xp_revokelogin.  I couldn't find any information on it in Books Online, and it's a very simple, self-explanatory function, but it could be useful if you work in a multi-domain environment.  It's also the kind of neat thing you can find by using this query: SELECT OBJECT_SCHEMA_NAME([object_id]) object_schema, name FROM sys.all_objects WHERE OBJECT_DEFINITION([object_id]) LIKE '%()%'  ORDER BY 1,2 I'll post some elaborations and enhancements to this query in a later post, but it will get you started exploring the functional SQL Server sea. UPDATE: I goofed earlier and said SQL Saturday #46 was in Columbia. It's actually SQL Saturday #48, and SQL Saturday #46 was in Raleigh, NC.

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  • rts libgdx design?

    - by user36531
    I am attempting to create a simple rts multi-player strategy game using libgdx. I am stumped at the moment. I want the underlying game world to run at all times and be aware of where all items are on the map.. so if player A logs in and moves unit to some location on the grid and logs off, that unit info is still there and can be accessed again by player A when they log back on to move somewhere else (if it didnt get attacked during the playerA was logged off). How can i do this? Do i create a main game world on the server and when players connect make client just sequentially request whats in each visible tile? Is there an easier way to get this done? Or go SQL route? Whats better?

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  • what are the best concert-ticket systems? comercial and open source

    - by helle
    can anybody recommend (of developers-opinion) such systems, where you can book tickets for concerts, conferences, etc. one should be able to book a seat as well, and it shell do the debitcard stuff, and has a good interface for accounting. I am looking for an open source solution, but I am also interested in commercial ones, to have a comparison of features and prices, etc. thanks for everybodys suggestions - pros and cons to it are very wellcome ;) well, it shouldn't has a flash component multi languages :) would be great an extra mobile-view is preferred the extra extra bonus for such a system would be a very good wordpress compatibility p.s. sorry for my english well ... I already googled a lot. But I found so very many, that I hope you could help me to find a good choice, to have a base from where I can do a further lookup. and for sure :) What are the things you I have to have in mind. What brings troubles, what brings costs?

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  • Oracle University Nouveaux cours (Week 42)

    - by rituchhibber
    Nouveaux cours Parmi les nouveautés d'Oracle Université de ce mois-ci, vous trouverez : Database Oracle Enterprise Manager Cloud Control 12c: Install & Upgrade (Training On Demand) MySQL Performance Tuning (Training On Demand) Fusion Middleware Oracle GoldenGate 11g Fundamentals for Oracle (4 days) Oracle WebCenter Content 11g: Site Studio Essentials (5 days) Oracle WebCenter Portal 11g: Build Portals with Spaces (3 days) Business Intelligence Oracle BI 11g R1: Create Analyses and Dashboards (4 days) SOA & BPM SOA Adoption and Architecture Fundamentals (3 Days) eBusiness Suite R12 Oracle Using and Maintaining Approvals Management - Self-Study Course R12 Oracle HRMS Advanced Benefits Fundamentals - Self-Study Course WebLogic Oracle WebLogic Server 11g: Monitor and Tune Performance (Training On Demand) Oracle WebLogic Server 11g: Administration Essentials Self-Study Course (in French) Financial Oracle Project Financial Planning 11.1.2: Create Projects ( 3 days) Tuxedo Oracle Tuxedo 12c: Application Administration (5 days) Java Java SE 7: The Platform Evolves - Self-Study Course Primevera Primavera Client/Server Partner Trainer Course - Self-Study Course Primavera Progress Reporter 8.2 - Self-Study Course Contacter l' équipe locale d' Oracle University pour toute information et dates de cours.

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  • Add autorandr before kdm starts

    - by Serge Tarkovski
    I want to add autorandr before kdm starts. Autorandr works well within KDE, however, in kdm I still have ugly 1024x768 resolution when my external monitor is connected. I tried adding autorandr --change to /etc/kde4/kdm/Xsetup: #! /bin/sh # Xsetup - run as root before the login dialog appears #xconsole -geometry 480x130-0-0 -notify -verbose -fn fixed -exitOnFail -file /dev/xconsole & /sbin/initctl -q emit login-session-start DISPLAY_MANAGER=kdm /usr/local/bin/autorandr --change >> /tmp/autorandr echo "Xsetup finished" >> /tmp/xsetup-finished A debug message in /tmp/xsetup-finished appears correctly. /tmp/autorandr is empty (so it seems autorandr runs without errors). I also tried to move autorandr --change line before /sbin/initctl -q emit login-session-start DISPLAY_MANAGER=kdm with no effect. P.S. Of course, autorandr profiles I created under KDE session, are in my home folder, but Xsetup script runs under root, so I created a symlink from my ~/.autorandr to /root/.autorandr.

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  • Release Notes for 10/18/2012

    Below are the release notes from this week's deployment. Improvements and Bug Fixes Updated the Source browsing to fixed width and full browser height. The source browsing experience now defaults to the fixed width layout. But, if you really want to take advantage of that 30" monitor you have on your desk, you can expand the source to fill the browser window. Just click on the little plus icon in the upper right. Let us know what you think.  Thank you A big thank you to CodePlex users Coilz and CursedPerVerse for reporting an issue with deploying to AppHarbor, that issue has been resolved.  Feedback Have ideas on how to improve CodePlex? Please visit our suggestions page! Vote for existing ideas or submit a new one. As always you can reach out to the CodePlex team on Twitter @codeplex or reach me directly @mgroves84

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  • How long does boot repair take?

    - by Emre
    Reinstalling Ubuntu messed up my boot loader so I I tried to fix it with boot repair. It detected my OSX installation and asked about removing the "separate boot/EFI". It also said my partition was full despite the fact that it wasn't and asked me to remove stuff. I declined both and proceeded. It's been stuck at the "purge and reinstall the GRUB" stage for half an hour. Is this typical, bearing in mind I have a fast SSD and CPU? Is there a better way to re-install grub on a multi-booting UEFI system? Does my pastebin provide any insight?

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  • Is there an 'off the shelf' platform for making a new website similar to Elance?

    - by user17747
    I am interested in developing a website that is similar to 'elance' but for a particular vertical. Is there an 'off the shelf' platform you can recommend for getting started with this, or would I need to develop this web service from scratch? When I write 'platform' I am referring to things such as 'shopify' for e-commerce sites, or 'ning' for social websites. I want to create a multi-merchant professional services site. The site would need to support functionality such as: allowing merchants to open and manage their own profile. merchants would accept payments from customers through the site. file transfers between merchants and customers. merchant ratings by customers.

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  • An introduction to Oracle Retail Data Model with Claudio Cavacini

    - by user801960
    In this video, Claudio Cavacini of Oracle Retail explains Oracle Retail Data Model, a solution that combines pre-built data mining, online analytical processing (OLAP) and dimensional models to deliver industry-specific metrics and insights that improve a retailers’ bottom line. Claudio shares how the Oracle Retail Data Model (ORDM) delivers retailer and market insight quickly and efficiently, allowing retailers to provide a truly multi-channel approach and subsequently an effective customer experience. The rapid implementation of ORDM results in predictable costs and timescales, giving retailers a higher return on investment. Please visit our website for further information on Oracle Retail Data Model.

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  • Can't use laptop display?

    - by Ian Rice
    I've just installed Ubuntu 11.10 with a LiveCD. During the installation, nothing was shown on screen unless I plugged in an external monitor. Same thing happens within Ubuntu. I have an Emachines E525. Could this just be a backlight issue or something? It works fine on Windows though. If anyone could help, that'd be great. Please explain everything throughly if you can though, I'm new to all of this.

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  • Could not apply stored configuration for monitors

    - by Hernantz
    Well this happened when I upgraded to Natty. Not only seems I can't change my resolution to higher than 1024x768 but it appears at the left and using only 70% of the monitor's width. I tried logging in but in ubuntu classic mode, and i was able to change it, but that trick did not work anymore. (May this be a compiz problem?) Anyways, here is my /var/log/Xorg.0.log http://pastebin.com/Ew4wwLab and lspci -nn | grep VGA: 00:02.0 VGA compatible controller [0300]: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller [8086:27a2] (rev 03) I tried using xrandr for adding manually a resolution of 1280x1768 but without luck. Here is the xrandr output Screen 0: minimum 320 x 200, current 1024 x 768, maximum 4096 x 4096 LVDS1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm 1024x768 60.0*+ 800x600 60.3 56.2 640x480 59.9 VGA1 disconnected (normal left inverted right x axis y axis) TV1 disconnected (normal left inverted right x axis y axis) 1280x1024 (0xc6) 109.0MHz h: width 1280 start 1368 end 1496 total 1712 skew 0 clock 63.7KHz v: height 1024 start 1027 end 1034 total 1063 clock 59.9Hz

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  • Blurry vertical sections using fglrx with Radeon hd 6970

    - by Jesus Ramos
    So I managed to get fglrx working by downloading the drivers from ATI because the ones from additional drivers boot to a black screen and the open source dont let me change resolution. My one issue is that half of my monitor is fine and the other half is blurry almost as if there's a blurry vertical stripe on the right side. I tried disabling Compiz and have the same issue in both gnome and kde, I was wondering if theres an xorg.conf change that could be made to fix this as I have already set the resolution and refresh rates to the correct values.

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  • Screen is very dim on an Acer Aspire 6920Z

    - by Justin
    I've been trying to figure this out for a week now, my laptops screen is on and working but you cannot see whats on the screen without shining a flashlight at it. I'm using a spare monitor by the VGA port right now to be able to use this laptop, which is kinda a pain. Been reading around a bit about this problem and it seems to be a common-ish problem it seems. I've tried to change the brightness which doesn't help whats so ever. It just happen one day after I turned off the laptop for the night. The screen flashes on for a bit at start up, then goes completely dim. Anyone with this problem and find a fix? You can search up this computers spec by the name/model in the title if you need hardware info. I never had this problem with the old Ubuntu 10.04.

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  • What Is Disk Fragmentation and Do I Still Need to Defragment?

    - by Jason Fitzpatrick
    Do modern computers still need the kind of routine defragmentation procedures that older computers called for? Read on to learn about fragmentation and what modern operating systems and file systems do to minimize performance impacts. Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-drive grouping of Q&A web sites. Secure Yourself by Using Two-Step Verification on These 16 Web Services How to Fix a Stuck Pixel on an LCD Monitor How to Factory Reset Your Android Phone or Tablet When It Won’t Boot

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  • HDMI audio output problems with Radeon card

    - by Matt Robinson
    No matter how much advice I follow, I still cannot get any audio to come out through my HDMI connection. I've tried downloading the latest proprietary FGLRX graphics drivers, and I've also gone into /etc/default/grub and altered GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" into this GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.audio=1" But still I cannot get any sound nor can I get HDMI sound output to show up in Sound Settings or Pulse Audio Volume Control. I can get video to show up just fine on my monitor through HDMI so I'm sure this problem is fixable! I know this is an old problem with Ubuntu, but any new strategies into the problem would be much appreciated. With that being said, here are some of my specs: Ubuntu 12.04 LTS AMD Radeon HD 7520G

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  • Disabling Navigation Flicks in WPF

    - by Brian Genisio's House Of Bilz
    I am currently working on a multi-touch application using WPF.  One thing that has been irritating me with this development is an automatic navigation forward/back command that is bound to forward and backwards flicks.  Many of my touch-based interactions were being thwarted by gestures picked up by WPF as navigation.  I just wanted to disable this behavior. My programmatic back/forward calls are not affected by this change, which is nice.  Here is how I did it:  In my main window, I added the following command bindings:<NavigationWindow.CommandBindings> <CommandBinding Command="NavigationCommands.BrowseBack" Executed="DoNothing" /> <CommandBinding Command="NavigationCommands.BrowseForward" Executed="DoNothing" /> </NavigationWindow.CommandBindings> Then, the DoNothing method in the code-behind does nothing:private void DoNothing(object sender, ExecutedRoutedEventArgs e) { } There may be a better way to do this, but I haven’t found one.

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  • Map Library: Client-side or Server-side?

    - by Mahdi
    As I have already asked here, I have to implement a Multi-Platform Map application. Now I have Mapstraction as an option which uses Javascript to implement the desired functionality. My question is, "Is there any reason/benefit to implement such a library (let say, Adapters) in Server-side (in my case, PHP)?" As these maps are all based on Javascript, there is a big reason to use Javascript again to make the adapter also, so it would not be dependent to PHP, Java, or .NET for example. But is that all? I wish to hear your ideas and comments also. :)

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  • How can I reduce lagging with GUI/GPU stuff -- make Unity run smaller, quicker, faster?

    - by chris
    Finally installed Ubuntu 12.04 on my HP Pavilion 2000. Have all of my apps on and loaded and am happy thus far. ONE ISSUE -- I'm experiencing a small amount of GUI/GPU style lagging when I go to open menus, move windows, etc. What settings can I disable to allow it to run sharply and quickly, even if i t means sacrificing some of the graphics? Have already installed pre-load. Just want the OS to run sharply and quickly with menu refreshes, window moves, etc. I do not mind sacrificing graphics. Somone mentionted to me I have to install video drivers but the two that come up in system settings under drivers it won't let me install. ALSO : I am driving a second 19" monitor -- would that make a difference performance wise as well? Thanks in advance. Chris

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  • no back light on my acer aspire 5734z

    - by Dave
    I installed Ubuntu (12.04) on my acer aspire 5734z and the back light stopped working. I have tried the fix by editing the grub file posted on here a couple of days ago but that hasn't fixed it. I have also looked for hardware drivers but that didn't get me anywhere. When I hook up an external monitor it works fine but i have been unsuccessful getting the laptop display to light up. Thanks edit removed link I found a fix here " http://crunchbanglinux.org/forums/post/66562/#p66562 " if anyone has a better fix than the one in that post, let me know.

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  • Oracle RightNow CX for Good Customer Experiences

    - by Andreea Vaduva
    Oracle RightNow CX is all about the customer experience, it’s about understanding what drives a good interaction and it’s about delivering a solution which works for our customers and by extension, their customers. One of the early guiding principles of Oracle RightNow was an 8-point strategy to providing good customer experiences. Establish a knowledge foundation Empowering the customer Empower employees Offer multi-channel choice Listen to the customer Design seamless experiences Engage proactively Measure and improve continuously The application suite provides all of the tools necessary to deliver a rewarding, repeatable and measurable relationship between business and customer. The Knowledge Authoring tool provides gap analysis, WYSIWIG editing (and includes HTML rich content for non-developers), multi-level categorisation, permission based publishing and Web self-service publishing. Oracle RightNow Customer Portal, is a complete web application framework that enables businesses to control their own end-user page branding experience, which in turn will allow customers to self-serve. The Contact Centre Experience Designer builds a combination of workspaces, agent scripting and guided assistances into a Desktop Workflow. These present an agent with the tools they need, at the time they need them, providing even the newest and least experienced advisors with consistently accurate and efficient information, whilst guiding them through the complexities of internal business processes. Oracle RightNow provides access points for customers to feedback about specific knowledge articles or about the support site in general. The system will generate ‘incidents’ based on the scoring of the comments submitted. This makes it easy to view and respond to customer feedback. It is vital, more now than ever, not to under-estimate the power of the social web – Facebook, Twitter, YouTube – they have the ability to cause untold amounts of damage to businesses with a single post – witness musician Dave Carroll and his protest song on YouTube, posted in response to poor customer services from an American airline. The first day saw 150,000 views and is currently at 12,011,375. The Times reported that within 4 days of the post, the airline’s stock price fell by 10 percent, which represented a cost to shareholders of $180 million dollars. It is a universally acknowledged fact, that when customers are unhappy, they will not come back, and, generally speaking, it only takes one bad experience to lose a customer. The idea that customer loyalty can be regained by using social media channels was the subject of a 2011 Survey commissioned by RightNow and conducted by Harris Interactive. The survey discovered that 68% of customers who posted a negative review about a holiday on a social networking site received a response from the business. It further found that 33% subsequently posted a positive review and 34% removed the original negative review. Cloud Monitor provides the perfect mechanism for seeing what is being said about a business on public Facebook pages, Twitter or YouTube posts; it allows agents to respond proactively – either by creating an Oracle RightNow incident or by using the same channel as the original post. This leaves step 8 – Measuring and Improving: How does a business know whether it’s doing the right thing? How does it know if its customers are happy? How does it know if its staff are being productive? How does it know if its staff are being effective? Cue Oracle RightNow Analytics – fully integrated across the entire platform – Service, Marketing and Sales – there are in excess of 800 standard reports. If this were not enough, a large proportion of the database has been made available via the administration console, allowing users without any prior database experience to write their own reports, format them and schedule them for e-mail delivery to a distribution list. It handles the complexities of table joins, and allows for the manipulation of data with ease. Oracle RightNow believes strongly in the customer owning their solution, and to provide the best foundation for success, Oracle University can give you the RightNow knowledge and skills you need. This is a selection of the courses offered: RightNow Customer Service Administration Rel 12.02 (3 days) Available as In Class and Live Virtual Class (Release 11.11 is available as In Class, Live Virtual Class and Training On Demand) This course familiarises users with the tasks and concepts needed to configure and maintain their system. RightNow Customer Portal Designer and Contact Center Experience Designer Administration Rel 12.02 (2 days) Available as In Class and Live Virtual Class (Release 11.11 is available as In Class, Live Virtual Class and Training On Demand) This course introduces basic CP structure and how to make changes to the look, feel and behaviour of their self-service pages RightNow Analytics Rel 12.02 (2 days) Available as In Class, Live Virtual Class and Training On Demand (Release 11.11 is available as In Class and Live Virtual Class) This course equips users with the skills necessary to understand data supplied by standard reports and to create custom reports RightNow Integration and Customization For Developers Rel 12.02 (5-days) Available as In Class and Live Virtual Class (Release 11.11 is available as In Class, Live Virtual Class and Training On Demand) This course is for experienced web developers and offers an introduction to Add-In development using the Desktop Add-In Framework and introduces the core knowledge that developers need to begin integrating Oracle RightNow CX with other systems A full list of courses offered can be found on the Oracle University website. For more information and course dates please get in contact with your local Oracle University team. On top of the Service components, the suite also provides marketing tools, complex survey creation and tracking and sales functionality. I’m a fan of the application, and I think I’ve made that clear: It’s completely geared up to providing customers with support at point of need. It can be configured to meet even the most stringent of business requirements. Oracle RightNow is passionate about, and committed to, providing the best customer experience possible. Oracle RightNow CX is the application that makes it possible. About the Author: Sarah Anderson worked for RightNow for 4 years in both in both a consulting and training delivery capacity. She is now a Senior Instructor with Oracle University, delivering the following Oracle RightNow courses: RightNow Customer Service Administration RightNow Analytics RightNow Customer Portal Designer and Contact Center Experience Designer Administration RightNow Marketing and Feedback

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  • Computer Networks UNISA - Chap 14 &ndash; Insuring Integrity &amp; Availability

    - by MarkPearl
    After reading this section you should be able to Identify the characteristics of a network that keep data safe from loss or damage Protect an enterprise-wide network from viruses Explain network and system level fault tolerance techniques Discuss issues related to network backup and recovery strategies Describe the components of a useful disaster recovery plan and the options for disaster contingencies What are integrity and availability? Integrity – the soundness of a networks programs, data, services, devices, and connections Availability – How consistently and reliably a file or system can be accessed by authorized personnel A number of phenomena can compromise both integrity and availability including… security breaches natural disasters malicious intruders power flaws human error users etc Although you cannot predict every type of vulnerability, you can take measures to guard against the most damaging events. The following are some guidelines… Allow only network administrators to create or modify NOS and application system users. Monitor the network for unauthorized access or changes Record authorized system changes in a change management system’ Install redundant components Perform regular health checks on the network Check system performance, error logs, and the system log book regularly Keep backups Implement and enforce security and disaster recovery policies These are just some of the basics… Malware Malware refers to any program or piece of code designed to intrude upon or harm a system or its resources. Types of Malware… Boot sector viruses Macro viruses File infector viruses Worms Trojan Horse Network Viruses Bots Malware characteristics Some common characteristics of Malware include… Encryption Stealth Polymorphism Time dependence Malware Protection There are various tools available to protect you from malware called anti-malware software. These monitor your system for indications that a program is performing potential malware operations. A number of techniques are used to detect malware including… Signature Scanning Integrity Checking Monitoring unexpected file changes or virus like behaviours It is important to decide where anti-malware tools will be installed and find a balance between performance and protection. There are several general purpose malware policies that can be implemented to protect your network including… Every compute in an organization should be equipped with malware detection and cleaning software that regularly runs Users should not be allowed to alter or disable the anti-malware software Users should know what to do in case the anti-malware program detects a malware virus Users should be prohibited from installing any unauthorized software on their systems System wide alerts should be issued to network users notifying them if a serious malware virus has been detected. Fault Tolerance Besides guarding against malware, another key factor in maintaining the availability and integrity of data is fault tolerance. Fault tolerance is the ability for a system to continue performing despite an unexpected hardware or software malfunction. Fault tolerance can be realized in varying degrees, the optimal level of fault tolerance for a system depends on how critical its services and files are to productivity. Generally the more fault tolerant the system, the more expensive it is. The following describe some of the areas that need to be considered for fault tolerance. Environment (Temperature and humidity) Power Topology and Connectivity Servers Storage Power Typical power flaws include Surges – a brief increase in voltage due to lightening strikes, solar flares or some idiot at City Power Noise – Fluctuation in voltage levels caused by other devices on the network or electromagnetic interference Brownout – A sag in voltage for just a moment Blackout – A complete power loss The are various alternate power sources to consider including UPS’s and Generators. UPS’s are found in two categories… Standby UPS – provides continuous power when mains goes down (brief period of switching over) Online UPS – is online all the time and the device receives power from the UPS all the time (the UPS is charged continuously) Servers There are various techniques for fault tolerance with servers. Server mirroring is an option where one device or component duplicates the activities of another. It is generally an expensive process. Clustering is a fault tolerance technique that links multiple servers together to appear as a single server. They share processing and storage responsibilities and if one unit in the cluster goes down, another unit can be brought in to replace it. Storage There are various techniques available including the following… RAID Arrays NAS (Storage (Network Attached Storage) SANs (Storage Area Networks) Data Backup A backup is a copy of data or program files created for archiving or safekeeping. Many different options for backups exist with various media including… These vary in cost and speed. Optical Media Tape Backup External Disk Drives Network Backups Backup Strategy After selecting the appropriate tool for performing your servers backup, devise a backup strategy to guide you through performing reliable backups that provide maximum data protection. Questions that should be answered include… What data must be backed up At what time of day or night will the backups occur How will you verify the accuracy of the backups Where and for how long will backup media be stored Who will take responsibility for ensuring that backups occurred How long will you save backups Where will backup and recovery documentation be stored Different backup methods provide varying levels of certainty and corresponding labour cost. There are also different ways to determine which files should be backed up including… Full backup – all data on all servers is copied to storage media Incremental backup – Only data that has changed since the last full or incremental backup is copied to a storage medium Differential backup – Only data that has changed since the last backup is coped to a storage medium Disaster Recovery Disaster recovery is the process of restoring your critical functionality and data after an enterprise wide outage has occurred. A disaster recovery plan is for extreme scenarios (i.e. fire, line fault, etc). A cold site is a place were the computers, devices, and connectivity necessary to rebuild a network exist but they are not appropriately configured. A warm site is a place where the computers, devices, and connectivity necessary to rebuild a network exists with some appropriately configured devices. A hot site is a place where the computers, devices, and connectivity necessary to rebuild a network exists and all are appropriately configured.

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