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  • IE7 preventDefault() not working on skip links

    - by josh
    I currently have skip links that jump to the div ids and was using e.preventDefault() to stop the url from changing when jumping to the element but in IE7 and IE8 it doesn't work at all using e.preventDefault() and if I take it out the url changes to the div the anchor tag contains reference to. Is their any fix or way around this? Here is the code $('body').delegate('a.skiplink-accessible-text', 'click', function (e) { //e.preventDefault(); if (!$.browser.msie) { e.preventDefault(); } var jumpTo = $(this).attr('href'); $('body').find(jumpTo).attr('tabindex', - 1).focus(); }); EDIT: heres a little jsbin example for testing purposes http://jsbin.com/welcome/20846/edit

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  • What is a good balance for having developers learn at work

    - by Mel
    So now I am the manager. One of the things I always promised myself I would do is have the other developers focus on learning new stuff. In fact I even want to force them to read a couple books that really helped me learn to program. However now I am also accountable for the product getting finished. I have this vision of everyone reading books instead of working and me getting fired. What is the best way to work learning into the developers schedules, especially for the ones that just don't care to learn. How much time should be spent on learning in a work week?

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  • How to show a window that acts like a popup menu?

    - by Edwin
    Hi, When window A is show, I want to show another none-modal popup window B, but: I don't want window A to become inactive due to window B becomes the front window; I want that when window B is focused, I pull down a combo box control on window A with one click (generally you have to click twice, one for moving the focus to window A and the second for pulling down the combo box); As you can see, the window B that I want is something like a more usable popup window like a popup menu (which is less a obstacle than a general none-modal window when you want it to get away by clicking on any other part of the parent window). Am I clear on my question? Thank you.

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  • Implement a top level window from a broadcast receiver

    - by kwatts
    I have a broadcast receiver that listens for incoming calls, then displays a popup. The popup is a dialog type of theme and has FLAG_NOT_FOCUSABLE and FLAG_NOT_TOUCHABLE - basically, it's an informational window that goes away after x seconds, and is not meant to interfere or take focus over anything else. The issue is that the incoming call intent, built into android, is getting the broadcast after my intent. This is causing that window to be stacked in front of mine. How to I get my window to always be on top? Thanks!

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  • Is SubSonic dying

    - by JimBobBillyBoy
    I'm real interested in using SubSonic, I've downloaded it and I'm enjoying it so far, but looking at the activity on github and googlegroups it doesn't seem to be very active and looks a lot like a project that's dying. There's no videos about it on tekpub and Rob seems to be using nHibernate for all his projects these days. I don't want to focus on learning SubSonic and integrating it into my projects if it's not going to live much longer. So my question is what's happening with subsonic development, is there a new release imminent is there lots going on behind the scenes or is it as inactive as it seems?

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  • While programming, what to do when facing with a seemingly unsolvable situation with a time limit?

    - by Ersan Tasan
    This is not a technical question, but rather a social and methodical one. I am a computer sciences student and I usually have really tough programming assignments. I don`t know if it is only happening to me but sometimes, particularly when deadline is approaching, i find myself in a harsh situation. I cannot find my mistake in the code or come up with a another great idea. Then boredom comes in and the problem begins to seem unsolvable. I know there are more-than-great professional coders here. I would like to learn their ideas to cope with this situation. Is it better to focus on something else for a while and try again or try harder and harder and look for the solution on the net etc...

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  • Implementing prompts in text-input

    - by AntonAL
    Hi, I have a form with some text-inputs: login, password. If user sees this form the first time, input-texts should "contain" prompts, like "enter login", "enter password". If user clicks text-input, it's prompt should disappear to allow typing. I have seen various examples, that uses background image with prerendered text on it. Those images are appearing with following jQuery: $("form > :text").focus(function(){ // hide image }).blur(function(){ // show image, if text-input is still empty if ( $(this).val() == "" ) // show image with prompt }); This approach has following problems: localization is impossible need to pre-render images for various textual prompts overhead with loading images How do you overcomes such a problems ?

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  • Reflection alternative for switch on enum in order to select namespace/class

    - by Am
    Hi, I have an interface named IHarvester. There are 3 implementations of that interface, each under their own namespace: Google Yahoo Bing A HarvesterManager uses the given harvester. It knows the interface and all 3 implementations. I want some way of letting the class user say in which harvester it wants to use. And in the code select that implementation, without a switch-case implementation. Can reflection save my day? Here is the code bits: // repeat for each harvester namespace Harvester.Google { public abstract class Fetcher : BaseHarvester, IInfoHarvester {...} } public enum HarvestingSource { Google, Yahoo, Bing, } class HarvesterManager { public HarvestingSource PreferedSource {get;set;} public HarvestSomthing() { switch (PreferedSource) .... // awful... } } Thanks. I will give my 2 cents of why I want to change this. There several people writing harvesters, I want them to focus only on building more harvesters, without ever needing to update the enum, or at worst, update only the enum.

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  • Vim's autocomplete is excruciatingly slow

    - by jnicklas
    Most of the time the autocomplete feature in VIM works nicely for me, but sometimes it seems to be scanning files which the current file references, and then it becomes painfully slow, sometimes taking several seconds to release focus back to me. Sometimes VIM tells me simply that it is "Scanning" other times, it's saying "Scanning tags" I've only this happen in Ruby files, and it happens mostly when there is a require in the file. My guess would be that this is some kind of feature which checks related files for autocomplete options, but I don't really need that, and would prefer quicker autocomplete.

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  • How to get option value (javascript)

    - by Mahmoud
    Below are the options that i have in my code <label id="subn"> <select name="subs" id="subs"> <option value="nothing">Choose a Subject</option> <option value="General Question">General Question</option> <option value="MemberShip Area">MemberShip Area</option> <option value="Others">Others</option> </select> </label> and i want to create a javascript that well check if the user select a subject other than the first below what i tried using if (document.getElementsByTagName('option') == "nothing"){ document.getElementById("subn").innerHTML = "Subject is Required!"; document.getElementById("subs").focus(); return false; }

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  • A global login (many sites)

    - by John
    We are a growing network but we figured we want to keep that the User only would need one account in order to access the network different sites. (Similar to Stackoverflow's login, If you login in to another "site" you use your account credentials and than your account is created). We want our own login system (Username, password) and not OpenId, as we'd probably have that in the future, but the main focus right now is the global login. How can I do this? Do a Curl request and send back a cookie? Have a "database" just for the login procedure and on first login also create a new "User" in the site specified database? Suggestions?.

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  • How to process credit card by using intuit's (quickbook) ?

    - by Grace Ladder
    How to process credit card by using Hello all, I am doing shopping cart project for my client and one of the requirement is using intuit's (http://www.intuit.com/) product to process credit card in real manner, as the client is going to integrate the online shop with quickbook in later stage. My question is, does intuit products purely payment gateway solution? as in this stage, we are not involved with any dev work about quickbook, the main focus for us is deliver the high quality shopping cart solution, we read something about intuit's web shop solution but seems this one require quickbook running in desktop to sync the data? Very confused now, if anyone had experience before, please help!

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  • Is it possible to align an element with the bottom of the window, yet make it scrollable, with CSS o

    - by last-child
    I have a design going on where I want to align the bottom of an intro paragraph with the bottom of the window, yet make it scroll with the rest of the page. So when the page opens, the visitor sees only the first paragraph (and a full screen background image, which is what I want to focus their attention on), but as they scroll they see the paragraph and the rest of the text. The height of the intro element can vary. Right now I think I have to introduce some javascript to do this - meassure the height of the window, the height of the paragraph, and adjust top: or margin-top of the paragraph to the difference between the two values. If there is a way to make a div have a height that corresponds exactly to the window height, and position the paragraph absolutely inside of this div, the let the rest of the text sit outside of the div, it could work... but I can't seem to make that happen with css. Any suggestions?

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  • JQuery (1.4.2)/Firefox (3.6.3) - .before and .after not working on div

    - by user355561
    I am trying to have a title bar appear when the user clicks on a box. It works perfectly in I.E. 8.0 but not at all in firefox 3.6.3. HTML [code] @import url('style.css'); blah blah blah save changes [/code] Javascript [code] $(document).ready(function(){ $("#edit2").live('click',function(){ if($("#menu").length == 0){ $("#edit2").before(''); } if($("#menu2").length == 0){ $("#edit2").after(''); } this.contentEditable = true; this.focus(); }); $("#edit2").live('blur',function(){ $("#menu").remove(); //$("#menu2").remove(); this.contentEditable = false; }); }); [/code] Could anyone suggest why it's not working? I have managed to use similar code to add/remove new table rows in both browser but I just can't see why this doesn't also work.

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  • Disable form submission via Enter key on only _some fields

    - by justSteve
    I want to retain the conventional 'form submits when i press Enter' behavior because users are familiar with. But by reflex, they often hit enter when they finish with a text input box - but before they are actually done with the complete form. I'd like to hijack the Enter key only when then focus is on a certain class of input. Looking Related Questions this looks like what I'm looking for: if (document.addEventListener) { document.getElementById('strip').addEventListener('keypress',HandleKeyPress,false); } else { document.getElementById('strip').onkeypress = HandleKeyPress; } but the if (document.addEventListener) { is unfamiliar.

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  • should a student be diversifying or mastering programming languages?

    - by Max Link
    As the question states, is it better if a student diversifies or explores when learning programming languages or should they focus only on 2-3 languages and really get to know them well? Example of what I mean by diversifying: Functional -> Scheme Procedural -> C Object Oriented -> Java Dynamic or scripting -> Python Other -> C++ I have a few breaks in between semesters sometimes (up to 3 months) and I'm thinking of either learning a new language or "master" those that I know right now. Which would benefit me in the future? I know some(about 3 months of self studying each) Java, C, and C++ already . If I'm not mistaken, where I live, the industry is heavy on Java, C++, and C#.

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  • How to distinguish between new and returning anonymous Drupal users?

    - by Matt V.
    Is there an easy way (or a module) in Drupal to distinguish between anonymous users who have never created an account versus those who are returning but are not currently logged in? For non-returning (ie, completely new) users, I'd like to have a front page that is very streamlined and focused on registration as the call-to-action. However, if someone is a returning user but not currently logged in, I'd like to present a lot more information on the front page and have login as the main call-to-action. I realize both pages would still need to have both login and register options available, I just want to make the focus significantly different between the two.

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  • Looking for a way to highlight specific words in textareas?

    - by Dan
    Hi i'm looking for a way to highlight specific words in text kind of like how a text editor might work with syntax highlighting. The highlighting will consist of the text being different colours and/or different styles such as italic, bold or regular. In order to narrow focus, how this might be achieved using Java Swing components. There are most probably a number of ways of doing this but one that is efficient in dealing with multiple highlighted words and large amounts of text. Any feedback is appreciated. Thanks.

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  • [WPF] When Should I Retrieve Values from Textbox?

    - by they_soft
    Suppose I have a Window with TextBoxes I want to use the values. Right now I'm thinking of either: 1) Updating each associated value once the cursor is out of focus, and once the user presses Ok I start the program 2) Once the user presses Ok, I retrieve all the values at once then start the program I'm not sure which one is better though. First alternative seems more modular, but there's more semantic coupling since I each new box is supposed to be updating its respective value. I realize this isn't all that important, but I'm trying to understand when to centralize and when not to. Other better approachers are appreciated too.

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  • The Internet of Things & Commerce: Part 2 -- Interview with Brian Celenza, Commerce Innovation Strategist

    - by Katrina Gosek, Director | Commerce Product Strategy-Oracle
    Internet of Things & Commerce Series: Part 2 (of 3) Welcome back to the second installation of my three part series on the Internet of Things & Commerce. A few weeks ago, I wrote “The Next 7,000 Days” about how we’ve become embedded in a digital architecture in the last 7,000 days since the birth of the internet – an architecture that everyday ties the massive expanse of the internet evermore closely with our physical lives. This blog series explores how this new blend of virtual and material will change how we shop and how businesses sell. Now enjoy reading my interview with Brian Celenza, one of the chief strategists in our Oracle Commerce innovation group. He comments on the past, present, and future of the how the growing Internet of Things relates and will relate to the buying and selling of goods on and offline. -------------------------------------------- QUESTION: You probably have one of the coolest jobs on our team, Brian – and frankly, one of the coolest jobs in our industry. As part of the innovation team for Oracle Commerce, you’re regularly working on bold features and groundbreaking commerce-focused experiences for our vision demos. As you look back over the past couple of years, what is the biggest trend (or trends) you’ve seen in digital commerce that started to bring us closer to this idea of what people are calling an “Internet of Things”? Brian: Well as you look back over the last couple of years, the speed at which change in our industry has moved looks like one of those blurred movement photos – you know the ones where the landscape blurs because the observer is moving so quickly your eye focus can’t keep up. But one thing that is absolutely clear is that the biggest catalyst for that speed of change – especially over the last three years – has been mobile. Mobile technology changed everything. Over the last three years the entire thought process of how to sell on (and offline) has shifted because of mobile technology advances. Particularly for eCommerce professionals who have started to move past the notion of “channels” for selling goods to this notion of “Mobile First”… then the Web site. Or more accurately, that everything – smartphones, web, store, tablet – is just one channel or has to act like one singular access point to the same product catalog, information and content. The most innovative eCommerce professionals realized some time ago that it’s not ideal to build an eCommerce Web site and then build everything on top of or off of it. Rather, they want to build an eCommerce API and then integrate it will all other systems. To accomplish this, they are leveraging all the latest mobile technologies or possibilities mobile technology has opened up: 4G and LTE, GPS, bluetooth, touch screens, apps, html5… How has this all started to come together for shopping experiences on and offline? Well to give you a personal example, I remember visiting an Apple store a few years ago and being amazed that I didn’t have to wait in line because a store associate knew everything about me from my ID – right there on the sales floor – and could check me out anywhere. Then just a few months later (when like any good addict) I went back to get the latest and greatest new gadget, I felt like I was stealing it because I could check myself out with my smartphone. I didn’t even need to see a sales associate OR go to a cash register. Amazing. And since then, all sort sorts of companies across all different types of industries – from food service to apparel –  are starting to see mobile payments in the billions of dollars now thanks not only to the convenience factor but to smart loyalty rewards programs as well. These are just some really simple current examples that come to mind. So many different things have happened in the last couple of years, it’s hard to really absorb all of the quickly – because as soon as you do, everything changes again! Just like that blurry speed photo image. For eCommerce, however, this type of new environment underscores the importance of building an eCommerce API – a platform that has services you can tap in to and build on as the landscape changes at a fever pitch. It’s a mobile first perspective. A web service perspective – particularly if you are thinking of how to engage customers across digital and physical spaces. —— QUESTION: Thanks for bringing us into the present – some really great examples you gave there to put things into perspective. So what do you see as the biggest trend right now around the “Internet of Things” – and what’s coming next few years? Brian: Honestly, even sitting where I am in the innovation group – it’s hard to look out even 12 months because, well, I don’t even think we’ve fully caught up with what is possible now. But I can definitely say that in the last 12 months and in the coming 12 months, in the technology and eCommerce world it’s all about iBeacons. iBeacons are awesome tools we have right now to tie together physical and digital shopping experiences. They know exactly where you are as a shopper and can communicate that to businesses. Currently there seem to be two camps of thought around iBeacons. First, many people are thinking of them like an “indoor GPS”, which to be fair they literally are. The use case this first camp envisions for iBeacons is primarily for advertising and marketing. So they use iBeacons to push location-based promotions to customers if they are close to a store or in a store. You may have seen these types of mobile promotions start to pop up occasionally on your smart phone as you pass by a store you’ve bought from in the past. That’s the work of iBeacons. But in my humble opinion, these promotions probably come too early in the customer journey and although they may be well timed and work to “convert” in some cases, I imagine in most they are just eroding customer trust because they are kind of a “one-size-fits-all” solution rather than one that is taking into account what exactly the customer might be looking for in that particular moment. Maybe they just want more information and a promotion is way too soon for that type of customer. The second camp is more in line with where my thinking falls. In this case, businesses take a more sensitive approach with iBeacons to customers’ needs. Instead of throwing out a “one-size-fits-all” to any passer by with iBeacons, the use case is more around looking at the physical proximity of a customer as an opportunity to provide a service: show expert reviews on a product they may be looking at in a particular aisle of a store, offer the opportunity to compare prices (and then offer a promotion), signal an in-store associate if a customer has been in the store for more than 10 minutes in one place. These are all less intrusive more value-driven uses of iBeacons. And they are more about building customer trust through service. To take this example a bit further into the future realm of “Big Data” and “Internet of Things” businesses could actually use the Oracle Commerce Platform and iBeacons to “silently” track customer movement w/in the store to provide higher quality service. And this doesn’t have to be creepy or intrusive. Simply if a customer has been in a particular department or aisle for more than a 5 or 10 minutes, an in-store associate could come over an offer some assistance already knowing customer preferences from their online profile and maybe even seeing the items in a shopping cart they started at home. None of this has to be revealed to the customer, but it certainly could boost the level of service an in-store sales associate could provide. Or, in another futuristic example, stores could use the digital footprint of the physical store transmitted by iBeacons to generate heat maps of the store that could be tracked over time. Imagine how much you could find out about which parts of the store are more busy during certain parts of the day or seasons. This could completely revolutionize how physical merchandising is deployed or where certain high value / new items are placed. And / or this use of iBeacons could also help businesses figure out if customers are getting held up in certain parts of the store during busy days like Black Friday. If long lines are causing customers to bounce from a physical store and leave those holiday gifts behind, maybe having employees with mobile check as an option could remove the cash register bottleneck. But going to back to my original statement, it’s all still very early in the story for iBeacons. The hardware manufacturers are still very new and there is still not one clear standard.  Honestly, it all goes back to building and maintaining an extensible and flexible platform for anywhere engagement. What you’re building today should allow you to rapidly take advantage of whatever unimaginable use cases wait around the corner. ------------------------------------------------------ I hope you enjoyed the brief interview with Brian. It’s really awesome to have such smart and innovation-minded individuals on our Oracle Commerce innovation team. Please join me again in a few weeks for Part 3 of this series where I interview one of the product managers on our team about how the blending of digital and in-store selling in influencing our product development and vision.

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  • HTG Explains: Do Non-Windows Platforms Like Mac, Android, iOS, and Linux Get Viruses?

    - by Chris Hoffman
    Viruses and other types of malware seem largely confined to Windows in the real world. Even on a Windows 8 PC, you can still get infected with malware. But how vulnerable are other operating systems to malware? When we say “viruses,” we’re actually talking about malware in general. There’s more to malware than just viruses, although the word virus is often used to talk about malware in general. Why Are All the Viruses For Windows? Not all of the malware out there is for Windows, but most of it is. We’ve tried to cover why Windows has the most viruses in the past. Windows’ popularity is definitely a big factor, but there are other reasons, too. Historically, Windows was never designed for security in the way that UNIX-like platforms were — and every popular operating system that’s not Windows is based on UNIX. Windows also has a culture of installing software by searching the web and downloading it from websites, whereas other platforms have app stores and Linux has centralized software installation from a secure source in the form of its package managers. Do Macs Get Viruses? The vast majority of malware is designed for Windows systems and Macs don’t get Windows malware. While Mac malware is much more rare, Macs are definitely not immune to malware. They can be infected by malware written specifically for Macs, and such malware does exist. At one point, over 650,000 Macs were infected with the Flashback Trojan. [Source] It infected Macs through the Java browser plugin, which is a security nightmare on every platform. Macs no longer include Java by default. Apple also has locked down Macs in other ways. Three things in particular help: Mac App Store: Rather than getting desktop programs from the web and possibly downloading malware, as inexperienced users might on Windows, they can get their applications from a secure place. It’s similar to a smartphone app store or even a Linux package manager. Gatekeeper: Current releases of Mac OS X use Gatekeeper, which only allows programs to run if they’re signed by an approved developer or if they’re from the Mac App Store. This can be disabled by geeks who need to run unsigned software, but it acts as additional protection for typical users. XProtect: Macs also have a built-in technology known as XProtect, or File Quarantine. This feature acts as a blacklist, preventing known-malicious programs from running. It functions similarly to Windows antivirus programs, but works in the background and checks applications you download. Mac malware isn’t coming out nearly as quick as Windows malware, so it’s easier for Apple to keep up. Macs are certainly not immune to all malware, and someone going out of their way to download pirated applications and disable security features may find themselves infected. But Macs are much less at risk of malware in the real world. Android is Vulnerable to Malware, Right? Android malware does exist and companies that produce Android security software would love to sell you their Android antivirus apps. But that isn’t the full picture. By default, Android devices are configured to only install apps from Google Play. They also benefit from antimalware scanning — Google Play itself scans apps for malware. You could disable this protection and go outside Google Play, getting apps from elsewhere (“sideloading”). Google will still help you if you do this, asking if you want to scan your sideloaded apps for malware when you try to install them. In China, where many, many Android devices are in use, there is no Google Play Store. Chinese Android users don’t benefit from Google’s antimalware scanning and have to get their apps from third-party app stores, which may contain infected copies of apps. The majority of Android malware comes from outside Google Play. The scary malware statistics you see primarily include users who get apps from outside Google Play, whether it’s pirating infected apps or acquiring them from untrustworthy app stores. As long as you get your apps from Google Play — or even another secure source, like the Amazon App Store — your Android phone or tablet should be secure. What About iPads and iPhones? Apple’s iOS operating system, used on its iPads, iPhones, and iPod Touches, is more locked down than even Macs and Android devices. iPad and iPhone users are forced to get their apps from Apple’s App Store. Apple is more demanding of developers than Google is — while anyone can upload an app to Google Play and have it available instantly while Google does some automated scanning, getting an app onto Apple’s App Store involves a manual review of that app by an Apple employee. The locked-down environment makes it much more difficult for malware to exist. Even if a malicious application could be installed, it wouldn’t be able to monitor what you typed into your browser and capture your online-banking information without exploiting a deeper system vulnerability. Of course, iOS devices aren’t perfect either. Researchers have proven it’s possible to create malicious apps and sneak them past the app store review process. [Source] However, if a malicious app was discovered, Apple could pull it from the store and immediately uninstall it from all devices. Google and Microsoft have this same ability with Android’s Google Play and Windows Store for new Windows 8-style apps. Does Linux Get Viruses? Malware authors don’t tend to target Linux desktops, as so few average users use them. Linux desktop users are more likely to be geeks that won’t fall for obvious tricks. As with Macs, Linux users get most of their programs from a single place — the package manager — rather than downloading them from websites. Linux also can’t run Windows software natively, so Windows viruses just can’t run. Linux desktop malware is extremely rare, but it does exist. The recent “Hand of Thief” Trojan supports a variety of Linux distributions and desktop environments, running in the background and stealing online banking information. It doesn’t have a good way if infecting Linux systems, though — you’d have to download it from a website or receive it as an email attachment and run the Trojan. [Source] This just confirms how important it is to only run trusted software on any platform, even supposedly secure ones. What About Chromebooks? Chromebooks are locked down laptops that only run the Chrome web browser and some bits around it. We’re not really aware of any form of Chrome OS malware. A Chromebook’s sandbox helps protect it against malware, but it also helps that Chromebooks aren’t very common yet. It would still be possible to infect a Chromebook, if only by tricking a user into installing a malicious browser extension from outside the Chrome web store. The malicious browser extension could run in the background, steal your passwords and online banking credentials, and send it over the web. Such malware could even run on Windows, Mac, and Linux versions of Chrome, but it would appear in the Extensions list, would require the appropriate permissions, and you’d have to agree to install it manually. And Windows RT? Microsoft’s Windows RT only runs desktop programs written by Microsoft. Users can only install “Windows 8-style apps” from the Windows Store. This means that Windows RT devices are as locked down as an iPad — an attacker would have to get a malicious app into the store and trick users into installing it or possibly find a security vulnerability that allowed them to bypass the protection. Malware is definitely at its worst on Windows. This would probably be true even if Windows had a shining security record and a history of being as secure as other operating systems, but you can definitely avoid a lot of malware just by not using Windows. Of course, no platform is a perfect malware-free environment. You should exercise some basic precautions everywhere. Even if malware was eliminated, we’d have to deal with social-engineering attacks like phishing emails asking for credit card numbers. Image Credit: stuartpilbrow on Flickr, Kansir on Flickr     

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  • Organizations &amp; Architecture UNISA Studies &ndash; Chap 7

    - by MarkPearl
    Learning Outcomes Name different device categories Discuss the functions and structure of I/.O modules Describe the principles of Programmed I/O Describe the principles of Interrupt-driven I/O Describe the principles of DMA Discuss the evolution characteristic of I/O channels Describe different types of I/O interface Explain the principles of point-to-point and multipoint configurations Discuss the way in which a FireWire serial bus functions Discuss the principles of InfiniBand architecture External Devices An external device attaches to the computer by a link to an I/O module. The link is used to exchange control, status, and data between the I/O module and the external device. External devices can be classified into 3 categories… Human readable – e.g. video display Machine readable – e.g. magnetic disk Communications – e.g. wifi card I/O Modules An I/O module has two major functions… Interface to the processor and memory via the system bus or central switch Interface to one or more peripheral devices by tailored data links Module Functions The major functions or requirements for an I/O module fall into the following categories… Control and timing Processor communication Device communication Data buffering Error detection I/O function includes a control and timing requirement, to coordinate the flow of traffic between internal resources and external devices. Processor communication involves the following… Command decoding Data Status reporting Address recognition The I/O device must be able to perform device communication. This communication involves commands, status information, and data. An essential task of an I/O module is data buffering due to the relative slow speeds of most external devices. An I/O module is often responsible for error detection and for subsequently reporting errors to the processor. I/O Module Structure An I/O module functions to allow the processor to view a wide range of devices in a simple minded way. The I/O module may hide the details of timing, formats, and the electro mechanics of an external device so that the processor can function in terms of simple reads and write commands. An I/O channel/processor is an I/O module that takes on most of the detailed processing burden, presenting a high-level interface to the processor. There are 3 techniques are possible for I/O operations Programmed I/O Interrupt[t I/O DMA Access Programmed I/O When a processor is executing a program and encounters an instruction relating to I/O it executes that instruction by issuing a command to the appropriate I/O module. With programmed I/O, the I/O module will perform the requested action and then set the appropriate bits in the I/O status register. The I/O module takes no further actions to alert the processor. I/O Commands To execute an I/O related instruction, the processor issues an address, specifying the particular I/O module and external device, and an I/O command. There are four types of I/O commands that an I/O module may receive when it is addressed by a processor… Control – used to activate a peripheral and tell it what to do Test – Used to test various status conditions associated with an I/O module and its peripherals Read – Causes the I/O module to obtain an item of data from the peripheral and place it in an internal buffer Write – Causes the I/O module to take an item of data form the data bus and subsequently transmit that data item to the peripheral The main disadvantage of this technique is it is a time consuming process that keeps the processor busy needlessly I/O Instructions With programmed I/O there is a close correspondence between the I/O related instructions that the processor fetches from memory and the I/O commands that the processor issues to an I/O module to execute the instructions. Typically there will be many I/O devices connected through I/O modules to the system – each device is given a unique identifier or address – when the processor issues an I/O command, the command contains the address of the address of the desired device, thus each I/O module must interpret the address lines to determine if the command is for itself. When the processor, main memory and I/O share a common bus, two modes of addressing are possible… Memory mapped I/O Isolated I/O (for a detailed explanation read page 245 of book) The advantage of memory mapped I/O over isolated I/O is that it has a large repertoire of instructions that can be used, allowing more efficient programming. The disadvantage of memory mapped I/O over isolated I/O is that valuable memory address space is sued up. Interrupts driven I/O Interrupt driven I/O works as follows… The processor issues an I/O command to a module and then goes on to do some other useful work The I/O module will then interrupts the processor to request service when is is ready to exchange data with the processor The processor then executes the data transfer and then resumes its former processing Interrupt Processing The occurrence of an interrupt triggers a number of events, both in the processor hardware and in software. When an I/O device completes an I/O operations the following sequence of hardware events occurs… The device issues an interrupt signal to the processor The processor finishes execution of the current instruction before responding to the interrupt The processor tests for an interrupt – determines that there is one – and sends an acknowledgement signal to the device that issues the interrupt. The acknowledgement allows the device to remove its interrupt signal The processor now needs to prepare to transfer control to the interrupt routine. To begin, it needs to save information needed to resume the current program at the point of interrupt. The minimum information required is the status of the processor and the location of the next instruction to be executed. The processor now loads the program counter with the entry location of the interrupt-handling program that will respond to this interrupt. It also saves the values of the process registers because the Interrupt operation may modify these The interrupt handler processes the interrupt – this includes examination of status information relating to the I/O operation or other event that caused an interrupt When interrupt processing is complete, the saved register values are retrieved from the stack and restored to the registers Finally, the PSW and program counter values from the stack are restored. Design Issues Two design issues arise in implementing interrupt I/O Because there will be multiple I/O modules, how does the processor determine which device issued the interrupt? If multiple interrupts have occurred, how does the processor decide which one to process? Addressing device recognition, 4 general categories of techniques are in common use… Multiple interrupt lines Software poll Daisy chain Bus arbitration For a detailed explanation of these approaches read page 250 of the textbook. Interrupt driven I/O while more efficient than simple programmed I/O still requires the active intervention of the processor to transfer data between memory and an I/O module, and any data transfer must traverse a path through the processor. Thus is suffers from two inherent drawbacks… The I/O transfer rate is limited by the speed with which the processor can test and service a device The processor is tied up in managing an I/O transfer; a number of instructions must be executed for each I/O transfer Direct Memory Access When large volumes of data are to be moved, an efficient technique is direct memory access (DMA) DMA Function DMA involves an additional module on the system bus. The DMA module is capable of mimicking the processor and taking over control of the system from the processor. It needs to do this to transfer data to and from memory over the system bus. DMA must the bus only when the processor does not need it, or it must force the processor to suspend operation temporarily (most common – referred to as cycle stealing). When the processor wishes to read or write a block of data, it issues a command to the DMA module by sending to the DMA module the following information… Whether a read or write is requested using the read or write control line between the processor and the DMA module The address of the I/O device involved, communicated on the data lines The starting location in memory to read from or write to, communicated on the data lines and stored by the DMA module in its address register The number of words to be read or written, communicated via the data lines and stored in the data count register The processor then continues with other work, it delegates the I/O operation to the DMA module which transfers the entire block of data, one word at a time, directly to or from memory without going through the processor. When the transfer is complete, the DMA module sends an interrupt signal to the processor, this the processor is involved only at the beginning and end of the transfer. I/O Channels and Processors Characteristics of I/O Channels As one proceeds along the evolutionary path, more and more of the I/O function is performed without CPU involvement. The I/O channel represents an extension of the DMA concept. An I/O channel ahs the ability to execute I/O instructions, which gives it complete control over I/O operations. In a computer system with such devices, the CPU does not execute I/O instructions – such instructions are stored in main memory to be executed by a special purpose processor in the I/O channel itself. Two types of I/O channels are common A selector channel controls multiple high-speed devices. A multiplexor channel can handle I/O with multiple characters as fast as possible to multiple devices. The external interface: FireWire and InfiniBand Types of Interfaces One major characteristic of the interface is whether it is serial or parallel parallel interface – there are multiple lines connecting the I/O module and the peripheral, and multiple bits are transferred simultaneously serial interface – there is only one line used to transmit data, and bits must be transmitted one at a time With new generation serial interfaces, parallel interfaces are becoming less common. In either case, the I/O module must engage in a dialogue with the peripheral. In general terms the dialog may look as follows… The I/O module sends a control signal requesting permission to send data The peripheral acknowledges the request The I/O module transfers data The peripheral acknowledges receipt of data For a detailed explanation of FireWire and InfiniBand technology read page 264 – 270 of the textbook

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  • OpenID and Iframes

    - by Phood
    hey guys, I'm having a little bit of trouble making OpenID work from within an iframe. basically I have some heavy handed content loaded on the main page and I want to build a log in system where the page doesn't need to be reloaded (and thus reload all of that content again). I fell in love with OpenID from using stack exchange websites, and have intergrated it relatively well into other projects. I feel to do what I want to do I would like to try and use an iframe (because new windows make me cry), however I have stumbled at some form of hurdle somewhere near the middle and for the life of me can't work out whats going on... basically I have a form in a jQuery generated DIV and openID form that seems to work to dynamically load an iframe. something along these lines: <script type="text/javascript"> contentboxs = 0; function contentbox() { if (contentboxs == 0){ $('#mainpage').append("<div id='contentbox'><div style='clear:both;' id='oritext'></div><div id='f_content'><iframe src ='' name='framedcontent' width='580' height='600' scrolling='false'></iframe></div></div>"); $('#f_content').hide(); contentboxs++; } else { $('#contentbox-wipe').remove(); $('#contentbox').remove(); contentboxs--; } } function loginpanel(){ contentbox(); if (contentboxs == 1){ $('#oritext').append("<form method='post' action='login.php' name='oidform' target='framedcontent'>Please Select your OpenID Provider: <br/><input type='text' name=\"id\" id='openidbox' /><br /><input type='submit' name='submit' value='Log In' onclick='loginsubmit();' ></form>"); } } function loginsubmit() { $('#oritext').html(''); $('#contentbox').animate({'height':'600px', 'width':'700px', 'margin-top' : '-300px', 'margin-left' : '-350px'},500, 'linear', function() { $('#f_content').show(); }); } </script> <a href='javascript:loginpanel();'>login</a> and as far as I can tell this all works fine. my problem comes in my re-direction to the openID remote sites (again doing it with JS along these lines:) echo("<div><p><center>Redirecting...</center></div>"); echo "<script type='text/javascript'> function delayer() { this.location = '".$url."' } setTimeout('delayer()', 3000) </script>"; sorry this is a bit long winded, but here is my problem (finally): this works fine for some of the OID sites that I have tried, but some are giving me problems: Google won't load at all, Yahoo and mySpace open fine in the iframe then instantly redirect the full window to the home page and the OID page respectively, and wordpress returns an error. I'm assuming that this is a counter measure put in place to stop me stealing login details (thats not what i'm trying to achieve btw, hence the preamble), and thats fair enough, but still bloody aggravating. is there any thing here that i'm doing retardedly, is there some way round this, and if neither of the above, is my only other options to create new windows or build my own login/registration. If you have got this far thank you very much for your time, and I hope you didn't mind too much the spelling mistakes.

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  • TDC: The Developer's Conference Day One

    - by Tori Wieldt
    The Developer's Conference (TDC) kicked off Wednesday in São Paulo, Brazil. With over 3000 developers in attendance over five days, it is the premier multi-community developer conference in Brazil, organized by Globalcode. Yara Senger, one of the organizers said, "We like to say multi-community rather than multi-technology because it is interesting and benefical when various communities get together. They learn so much from each other!" TDC includes tracks on Java and several other technologies, including SOA, Python, Ruby, mobile and digital TV. In the mobile track, developers who create a Java ME app will get a Nokia S40 phone!New this year at TDC is the Java University track, sponsored by Oracle.  It is aimed at university students and professionals who are new to Java. The lectures are introductory level, with an educational focus and practical exercises. The Java track and other tracks, such as SOA, mobile and Digital TV, are getting lots of help from the expertise of Brazilian JUGS members. Thanks to GoJava, JavaBahia, JavaNoroeste and SouJava!Carlos Fernando, one of the coordinators on the Digital TV track, said "My goal is to teach developers the basics of digital TV, and show them the tools used to build interactive TV applications." Fernando explained the concept of "the second screen:" that many people watch TV and have second smart device (tablet or smartphone) with them, and this creates many opportunities for developers. For example, while watching TV, a viewer can get extra content (interviews, behind the scenes) on their tablet. More interestingly, while watching their favorite TV show a viewer likes an outfit one of the actors is wearing, their smartphone can tell them where they can buy it nearby, or they can order it online immediately. Fernando exclaimed, "The opportunities for developers are nearly infinite in the area of digital TV!" At the TDC opening keynote, Debora Palermo, Oracle University country manager for Brazil, reminded attendees that Java is present in many devices, from simple to complex, and knowledge of this platform can open many doors in the labor market. She explained Oracle's Workforce Development Program (WDP), managed by Oracle University, which allows educational institutions to deliver Oracle training. WDP allows for easy and low-cost access to Oracle training in local communities across the world. "Oracle University is committed to creating the next generation of Java developers, and WDP can make that happen," Palermo said. As of March 2012, Oracle University is partnering with Globalcode to offer WDP. Students can earn official Oracle Course Certifications, a great way to learn Java.Brazilian developers that cannot attend TDC can watch live streaming.

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  • Managing Database Clusters - A Whole Lot Simpler

    - by mat.keep(at)oracle.com
    Clustered computing brings with it many benefits: high performance, high availability, scalable infrastructure, etc.  But it also brings with it more complexity.Why ?  Well, by its very nature, there are more "moving parts" to monitor and manage (from physical, virtual and logical hosts) to fault detection and failover software to redundant networking components - the list goes on.  And a cluster that isn't effectively provisioned and managed will cause more downtime than the standalone systems it is designed to improve upon.  Not so great....When it comes to the database industry, analysts already estimate that 50% of a typical database's Total Cost of Ownership is attributable to staffing and downtime costs.  These costs will only increase if a database cluster is to hard to properly administer.Over the past 9 months, monitoring and management has been a major focus in the development of the MySQL Cluster database, and on Tuesday 12th January, the product team will be presenting the output of that development in a new webinar.Even if you can't make the date, it is still worth registering so you will receive automatic notification when the on-demand replay is availableIn the webinar, the team will cover:    * NDBINFO: released with MySQL Cluster 7.1, NDBINFO presents real-time status and usage statistics, providing developers and DBAs with a simple means of pro-actively monitoring and optimizing database performance and availability.    * MySQL Cluster Manager (MCM): available as part of the commercial MySQL Cluster Carrier Grade Edition, MCM simplifies the creation and management of MySQL Cluster by automating common management tasks, delivering higher administration productivity and enhancing cluster agility. Tasks that used to take 46 commands can be reduced to just one!    * MySQL Cluster Advisors & Graphs: part of the MySQL Enterprise Monitor and available in the commercial MySQL Cluster Carrier Grade Edition, the Enterprise Advisor includes automated best practice rules that alert on key performance and availability metrics from MySQL Cluster data nodes.You'll also learn how you can get started evaluating and using all of these tools to simplify MySQL Cluster management.This session will last round an hour and will include interactive Q&A throughout. You can learn more about MySQL Cluster Manager from this whitepaper and on-line demonstration.  You can also download the packages from eDelivery (just select "MySQL Database" as the product pack, select your platform, click "Go" and then scroll down to get the software).While managing clusters will never be easy, the webinar will show hou how it just got a whole lot simpler !

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