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  • Deliberate Practice

    - by Jeff Foster
    It’s easy to assume, as software engineers, that there is little need to “practice” writing code. After all, we write code all day long! Just by writing a little each day, we’re constantly learning and getting better, right? Unfortunately, that’s just not true. Of course, developers do improve with experience. Each time we encounter a problem we’re more likely to avoid it next time. If we’re in a team that deploys software early and often, we hone and improve the deployment process each time we practice it. However, not all practice makes perfect. To develop true expertise requires a particular type of practice, deliberate practice, the only goal of which is to make us better programmers. Everyday software development has other constraints and goals, not least the pressure to deliver. We rarely get the chance in the course of a “sprint” to experiment with potential solutions that are outside our current comfort zone. However, if we believe that software is a craft then it’s our duty to strive continuously to raise the standard of software development. This requires specific and sustained efforts to get better at something we currently can’t do well (from Harvard Business Review July/August 2007). One interesting way to introduce deliberate practice, in a sustainable way, is the code kata. The term kata derives from martial arts and refers to a set of movements practiced either solo or in pairs. One of the better-known examples is the Bowling Game kata by Bob Martin, the goal of which is simply to write some code to do the scoring for 10-pin bowling. It sounds too easy, right? What could we possibly learn from such a simple example? Trust me, though, that it’s not as simple as five minutes of typing and a solution. Of course, we can reach a solution in a short time, but the important thing about code katas is that we explore each technique fully and in a controlled way. We tackle the same problem multiple times, using different techniques and making different decisions, understanding the ramifications of each one, and exploring edge cases. The short feedback loop optimizes opportunities to learn. Another good example is Conway’s Game of Life. It’s a simple problem to solve, but try solving it in a functional style. If you’re used to mutability, solving the problem without mutating state will push you outside of your comfort zone. Similarly, if you try to solve it with the focus of “tell-don’t-ask“, how will the responsibilities of each object change? As software engineers, we don’t get enough opportunities to explore new ideas. In the middle of a development cycle, we can’t suddenly start experimenting on the team’s code base. Code katas offer an opportunity to explore new techniques in a safe environment. If you’re still skeptical, my challenge to you is simply to try it out. Convince a willing colleague to pair with you and work through a kata or two. It only takes an hour and I’m willing to bet you learn a few new things each time. The next step is to make it a sustainable team practice. Start with an hour every Friday afternoon (after all who wants to commit code to production just before they leave for the weekend?) for month and see how that works out. Finally, consider signing up for the Global Day of Code Retreat. It’s like a daylong code kata, it’s on December 8th and there’s probably an event in your area!

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  • Sitting Pretty

    - by Phil Factor
    Guest Editorial for Simple-Talk IT Pro newsletter'DBAs and SysAdmins generally prefer an expression of calmness under adversity. It is a subtle trick, and requires practice in front of a mirror to get it just right. Too much adversity and they think you're not coping; too much calmness and they think you're under-employed' I dislike the term 'avatar', when used to describe a portrait photograph. An avatar, in the sense of a picture, is merely the depiction of one's role-play alter-ego, often a ridiculous bronze-age deity. However, professional image is important. The choice and creation of online photos has an effect on the way your message is received and it is important to get that right. It is fine to use that photo of you after ten lagers on holiday in an Ibiza nightclub, but what works on Facebook looks hilarious on LinkedIn. My splendid photograph that I use online was done by a professional photographer at great expense and I've never had the slightest twinge of regret when I remember how much I paid for it. It is me, but a more pensive and dignified edition, oozing trust and wisdom. One gasps at the magical skill that a professional photographer can conjure up, without digital manipulation, to make the best of a derisory noggin (ed: slang for a head). Even if he had offered to depict me as a semi-naked, muscle-bound, sword-wielding hero, I'd have demurred. No, any professional person needs a carefully cultivated image that looks right. I'd never thought of using that profile shot, though I couldn't help noticing the photographer flinch slightly when he first caught sight of my face. There is a problem with using an avatar. The use of a single image doesn't express the appropriate emotion. At the moment, it is weird to see someone with a laughing portrait writing something solemn. A neutral cast to the face, somewhat like a passport photo, is probably the best compromise. Actually, the same is true of a working life in IT. One of the first skills I learned was not to laugh at managers, but, instead, to develop a facial expression that promoted a sense of keenness, energy and respect. Every profession has its own preferred facial cast. A neighbour of mine has the natural gift of a face that displays barely repressed grief. Though he is characteristically cheerful, he earns a remarkable income as a pallbearer. DBAs and SysAdmins generally prefer an expression of calmness under adversity. It is a subtle trick, and requires practice in front of a mirror to get it just right. Too much adversity and they think you're not coping; too much calmness and they think you're under-employed. With an appropriate avatar, you could do away with a lot of the need for 'smilies' to give clues as to the meaning of what you've written on forums and blogs. If you had a set of avatars, showing the full gamut of human emotions expressible in writing: Rage, fear, reproach, joy, ebullience, apprehension, exasperation, dissembly, irony, pathos, euphoria, remorse and so on. It would be quite a drop-down list on forums, but given the vast prairies of space on the average hard drive, who cares? It would cut down on the number of spats in Forums just as long as one picks the right avatar. As an unreconstructed geek, I find it hard to admit to the value of image in the workplace, but it is true. Just as we use professionals to tidy up and order our CVs and job applications, we should employ experts to enhance our professional image. After all you don't perform surgery or dentistry on yourself do you?

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  • Comparing Apples and Pairs

    - by Tony Davis
    A recent study, High Costs and Negative Value of Pair Programming, by Capers Jones, pulls no punches in its assessment of the costs-to- benefits ratio of pair programming, two programmers working together, at a single computer, rather than separately. He implies that pair programming is a method rushed into production on a wave of enthusiasm for Agile or Extreme Programming, without any real regard for its effectiveness. Despite admitting that his data represented a far from complete study of the economics of pair programming, his conclusions were stark: it was 2.5 times more expensive, resulted in a 15% drop in productivity, and offered no significant quality benefits. The author provides a more scientific analysis than Jon Evans’ Pair Programming Considered Harmful, but the theme is the same. In terms of upfront-coding costs, pair programming is surely more expensive. The claim of productivity loss is dubious and contested by other studies. The third claim, though, did surprise me. The author’s data suggests that if both the pair and the individual programmers employ static code analysis and testing, then there is no measurable difference in the resulting code quality, in terms of defects per function point. In other words, pair programming incurs a massive extra cost for no tangible return in investment. There were, inevitably, many criticisms of his data and his conclusions, a few of which are persuasive. Firstly, that the driver/observer model of pair programming, on which the study bases its findings, is far from the most effective. For example, many find Ping-Pong pairing, based on use of test-driven development, far more productive. Secondly, that it doesn’t distinguish between “expert” and “novice” pair programmers– that is, independently of other programming skills, how skilled was an individual at pair programming. Thirdly, that his measure of quality is too narrow. This point rings true, certainly at Red Gate, where developers don’t pair program all the time, but use the method in short bursts, while tackling a tricky problem and needing a fresh perspective on the best approach, or more in-depth knowledge in a particular domain. All of them argue that pair programming, and collective code ownership, offers significant rewards, if not in terms of immediate “bug reduction”, then in removing the likelihood of single points of failure, and improving the overall quality and longer-term adaptability/maintainability of the design. There is also a massive learning benefit for both participants. One developer told me how he once worked in the same team over consecutive summers, the first time with no pair programming and the second time pair-programming two-thirds of the time, and described the increased rate of learning the second time as “phenomenal”. There are a great many theories on how we should develop software (Scrum, XP, Lean, etc.), but woefully little scientific research in their effectiveness. For a group that spends so much time crunching other people’s data, I wonder if developers spend enough time crunching data about themselves. Capers Jones’ data may be incomplete, but should cause a pause for thought, especially for any large IT departments, supporting commerce and industry, who are considering pair programming. It certainly shouldn’t discourage teams from exploring new ways of developing software, as long as they also think about how to gather hard data to gauge their effectiveness.

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  • Need help with chronic slow wifi connections

    - by mgeorge
    I have had chronic slow wifi connections on several networks for a while now, I think since my update to 12.04 when it came out. I have tried many of the tips and tricks already available out there in the forums with no luck (wicd, etc..). I want to see if any of you experts out there might be able to help me, and thanks in advance!! I use ubuntu 12.04 on a lenovo ideapad y650, and most networks I connect to lose the connection frequently or do not give appropriate bandwidth when I am connected. Here are some results of the usual go-to system checks: cat /etc/lsb-release; uname -a: DISTRIB_ID=Ubuntu DISTRIB_RELEASE=12.04 DISTRIB_CODENAME=precise DISTRIB_DESCRIPTION="Ubuntu 12.04.2 LTS" Linux mgeorge-lenovo 3.2.0-48-generic-pae #74-Ubuntu SMP Thu Jun 6 20:05:01 UTC 2013 i686 i686 i386 GNU/Linux lspci -nnk | grep -iA2 net: 04:00.0 Network controller [0280]: Intel Corporation PRO/Wireless 5100 AGN [Shiloh] Network Connection [8086:4237] Subsystem: Intel Corporation WiFi Link 5100 AGN [8086:1211] Kernel driver in use: iwlwifi -- 08:00.0 Ethernet controller [0200]: Broadcom Corporation NetLink BCM5784M Gigabit Ethernet PCIe [14e4:1698] (rev 10) Subsystem: Lenovo Device [17aa:3878] Kernel driver in use: tg3 lsusb: Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 008 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 002 Device 002: ID 090c:7371 Silicon Motion, Inc. - Taiwan (formerly Feiya Technology Corp.) iwconfig: lo no wireless extensions. wlan0 IEEE 802.11abgn ESSID:"Dyno" Mode:Managed Frequency:2.412 GHz Access Point: CC:5D:4E:46:0A:93 Bit Rate=150 Mb/s Tx-Power=15 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off Link Quality=70/70 Signal level=-40 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:948 Invalid misc:728 Missed beacon:0 eth0 no wireless extensions. rfkill list all: 0: ideapad_wlan: Wireless LAN Soft blocked: no Hard blocked: no 1: ideapad_bluetooth: Bluetooth Soft blocked: yes Hard blocked: no 2: phy0: Wireless LAN Soft blocked: no Hard blocked: no lsmod: Module Size Used by uvcvideo 67203 0 videodev 86588 1 uvcvideo nouveau 712674 3 ttm 65344 1 nouveau drm_kms_helper 45466 1 nouveau drm 197641 5 nouveau,ttm,drm_kms_helper i2c_algo_bit 13199 1 nouveau mxm_wmi 12893 1 nouveau wmi 18744 1 mxm_wmi joydev 17393 0 arc4 12473 2 snd_hda_codec_realtek 174313 1 snd_hda_codec_hdmi 31775 1 snd_hda_intel 32719 3 snd_hda_codec 109562 3 snd_hda_codec_realtek,snd_hda_codec_hdmi,snd_hda_intel snd_hwdep 13276 1 snd_hda_codec snd_pcm 80916 3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec snd_seq_midi 13132 0 snd_rawmidi 25424 1 snd_seq_midi snd_seq_midi_event 14475 1 snd_seq_midi psmouse 86520 0 snd_seq 51592 2 snd_seq_midi,snd_seq_midi_event serio_raw 13027 0 snd_timer 28931 2 snd_pcm,snd_seq snd_seq_device 14172 3 snd_seq_midi,snd_rawmidi,snd_seq iwlwifi 366509 0 mac80211 436493 1 iwlwifi snd 62218 16 snd_hda_codec_realtek,snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,sn d_rawmidi,snd_seq,snd_timer,snd_seq_device ideapad_laptop 17890 0 sparse_keymap 13658 1 ideapad_laptop cfg80211 178877 2 iwlwifi,mac80211 ir_lirc_codec 12739 0 lirc_dev 18700 1 ir_lirc_codec soundcore 14635 1 snd snd_page_alloc 14108 2 snd_hda_intel,snd_pcm ir_mce_kbd_decoder 12681 0 ir_sony_decoder 12462 0 ir_jvc_decoder 12459 0 ir_rc6_decoder 12459 0 ir_rc5_decoder 12459 0 rc_rc6_mce 12454 0 ir_nec_decoder 12459 0 video 19115 1 nouveau ene_ir 18019 0 rc_core 21263 10 ir_lirc_codec,ir_mce_kbd_decoder,ir_sony_decoder,ir_jvc_decoder,ir_rc6_decoder,ir_rc5_decoder,rc_rc6_mce,ir_nec_decoder,ene_ir bnep 17830 2 rfcomm 38139 0 parport_pc 32114 0 bluetooth 158479 10 bnep,rfcomm ppdev 12849 0 binfmt_misc 17292 1 mac_hid 13077 0 lp 17455 0 parport 40930 3 parport_pc,ppdev,lp tg3 141414 0 nm-tool: NetworkManager Tool State: connected (global) - Device: eth0 ----------------------------------------------------------------- Type: Wired Driver: tg3 State: unavailable Default: no HW Address: 00:23:5A:CC:85:BD Capabilities: Carrier Detect: yes Wired Properties Carrier: off - Device: wlan0 [Dyno] -------------------------------------------------------- Type: 802.11 WiFi Driver: iwlwifi State: connected Default: yes HW Address: 00:22:FA:D0:94:CA Capabilities: Speed: 150 Mb/s Wireless Properties WEP Encryption: yes WPA Encryption: yes WPA2 Encryption: yes Wireless Access Points (* = current AP) *Dyno: Infra, CC:5D:4E:46:0A:93, Freq 2412 MHz, Rate 54 Mb/s, Strength 81 WPA2 IPv4 Settings: Address: 10.0.0.43 Prefix: 24 (255.255.255.0) Gateway: 10.0.0.1 DNS: 10.0.0.1

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  • PowerShell and SMO – be careful how you iterate

    - by Fatherjack
    I’ve yet to have a totally smooth experience with PowerShell and it was late on Friday when I crashed into this problem. I haven’t investigated if this is a generally well understood circumstance and if it is then I apologise for repeating everything. Scenario: I wanted to scan a number of server for many properties, including existing logins and to identify which accounts are bestowed with sysadmin privileges. A great task to pass to PowerShell, so with a heavy heart I started up PowerShellISE and started typing. The script doesn’t come easily to me but I follow the logic of SMO and the properties and methods available with the language so it seemed something I should be able to master. Version #1 of my script. And the results it returns when executed against my home laptop server. These results looked good and for a long time I was concerned with other parts of the script, for all intents and purposes quite happy that this was an accurate assessment of the server. Let’s just review my logic for each step of the code at the top. Lines 1 to 7 just set up our variables and write out the header message Line 8 our first loop, to go through each login on the server Line 10 an inner loop that will assess each role name that each login has been assigned Line 11 a test to see if each role has the name ‘sysadmin’ Line 13 write out the login name with a bright format as it is a sysadmin login Line 17 write out the login name with no formatting It is quite possible that here someone with more PowerShell experience than me will be shouting at their screen pointing at the error I made but to me this made total sense. Until I altered the code, I altered lines 6 and 7 of code above to be: $c = $Svr.Logins.Count write-host “There are $c Logins on the server” This changed my output to look like this: This started alarm bells ringing – there are clearly not 13 logins listed So, let’s see where things are going wrong, edit the script so it looks like this. I’ve highlighted the changes to make Running this code shows me these results Our $n variable should count up by one for each login returned and We are clearly missing some logins. I referenced this list back to Management Studio for my server and see the Logins as below, where there are clearly 13 logins. We see a Login called Annette in SSMS but not in the script results so I opened that up and looked at its properties and it’s server roles in particular. The account has only public access to the server. Inspection of the other logins that the PowerShell script misses out show they too are only members of the public role. Right now I can’t work out whether there is a good reason for this and if it should be expected behaviour or not. Please spend a few minutes to leave a comment if you have an opinion or theory for this. How to get the full list of logins. Clearly I needed to get a full list of the logins so set about reviewing my code to see if there was a better way to iterate through the roles for each login. This is the code that I came up with and I think it is doing everything that I need it to. It gives me the expected results like this: So it seems that the ListMembers() method is the trouble maker in my first versions of the code. I would have expected that ListMembers should return Logins that are only members of the public role, certainly Technet makes no reference to it being left out in it’s Login.ListMembers details. Suffice to say, it’s a lesson learned and I will approach using it with caution in future circumstances.

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  • Bumblebee [ERROR]Cannot access secondary GPU - error: [XORG]

    - by Lunchbox
    Though this may seem like a duplicate question, none of the suggestions I've seen have worked for me, however nearly all posters get good results. I'll start with hardware: Metabox W350ST notebook Intel Core i7 4700 16GB RAM GTX 765M (with Optimus) 128GB SSD 1TB SSHD My initial error output when trying to optirun a game is: [ERROR]Cannot access secondary GPU - error: [XORG] (EE) NVIDIA(0): Failed to initialize the NVIDIA GPU at PCI:1:0:0. Please [133.973920] [ERROR]Aborting because fallback start is disabled. If anything else is needed to troubleshoot this just let me know. Adding bumblebee.conf: # Configuration file for Bumblebee. Values should **not** be put between quotes ## Server options. Any change made in this section will need a server restart # to take effect. [bumblebeed] # The secondary Xorg server DISPLAY number VirtualDisplay=:8 # Should the unused Xorg server be kept running? Set this to true if waiting # for X to be ready is too long and don't need power management at all. KeepUnusedXServer=false # The name of the Bumbleblee server group name (GID name) ServerGroup=bumblebee # Card power state at exit. Set to false if the card shoud be ON when Bumblebee # server exits. TurnCardOffAtExit=false # The default behavior of '-f' option on optirun. If set to "true", '-f' will # be ignored. NoEcoModeOverride=false # The Driver used by Bumblebee server. If this value is not set (or empty), # auto-detection is performed. The available drivers are nvidia and nouveau # (See also the driver-specific sections below) Driver=nvidia # Directory with a dummy config file to pass as a -configdir to secondary X XorgConfDir=/etc/bumblebee/xorg.conf.d ## Client options. Will take effect on the next optirun executed. [optirun] # Acceleration/ rendering bridge, possible values are auto, virtualgl and # primus. Bridge=auto # The method used for VirtualGL to transport frames between X servers. # Possible values are proxy, jpeg, rgb, xv and yuv. VGLTransport=proxy # List of paths which are searched for the primus libGL.so.1 when using # the primus bridge PrimusLibraryPath=/usr/lib/x86_64-linux-gnu/primus:/usr/lib/i386-linux-gnu/primus # Should the program run under optirun even if Bumblebee server or nvidia card # is not available? AllowFallbackToIGC=false # Driver-specific settings are grouped under [driver-NAME]. The sections are # parsed if the Driver setting in [bumblebeed] is set to NAME (or if auto- # detection resolves to NAME). # PMMethod: method to use for saving power by disabling the nvidia card, valid # values are: auto - automatically detect which PM method to use # bbswitch - new in BB 3, recommended if available # switcheroo - vga_switcheroo method, use at your own risk # none - disable PM completely # https://github.com/Bumblebee-Project/Bumblebee/wiki/Comparison-of-PM-methods ## Section with nvidia driver specific options, only parsed if Driver=nvidia [driver-nvidia] # Module name to load, defaults to Driver if empty or unset KernelDriver=nvidia PMMethod=auto # colon-separated path to the nvidia libraries LibraryPath=/usr/lib/nvidia-current:/usr/lib32/nvidia-current # comma-separated path of the directory containing nvidia_drv.so and the # default Xorg modules path XorgModulePath=/usr/lib/nvidia-current/xorg,/usr/lib/xorg/modules XorgConfFile=/etc/bumblebee/xorg.conf.nvidia ## Section with nouveau driver specific options, only parsed if Driver=nouveau [driver-nouveau] KernelDriver=nouveau PMMethod=auto XorgConfFile=/etc/bumblebee/xorg.conf.nouveau DRIVER VERSION - Output of jockey-text -l: nvidia_304_updates - nvidia_304_updates (Proprietary, Enabled, Not in use)

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  • It’s official – Red Gate is a great place to work!

    - by red@work
    At a glittering award ceremony last week, we found out that we’re officially the 14th best small company to work for in the whole of the UK! This is no mean feat, considering that about 1,000 companies enter the Sunday Times Top 100 best companies awards each year. Most of these are in the small companies category too. It's the fourth year in a row for us to be in the Top 100 list and we're tickled pink because the results are based on employee opinion. We’re particularly proud to be the best small company in Cambridge (in the whole of East Anglia, in fact) and the best small software development company in the entire UK. So how does it all work? Well, 90% of us took the time to answer over 70 questions on categories such as management, benefits, wellbeing, leadership, giving something back and what we think of Red Gate as a whole. It makes you think about every part of day to day working life and how you feel about it. Do you slightly or strongly agree or disagree that your manager motivates your to do your best every day, or that you have confidence in Red Gate's leaders, or that you’re not spending too much time working? It's great to see that we had one of the best scores in the country for the question "Do you think your company takes advantage of you?" We got particularly high scores for management, wellbeing and for giving something back too. A few of us got dressed up and headed to London for the awards; very excited about where we’d place but slightly nervous about having to get up on stage. There was a last minute hic up with a bow tie but the Managing Editor of the Sunday Times kindly stepped in to offer his assistance just before we had our official photo taken. We were nominated for two Special Recognition Awards. Despite not bringing them home this year, we're very proud to be nominated as there are only three nominations in each category. First we were up for the Training and Development award. Best Companies loved that we get together at lunchtimes to teach each other photography, cookery and French, as well as our book clubs and techie talks. And of course they liked our opportunities to go on training courses and to jet off to international conferences. Our other nomination was for the Wellbeing award. Best Companies loved our free food (and let’s face it, so do we). Porridge or bacon sandwiches for breakfast, a three course hot dinner, and free fruit and cereals all day long. If all that has an affect on the waistline then there are plenty of sporty activities for us all to get involved in, such as yoga, running or squash. Or if that’s not your thing then a relaxing massage helps us all to unwind every few months or so. The awards were hosted by news presenter Kate Silverton. She gave us a special mention during the ceremony for having great customer engagement as well as employee engagement, after we told her about Rodney Landrum (a Friend of Red Gate) tattooing our logo on his arm. We showed off our customised dinner jacket (thanks to Dom from Usability) with a flashing Red Gate logo on the back and she seemed suitability impressed. Back in the office the next day, we popped open the champagne and raised a glass to our success. Neil, our joint CEO, talked about how pleased he was with the award because it's based on the opinions of the people that count – us. You can read more about the Sunday Times awards here. By the way, we're still growing and are still hiring. If you’d like to keep up with our latest vacancies then why not follow us on Twitter at twitter.com/redgatecareers. Right now we're busy hiring in development, test, sales, product management, web development, and project management. Here's a link to our current job opportunities page – we'd love to hear from great people who are looking for a great place to work! After all, we're only great because of the people who work here. Post by: Alice Chapman

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  • Build 2012, the first post

    - by Dennis Vroegop
    Yes, I was one of the lucky few who made it to Build. Build, formerly known as the Professional Developers Conference (or PDC) is the place to be if you are a developer on the Microsoft platform. Since I take my job seriously I took out some time on my busy schedule, sighed at the thought of not seeing my family for another week and signed up for it. Now, before I talk about the amazing Surface devices (yes, this posting is written on one of them), the great Lumia 920 we all got, the long deserved love for touch, NUI and other things I have been talking about for years, I need to do some ranting. So if you are anxious to read about the technical goodies you’ll have to wait until the next post. Still here? Good. When I signed up for the Build conference during my holidays this summer it was pretty obvious that demand would be high. Therefor I made sure I was on time. But even though I registered only 7 minutes after the initial opening time the Early Bird discount for the first 500 attendees was already sold out. I later learned that registration actually started 5 minutes before the scheduled time but even though it is still impressive how fast things went. The whole event sold out in 57 minutes Or so they say… A lot of people got put on the waiting list. There was room for about 1500 attendees and I heard that at least 1000 people were on that waiting list, including a lot of people I know. Strangely, all of them got tickets assigned after 2 weeks. Here at the conference I heard from a guy from Nokia that they had shipped 2500 Lumia 920 phones. That number matches the rumors that the organization added 1000 extra tickets. This, of course is no problem. I am not an elitist and I think large crowds have a special atmosphere that I quite like. But…. The Microsoft Campus is not equipped for that sheer volume of visitors. That was painfully obvious during on-site registration where people had to stand in line for over 2 hours. The conference is spread out over 2 buildings, divided by a 15 minute busride (yes, the campus is that big). I have seen queues of over 200 people waiting for the bus and when that arrived it had a capacity of 16. I can assure you: that doesn’t fit. This of course means that travelling from one site to the other might take about 30 minutes. So you arrive at the session room just in time, only to find out it’s full. Since you can’ get into that session you try to find another one but now you’re even more late so you have no chance at all of entering. The doors are closed and you’re told: “Well, you can watch the live stream online”. Mmmm… So I spend thousands of dollars, a week away from home, family and work to be told I can also watch the sessions online? Are you fricking kidding me? I could go on but I won’t. You get the idea. It’s jus badly organized, something I am not really used to in my 20 years of experience at Microsoft events. Yes, I am disappointed. I hope a lot of people here in Redmond will also fill in the evals and that the organization next year will do a better job. Really, Build deserves better. </rantmode>

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  • How to fix: Ubuntu 12.04 reboots after loading with elilo

    - by Casey
    I have an HP p6-2120 with CPU: AMD A6-3620 APU with Radeon Graphics RAM: 6GB BIOS: HO2_710.ROM v7.10 [AMI v7.10 4/19/2012] Disk: SATA1 (/dev/sda) - 1 TB (windows) Disk: SATA2 (/dev/sdb) - 1 TB partitioned using "parted -a optimal /dev/sdb" as follows: .. 1049KB 201MB FAT32 boot flag set .. 201MB 60GB ext2 (/) .. 68GB 78GB linux-swap(v1) (swap) .. 78GB 790GB ext4 (/home) .. - rest is "free" space reserved for other purposes (eventually) ubuntu: 12.04.1 LTS [specifically: Release 12.04 (precise) 64-bit] kernel: linux 3.2.0-29-generic I created a bootable EFI USB from the ISO (64-bit) which I downloaded. I can run and install from the USB without any problems. The BIOS is an EFI bios that appears to be capable of booting in either EFI or Legacy mode. Initially, I did the "standard" install with NOTHING on disk2, and let the installer configure everything. The net result of this was that when I started the computer and forced it into "boot" menu mode, it DOES NOT recognize SATA2 as an EFI drive, and when I attempt to "legacy" boot from it, I get the message "ERROR: No Boot Disk has been detected." The "standard" install created one large partition that consumed the entire disk. At that point, I manually partitioned the disk (using sudo parted -a optimal /dev/sdb) as described above. I selected the "other" install, and changed the /dev/sdb1 to "bios_grub", /dev/sdb2 as "/" (ext4), /dev/sdb3 as swap, and /dev/sdb4 as "/home". [Note: fearing that possibly elilo did not recognize ext4, I switched /dev/sdb2 to ext2 and re-insalled] The net result was that the install appeared to trash the /dev/sdb1 partition so that it was NOT readable by anything. I re-formated /dev/sdb1 as FAT32 and set the boot flag. I repeated the install ignoring the messages about no bios_grub partition. After several attempts to get GRUB2 to work, I switched to elilo. I downloaded the most recent version and copied it (elilo-3.14-ia64.efi) to /dev/sdb1/efi/boot/bootx64.efi. (The BIOS boot loader did not recognize it either as elilo-3.14.ia64.efi or as elilo.efi. Based on the advice in one of the web-pages I found, I renamed it to bootx64.efi. This worked.) In that same directory (/efi/boot), I copied the file pointed to the link in /dev/sdb2/vmlinuz to /efi/boot/vmlinuz, and the file pointed to the link in /dev/sdb2/initrd.img to /efi/boot/initrd.img. I created an elilo.conf file as follows: timeout=5000 prompt default=linux-boot image=vmlinuz label=linux-boot read-only initrd=initrd.img root=/dev/sdb2 The /efi/boot directory contains 4 files: bootx64.efi elilo.conf vmlinuz initrd.img When I power-cycle the computer and force the boot menu, drive2 shows up as an EFI bootable drive. When I select it, I get the elilo prompt. Pressing , it appears to load the kernal (I have tried it with verbose=5, and there is a long string of messages with the final one a command line to load the kernel and a series of several dots that fly by) then the screen goes blank, and it reboots the computer. [Note: I have also tried substituting the UUID as found in the /etc/fstab of the installed system for the root directory. This had no effect.] This is a brief synopsis of several nights of fiddling with this. I would deeply appreciate any help you can give.

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  • Minimum team development sizes

    - by MarkPearl
    Disclaimer - these are observations that I have had, I am not sure if this follows the philosophy of scrum, agile or whatever, but most of these insights were gained while implementing a scrum scenario. Two is a partnership, three starts a team For a while I thought that a team was anything more than one and that scrum could be effective methodology with even two people. I have recently adjusted my thinking to a scrum team being a minimum of three, so what happened to two and what do you call it? For me I consider a group of two people working together a partnership - there is value in having a partnership, but some of the dynamics and value that you get from having a team is lost with a partnership. Avoidance of a one on one confrontation The first dynamic I see missing in a partnership is the team motivation to do better and how this is delivered to individuals that are not performing. Take two highly motivated individuals and put them together and you will typically see them continue to perform. Now take a situation where you have two individuals, one performing and one not and the behaviour is totally different compared to a team of three or more individuals. With two people, if one feels the other is not performing it becomes a one on one confrontation. Most people avoid confrontations and so nothing changes. Compare this to a situation where you have three people in a team, 2 performing and 1 not the dynamic is totally different, it is no longer a personal one on one confrontation but a team concern and people seem more willing to encourage the individual not performing and express their dissatisfaction as a team if they do not improve. Avoiding the effects of Tuckman’s Group Development Theory If you are not familiar with Tuckman’s group development theory give it a read (http://en.wikipedia.org/wiki/Tuckman's_stages_of_group_development) In a nutshell with Tuckman’s theory teams go through these stages of Forming, Storming, Norming & Performing. You want your team to reach and remain in the Performing stage for as long as possible - this is where you get the most value. When you have a partnership of two and you change the individuals in the partnership you basically do a hard reset on the partnership and go back to the beginning of Tuckman’s model each time. This has a major effect on the performance of a team and what they can deliver. What I have seen is that you reduce the effects of Tuckman's theory the more individuals you have in the team (until you hit the maximum team size in which other problems kick in). While you will still experience Tuckman's theory with a team of three, the impact will be greatly reduced compared to two where it is guaranteed every time a change occurs. It's not just in the numbers, it's in the people One final comment - while the actual numbers of a team do play a role, the individuals in the team are even more important - ideally you want to keep individuals working together for an extended period. That doesn't mean that you never change the individuals in a team, or that once someone joins a team they are stuck there - there is value in an individual moving from team to team and getting cross pollination, but the period of time that an individual moves should be in month's or years, not days or weeks. Why? So why is it important to know this? Why is it important to know how a team works and what motivates them? I have been asking myself this question for a while and where I am at right now is this… the aim is to achieve the stage where the sum of the total (team) is greater than the sum of the parts (team members). This is why we form teams and why understanding how they work is a challenge and also extremely stimulating.

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  • News From EAP Testing

    - by Fatherjack
    There is a phrase that goes something like “Watch the pennies and the pounds/dollars will take care of themselves”, meaning that if you pay attention to the small things then the larger things are going to fare well too. I am lucky enough to be a Friend of Red Gate and once in a while I get told about new features in their tools and have a test copy of the software to trial. I got one of those emails a week or so ago and I have been exploring the SQL Prompt 6 EAP since then. One really useful feature of long standing in SQL Prompt is the idea of a code snippet that is automatically pasted into the SSMS editor when you type a few key letters. For example I can type “ssf” and then press the tab key and the text is expanded to SELECT * FROM. There are lots of these combinations and it is possible to create your own really easily. To create your own you use the Snippet Manager interface to define the shortcut letters and the code that you want to have put in their place. Let’s look at an example. Say I am writing a blog about something and want to have the demo code create a temporary table. It might looks like this; The first time you run the code everything is fine, a lovely set of dates fill the results grid but run it a second time and this happens.   Yep, we didn’t destroy the temporary table so the CREATE statement fails when it finds the table already exists. No matter, I have a snippet created that takes care of this.   Nothing too technical here but you will see that in the Code section there is $CURSOR$, this isn’t a TSQL keyword but a marker for SQL Prompt to place the cursor in that position when the Code is pasted into the SSMS Editor. I just place my cursor above the CREATE statement and type “ifobj” – the shortcut for my code to DROP the temporary table – which has been defined in the Snippet Manager as below. This means I am right-away ready to type the name of the offending table. Pretty neat and it’s been very useful in saving me lots of time over many years.   The news for SQL Prompt 6 is that Red Gate have added a new Snippet Command of $PASTE$. Let’s alter our snippet to the following and try it out   Once again, we will type type “ifobj” in the SSMS Editor but first of all, highlight the name of the table #TestTable and copy it to your clipboard. Now type “ifobj” and press Tab… Wherever the string $PASTE$ is placed in the snippet, the contents of your clipboard are merged into the pasted TSQL. This means I don’t need to type the table name into the code snippet, it’s already there and I am seeing a fully functioning piece of TSQL ready to run. This means it is it even easier to write TSQL quickly and consistently. Attention to detail like this from Red Gate means that their developer tools stay on track to keep winning awards year after year and help take the hard work out of writing neat, accurate TSQL. If you want to try out SQL Prompt all the details are at http://www.red-gate.com/products/sql-development/sql-prompt/.

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  • It happens only at Devoxx ...

    - by arungupta
    After attending several Java conferences world wide, this was my very first time at Devoxx. Here are some items I found that happens only at Devoxx ... Pioneers of theater-style seating - This not only provides comfortable seating for each attendee but the screens are very clearly visible to everybody in the room. Intellectual level of attendees is very high - Read more explanation on the Java EE 6 lab blog. In short, a lab, 1/3 of the content delivered at Devoxx 2011, could not be completed at other developer days in more than 1/3 the time. Snack box for lunches - Even though this suits well to the healthy lifestyle of multiple-snacks-during-a-day style but leaves attendees hungry sooner in the day. The longer breaks before the next snack in the evening does not help at all. Fortunately, Azure cupcakes and Android ice creams turned out to be handy. I finally carried my own apple :-) Wrist band instead of lanyard - The good part about this is that once tied to your hand then you are less likely to forget in your room. But OTOH you are a pretty much a branded conference attendee all through out the city. It was cost effective as it costed 20c as opposed to 1 euro for the lanyard. Live streaming from theater #8 (the biggest room) on parleys.com All talks recorded and released on parleys.com over next year. This allows attendees to not to miss any session and watch replay at their own leisure. Stephan promised to start sharing the sessions by mid December this year. No need to pre-register for a session - This is true for most of the conferences but bigger rooms (+ overflow room for key sessions) provide sufficient space for all those who want to attend the session. And of course all sessions are available on parleys.com anyway! Community votes on whiteboard - Devoxx attendees gets a chance to vote on topics ranging from their favorite non-Java language, operating system, or love from Oracle. Captured pictures at the end of Day 2 are shown below. Movie on the last but one night - This year it was The Adventures of Tintin and was lots of fun. Fries with mayo - This is a typical Belgian thing. Guys going in ladies room to avoid the long queues ... wow! Tweet wall everywhere and I mean literally everywhere, in rooms, hallways, front desk, and other places. The tweet picking algorithm was not very clear as I never saw my tweet appear on the wall ;-) You can also watch it at wall.devoxx.com. Cozy speaker dinner with great food and wine List of parallel and upcoming sessions displayed on the screen - This makes the information more explicit with the attendees. REST API with multiple mobile clients - This API is also used by some other conferences as well. And there always is iphone.devoxx.com. Steering committee members were recognized multiple times. The committee members were clearly identifiable wearing red hoodies. The wireless SSID was intuitive "Devoxx" but hidden to avoid some crap from Microsoft Windows. All of 9000 addresses were used up most of the times with each attendee having multiple devices. A 1 GB fibre optic cable was stretched to Metropolis to support the required network bandwidth. Stephan is already planning to upgrade the equipment and have a better infrastructure next year. Free water, soda, juice in a cooler Kinect connected to TV screens so that attendees can use their hands to browse through the list of sesssions. #devoxxblog, #devoxxwomen, #devoxxfrance, #devoxxgreat, #devoxxsuggestions And Devoxx attendees are called Devoxxians ... how cool is that ? :-) What other things do you think happen only at Devoxx ? And now the pictures from the community whiteboard: And a more complete album (including bigger pics of community votes) is available below:

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  • The Social Enterprise: Gangnam Style

    - by Mike Stiles
    Are only small and medium businesses able to put social strategies in place, generate consistent, compelling content for customers, and be nimble enough to listen and respond to the social communities they build? Or are enterprise organizations eagerly and effectively adopting social as well? It depends on whom inside the organization you ask. A study from Attensity looked at who “gets” social inside enterprise organizations. The results were unsurprising. Mostly, Generation X and Y employees who came of age with social as part of their lives and as a key communications vehicle understand it. Imagine being a 25-year-old at a company that bans employees from accessing Facebook at work. You may as well tell them they can’t use phones and must do all calculations on an abacus. To them, such policy is absent of real-world logic and signals to them the organization is destined to be the victim of an up-and-comer. After that, it’s senior management that gets social. You don’t get to be in senior management without reading a few things and paying attention. Most senior managers are well aware of the impact social has had and will have, though they may be unsure of what to do about it. The better ones will utilize those on the inside who do inherently know how to communicate and build virtual relationships using social. The very best will get the past out of the way for these social innovators, so the new communications can be enacted minus counterproductive dictums, double-clutching, meeting-creep, and all the other fading internal practices that water down content and impede change. Organizationally, the Attensity study found 81% of enterprise companies believe failing to embrace social will result in their being left behind. Yet our old friend fear still has many captive in its clutches. 79% feel overwhelmed by the volume of social data available, something a social technology partner with goal-oriented analytics expertise could go a long way toward alleviating. Then there’s the fear of social having a negative impact. This comes from a lack of belief in the product, the customer service, or both. The public uses social not to go out and slay brands. They’re using it to be honest. If the fear is that honesty will reflect badly on the brand, the brand has much bigger, broader problems than what happens on Facebook. Sadly, most enterprise organizations still see social as a megaphone, a one-way channel with which to hit people with ads. They either don’t understand social relationships, or don’t want any. The truly unenlightened manager will always say, “We help them by selling them our stuff.” “Brand affinity” is a term, it’s just not one assigned much value in enterprise organizations. Which brings us to Psy, the Korean performer whose Internet video phenom “Gangnam Style,” as of this writing, has been viewed 438,550,238 times on YouTube. It’s bigger than anything a brand will probably ever publish. Most brands would never have seen the point of making or publishing it. But a funny thing happened on the way to Internet success. The video literally doubled the stock price of Psy’s father’s software firm. NH Investment and Securities said, "The positive sentiment has attracted investors just because of the fact the company is owned by Psy's father and uncle.” The company wasn’t mentioned or seen in the video in any way, yet reaped tangible rewards just for being tangentially associated with it. Imagine your brand being visibly and directly responsible for such a smash and tell me it’s worthless. When enterprise organizations embrace the value of igniting passions, making people happier, solving their problems, informing them, helping them have fun, etc., then they will have fully embraced social, and will reap the brand affinity rewards of heightened awareness, brand loyalty and yes, sales.

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  • What Color is your Jetpack ?

    - by JoshReuben
    I’m a programmer, Im approaching 40, and I’m fairly decent at my job – I’ll keep doing what I’m doing for as long as they let me!   So what are your career options if you know how to code? A Programmer could be ..   An Algorithm developer Pros Interesting High barriers of entry, potential for startup competitive factor Cons Do you have the skill, qualifications? What are working conditions n this mystery niche ? micro-focus An Academic Pros Low pressure Job security – or is this an illusion ? Cons Low Pay Need a PhD A Software Architect Pros: strategic, rather than tactical Setting technology platform and high level vision You say how it should work, others have to figure out why its not working the way its supposed to ! broad view – you are paid to learn (how do you con people into paying for you to learn ??) Cons: Glorified developer – more often than not! competitive – everyone wants to do it ! loose touch with underlying tech in tough times, first guy to get the axe ! A Software Engineer Pros: interesting, always more to learn fun I can do it Fallback Cons: Nothing new under the sun – been there, done that Dealing with poor requirements, deadlines, other peoples code, overtime C#, XAML, Web - Low barriers of entry –> à race to the bottom A Team leader Pros: Setting code standards and proposing technology choices Cons: Glorified developer – more often than not! Inspecting other peoples code and debugging the problems they cannot fix Dealing with mugbies and prima donas Responsible for QA of others A Project Manager Pros No need for debugging other peoples code Cons Low barrier of entry High pressure Responsible for QA of others Loosing touch with technology A lot of bullshit meetings Have to be an asshole A Product Manager Pros No need for debugging other peoples code Learning new skillset of sales and marketing Cons Travel (I'm a family man) May need to know the bs details of an uninteresting product things I want to work with: AI, algorithms, Numerical Computing, Mathematica, C++ AMP – unfortunately, the work here is few & far between. VS & TFS Extensibility, DSLs (Workflow , Lightswitch), Code Generation – one day, code will write code ! Unity3D, WebGL – fun, fun, fun ! Modern Web – Knockout, SignalR, MVC, Node.Js ??? (tentative – I'll wait until things stabilize as this area is undergoing a pre-Cambrian explosion) Things I don’t want to work with: (but will if I'm asked to !) C# – same old, same old – not learning anything new here Old code – blech ! Environment with code & fix mentality , ad hoc requirements, excessive overtime Pc support, System administration – even after 20 years, people still ask you to do this sometimes ! debugging – my skills are just not there yet Oracle Old tech: VB 6, XSLT, WinForms, Net 3.51 or less Old style Web dev Information Systems: ASP.NET webforms, Reporting services / crystal reports, SQL Server CRUD with manual data layer, XAML MVVM – variations of the same concept, ad nauseaum. Low barriers of entry –> race to the bottom.  Metro – an elegant API coupled to a horrendous UX – I'll wait for market penetration viability before investing further in this.   Conclusion So if you are in a slump, take heart: Programming is a great career choice compared to every other job !

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  • Teminal hands on load, can't enter anything until CTRL+C

    - by Silver Light
    Hello! I have an issue with terminal in Ubuntu 10.04. When I launch it, it hangs, like this: I cannot do anything until I press CTRL+C: I cannot remember when this started. What can be wrong? Looks like teminal is loading or processing something each time it loads. How can I diagnose and solve this problem? EDIT: Here are the conents of ~/.bashrc: # ~/.bashrc: executed by bash(1) for non-login shells. # see /usr/share/doc/bash/examples/startup-files (in the package bash-doc) # for examples # If not running interactively, don't do anything [ -z "$PS1" ] && return # don't put duplicate lines in the history. See bash(1) for more options # ... or force ignoredups and ignorespace HISTCONTROL=ignoredups:ignorespace # append to the history file, don't overwrite it shopt -s histappend # for setting history length see HISTSIZE and HISTFILESIZE in bash(1) HISTSIZE=1000 HISTFILESIZE=2000 # check the window size after each command and, if necessary, # update the values of LINES and COLUMNS. shopt -s checkwinsize # make less more friendly for non-text input files, see lesspipe(1) [ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)" # set variable identifying the chroot you work in (used in the prompt below) if [ -z "$debian_chroot" ] && [ -r /etc/debian_chroot ]; then debian_chroot=$(cat /etc/debian_chroot) fi # set a fancy prompt (non-color, unless we know we "want" color) case "$TERM" in xterm-color) color_prompt=yes;; esac # uncomment for a colored prompt, if the terminal has the capability; turned # off by default to not distract the user: the focus in a terminal window # should be on the output of commands, not on the prompt #force_color_prompt=yes if [ -n "$force_color_prompt" ]; then if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then # We have color support; assume it's compliant with Ecma-48 # (ISO/IEC-6429). (Lack of such support is extremely rare, and such # a case would tend to support setf rather than setaf.) color_prompt=yes else color_prompt= fi fi if [ "$color_prompt" = yes ]; then PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ ' else PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ ' fi unset color_prompt force_color_prompt # If this is an xterm set the title to user@host:dir case "$TERM" in xterm*|rxvt*) PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1" ;; *) ;; esac # enable color support of ls and also add handy aliases if [ -x /usr/bin/dircolors ]; then test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)" alias ls='ls --color=auto' #alias dir='dir --color=auto' #alias vdir='vdir --color=auto' alias grep='grep --color=auto' alias fgrep='fgrep --color=auto' alias egrep='egrep --color=auto' fi # some more ls aliases alias ll='ls -alF' alias la='ls -A' alias l='ls -CF' # Add an "alert" alias for long running commands. Use like so: # sleep 10; alert alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"' # Alias definitions. # You may want to put all your additions into a separate file like # ~/.bash_aliases, instead of adding them here directly. # See /usr/share/doc/bash-doc/examples in the bash-doc package. if [ -f ~/.bash_aliases ]; then . ~/.bash_aliases fi # enable programmable completion features (you don't need to enable # this, if it's already enabled in /etc/bash.bashrc and /etc/profile # sources /etc/bash.bashrc). if [ -f /etc/bash_completion ] && ! shopt -oq posix; then . /etc/bash_completion fi # Source .profile if [ -f ~/.profile ]; then . ~/.profile fi Setting -x at the beginning showed me that it tries to repeat this without stopping: +++++++++++++++++++ '[' 'complete -f -X '\''!*.@(pdf|PDF)'\'' acroread gpdf xpdf' '!=' 'complete -f -X '\''!*.@(pdf|PDF)'\'' acroread gpdf xpdf' ']' +++++++++++++++++++ line='complete -f -X '\''!*.@(pdf|PDF)'\'' acroread gpdf xpdf' +++++++++++++++++++ line='complete -f -X '\''!*.@(pdf|PDF)'\'' acroread gpdf xpdf' +++++++++++++++++++ line=' acroread gpdf xpdf' +++++++++++++++++++ list=("${list[@]}" $line) +++++++++++++++++++ read line

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  • how to write the code for this program specially in mathematica? [closed]

    - by asd
    I implemented a solution to the problem below in Mathematica, but it takes a very long time (hours) to compute f of kis or the set B for large numbers. Somebody suggested that implementing this in C++ resulted in a solution in less than 10 minutes. Would C++ be a good language to learn to solve these problems, or can my Mathematica code be improved to fix the performance issues? I don't know anything about C or C++ and it should be difficult to start to learn this languages. I prefer to improve or write new code in mathematica. Problem Description Let $f$ be an arithmetic function and A={k1,k2,...,kn} are integers in increasing order. Now I want to start with k1 and compare f(ki) with f(k1). If f(ki)f(k1), put ki as k1. Now start with ki, and compare f(kj) with f(ki), for ji. If f(kj)f(ki), put kj as ki, and repeat this procedure. At the end we will have a sub sequence B={L1,...,Lm} of A by this property: f(L(i+1))f(L(i)), for any 1<=i<=m-1 For example, let f is the divisor function of integers. Here I put some part of my code and this is just a sample and the question in my program could be more larger than these: «««««««««««««««««««««««««««««««««««« f[n_] := DivisorSigma[0, n]; g[n_] := Product[Prime[i], {i, 1, PrimePi[n]}]; k1 = g[67757] g[353] g[59] g[19] g[11] g[7] g[5]^2 6^3 2^7; k2 = g[67757] g[353] g[59] g[19] g[11] g[7] g[5] 6^5 2^7; k3 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5] 6^4 2^7; k4 = g[67759] g[349] g[53] g[19] g[11] g[7] g[5] 6^5 2^6; k5 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5] 6^4 2^8; k6 = g[67759] g[349] g[53] g[19] g[11] g[7] g[5]^2 6^3 2^7; k7 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5] 6^5 2^6; k8 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5] 6^4 2^9; k9 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5]^2 6^3 2^7; k10 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5] 6^5 2^7; k11 = g[67759] g[349] g[53] g[19] g[11] g[7] g[5]^2 6^4 2^6; k12 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5]^2 6^3 2^8; k13 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5]^2 6^4 2^6; k14 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5]^2 6^3 2^9; k15 = g[67757] g[359] g[53] g[19] g[11] g[7] g[5]^2 6^4 2^7; k16 = g[67757] g[359] g[53] g[23] g[11] g[7] g[5] 6^4 2^8; k17 = g[67757] g[359] g[59] g[19] g[11] g[7] g[5] 6^4 2^7; k18 = g[67757] g[359] g[53] g[23] g[11] g[7] g[5] 6^4 2^9; k19 = g[67759] g[353] g[53] g[19] g[11] g[7] g[5] 6^4 2^6; k20 = g[67763] g[347] g[53] g[19] g[11] g[7] g[5] 6^4 2^7; k = Table[k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12, k13, k14, k15, k16, k17, k18, k19, k20]; i = 1; count = 0; For[j = i, j <= 20, j++, If[f[k[[j]]] - f[k[[i]]] > 0, i = j; Print["k",i]; count = count + 1]]; Print["count= ", count] ««««««««««««««««««««««««««««««««««««

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  • Approach for packing 2D shapes while minimizing total enclosing area

    - by Dennis
    Not sure on my tags for this question, but in short .... I need to solve a problem of packing industrial parts into crates while minimizing total containing area. These parts are motors, or pumps, or custom-made components, and they have quite unusual shapes. For some, it may be possible to assume that a part === rectangular cuboid, but some are not so simple, i.e. they assume a shape more of that of a hammer or letter T. With those, (assuming 2D shape), by alternating direction of top & bottom, one can pack more objects into the same space, than if all tops were in the same direction. Crude example below with letter "T"-shaped parts: ***** xxxxx ***** x ***** *** ooo * x vs * x vs * x vs * x o * x * xxxxx * x * x o xxxxx xxx Right now we are solving the problem by something like this: using CAD software, make actual models of how things fit in crate boxes make estimates of actual crate dimensions & write them into Excel file (1) is crazy amount of work and as the result we have just a limited amount of possible entries in (2), the Excel file. The good things is that programming this is relatively easy. Given a combination of products to go into crates, we do a lookup, and if entry exists in the Excel (or Database), we bring it out. If it doesn't, we say "sorry, no data!". I don't necessarily want to go full force on making up some crazy algorithm that given geometrical part description can align, rotate, and figure out best part packing into a crate, given its shape, but maybe I do.. Question Well, here is my question: assuming that I can represent my parts as 2D (to be determined how), and that some parts look like letter T, and some parts look like rectangles, which algorithm can I use to give me a good estimate on the dimensions of the encompassing area, while ensuring that the parts are packed in a minimal possible area, to minimize crating/shipping costs? Are there approximation algorithms? Seeing how this can get complex, is there an existing library I could use? My thought / Approach My naive approach would be to define a way to describe position of parts, and place the first part, compute total enclosing area & dimensions. Then place 2nd part in 0 degree orientation, repeat, place it at 180 degree orientation, repeat (for my case I don't think 90 degree rotations will be meaningful due to long lengths of parts). Proceed using brute force "tacking on" other parts to the enclosing area until all parts are processed. I may have to shift some parts a tad (see 3rd pictorial example above with letters T). This adds a layer of 2D complexity rather than 1D. I am not sure how to approach this. One idea I have is genetic algorithms, but I think those will take up too much processing power and time. I will need to look out for shape collisions, as well as adding extra padding space, since we are talking about real parts with irregularities rather than perfect imaginary blocks. I'm afraid this can get geometrically messy fairly fast, and I'd rather keep things simple, if I can. But what if the best (practical) solution is to pack things into different crate boxes rather than just one? This can get a bit more tricky. There is human element involved as well, i.e. like parts can go into same box and are thus a constraint to be considered. Some parts that are not the same are sometimes grouped together for shipping and can be considered as a common grouped item. Sometimes customers want things shipped their way, which adds human element to constraints. so there will have to be some customization.

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  • Any tips on getting hired as a software project manager straight out of college?

    - by MHarrison
    I graduated with a BS in compsci last September, and I've been trying (unsuccessfully) to find a job as a project manager ever since. I fell in love with software engineering (the formal practice behind it all, not just coding) in school, and I've dedicated the last 3-4 years of my life to learning everything I can about project management and gaining experience. I've managed several projects (with teams around 12 people) while in school, and I worked with my university's software engineering research lab. My résumé is also decent - I worked as a programmer before I went to school (I'm 27 now), and I did Google Summer of Code for 3 summers. I also have general "people management" experience via working as the photo editor for my university's newspaper for 2 years. My first problem with the job hunt is not getting enough interviews. I use careers.stackoverflow.com, which is awesome because I usually get contacted by non-HR people who know what they're talking about, but there's just not enough companies using it for me to get interviews on a regular basis. I've also tried sites like monster.com, and in a fit of desperation, I sent out no less than 60 applications to project management positions. I've gotten 3 automated rejection letters and that's it. At least careers.stackoverflow gets me a phone interview with 8/10 places I apply to. But the main (and extremely frustrating) problem is the matter of experience. I've successfully managed projects from start to finish (in my software engineering classes we had real customers come in with a real software need and we built it for them), but I've never had to deal with budgets and money (I know this is why HR people immediately turn me away). Most of these positions require 5+ years PM experience, and I've seen absurd things like 12+ years required. Interviews are also maddening. I've had so many places who absolutely loved me and I made it to the final round of interviews, and I left thinking things went extremely well and they'd consider me. However, when I check in with them a week later, they tell me "We really liked you and your qualifications are excellent, but we're hoping to find someone with more experience." The bad interviews I can understand - like the PM position that would have had me managing developers both locally and overseas - I had 3 interviews with them and the ENTIRE interview process was them asking me CS brainteasers and having me waste time on things like writing quicksort on paper or writing binary search trees. Even when I tried steering the discussion towards more relevant PM stuff, they gave me some vague generic replies and went back to the "We want to be Google/MS" crap. But when I have a GOOD interview, they say my "qualifications are excellent" but they want "more experience"...that makes me want to tear my hair out. What else can I DO? While I'm aiming for technically-involved PM positions (not just crunching budget numbers), I really don't want a straight development job because I like creating software from the very high-level vs. spending a lot of time debugging memory leaks. In fact, I can't even GET development positions that I'm qualified for because I make the mistake of telling them that my future career goals are as PM (which usually results in them saying something like "Well we already have PMs and this position isn't really set up to get you there." - which I take to mean "No, that's my job, stay away.") My apologies on the long rant, but I'm seriously hellbent on getting hired as a PM since it's both my career goal and the passion that keeps me awake at night. Any suggestions on what the heck else I can do? I'm currently writing a blog where I talk about my philosophies about software engineering, and I'm writing up specs for an iOS app which I will design, code, and show employers, but this takes an awful lot of time that I don't have.

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  • Welcome To The Nashorn Blog

    - by jlaskey
    Welcome to all.  Time to break the ice and instantiate The Nashorn Blog.  I hope to contribute routinely, but we are very busy, at this point, preparing for the next development milestone and, of course, getting ready for open source. So, if there are long gaps between postings please forgive. We're just coming back from JavaOne and are stoked by the positive response to all the Nashorn sessions. It was great for the team to have the front and centre slide from Georges Saab early in the keynote. It seems we have support coming from all directions. Most of the session videos are posted. Check out the links. Nashorn: Optimizing JavaScript and Dynamic Language Execution on the JVM. Unfortunately, Marcus - the code generation juggernaut,  got saddled with the first session of the first day. Still, he had a decent turnout. The talk focused on issues relating to optimizations we did to get good performance from the JVM. Much yet to be done but looking good. Nashorn: JavaScript on the JVM. This was the main talk about Nashorn. I delivered the little bit of this and a little bit of that session with an overview, a follow up on the open source announcement, a run through a few of the Nashorn features and some demos. The room was SRO, about 250±. High points: Sam Pullara, from Twitter, came forward to describe how painless it was to get Mustache.js up and running (20x over Rhino), and,  John Ceccarelli, from NetBeans came forward to describe how Nashorn has become an integral part of Netbeans. A healthy Q & A at the end was very encouraging. Meet the Nashorn JavaScript Team. Michel, Attila, Marcus and myself hosted a Q & A. There was only a handful of people in the room (we assume it was because of a conflicting session ;-) .) Most of the questions centred around Node.jar, which leads me to believe, Nashorn + Node.jar is what has the most interest. Akhil, Mr. Node.jar, sitting in the audience, fielded the Node.jar questions. Nashorn, Node, and Java Persistence. Doug Clarke, Akhil and myself, discussed the title topics, followed by a lengthy Q & A (security had to hustle us out.) 80 or so in the room. Lots of questions about Node.jar. It was great to see Doug's use of Nashorn + JPA. Nashorn in action, with such elegance and grace. Putting the Metaobject Protocol to Work: Nashorn’s Java Bindings. Attila discussed how he applied Dynalink to Nashorn. Good turn out for this session as well. I have a feeling that once people discover and embrace this hidden gem, great things will happen for all languages running on the JVM. Finally, there were quite a few JavaOne sessions that focused on non-Java languages and their impact on the JVM. I've always believed that one's tool belt should carry a variety of programming languages, not just for domain/task applicability, but also to enhance your thinking and approaches to problem solving. For the most part, future blog entries will focus on 'how to' in Nashorn, but if you have any suggestions for topics you want discussed, please drop a line.  Cheers. 

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  • Oh no! My padding's invalid!

    - by Simon Cooper
    Recently, I've been doing some work involving cryptography, and encountered the standard .NET CryptographicException: 'Padding is invalid and cannot be removed.' Searching on StackOverflow produces 57 questions concerning this exception; it's a very common problem encountered. So I decided to have a closer look. To test this, I created a simple project that decrypts and encrypts a byte array: // create some random data byte[] data = new byte[100]; new Random().NextBytes(data); // use the Rijndael symmetric algorithm RijndaelManaged rij = new RijndaelManaged(); byte[] encrypted; // encrypt the data using a CryptoStream using (var encryptor = rij.CreateEncryptor()) using (MemoryStream encryptedStream = new MemoryStream()) using (CryptoStream crypto = new CryptoStream( encryptedStream, encryptor, CryptoStreamMode.Write)) { crypto.Write(data, 0, data.Length); encrypted = encryptedStream.ToArray(); } byte[] decrypted; // and decrypt it again using (var decryptor = rij.CreateDecryptor()) using (CryptoStream crypto = new CryptoStream( new MemoryStream(encrypted), decryptor, CryptoStreamMode.Read)) { byte[] decrypted = new byte[data.Length]; crypto.Read(decrypted, 0, decrypted.Length); } Sure enough, I got exactly the same CryptographicException when trying to decrypt the data even in this simple example. Well, I'm obviously missing something, if I can't even get this single method right! What does the exception message actually mean? What am I missing? Well, after playing around a bit, I discovered the problem was fixed by changing the encryption step to this: // encrypt the data using a CryptoStream using (var encryptor = rij.CreateEncryptor()) using (MemoryStream encryptedStream = new MemoryStream()) { using (CryptoStream crypto = new CryptoStream( encryptedStream, encryptor, CryptoStreamMode.Write)) { crypto.Write(data, 0, data.Length); } encrypted = encryptedStream.ToArray(); } Aaaah, so that's what the problem was. The CryptoStream wasn't flushing all it's data to the MemoryStream before it was being read, and closing the stream causes it to flush everything to the backing stream. But why does this cause an error in padding? Cryptographic padding All symmetric encryption algorithms (of which Rijndael is one) operates on fixed block sizes. For Rijndael, the default block size is 16 bytes. This means the input needs to be a multiple of 16 bytes long. If it isn't, then the input is padded to 16 bytes using one of the padding modes. This is only done to the final block of data to be encrypted. CryptoStream has a special method to flush this final block of data - FlushFinalBlock. Calling Stream.Flush() does not flush the final block, as you might expect. Only by closing the stream or explicitly calling FlushFinalBlock is the final block, with any padding, encrypted and written to the backing stream. Without this call, the encrypted data is 16 bytes shorter than it should be. If this final block wasn't written, then the decryption gets to the final 16 bytes of the encrypted data and tries to decrypt it as the final block with padding. The end bytes don't match the padding scheme it's been told to use, therefore it throws an exception stating what is wrong - what the decryptor expects to be padding actually isn't, and so can't be removed from the stream. So, as well as closing the stream before reading the result, an alternative fix to my encryption code is the following: // encrypt the data using a CryptoStream using (var encryptor = rij.CreateEncryptor()) using (MemoryStream encryptedStream = new MemoryStream()) using (CryptoStream crypto = new CryptoStream( encryptedStream, encryptor, CryptoStreamMode.Write)) { crypto.Write(data, 0, data.Length); // explicitly flush the final block of data crypto.FlushFinalBlock(); encrypted = encryptedStream.ToArray(); } Conclusion So, if your padding is invalid, make sure that you close or call FlushFinalBlock on any CryptoStream performing encryption before you access the encrypted data. Flush isn't enough. Only then will the final block be present in the encrypted data, allowing it to be decrypted successfully.

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  • Questions to ask to ensure someone understands programming? (and iOS)

    - by Stephen J
    So, I've been tutoring my friend for 2 years. Most people learn programming on their own in 3-6 months, (sans algorithms). It's confusing 'cause he'll run anywhere I tell him to, understands how to read C and C++ honestly better than the average college student, and he'll modify and repeat anything I do... but for the love of god he doesn't move on to new things and he still has test anxiety. I've recently realized he's copied and toyed with existing, but not once gained an understanding of why. I was under the impression he was learning fast because he could write it, but when you say "Make a function that takes an NSString" and he says "How?" and I say "The same way you make ANY function that takes any parameter, NSString is just a type like int" and all I hear is "No, it's an NSString, it's a special thing." and we get into an arguing match 'cause I'm like "It's just a class like any other class, you've used them for months now" and blah... I've subconsciously avoided comprehension questions because of this. Anyway, if you have him copy a program and say "Just initialize it" "Where?" "I don't care, didLoad or initWithCoder or Awake from nib, anywhere it gets initialized" and "No, it has to be exactly where you had it!" "No it doesn't!" I'm sick of this, but he won't give up. So I'm done avoiding these yelling matches and becoming a sadist from now on. I would like some help in finding questions to ask him that force him to understand what he's doing. I'd like some help and any resources I can find. CQuestions looked like a good site, but now I need some iPhone stuff. For example: *What do properties do? How are they changed? How do you change the name of the getter? *Why are Booleans inefficent? What advantage does int have over a boolean and how does the bit-shift operator help? *What does Copy do to a string? *What's the difference between a view controller and a uiview? *Write a program from memory that displays blah on screen, and flashes each view one by one. From beginner up to intermediate, hobbyist with some algebra at most. I'm just looking for resources to work with. I left in backstory so you know to "twist" the questions so he doesn't know he's supposed to init a variable here or there, but has to figure it out, and learn why it goes "here" or that "anywhere is fine as long as it's". Sample programs, anything. I'm relatively open about this because, being a programmer, I seriously doubt he's the only one who has this issue. I'd like to know how others have overcome similar. What made things "click"? for you? Did you have a hard time finding answers on Google, and how did you learn a better way to find what you were looking for? (He's so exact, he'll search for how to write a checkers program with color X and Y inside a uiview, as his search string, instead of breaking it up into components, I need help with that too, and believe it is related). This type of problem has to remind one of us of someone they know. So, Exercises to force them to think? Ways we overcame this thing in the past? I greatly appreciate any help.

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  • Teminal non-responsive on load, can't enter anything until CTRL+C

    - by Silver Light
    Hello! I have an issue with terminal in Ubuntu 10.04. When I launch it, it hangs, like this: I cannot do anything until I press CTRL+C: I cannot remember when this started. What can be wrong? Looks like teminal is loading or processing something each time it loads. How can I diagnose and solve this problem? EDIT: Here are the conents of ~/.bashrc: # ~/.bashrc: executed by bash(1) for non-login shells. # see /usr/share/doc/bash/examples/startup-files (in the package bash-doc) # for examples # If not running interactively, don't do anything [ -z "$PS1" ] && return # don't put duplicate lines in the history. See bash(1) for more options # ... or force ignoredups and ignorespace HISTCONTROL=ignoredups:ignorespace # append to the history file, don't overwrite it shopt -s histappend # for setting history length see HISTSIZE and HISTFILESIZE in bash(1) HISTSIZE=1000 HISTFILESIZE=2000 # check the window size after each command and, if necessary, # update the values of LINES and COLUMNS. shopt -s checkwinsize # make less more friendly for non-text input files, see lesspipe(1) [ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)" # set variable identifying the chroot you work in (used in the prompt below) if [ -z "$debian_chroot" ] && [ -r /etc/debian_chroot ]; then debian_chroot=$(cat /etc/debian_chroot) fi # set a fancy prompt (non-color, unless we know we "want" color) case "$TERM" in xterm-color) color_prompt=yes;; esac # uncomment for a colored prompt, if the terminal has the capability; turned # off by default to not distract the user: the focus in a terminal window # should be on the output of commands, not on the prompt #force_color_prompt=yes if [ -n "$force_color_prompt" ]; then if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then # We have color support; assume it's compliant with Ecma-48 # (ISO/IEC-6429). (Lack of such support is extremely rare, and such # a case would tend to support setf rather than setaf.) color_prompt=yes else color_prompt= fi fi if [ "$color_prompt" = yes ]; then PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ ' else PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ ' fi unset color_prompt force_color_prompt # If this is an xterm set the title to user@host:dir case "$TERM" in xterm*|rxvt*) PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1" ;; *) ;; esac # enable color support of ls and also add handy aliases if [ -x /usr/bin/dircolors ]; then test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)" alias ls='ls --color=auto' #alias dir='dir --color=auto' #alias vdir='vdir --color=auto' alias grep='grep --color=auto' alias fgrep='fgrep --color=auto' alias egrep='egrep --color=auto' fi # some more ls aliases alias ll='ls -alF' alias la='ls -A' alias l='ls -CF' # Add an "alert" alias for long running commands. Use like so: # sleep 10; alert alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"' # Alias definitions. # You may want to put all your additions into a separate file like # ~/.bash_aliases, instead of adding them here directly. # See /usr/share/doc/bash-doc/examples in the bash-doc package. if [ -f ~/.bash_aliases ]; then . ~/.bash_aliases fi # enable programmable completion features (you don't need to enable # this, if it's already enabled in /etc/bash.bashrc and /etc/profile # sources /etc/bash.bashrc). if [ -f /etc/bash_completion ] && ! shopt -oq posix; then . /etc/bash_completion fi # Source .profile if [ -f ~/.profile ]; then . ~/.profile fi Setting -x at the beginning showed me that it tries to repeat this without stopping: +++++++++++++++++++ '[' 'complete -f -X '\''!*.@(pdf|PDF)'\'' acroread gpdf xpdf' '!=' 'complete -f -X '\''!*.@(pdf|PDF)'\'' acroread gpdf xpdf' ']' +++++++++++++++++++ line='complete -f -X '\''!*.@(pdf|PDF)'\'' acroread gpdf xpdf' +++++++++++++++++++ line='complete -f -X '\''!*.@(pdf|PDF)'\'' acroread gpdf xpdf' +++++++++++++++++++ line=' acroread gpdf xpdf' +++++++++++++++++++ list=("${list[@]}" $line) +++++++++++++++++++ read line

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  • New Version 3.1 Endeca Information Discovery Now Available

    - by Mike.Hallett(at)Oracle-BI&EPM
    Normal 0 false false false EN-GB X-NONE X-NONE MicrosoftInternetExplorer4 Business User Self-Service Data Mash-up Analysis and Discovery integrated with OBI11g and Hadoop Oracle Endeca Information Discovery 3.1 (OEID) is a major release that incorporates significant new self-service discovery capabilities for business users, including agile data mashup, extended support for unstructured analytics, and an even tighter integration with Oracle BI.  · Self-Service Data Mashup and Discovery Dashboards: business users can combine information from multiple sources, including their own up-loaded spreadsheets, to conduct analysis on the complete set.  Creating discovery dashboards has been made even easier by intuitive drag-and drop layouts and wizard-based configuration.  Business users can now build new discovery applications in minutes, without depending on IT. · Enhanced Integration with Oracle BI: OEID 3.1 enhances its’ native integration with Oracle Business Intelligence Foundation. Business users can now incorporate information from trusted BI warehouses, leveraging dimensions and attributes defined in Oracle’s Common Enterprise Information Model, but evolve them based on the varying day-to-day demands and requirements that they personally manage. · Deep Unstructured Analysis: business users can gain new insights from a wide variety of enterprise and public sources, helping companies to build an actionable Big Data strategy.  With OEID’s long-standing differentiation in correlating unstructured information with structured data, business users can now perform their own text mining to identify hidden concepts, without having to request support from IT. They can augment these insights with best in class keyword search and pattern matching, all in the context of rich, interactive visualizations and analytic summaries. · Enterprise-Class Self-Service Discovery:  OEID 3.1 enables IT to provide a powerful self-service platform to the business as part of a broader Business Analytics strategy, preserving the value of existing investments in data quality, governance, and security.  Business users can take advantage of IT-curated information to drive discovery across high volumes and varieties of data, and share insights with colleagues at a moment’s notice. · Harvest Content from the Web with the Endeca Web Acquisition Toolkit:  Oracle now provides best-of-breed data access to website content through the Oracle Endeca Web Acquisition Toolkit.  This provides an agile, graphical interface for developers to rapidly access and integrate any information exposed through a web front-end.  Organizations can now cost-effectively include content from consumer sites, industry forums, government or supplier portals, cloud applications, and myriad other web sources as part of their overall strategy for data discovery and unstructured analytics. For more information: OEID 3.1 OTN Software and Documentation Download And Endeca available for download on Software Delivery Cloud (eDelivery) New OEID 3.1 Videos on YouTube Oracle.com Endeca Site /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;}

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  • Creating a voxel world with 3D arrays using threads

    - by Sean M.
    I am making a voxel game (a bit like Minecraft) in C++(11), and I've come across an issue with creating a world efficiently. In my program, I have a World class, which holds a 3D array of Region class pointers. When I initialize the world, I give it a width, height, and depth so it knows how large of a world to create. Each Region is split up into a 32x32x32 area of blocks, so as you may guess, it takes a while to initialize the world once the world gets to be above 8x4x8 Regions. In order to alleviate this issue, I thought that using threads to generate different levels of the world concurrently would make it go faster. Having not used threads much before this, and being still relatively new to C++, I'm not entirely sure how to go about implementing one thread per level (level being a xz plane with a height of 1), when there is a variable number of levels. I tried this: for(int i = 0; i < height; i++) { std::thread th(std::bind(&World::load, this, width, height, depth)); th.join(); } Where load() just loads all Regions at height "height". But that executes the threads one at a time (which makes sense, looking back), and that of course takes as long as generating all Regions in one loop. I then tried: std::thread t1(std::bind(&World::load, this, w, h1, h2 - 1, d)); std::thread t2(std::bind(&World::load, this, w, h2, h3 - 1, d)); std::thread t3(std::bind(&World::load, this, w, h3, h4 - 1, d)); std::thread t4(std::bind(&World::load, this, w, h4, h - 1, d)); t1.join(); t2.join(); t3.join(); t4.join(); This works in that the world loads about 3-3.5 times faster, but this forces the height to be a multiple of 4, and it also gives the same exact VAO object to every single Region, which need individual VAOs in order to render properly. The VAO of each Region is set in the constructor, so I'm assuming that somehow the VAO number is not thread safe or something (again, unfamiliar with threads). So basically, my question is two one-part: How to I implement a variable number of threads that all execute at the same time, and force the main thread to wait for them using join() without stopping the other threads? How do I make the VAO objects thread safe, so when a bunch of Regions are being created at the same time across multiple threads, they don't all get the exact same VAO? Turns out it has to do with GL contexts not working across multiple threads. I moved the VAO/VBO creation back to the main thread. Fixed! Here is the code for block.h/.cpp, region.h/.cpp, and CVBObject.h/.cpp which controls VBOs and VAOs, in case you need it. If you need to see anything else just ask. EDIT: Also, I'd prefer not to have answers that are like "you should have used boost". I'm trying to do this without boost to get used to threads before moving onto other libraries.

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  • Randomely loosing wireless connexion with Cubuntu 12.04

    - by statquant
    I am presently experiencing random disconnections from my wireless network. It looks like it is more and more frequent (however I have not seen any clear pattern). This is killing me... Here is some information that should help (from ubuntu forums). Thanks for reading Machine : Acer Aspire S3 statquant@euclide:~$ lsb_release -d Description: Ubuntu 12.04.1 LTS statquant@euclide:~$ uname -mr 3.2.0-33-generic x86_64 statquant@euclide:~$ sudo /etc/init.d/networking restart * Running /etc/init.d/networking restart is deprecated because it may not enable again some interfaces * Reconfiguring network interfaces... statquant@euclide:~$ lspci 02:00.0 Network controller: Atheros Communications Inc. AR9485 Wireless Network Adapter (rev 01) statquant@euclide:~$ lsusb Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 004: ID 064e:c321 Suyin Corp. Bus 002 Device 003: ID 0bda:0129 Realtek Semiconductor Corp. statquant@euclide:~$ ifconfig wlan0 Link encap:Ethernet HWaddr 74:de:2b:dd:c4:78 inet addr:192.168.1.3 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::76de:2bff:fedd:c478/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:913 errors:0 dropped:0 overruns:0 frame:0 TX packets:802 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:873218 (873.2 KB) TX bytes:125826 (125.8 KB) statquant@euclide:~$ iwconfig wlan0 IEEE 802.11bgn ESSID:"Bbox-D646D1" Mode:Managed Frequency:2.437 GHz Access Point: 00:19:70:80:01:6C Bit Rate=65 Mb/s Tx-Power=16 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:on Link Quality=56/70 Signal level=-54 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:71 Missed beacon:0 statquant@euclide:~$ dmesg | grep "wlan" [ 17.495866] ADDRCONF(NETDEV_UP): wlan0: link is not ready [ 17.498950] ADDRCONF(NETDEV_UP): wlan0: link is not ready [ 20.072015] wlan0: authenticate with 00:19:70:80:01:6c (try 1) [ 20.269853] wlan0: authenticate with 00:19:70:80:01:6c (try 2) [ 20.272386] wlan0: authenticated [ 20.298682] wlan0: associate with 00:19:70:80:01:6c (try 1) [ 20.302321] wlan0: RX AssocResp from 00:19:70:80:01:6c (capab=0x431 status=0 aid=1) [ 20.302325] wlan0: associated [ 20.307307] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready [ 30.402292] wlan0: no IPv6 routers present statquant@euclide:~$ sudo lshw -C network [sudo] password for statquant: *-network description: Wireless interface product: AR9485 Wireless Network Adapter vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:02:00.0 logical name: wlan0 version: 01 serial: 74:de:2b:dd:c4:78 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical wireless configuration: broadcast=yes driver=ath9k driverversion=3.2.0-33-generic firmware=N/A ip=192.168.1.3 latency=0 link=yes multicast=yes wireless=IEEE 802.11bgn resources: irq:17 memory:c0400000-c047ffff memory:afb00000-afb0ffff statquant@euclide:~$ iwlist scan wlan0 Scan completed : Cell 01 - Address: 00:19:70:80:01:6C Channel:6 Frequency:2.437 GHz (Channel 6) Quality=56/70 Signal level=-54 dBm Encryption key:on ESSID:"Bbox-D646D1" Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s Bit Rates:24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s Mode:Master Extra:tsf=000000125fb152bb Extra: Last beacon: 40020ms ago IE: Unknown: 000B42626F782D443634364431 IE: Unknown: 010882848B960C121824 IE: Unknown: 030106 IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK IE: Unknown: 2A0100 IE: Unknown: 32043048606C IE: Unknown: DD180050F2020101820003A4000027A4000042435E0062322F00 IE: Unknown: 2D1A4C101BFF00000000000000000000000000000000000000000000 IE: Unknown: 3D1606080800000000000000000000000000000000000000 IE: Unknown: DD0900037F01010000FF7F IE: Unknown: DD0A00037F04010000000000 And... finally, please note that I did the following (after looking for fixes of similar problems), but unfortunately it did not work sudo modprobe -r iwlwifi sudo modprobe iwlwifi 11n_disable=1

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