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  • Source-control 'wet-work'?

    - by Phil Factor
    When a design or creative work is flawed beyond remedy, it is often best to destroy it and start again. The other day, I lost the code to a long and intricate SQL batch I was working on. I’d thought it was impossible, but it happened. With all the technology around that is designed to prevent this occurring, this sort of accident has become a rare event.  If it weren’t for a deranged laptop, and my distraction, the code wouldn’t have been lost this time.  As always, I sighed, had a soothing cup of tea, and typed it all in again.  The new code I hastily tapped in  was much better: I’d held in my head the essence of how the code should work rather than the details: I now knew for certain  the start point, the end, and how it should be achieved. Instantly the detritus of half-baked thoughts fell away and I was able to write logical code that performed better.  Because I could work so quickly, I was able to hold the details of all the columns and variables in my head, and the dynamics of the flow of data. It was, in fact, easier and quicker to start from scratch rather than tidy up and refactor the existing code with its inevitable fumbling and half-baked ideas. What a shame that technology is now so good that developers rarely experience the cleansing shock of losing one’s code and having to rewrite it from scratch.  If you’ve never accidentally lost  your code, then it is worth doing it deliberately once for the experience. Creative people have, until Technology mistakenly prevented it, torn up their drafts or sketches, threw them in the bin, and started again from scratch.  Leonardo’s obsessive reworking of the Mona Lisa was renowned because it was so unusual:  Most artists have been utterly ruthless in destroying work that didn’t quite make it. Authors are particularly keen on writing afresh, and the results are generally positive. Lawrence of Arabia actually lost the entire 250,000 word manuscript of ‘The Seven Pillars of Wisdom’ by accidentally leaving it on a train at Reading station, before rewriting a much better version.  Now, any writer or artist is seduced by technology into altering or refining their work rather than casting it dramatically in the bin or setting a light to it on a bonfire, and rewriting it from the blank page.  It is easy to pick away at a flawed work, but the real creative process is far more brutal. Once, many years ago whilst running a software house that supplied commercial software to local businesses, I’d been supervising an accounting system for a farming cooperative. No packaged system met their needs, and it was all hand-cut code.  For us, it represented a breakthrough as it was for a government organisation, and success would guarantee more contracts. As you’ve probably guessed, the code got mangled in a disk crash just a week before the deadline for delivery, and the many backups all proved to be entirely corrupted by a faulty tape drive.  There were some fragments left on individual machines, but they were all of different versions.  The developers were in despair.  Strangely, I managed to re-write the bulk of a three-month project in a manic and caffeine-soaked weekend.  Sure, that elegant universally-applicable input-form routine was‘nt quite so elegant, but it didn’t really need to be as we knew what forms it needed to support.  Yes, the code lacked architectural elegance and reusability. By dawn on Monday, the application passed its integration tests. The developers rose to the occasion after I’d collapsed, and tidied up what I’d done, though they were reproachful that some of the style and elegance had gone out of the application. By the delivery date, we were able to install it. It was a smaller, faster application than the beta they’d seen and the user-interface had a new, rather Spartan, appearance that we swore was done to conform to the latest in user-interface guidelines. (we switched to Helvetica font to look more ‘Bauhaus’ ). The client was so delighted that he forgave the new bugs that had crept in. I still have the disk that crashed, up in the attic. In IT, we have had mixed experiences from complete re-writes. Lotus 123 never really recovered from a complete rewrite from assembler into C, Borland made the mistake with Arago and Quattro Pro  and Netscape’s complete rewrite of their Navigator 4 browser was a white-knuckle ride. In all cases, the decision to rewrite was a result of extreme circumstances where no other course of action seemed possible.   The rewrite didn’t come out of the blue. I prefer to remember the rewrite of Minix by young Linus Torvalds, or the rewrite of Bitkeeper by a slightly older Linus.  The rewrite of CP/M didn’t do too badly either, did it? Come to think of it, the guy who decided to rewrite the windowing system of the Xerox Star never regretted the decision. I’ll agree that one should often resist calls for a rewrite. One of the worst habits of the more inexperienced programmer is to denigrate whatever code he or she inherits, and then call loudly for a complete rewrite. They are buoyed up by the mistaken belief that they can do better. This, however, is a different psychological phenomenon, more related to the idea of some motorcyclists that they are operating on infinite lives, or the occasional squaddies that if they charge the machine-guns determinedly enough all will be well. Grim experience brings out the humility in any experienced programmer.  I’m referring to quite different circumstances here. Where a team knows the requirements perfectly, are of one mind on methodology and coding standards, and they already have a solution, then what is wrong with considering  a complete rewrite? Rewrites are so painful in the early stages, until that point where one realises the payoff, that even I quail at the thought. One needs a natural disaster to push one over the edge. The trouble is that source-control systems, and disaster recovery systems, are just too good nowadays.   If I were to lose this draft of this very blog post, I know I’d rewrite it much better. However, if you read this, you’ll know I didn’t have the nerve to delete it and start again.  There was a time that one prayed that unreliable hardware would deliver you from an unmaintainable mess of a codebase, but now technology has made us almost entirely immune to such a merciful act of God. An old friend of mine with long experience in the software industry has long had the idea of the ‘source-control wet-work’,  where one hires a malicious hacker in some wild eastern country to hack into one’s own  source control system to destroy all trace of the source to an application. Alas, backup systems are just too good to make this any more than a pipedream. Somehow, it would be difficult to promote the idea. As an alternative, could one construct a source control system that, on doing all the code-quality metrics, would systematically destroy all trace of source code that failed the quality test? Alas, I can’t see many managers buying into the idea. In reading the full story of the near-loss of Toy Story 2, it set me thinking. It turned out that the lucky restoration of the code wasn’t the happy ending one first imagined it to be, because they eventually came to the conclusion that the plot was fundamentally flawed and it all had to be rewritten anyway.  Was this an early  case of the ‘source-control wet-job’?’ It is very hard nowadays to do a rapid U-turn in a development project because we are far too prone to cling to our existing source-code.

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  • Visiting the Fire Station in Coromandel

    Hm, I just tried to remember how we actually came up with this cool idea... but it's already too blurred and it doesn't really matter after all. Anyway, if I remember correctly (IIRC), it happened during one of the Linux meetups at Mugg & Bean, Bagatelle where Ajay and I brought our children along and we had a brief conversation about how cool it would be to check out one of the fire stations here in Mauritius. We both thought that it would be a great experience and adventure for the little ones. An idea takes shape And there we go, down the usual routine these... having an idea, checking out the options and discussing who's doing what. Except this time, it was all up to Ajay, and he did a fantastic job. End of August, he told me that he got in touch with one of his friends which actually works as a fire fighter at the station in Coromandel and that there could be an option to come and visit them (soon). A couple of days later - Confirmed! Be there, and in time... What time? Anyway, doesn't really matter... Everything was settled and arranged. I asked the kids on Friday afternoon if they might be interested to see the fire engines and what a fire fighter is doing. Of course, they were all in! Getting up early on Sunday morning isn't really a regular exercise for all of us but everything went smooth and after a short breakfast it was time to leave. Where are we going? Are we there yet? Now, we are in Bambous. Why do you go this way? The kids were so much into it. Absolutely amazing to see their excitement. Are we there yet? Well, we went through the sugar cane fields towards Chebel and then down into the industrial zone at Coromandel. Honestly, I had a clue where the fire station is located but having Google Maps in reach that shouldn't be a problem in case that we might get lost. But my worries were washed away when our children guided us... "There! Over there are the fire engines! We have to turn left, dad." - No comment, the kids were right! As we were there a little bit too early, we parked the car and the kids started to explore the area and outskirts of the fire station. Some minutes later, as if we had placed an order a unit of two cars had to go out for an alarm and the kids could witness them leaving as closely as possible. Sirens on and wow!!! Ladder truck L32 - MAN truck with Rosenbauer built-up and equipment by Metz Taking the tour Ajay arrived shortly after that and guided us finally inside the station to meet with his pal. The three guys were absolutely well-prepared and showed us around in the hall, explaining that there two units out at the moment. But the ladder truck (with max. 32m expandable height) was still around we all got a great insight into the technique and equipment on the vehicle. It was amazing to see all three kids listening to Mambo as give some figures about the truck and how the fire fighters are actually it. The children and 'our' fire fighters of the day had great fun with the various fire engines Absolutely fantastic that the children were allowed to experience this - we had so much fun! Ajay's son brought two of his toy fire engines along, shared them with ours, and they all played very well together. As a parent it was really amazing to see them at such an ease. Enough theory Shortly afterwards the ladder truck was moved outside, got stabilised and ready to go for 'real-life' exercising. With the additional equipment of safety helmets, security belts and so on, we all got a first-hand impression about how it could be as a fire-fighter. Actually, I was totally amazed by the curiousity and excitement of my BWE. She was really into it and asked lots of interesting questions - in general but also technical. And while our fighters were busy with Ajay and family, I gave her some more details and explanations about the truck, the expandable ladder, the safety cage at the top and other equipment available. Safety first! No exceptions and always be prepared for the worst case... Also, the equipped has been checked prior to excuse - This is your life saver... Hooked up and ready to go... ...of course not too high. This is just a demonstration - and 32 meters above ground isn't for everyone. Well, after that it was me that had the asking looks on me, and I finally revealed to the local fire fighters that I was in the auxiliary fire brigade, more precisely in the hazard department, for more than 10 years. So not a professional fire fighter but at least a passionate and educated one as them. Inside the station Our fire fighters really took their time to explain their daily job to kids, provided them access to operation seat on the ladder truck and how the truck cabin is actually equipped with the different radios and so on. It was really a great time. Later on we had a brief tour through the building itself, and again all of our questions were answered. We had great fun and started to joke about bits and pieces. For me it was also very interesting to see the comparison between the fire station here in Mauritius and the ones I have been to back in Germany. Amazing to see them completely captivated in the play - the children had lots of fun! Also, that there are currently ten fire stations all over the island, plus two additional but private ones at the airport and at the harbour. The newest one is actually down in Black River on the west coast because the time from Quatre Bornes takes too long to have any chance of an effective alarm at all. IMHO, a very good decision as time is the most important factor in getting fire incidents under control. After all it was great experience for all of us, especially for the children to see and understand that their toy trucks are only copies of the real thing and that the job of a (professional) fire fighter is very important in our society. Don't forget that those guys run into the danger zone while you're trying to get away from it as much as possible. Another unit just came back from a grass fire - and shortly after they went out again. No time to rest, too much to do! Mauritian Fire Fighters now and (maybe) in the future... Thank you! It was an honour to be around! Thank you to Ajay for organising and arranging this Sunday morning event, and of course of Big Thank You to the three guys that took some time off to have us at the Fire Station in Coromandel and guide us through their daily job! And remember to call 115 in case of emergencies!

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  • Thou shalt not put code on a piedestal - Code is a tool, no more, no less

    - by Ralf Westphal
    “Write great code and everything else becomes easier” is what Paul Pagel believes in. That´s his version of an adage by Brian Marick he cites: “treat code as an end, not just a means.” And he concludes: “My post-Agile world is software craftsmanship.” I wonder, if that´s really the way to go. Will “simply” writing great code lead the software industry into the light? He´s alluding to the philosopher Kant who proposed, a human beings should never be treated as a means, but always as an end. But should we transfer this ethical statement into the world of software? I doubt it.   Reason #1: Human beings are categorially different from code. They are autonomous entities who need to find a way of living happily together. To Kant it seemed this goal could only be reached if nobody (ab)used a human being for his/her purposes. Because using a human being, i.e. treating it as a means, would contradict the fundamental autonomy and freedom of human beings. People should hold up a symmetric view of their relationships: Since nobody wants to be (ab)used, nobody should (ab)use anybody else. If you want to be treated decently, with respect, in accordance with your own free will - which means as an end - then do the same to other people. Code is dead, it´s a product, it´s a tool for people to reach their goals. No company spends any money on code other than to save money or earn money in the long run. Code is not a puppy. Enterprises do not commission software development to just feel good in its company. Code is not a buddy. Code is a slave, if you will. A mechanical slave, a non-tangible robot. Code is a tool, is a tool. And if we start to treat it differently, if we elevate its status unduely… I guess that will contort our relationship in a contraproductive way. Please get me right: Just because something is “just a tool”, “just a product” does not mean we should not be careful while designing, building, using it. Right to the contrary. We should be very careful when writing code – but not for the code´s sake! We should be careful because we respect our customers who are fellow human beings who should be treated as an end. If we are careless, neglectful, ignorant when producing code on their behalf, then we´re using them. Being sloppy means you´re caring more for yourself that for your customer. You´re then treating the customer as a means to fulfill some of your own needs. That´s plain unethical behavior.   Reason #2: The focus should always be on your purpose, not on any tool. But if code is treated as an end, then the focus is on the code. That might sound right, because where else should be your focus as a software developer? But, well, I´d say, your focus should be on delivering value to your customer. Because in the end your customer does not care if you write a single line of code. She just wants her problem to be solved. Solving problems is the purpose of any contractor. Code must be treated just as a means, a tool we know how to handle very well. But if we´re really trying to be craftsmen then we should be conscious about exactly that and act ethically. That means we must never be so focused on our tool as to be unable to suggest better solutions to the problems of our customers than code.   I´m all with Paul when he urges us to “Write great code”. Sure, if you need to write code, then by all means do so. Write the best code you can think of – and then try to improve it. Paul has all the best intentions when he signs Brians “treat code as an end” - but as we all know: “The road to hell is paved with best intentions” ;-) Yes, I can imagine a “hell of code focus”. In fact, I don´t need to imagine it, I´m seeing it quite often. Because code hell is whereever two developers stand together and are so immersed in talking about all sorts of coding tricks, design patterns, code smells, technologies, platforms, tools that they lose sight of the big picture. Talking about TDD or SOLID or refactoring is a sign of consciousness – relative to the “cowboy coders” view of the world. But from yet another point of view TDD, SOLID, and refactoring are just cures for ailments within a system. And I fear, if “Writing great code” is the only focus or the main focus of software development, then we as an industry lose the ability to see that. Focus draws a line around something, it defines a horizon for perceptions and thinking. So if we focus on code our horizon ends where “the land of code” ends. I don´t think that should be our professional attitude.   So what about Software Craftsmanship as the next big thing after Agility? I think Software Craftsmanship has an important message for all software developers and beyond. But to make it the successor of the Agility movement seems to miss a point. Agility never claimed to solve all software development problems, I´d say. So to blame it for having missed out on certain aspects of it is wrong. If I had to summarize Agility in one word I´d say “Value”. Agility put value for the customer back in software development. Focus on delivering value early and often – that´s Agility´s mantra. All else follows from that. And I ask you: Is that obsolete? Is delivering value not hip anymore? No, sure not. That´s our very purpose as software developers. So how can Agility become obsolete and need to be replaced? We need to do away with this “either/or”-thinking. It´s either Agility or Lean or Software Craftsmanship or whatnot. Instead we should start integrating concepts and movements. Think “both/and”. Think Agility plus Software Craftsmanship plus Lean plus whatnot. We don´t neet to tear down anything from a piedestal and replace it with a new idol. Instead we should do away with piedestals and arrange whatever is helpful is a circle. Then we can turn to concepts, movements for whatever they are best. After 10 years of Agility we should be able to identify what it was good at – and keep that. Keep Agility around and add whatever Agility was lacking or never concerned with. Add whatever is at the core of Software Craftsmanship. Add whatever is at the core of Lean etc. But don´t call out the age of Post-Agility. Because it better never will end. Because once we start to lose Agility´s core we´re losing focus of the customer.

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  • Finally, upgrade from Nokia X3 to Samsung Galaxy S III

    This time, something slightly different but nonetheless not less interesting, hopefully. Living on a remote island like Mauritius, ill-praised 'Cyber Island' in the Indian Ocean, has its advantages in life style and relaxed environment to life in but in terms of technological aspects it can be quite a nightmare. Well, I guess this might be different story to report about... one day. Cyber Island Mauritius Despite it's shiny advertisement as Cyber Island and business in ICT hub to Africa, Mauritius is not on the latest track of available models in computer hardware or, in the context of this article, cellulars or smart-phone, or communication technology in general. Okay, I have to admit that this statement is only partly true. Money can buy, even here in Mauritius. Luckily, there are ways and ways to deal with this outcry of modern, read: technological, civilisation issues. Online shopping you might think? Yes, for sure, until you discover in your checkout procedure that a small island in the Indian Ocean isn't a preferred destination for delivery and the precious time you spent on putting your items into your cart and feeding your personal level of anticipation gets ruined on the last stint. Ordering from abroad saves you money Anyway, I got in touch with my personal courier and luckily there were some extra-kilos left in the luggage. First obstacle sorted, we have a Transporter! Okay, on the next occasion off to Amazon online and using their Prime service for fast delivery. Actually, the order was placed on Saturday evening and everything got delivered on Tuesday morning - nice job in less than 72 hours. Okay, among the items of that shopping rush I ordered a shiny Samsung Galaxy S III 16GB in oceanic blue - did I mention, that you hardly get a blue model in Mauritius? - for my BWE. Interesting side-notes: First, Amazon Germany dropped the prices for roughly 30% on the S3, and we got the 16GB model for less than 500 Euro (or approx. Rs. 19.500,-) compared to the usual Rs. 27.000,- on the local market. It even varies whether the local price is inclusive or exclusive VAT (15%). Second, since a while she was bothering me to get an iPhone and an iPad for her, fair enough I thought, decent hardware, posh design and reliable services. Until we watched the 'magical' introduction of Samsung's new models at the IFA exhibition, she read the bashing comments on Google+ on the iPhone 5 and I gave her a brief summary on the law suit between Apple and Samsung in the USA. So, yes, Samsung USA is right, the next big thing is already here - literally. My BWE loves the look and touch of the Galaxy S3. And for me it was more cost-effective in terms of purchases done at the App Store, ups, Play Store. Transfer of contacts, text messages and media files Okay, now that the hardware is in place, how to transfer all those contacts, text messages, media files, etc. between those two devices? In the past, I used to use the Nokia Communication Suite between various models but now for Android? Well, as usual Google and Bing are reliable friends and among the first hits I came across an article about How to Transfer Contacts from Nokia to Android. Couldn't be easier, right? Well, sort of... my main Windows systems are already running on Windows 8, and this actually caused problems with the mobile/smart-phone device drivers. The article provides the download for an older version 1.10 which upgrades to 2.11 (as time of writing this entry) but both couldn't get the Galaxy S3 and the Nokia connected. Shame on me... the product page clearly doesn't mention Windows 8 (for now) and Windows 8 isn't available for the general audience at all... After I took a spare machine running on Windows Vista everything went smooth. Software installed, upgrade done, device drivers for Android automatically downloaded and installed, and the same painless routine for the Nokia part. I think, I rebooted the system twice during the whole setup procedure but hey, it was more or less a distraction while coding some stuff in ASP.NET MVC and Telerik Kendo UI. The transfer of contacts and text messages was done via Wondershare MobileGo for Android, and all media files by moving the additional microSD card from one device to the other. But even without an external SD card, it would have been very easy to copy the files via Windows Explorer directly. Little catch and excellent service Fine, we are almost done and the only step left is to shift the SIM card... Ouch, gotcha! The X3 uses a standard size SIM card while the S III only accepts microSIM form factor. What an irony, bigger smartphone needs smaller SIM card. Luckily, the next showroom of Emtel is just 5 mins away up the road, and the service staff over there know their job. Finally, after roughly 10 mins of paper work, activation and small chit-chat, the S3 came to life on the mobile network. Owning a smart-phone now and knowing that my BWE would like to interact more on social networks away from home, especially to upload pictures and provide local 'check-ins', I activated a data package for her in advance, too. Even that it is Saturday, everything was already done and ready to be used. Nice bonus: The Emtel clerk directly offered me to set up the configuration for the Emtel data services, yes sure, go ahead, this saves me to search for that in the settings. Okay, spoiler-alert here, setting a static APN to access the Emtel network and the internet wouldn't be a challenge. But hey, she already had the phone in her hands and I could keep my eyes on the children. Well done, Emtel! Resume Thanks to the useful software package by Wondershare is was a hands-free experience to transfer all the data from a Nokia mobile on Symbian S60 to a Samsung Galaxy S III on Android Ice Cream Sandwich (ICS). In the future, this wont be a serious issue at all anymore thanks to synchronisation services and cloud storage. And for now, I'm only waiting for the official upgrades for Jelly Bean.

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  • Source-control 'wet-work'?

    - by Phil Factor
    When a design or creative work is flawed beyond remedy, it is often best to destroy it and start again. The other day, I lost the code to a long and intricate SQL batch I was working on. I’d thought it was impossible, but it happened. With all the technology around that is designed to prevent this occurring, this sort of accident has become a rare event.  If it weren’t for a deranged laptop, and my distraction, the code wouldn’t have been lost this time.  As always, I sighed, had a soothing cup of tea, and typed it all in again.  The new code I hastily tapped in  was much better: I’d held in my head the essence of how the code should work rather than the details: I now knew for certain  the start point, the end, and how it should be achieved. Instantly the detritus of half-baked thoughts fell away and I was able to write logical code that performed better.  Because I could work so quickly, I was able to hold the details of all the columns and variables in my head, and the dynamics of the flow of data. It was, in fact, easier and quicker to start from scratch rather than tidy up and refactor the existing code with its inevitable fumbling and half-baked ideas. What a shame that technology is now so good that developers rarely experience the cleansing shock of losing one’s code and having to rewrite it from scratch.  If you’ve never accidentally lost  your code, then it is worth doing it deliberately once for the experience. Creative people have, until Technology mistakenly prevented it, torn up their drafts or sketches, threw them in the bin, and started again from scratch.  Leonardo’s obsessive reworking of the Mona Lisa was renowned because it was so unusual:  Most artists have been utterly ruthless in destroying work that didn’t quite make it. Authors are particularly keen on writing afresh, and the results are generally positive. Lawrence of Arabia actually lost the entire 250,000 word manuscript of ‘The Seven Pillars of Wisdom’ by accidentally leaving it on a train at Reading station, before rewriting a much better version.  Now, any writer or artist is seduced by technology into altering or refining their work rather than casting it dramatically in the bin or setting a light to it on a bonfire, and rewriting it from the blank page.  It is easy to pick away at a flawed work, but the real creative process is far more brutal. Once, many years ago whilst running a software house that supplied commercial software to local businesses, I’d been supervising an accounting system for a farming cooperative. No packaged system met their needs, and it was all hand-cut code.  For us, it represented a breakthrough as it was for a government organisation, and success would guarantee more contracts. As you’ve probably guessed, the code got mangled in a disk crash just a week before the deadline for delivery, and the many backups all proved to be entirely corrupted by a faulty tape drive.  There were some fragments left on individual machines, but they were all of different versions.  The developers were in despair.  Strangely, I managed to re-write the bulk of a three-month project in a manic and caffeine-soaked weekend.  Sure, that elegant universally-applicable input-form routine was‘nt quite so elegant, but it didn’t really need to be as we knew what forms it needed to support.  Yes, the code lacked architectural elegance and reusability. By dawn on Monday, the application passed its integration tests. The developers rose to the occasion after I’d collapsed, and tidied up what I’d done, though they were reproachful that some of the style and elegance had gone out of the application. By the delivery date, we were able to install it. It was a smaller, faster application than the beta they’d seen and the user-interface had a new, rather Spartan, appearance that we swore was done to conform to the latest in user-interface guidelines. (we switched to Helvetica font to look more ‘Bauhaus’ ). The client was so delighted that he forgave the new bugs that had crept in. I still have the disk that crashed, up in the attic. In IT, we have had mixed experiences from complete re-writes. Lotus 123 never really recovered from a complete rewrite from assembler into C, Borland made the mistake with Arago and Quattro Pro  and Netscape’s complete rewrite of their Navigator 4 browser was a white-knuckle ride. In all cases, the decision to rewrite was a result of extreme circumstances where no other course of action seemed possible.   The rewrite didn’t come out of the blue. I prefer to remember the rewrite of Minix by young Linus Torvalds, or the rewrite of Bitkeeper by a slightly older Linus.  The rewrite of CP/M didn’t do too badly either, did it? Come to think of it, the guy who decided to rewrite the windowing system of the Xerox Star never regretted the decision. I’ll agree that one should often resist calls for a rewrite. One of the worst habits of the more inexperienced programmer is to denigrate whatever code he or she inherits, and then call loudly for a complete rewrite. They are buoyed up by the mistaken belief that they can do better. This, however, is a different psychological phenomenon, more related to the idea of some motorcyclists that they are operating on infinite lives, or the occasional squaddies that if they charge the machine-guns determinedly enough all will be well. Grim experience brings out the humility in any experienced programmer.  I’m referring to quite different circumstances here. Where a team knows the requirements perfectly, are of one mind on methodology and coding standards, and they already have a solution, then what is wrong with considering  a complete rewrite? Rewrites are so painful in the early stages, until that point where one realises the payoff, that even I quail at the thought. One needs a natural disaster to push one over the edge. The trouble is that source-control systems, and disaster recovery systems, are just too good nowadays.   If I were to lose this draft of this very blog post, I know I’d rewrite it much better. However, if you read this, you’ll know I didn’t have the nerve to delete it and start again.  There was a time that one prayed that unreliable hardware would deliver you from an unmaintainable mess of a codebase, but now technology has made us almost entirely immune to such a merciful act of God. An old friend of mine with long experience in the software industry has long had the idea of the ‘source-control wet-work’,  where one hires a malicious hacker in some wild eastern country to hack into one’s own  source control system to destroy all trace of the source to an application. Alas, backup systems are just too good to make this any more than a pipedream. Somehow, it would be difficult to promote the idea. As an alternative, could one construct a source control system that, on doing all the code-quality metrics, would systematically destroy all trace of source code that failed the quality test? Alas, I can’t see many managers buying into the idea. In reading the full story of the near-loss of Toy Story 2, it set me thinking. It turned out that the lucky restoration of the code wasn’t the happy ending one first imagined it to be, because they eventually came to the conclusion that the plot was fundamentally flawed and it all had to be rewritten anyway.  Was this an early  case of the ‘source-control wet-job’?’ It is very hard nowadays to do a rapid U-turn in a development project because we are far too prone to cling to our existing source-code.

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  • How I Work: Staying Productive Whilst Traveling

    - by BuckWoody
    I travel a lot. Not like some folks that are gone every week, mind you, although in the last month I’ve been to: Cambridge, UK; Anchorage, AK; San Jose, CA; Copenhagen, DK, Boston, MA; and I’m currently en-route to Anaheim, CA.  While this many places in a month is a bit unusual for me, I would say I travel frequently. I’ve travelled most of my 28+ years in IT, and at one time was a consultant traveling weekly.   With that much time away from my primary work location, I have to find ways to stay productive. Some might say “just rest – take a nap!” – but I’m not able to do that. For one thing, I’m a very light sleeper and I’ve never slept on a plane - even a 30+ hour trip to New Zealand in Business Class - so that just isn’t option. I also am not always in the plane, of course. There’s the hotel, the taxi/bus/train, the airport and then all that over again when I arrive. Since my regular jobs have many demands, I have to get work done.   Note: No, I’m not always focused on work. I need downtime just like everyone else. Sometimes I just think, watch a movie or listen to tunes – and I give myself permission to do that anytime – sometimes the whole trip. I have too fewheartbeats left in life to only focus on work – it’s just not that important, and neither am I. Some of these tasks are letters to friends and family, or other personal things. What I’m talking about here is a plan, not some task list I have to follow. When I get to the location I’m traveling to, I always build in as much time as I can to ensure I enjoy those sights and the people I’m with. I would find traveling to be a waste if not for that.   The Unrealistic Expectation As I would evaluate the trip I was taking – say a 6-8 hour flight – I would expect to get 10-12 hours of work done. After all, there’s the time at the airport, the taxi and so on, and then of course the time in the air with all of the room, power, internet and everything else I needed to get my work done. I would pile up tasks at home, pack my bags, and head happily to the magical land of the TSA.   Right. On return from the trip, I had accomplished little, had more e-mails and other work that had piled up, and I was tired, hungry, and unorganized. This had to change. So, I decided to do three things: Segment my work Set realistic expectations Plan accordingly  Segmenting By Available Resources The first task was to decide what kind of work I could do in each location – if any. I found that I was dependent on a few things to get work done, such as power, the Internet, and a place to sit down. Before I fly, I take some time at home to get all of the work I’d like to accomplish while away segmented into these areas, and print that out on paper, which goes in my suit-coat pocket along with a mechanical pencil. I print my tickets, and I’m all set for the adventure ahead. Then I simply do each kind of work whenever I’m in that situation. No power There are certain times when I don’t have power available. But not only that, I might not even be able to use most of my electronics. So I now schedule as many phone calls as I can for the taxi/bus/train ride and the airports as I can. I have a paper notebook (Moleskine, of course) and a pencil and I print out any notes or numbers I need prior to the trip. Once I’m airborne or at the airport, I work on my laptop. I check and respond to e-mails, create slides, write code, do architecture, whatever I can.  If I can’t use any electronics, or once the power runs out, I schedule time for reading. I can read at the airport or anywhere, actually, even in-flight or any other transport. I “read with a pencil”, meaning I take a lot of notes, which I liketo put in OneNote, but since in most cases I don’t have power, I use the Moleskine to do that. Speaking of which, sometimes as I’m thinking I come up with new topics, ideas, blog posts, or things to teach in my classes. Once again I take out the notebook and write it down. All of these notes get a check-mark when I get back to the office and transfer the writing to OneNote. I’ve tried those “smart pens” and so on to automate this, but it just never works out. Pencil and paper are just fine. As I mentioned, sometime I just need to think. I’ll do nothing, and let my mind wander, thinking of nothing in particular, or some math problem or science question I’m interested in. My only issue with this is that I communicate tothink, and I don’t want to drive people crazy by being that guy that won’t shut up, so I think in a different way. Power, but no Internet or Phone If I have power but no Internet or phone, I focus on the laptop and the tablet as before, and I also recharge my other gadgets. Power, Internet, Phone and a Place to Work At first I thought that when I arrived at the hotel or event I could get the same amount of work done that I do at the office. Not so. There’s simply too many distractions, things you need, or other issues that allow this. Of course, Ican work on any device, read, think, write or whatever, but I am simply not as productive as I am in my home office. So I plan for about 25-50% as much work getting done in this environment as I think I could really do. I’ve done some measurements, and this holds out to be true almost every time. The key is that I re-set my expectations (and my co-worker’s expectations as well) that this is the case. I use the Out-Of-Office notices to let people know that I’m just not going to be 100% at this time – it’s hard for everyone, but it’s more honest and realistic, and I’d rather they know that – and that I realize that – than to let them think I’m totally available. Because I’m not – I’m traveling. I don’t tend to put too much detail, because after all I don’t necessarily want to let people know when I’m not home :) but I do think it’s important to let people that depend on my know that I’ll get back with them later. I hope this helps you think through your own methodology of staying productive when you travel. Or perhaps you just go offline, and don’t worry about any of this – good for you! That’s completely valid as well.   (Oh, and yes, I wrote this at 35K feet, on Alaska Airlines on a trip. :)  Practice what you preach, Buck.)

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  • I Clobbered a Leopard with a Window Last Night

    - by D'Arcy Lussier
    I’ve had my 15” Mac Book Pro for a little over a year now, and its hands-down the best laptop I’ve ever owned…hardware wise. And I tried, I really really tried, to like OSX. I even bought Parallels so I could run Windows 7 and all my development tools while still trying to live in an OSX world. But in the end, I missed Windows too much. There were just too many shortcomings with OSX that kept me from being productive. For one thing, Office for Mac is *not* Office for Windows. The applications are written by different teams, and Excel on the Mac is just different enough to be painful. The VM experience was adequate, but my MBP would heat up like crazy when running it and the experience trying to get Windows apps to interact with an OSX file system was awkward. And I found I was in the VM more than I thought I’d be. iMovie is not as easy to use for doing simple movie editing as Windows Movie Maker. There’s no free blog editing software for OSX that’s on par with Windows Live Writer. And really, all I was using OSX for was Twitter (which I can use a Windows client for) and web browsing (also something Windows can provide obviously). So I had to ask myself – why am I forcing myself to use an operating system I don’t like, on a laptop that can support Windows 7? And so I paved my MBP and am happily running Windows 7 on it…and its fantastic! All the good stuff with the hardware is still there with the goodness of Win 7. Happy happy. I did run into some snags doing this though, and that’s really what this blog post is about – things to be aware of if you want to install Win 7 directly on your MBP metal. First, Ensure You Have Your Original Mac Install Disk This was a warning my buddy Dylan, who’s been running Win 7 on his MBP for a while now, gave me early on. The reason you need that original disk is that the hardware drivers you need are all located there. Apparently you can’t easily download them, so make sure you have them ahead of time. Second, Forget BootCamp The only reason you need BootCamp is if you still want the option to boot into OSX. If you don’t, then you don’t need BootCamp. In fact, you don’t even need BootCamp to install Win 7. What you *will* need though is a DVD with Win 7 burnt on it. Apple doesn’t support bootable USB drives. Well, actually they do for Mac Book Airs which don’t come with optical drives…but to get it working you’ll need to edit a system file of BootCamp so your make of MBP is included in an XML document, and even then you *still* are using BootCamp meaning you’ll be making an OSX partition. So don’t worry about BootCamp, just burn a Windows 7 disc, put it into the DVD drive, and restart your MBP. Third, Know The Secret Commands So after putting in the Windows 7 DVD and restarting your MBP, you’ll want to hold down the ‘C’ key during boot up. This tells the MBP that it should boot from the DVD drive instead of the hard drive. Interestingly, it appears you don’t have to do this if its the Mac OSX install disc (more on that in a second), but regardless – hold down C and Windows will start the install process. Next up is the partition process. You’ll notice that there’s a partition called ETI or something like that. This has to do with the drive format that Apple uses and how they partition their system drives. What I did – I blew it away! At first I didn’t, but I was told I couldn’t install Windows on the remaining space due to the different drive format. Blowing away the ETI partition (and all other partitions) allowed me to continue the Windows install. *REMEMBER –  No warranty is provided or implied, just telling you what I did and how I got it to work. Ok, so now Windows is installed and I’m rebooting. Everything looks good, but I need drivers! So I put in the OSX install DVD and run the BootCamp assistant which installs all the Windows drivers I need. Fantastic! Oh, I need to restart – no problem. OH NO, PROBLEM! I left the OSX install DVD in the drive and now the MBP wants to boot from the drive and install OSX! I’m not holding down the C key, what the heck?! Ok, well there must be a way to eject this disk…hmm…no physical button on the side…the eject button doesn’t seem to work on the keyboard…no little pin hole to insert something to force the disc out…well what the…?! It turns out, if you want to eject a disc at boot up, you need (and I kid you not) to plug a mouse into the laptop and hold down the right-click button while its booting. This ejected the disc for me. Seriously. Finally, Things You Should Be Aware Of Once you have Windows up and running there’s a few things you need to be aware of, mainly new keyboard shortcuts. For instance, on the Mac keyboard there is no Home, End, PageUp or PageDown. There’s also no obvious way to do something like select large amounts of text (like you would by holding Shift-Home at the end of a line of text for instance). So here’s some shortcuts you need to know: Home – fn + left arrow End – fn + right arrow Select a line of text as you would with the Home key – Shift + fn + left arrow Select a line of text as you would with the End key – Shift + fn + right arrow Page Up – fn + up arrow Page Down – fn + down arrow Also, you’ll notice that the awesome Mac track pad doesn’t respond to taps as clicks. No fear, this is just a setting that needs to be altered in the BootCamp control panel (that controls the Mac Hardware-specific settings within Windows, you can access it easily from the system tray icon) One other thing, battery life seems a bit lower than with OSX, but then again I’m also doing more than Twitter or web browsing on this thing now. Conclusion My laptop runs awesome now that I have Windows 7 on there. It’s obviously up to individual taste, but for me I just didn’t see benefits to living in an OSX world when everything I needed lived in Windows. And also, I finally am back to an operating system that doesn’t require me to eject a USB drive before physically removing it! It’s 2012 folks, how has this not been fixed?! D

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  • Making Those PanelBoxes Behave

    - by Duncan Mills
    I have a little problem to solve earlier this week - misbehaving <af:panelBox> components... What do I mean by that? Well here's the scenario, I have a page fragment containing a set of panelBoxes arranged vertically. As it happens, they are stamped out in a loop but that does not really matter. What I want to be able to do is to provide the user with a simple UI to close and open all of the panelBoxes in concert. This could also apply to showDetailHeader and similar items with a disclosed attrubute, but in this case it's good old panelBoxes.  Ok, so the basic solution to this should be self evident. I can set up a suitable scoped managed bean that the panelBoxes all refer to for their disclosed attribute state. Then the open all / close commandButtons in the UI can simply set the state of that bean for all the panelBoxes to pick up via EL on their disclosed attribute. Sound OK? Well that works basically without a hitch, but turns out that there is a slight problem and this is where the framework is attempting to be a little too helpful. The issue is that is the user manually discloses or hides a panelBox then that will override the value that the EL is setting. So for example. I start the page with all panelBoxes collapsed, all set by the EL state I'm storing on the session I manually disclose panelBox no 1. I press the Expand All button - all works as you would hope and all the panelBoxes are now disclosed, including of course panelBox 1 which I just expanded manually. Finally I press the Collapse All button and everything collapses except that first panelBox that I manually disclosed.  The problem is that the component remembers this manual disclosure and that overrides the value provided by the expression. If I change the viewId (navigate away and back) then the panelBox will start to behave again, until of course I touch it again! Now, the more astute amoungst you would think (as I did) Ah, sound like the MDS personalizaton stuff is getting in the way and the solution should simply be to set the dontPersist attribute to disclosed | ALL. Alas this does not fix the issue.  After a little noodling on the best way to approach this I came up with a solution that works well, although if you think of an alternative way do let me know. The principle is simple. In the disclosureListener for the panelBox I take a note of the clientID of the panelBox component that has been touched by the user along with the state. This all gets stored in a Map of Booleans in ViewScope which is keyed by clientID and stores the current disclosed state in the Boolean value.  The listener looks like this (it's held in a request scope backing bean for the page): public void handlePBDisclosureEvent(DisclosureEvent disclosureEvent) { String clientId = disclosureEvent.getComponent().getClientId(FacesContext.getCurrentInstance()); boolean state = disclosureEvent.isExpanded(); pbState.addTouchedPanelBox(clientId, state); } The pbState variable referenced here is a reference to the bean which will hold the state of the panelBoxes that lives in viewScope (recall that everything is re-set when the viewid is changed so keeping this in viewScope is just fine and cleans things up automatically). The addTouchedPanelBox() method looks like this: public void addTouchedPanelBox(String clientId, boolean state) { //create the cache if needed this is just a Map<String,Boolean> if (_touchedPanelBoxState == null) { _touchedPanelBoxState = new HashMap<String, Boolean>(); } // Simply put / replace _touchedPanelBoxState.put(clientId, state); } So that's the first part, we now have a record of every panelBox that the user has touched. So what do we do when the Collapse All or Expand All buttons are pressed? Here we do some JavaScript magic. Basically for each clientID that we have stored away, we issue a client side disclosure event from JavaScript - just as if the user had gone back and changed it manually. So here's the Collapse All button action: public String CloseAllAction() { submitDiscloseOverride(pbState.getTouchedClientIds(true), false); _uiManager.closeAllBoxes(); return null; }  The _uiManager.closeAllBoxes() method is just manipulating the master-state that all of the panelBoxes are bound to using EL. The interesting bit though is the line:  submitDiscloseOverride(pbState.getTouchedClientIds(true), false); To break that down, the first part is a call to that viewScoped state holder to ask for a list of clientIDs that need to be "tweaked": public String getTouchedClientIds(boolean targetState) { StringBuilder sb = new StringBuilder(); if (_touchedPanelBoxState != null && _touchedPanelBoxState.size() > 0) { for (Map.Entry<String, Boolean> entry : _touchedPanelBoxState.entrySet()) { if (entry.getValue() == targetState) { if (sb.length() > 0) { sb.append(','); } sb.append(entry.getKey()); } } } return sb.toString(); } You'll notice that this method only processes those panelBoxes that will be in the wrong state and returns those as a comma separated list. This is then processed by the submitDiscloseOverride() method: private void submitDiscloseOverride(String clientIdList, boolean targetDisclosureState) { if (clientIdList != null && clientIdList.length() > 0) { FacesContext fctx = FacesContext.getCurrentInstance(); StringBuilder script = new StringBuilder(); script.append("overrideDiscloseHandler('"); script.append(clientIdList); script.append("',"); script.append(targetDisclosureState); script.append(");"); Service.getRenderKitService(fctx, ExtendedRenderKitService.class).addScript(fctx, script.toString()); } } This method constructs a JavaScript command to call a routine called overrideDiscloseHandler() in a script attached to the page (using the standard <af:resource> tag). That method parses out the list of clientIDs and sends the correct message to each one: function overrideDiscloseHandler(clientIdList, newState) { AdfLogger.LOGGER.logMessage(AdfLogger.INFO, "Disclosure Hander newState " + newState + " Called with: " + clientIdList); //Parse out the list of clientIds var clientIdArray = clientIdList.split(','); for (var i = 0; i < clientIdArray.length; i++){ var panelBox = flipPanel = AdfPage.PAGE.findComponentByAbsoluteId(clientIdArray[i]); if (panelBox.getComponentType() == "oracle.adf.RichPanelBox"){ panelBox.broadcast(new AdfDisclosureEvent(panelBox, newState)); } }  }  So there you go. You can see how, with a few tweaks the same code could be used for other components with disclosure that might suffer from the same problem, although I'd point out that the behavior I'm working around here us usually desirable. You can download the running example (11.1.2.2) from here. 

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  • SSH: Connection Reset by Peer

    - by hopeless
    I have a Solaris 10 server on another network. I can ping it and telnet to it, but ssh doesn't connect. PuTTY log contains nothing of interest (they both negotiate to ssh v2) and then I get "Event Log: Network error: Software caused connection abort". ssh is defintely running: svcs -a | grep ssh online 12:12:04 svc:/network/ssh:default Here's an extract from the server's /var/adm/messages (anonymised) Jun 8 19:51:05 ******* sshd[26391]: [ID 800047 auth.crit] fatal: Read from socket failed: Connection reset by peer However, if I telnet to the box, I can login to ssh locally. I can also ssh to other (non-Solaris) machines on that network fine so I don't believe that it's a network issue (though, since I'm a few hundred miles away, I can't be sure). The server's firewall is disabled, so that shouldn't be a problem root@******** # svcs -a | grep -i ipf disabled Apr_27 svc:/network/ipfilter:default Any ideas what I should start checking? Update: Based on the feedback below, I've run sshd in debug mode. Here's the client output: $ ssh -vvv root@machine -p 32222 OpenSSH_5.0p1, OpenSSL 0.9.8h 28 May 2008 debug2: ssh_connect: needpriv 0 debug1: Connecting to machine [X.X.X.X] port 32222. debug1: Connection established. debug1: identity file /home/lawrencj/.ssh/identity type -1 debug1: identity file /home/lawrencj/.ssh/id_rsa type -1 debug1: identity file /home/lawrencj/.ssh/id_dsa type -1 debug1: Remote protocol version 2.0, remote software version Sun_SSH_1.1 debug1: no match: Sun_SSH_1.1 debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_5.0 debug2: fd 3 setting O_NONBLOCK debug1: SSH2_MSG_KEXINIT sent Read from socket failed: Connection reset by peer And here's the server output: root@machine # /usr/lib/ssh/sshd -d -p 32222 debug1: sshd version Sun_SSH_1.1 debug1: read PEM private key done: type RSA debug1: private host key: #0 type 1 RSA debug1: read PEM private key done: type DSA debug1: private host key: #1 type 2 DSA debug1: Bind to port 32222 on ::. Server listening on :: port 32222. debug1: Bind to port 32222 on 0.0.0.0. Server listening on 0.0.0.0 port 32222. debug1: Server will not fork when running in debugging mode. Connection from 1.2.3.4 port 2652 debug1: Client protocol version 2.0; client software version OpenSSH_5.0 debug1: match: OpenSSH_5.0 pat OpenSSH* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-Sun_SSH_1.1 debug1: list_hostkey_types: ssh-rsa,ssh-dss debug1: Failed to acquire GSS-API credentials for any mechanisms (No credentials were supplied, or the credentials were unavailable or inaccessible Unknown code 0 ) debug1: SSH2_MSG_KEXINIT sent Read from socket failed: Connection reset by peer debug1: Calling cleanup 0x4584c(0x0) This line seems a likely candidate: debug1: Failed to acquire GSS-API credentials for any mechanisms (No credentials were supplied, or the credentials were unavailable or inaccessible

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  • Is real-time or synchronous replication possible over WAN link?

    - by johnnyb10
    The company I work for is looking to implement truly real-time file replication with file locking over a WAN link that spans over 2000 miles. We currently have a 16-drive SAN setup in our east coast office. We also have an office out in Colorado that will have the same exact SAN setup. The idea is to have those two SANs contain the same exact data at all times, which will allow us to work with the same data pool, and which will also provide use with an offsite backup solution, should a failure occur on either end. We're running Server 2008. The objective is to enable users in the east coast office to work on files and have those changes be instantly updated on the Colorado SAN as well. We also need there to be file locking so that there will be no conflicts or overwritten changes if users attempt to work on the same file. Is this scenario even possible, at speeds that would make the files usable? And if so, what software would we need to pull this off? As I understand it, DFS-R does not provide file locking, so if we used that, we would need to go with a third-party product like Peerlock. But I don't even know if DFS-R is an option. Can it replicate quickly enough over a WAN link? Can any product? It seems that if we were to use synchronous replication, the programs would be unacceptably slow, as every write would have to wait for confirmation from the other end of the link. But if we used asynchronous replication, what kind of latency would we be looking at? There is a product from GlobalScape called WAFS that claims to provide "File coherence with real-time file locking, file release, and synchronization" and says that "As files are modified, changes are mirrored instantly using intelligent byte-level differencing to minimize the impact on network bandwidth". So this sounds like synchronous replication, but that doesn't even seem possible, given physical limitations such as the speed of light. If anyone has any experience with this kind of setup, or knows whether it's even possible, I'd appreciate your input and suggestions, including recommendations for software that we should check out.

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  • mac + parallels and https site test = router restarts

    - by Erik
    Ok I have an interesting & very frustrating problem happening. I'm going to explain it the best I can. I work as a graphic designer & web designer on a mac and have a Comcast internet connection that comes through a Comcast branded router (SMC8014) which then ties into an Airport Extreme Base Station which runs my office network. I run OS 10.5.7 and also run Parallels 4.0.3 (running Windows XP) for testing websites in Internet Explorer and so on. Ok, so that the basic background. Here's my issue. I've been collaborating an ecommerce website with another designer/developer and when testing the site on the PC side we have started to run into some sort of network problem. The site is https if that matters at all I suspect it may. Basically when I run parallels for testing I am constantly having to restart the router in order to connect to the test site (it's hosted). Funny thing is I can access the rest of the internet fine, just not this site I'm working on until I restart the router (It's sorta like the site is timing out). This never happens when just running the Mac side of things. It only becomes an issue when Parallels is open and I am doing page refreshes while making css or HTML edits via something like Coda or CSS edit (connected to the hosting server via ftp). The real problem is that once the problem starts I only get about 2 or 3 page loads before I have to restart the router again. It's absolutely crippling. I cannot get any work done when I have to restart the router every couple of minutes. So, if you think this problem is isolated to me, the answer is no. The designer/developer I'm collaborating with has an office a couple miles away and experiences very similar problems under slightly different setup. He also has Comcast as his internet provider and connects his router to an Airport and primarily works on a mac. The main difference is that rather than using a visualizer like parallels to test the website on the PC he uses a real live PC that is on his network. Once he fire up the PC to do testing he runs into the same issue described above. After a couple of page refreshes in Internet Explorer or other browser on the PC the site becomes unresponsive and the router has to get restarted. Any thoughts on what is going on here would be greatly appreciated. Thanks in advance.

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  • ubuntu: sem_timedwait not waking (C)

    - by gillez
    I have 3 processes which need to be synchronized. Process one does something then wakes process two and sleeps, which does something then wakes process three and sleeps, which does something and wakes process one and sleeps. The whole loop is timed to run around 25hz (caused by an external sync into process one before it triggers process two in my "real" application). I use sem_post to trigger (wake) each process, and sem_timedwait() to wait for the trigger. This all works successfully for several hours. However at some random time (usually after somewhere between two and four hours), one of the processes starts timing out in sem_timedwait(), even though I am sure the semaphore is being triggered with sem_post(). To prove this I even use sem_getvalue() immediately after the timeout, and the value is 1, so the timedwait should have been triggered. Please see following code: #include <stdio.h> #include <time.h> #include <string.h> #include <errno.h> #include <semaphore.h> sem_t trigger_sem1, trigger_sem2, trigger_sem3; // The main thread process. Called three times with a different num arg - 1, 2 or 3. void *thread(void *arg) { int num = (int) arg; sem_t *wait, *trigger; int val, retval; struct timespec ts; struct timeval tv; switch (num) { case 1: wait = &trigger_sem1; trigger = &trigger_sem2; break; case 2: wait = &trigger_sem2; trigger = &trigger_sem3; break; case 3: wait = &trigger_sem3; trigger = &trigger_sem1; break; } while (1) { // The first thread delays by 40ms to time the whole loop. // This is an external sync in the real app. if (num == 1) usleep(40000); // print sem value before we wait. If this is 1, sem_timedwait() will // return immediately, otherwise it will block until sem_post() is called on this sem. sem_getvalue(wait, &val); printf("sem%d wait sync sem%d. val before %d\n", num, num, val); // get current time and add half a second for timeout. gettimeofday(&tv, NULL); ts.tv_sec = tv.tv_sec; ts.tv_nsec = (tv.tv_usec + 500000); // add half a second if (ts.tv_nsec > 1000000) { ts.tv_sec++; ts.tv_nsec -= 1000000; } ts.tv_nsec *= 1000; /* convert to nanosecs */ retval = sem_timedwait(wait, &ts); if (retval == -1) { // timed out. Print value of sem now. This should be 0, otherwise sem_timedwait // would have woken before timeout (unless the sem_post happened between the // timeout and this call to sem_getvalue). sem_getvalue(wait, &val); printf("!!!!!! sem%d sem_timedwait failed: %s, val now %d\n", num, strerror(errno), val); } else printf("sem%d wakeup.\n", num); // get value of semaphore to trigger. If it's 1, don't post as it has already been // triggered and sem_timedwait on this sem *should* not block. sem_getvalue(trigger, &val); if (val <= 0) { printf("sem%d send sync sem%d. val before %d\n", num, (num == 3 ? 1 : num+1), val); sem_post(trigger); } else printf("!! sem%d not sending sync, val %d\n", num, val); } } int main(int argc, char *argv[]) { pthread_t t1, t2, t3; // create semaphores. val of sem1 is 1 to trigger straight away and start the whole ball rolling. if (sem_init(&trigger_sem1, 0, 1) == -1) perror("Error creating trigger_listman semaphore"); if (sem_init(&trigger_sem2, 0, 0) == -1) perror("Error creating trigger_comms semaphore"); if (sem_init(&trigger_sem3, 0, 0) == -1) perror("Error creating trigger_vws semaphore"); pthread_create(&t1, NULL, thread, (void *) 1); pthread_create(&t2, NULL, thread, (void *) 2); pthread_create(&t3, NULL, thread, (void *) 3); pthread_join(t1, NULL); pthread_join(t2, NULL); pthread_join(t3, NULL); } The following output is printed when the program is running correctly (at the start and for a random but long time after). The value of sem1 is always 1 before thread1 waits as it sleeps for 40ms, by which time sem3 has triggered it, so it wakes straight away. The other two threads wait until the semaphore is received from the previous thread. [...] sem1 wait sync sem1. val before 1 sem1 wakeup. sem1 send sync sem2. val before 0 sem2 wakeup. sem2 send sync sem3. val before 0 sem2 wait sync sem2. val before 0 sem3 wakeup. sem3 send sync sem1. val before 0 sem3 wait sync sem3. val before 0 sem1 wait sync sem1. val before 1 sem1 wakeup. sem1 send sync sem2. val before 0 [...] However, after a few hours, one of the threads begins to timeout. I can see from the output that the semaphore is being triggered, and when I print the value after the timeout is is 1. So sem_timedwait should have woken up well before the timeout. I would never expect the value of the semaphore to be 1 after the timeout, save for the very rare occasion (almost certainly never but it's possible) when the trigger happens after the timeout but before I call sem_getvalue. Also, once it begins to fail, every sem_timedwait() on that semaphore also fails in the same way. See the following output, which I've line-numbered: 01 sem3 wait sync sem3. val before 0 02 sem1 wakeup. 03 sem1 send sync sem2. val before 0 04 sem2 wakeup. 05 sem2 send sync sem3. val before 0 06 sem2 wait sync sem2. val before 0 07 sem1 wait sync sem1. val before 0 08 !!!!!! sem3 sem_timedwait failed: Connection timed out, val now 1 09 sem3 send sync sem1. val before 0 10 sem3 wait sync sem3. val before 1 11 sem3 wakeup. 12 !! sem3 not sending sync, val 1 13 sem3 wait sync sem3. val before 0 14 sem1 wakeup. [...] On line 1, thread 3 (which I have confusingly called sem1 in the printf) waits for sem3 to be triggered. On line 5, sem2 calls sem_post for sem3. However, line 8 shows sem3 timing out, but the value of the semaphore is 1. thread3 then triggers sem1 and waits again (10). However, because the value is already 1, it wakes straight away. It doesn't send sem1 again as this has all happened before control is given to thread1, however it then waits again (val is now 0) and sem1 wakes up. This now repeats for ever, sem3 always timing out and showing that the value is 1. So, my question is why does sem3 timeout, even though the semaphore has been triggered and the value is clearly 1? I would never expect to see line 08 in the output. If it times out (because, say thread 2 has crashed or is taking too long), the value should be 0. And why does it work fine for 3 or 4 hours first before getting into this state? This is using Ubuntu 9.4 with kernel 2.6.28. The same procedure has been working properly on Redhat and Fedora. But I'm now trying to port to ubuntu! Thanks for any advice, Giles

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  • Windows Server Backup "Reading Data; please wait..."

    - by Reafidy
    On windows Server 2008 R2 I have recently added the windows server backup (WSB) feature. Opening WSB I get the message "Reading Data; please wait...". This message fails to go away, even after leaving the server for over 12 hours. I also notice in the task manager that svchost.exe (username: networkservice) is using all available processing power. So I terminated that process and then WSB comes on-line. However after restarting the server and WSB the issue reoccurs. WSB also fails to recognize my store-in-go flash drive (2gb). What is the underlying problem here?

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  • Perforce: File tampered with after resolve - edit or revert

    - by fbrereto
    I'm doing an integration in Perforce and am being met with the following: p4 integrate -1 -d -i -t -r -b my_branchspec //Foo/file.txt#6 - integrate from //Bar/file.txt#6 p4 resolve -am /Foo/file.txt - merging //Bar/file.txt#6 /Foo/file.txt tampered with before resolve - edit or revert. It seems no matter what I do, I am unable to make this issue go away: the next forward integration will show a similar message. The file is a text file. I can confirm that the MD5 hash for both files before the integration takes place is the same. What other issues might be going on with this file that I can resolve to fix this nagging message?

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  • Meraki wireless access point disconnects clients

    - by resolver101
    We have a Meraki MR16 Cloud Managed AP and it disconnects certain clients. The clients with Intel wireless cards work without any disconnects. The Meraki reports the follow in its event log: Sep 4 09:55:47 WPA authentication Sep 4 09:55:47 802.11 association channel: 11, rssi: 64 Sep 4 09:55:38 802.11 disassociation client has left AP Sep 4 09:55:38 WPA deauthentication vap: 0, radio: 0, aid: 1633956416 An example wireless network card which the Meraki disconnects is Realtek RTL8191SE 802.11b/g/n WiFi Adapter. The realtek laptop is sat 2 meters away from the AP and has a lot of signal and the Meraki reports minimal interference. Any ideas why it disconnects non-intel wireless network cards?

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  • Illustrator CS4: SVG Export error "Transforms are Expanded"??

    - by neezer
    I get the following error when trying to save my image to SVG (via "Save Copy As"): Transforms are expanded. When I try to load the SVG in another program, all I get is a blank canvas. I ultimately want the path data to feed into RaphaelJS, but the path data that I got by clicking on the Show Code button during the SVG export also yields a blank canvas with RaphaelJS (and I've verified that RaphaelJS is loaded, and it is rendering properly). I'm convinced that this export error in Illustrator is the problem, but I can't figure out how to make it go away and export my SVG graphic properly. Can anyone help? Thanks!

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  • Installing SSL Certificate for use in IIS7, installation "works", but cert listing disappears

    - by Matt
    Windows Server 2008 R2, IIS7. We have an SSL cert from Go Daddy. It's a wildcard cert, so it will work across subdomains (e.g. *.domain.com). I followed the instructions located at http://help.godaddy.com/topic/742/article/4801 for installing the certificate. I get to the IIS step, where I: Click on "Security Certificates" feature when the server is selected in the left pane Click on "Complete Certificate Request" Navigate to the .crt file on the file system Give it a "friendly" name, click finish The cert gets listed on the main pane now of this "Server Certificates" panel. But, if I refresh the page, or navigate away and come back, it's gone. And the cert is not listed as a viable binding when trying to bind a site to https. This seems like a pretty straight forward process, but clearly I'm missing something here. Any ideas?

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  • Animating the offset of the scrollView in a UICollectionView/UITableView causes prematurely disappearing cells

    - by radutzan
    We have a UICollectionView with a custom layout very similar to UITableView (it scrolls vertically). The UICollectionView displays only 3 cells simultaneously, with one of them being the currently active cell: [ 1 ] [*2*] [ 3 ] (The active cell here is #2.) The cells are roughly 280 points high, so only the active cell is fully visible on the screen. The user doesn't directly scroll the view to navigate, instead, she swipes the active cell horizontally to advance to the next cell. We then do some fancy animations and scroll the UICollectionView so the next cell is in the "active" position, thus making it the active one, moving the old one away and bringing up the next cell in the queue: [ 2 ] [*3*] [ 4 ] The problem here is setting the UICollectionView's offset. We currently set it in a UIView animation block (self.collectionView.contentOffset = targetOffset;) along with three other animating properties, which mostly works great, but causes the first cell (the previously active one, in the latter case, #2) to vanish as soon as the animation starts running, even before the delay interval completes. This is definitely not ideal. I've thought of some solutions, but can't figure out the best one: Absurdly enlarge the UICollectionView's frame to fit five cells instead of three, thus forcing it to keep the cells in memory even if they are offscreen. I've tried this and it works, but it sounds like an awfully dirty hack. Take a snapshot of the rendered content of the vanishing cell, put it in a UIImageView, add the UIImageView as a subview of the scrollView just before the cell goes away in the exact same position of the old cell, removing it once the animation ends. Sounds less sucky than the previous option (memory-wise, at least), but still kinda hacky. I also don't know the best way to accomplish this, please point me in the right direction. Switch to UIScrollView's setContentOffset:animated:. We actually used to have this, and it fixed the disappearing cell issue, but running this in parallel with the other UIView animations apparently competes for the attention of the main thread, thus creating a terribly choppy animation on single-core devices (iPhone 3GS/4). It also doesn't allow us to change the duration or easing of the animation, so it feels out of sync with the rest. Still an option if we can find a way to make it work in harmony with the UIView block animations. Switch to UICollectionView's scrollToItemAtIndexPath:atScrollPosition:animated:. Haven't tried this, but it has a big downside: it only takes 3 possible constants (that apply to this case, at least) for the target scroll position: UICollectionViewScrollPositionTop, UICollectionViewScrollPositionCenteredVertically and UICollectionViewScrollPositionBottom. The active cell could vary its height, but it always has to be 35 points from the top of the window, and these options don't provide enough control to accomplish the design. It could also potentially be just as problematic as 3.1. Still an option because there might be a way to go around the scroll position thing that I don't know of, and it might not have the same issue with the main thread, which seems unlikely. Any help will be greatly appreciated. Please ask if you need clarification. Thanks a lot!

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  • WinSat command line closes too fast

    - by Rob Cowell
    I'm trying to do some analysis under Windows 7 as to why I can't get a Windows Experience Index (WEI) rating due to disk issues. To this end, I'm trying to run winsat from the command line with :- winsat disk -seq -read -drive c and winsat disk -ran -write -n 2 but the command window is closing too quickly to be able to read the results. I've tried opening a seperate cmd window to run it in but it still insists on launching its own window to run in, closing straight away. Any idea how I can see the output?

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  • NFS to NFS mount

    - by dude
    I have a machine that I need to bridge NFS files to. Can I mount an NFS directory on machine2 from machine1 and then mount the mounted NFS directory on machine2 on machine3 via NFS? Do you see any problems with that? I am basically bridging some subnet domains this way, in a certain fashion. My development machine is on a different and separate (unbridged) than where I would like to use the files, and I would like this machine1(dev machine) - machine2(passthrough machine) - machine3(test machine) connection. And no there is no way to move the test machine as it's a chassis :) and it's two buildings away.

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  • Virtual Disk Degraded

    - by TheD
    There is a physical DC with a Raid 1 Mirror, 2 Physical Disks, 500GB each. Dell Server Administrator is installed on the DC, and is reporting both physical disks are fine, online, in a good state etc. On a PERC S300 Raid Controller: Physical Disk 0:0 Physical Disk 0:1 However at the same time it's reporting that a virtual disk is degraded, what exactly does this mean? The virtual disk indicates it's State is in a Raid 1 Layout. Device Name: Windows Disk 0 If my understanding is correct then the Virtual Disk, when you drill down into Dell OpenManage should have both physical disks as members, as it is a mirror? Is this correct? However, when I drill down into the Virtual Disk, it only displays Physical Disk 0:0 included in Virtual Disk 1. I'm very new to server side/raid management etc. just while our server techy is away! Thanks!

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  • Changing Apple Mac environment www record

    - by chairish
    Apple server gurus? I have a Mac OSX Snow Leopard server question. How to be able to view a company's externally hosted website from inside the company? I inherited a company using Mac OSX Snow Leopard server. We moved the website away from MobileMe and into an environment that offers PHP etc. Although the site shows up correctly outside of the company, internally it looks to the MobileMe page and shows an error. I need to change the www record to reflect the change. Where do I do this on OSX Server?

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  • MS SideWinder Force Feedback Wheel under Win7 x64 - steering works but force feedback not

    - by user24752
    I just bought this second-hand ancient but professional steering wheel: Microsoft SideWinder Force Feedback Wheel. I hooked it up to my Win7 x64 machine, it recognized it without installing anything, it did show up in the "Devices and Printers" section. Right-click - I could calibrate it, I could use it under Flatout2 right away. However, force feedback does not seem to work. The steering wheel has a force-button. If I set it using force feedback, it should lit up according to the manual (originally written for Win98). However, instead of lighting up, it blinks. The manual does not associate anything to blinking. I never used any game controllers before on any Windows. Is there a way to check/calibrate force feedback?

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  • Illustrator CS4: SVG Export error "Transforms are Expanded"?

    - by neezer
    I get the following error when trying to save my image to SVG (via "Save Copy As"): Transforms are expanded. When I try to load the SVG in another program, all I get is a blank canvas. I ultimately want the path data to feed into RaphaelJS, but the path data that I got by clicking on the Show Code button during the SVG export also yields a blank canvas with RaphaelJS (and I've verified that RaphaelJS is loaded, and it is rendering properly). I'm convinced that this export error in Illustrator is the problem, but I can't figure out how to make it go away and export my SVG graphic properly. Can anyone help? Thanks!

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  • How to get rid of Thunderbird error "[NONEXISTENT] Unknown Mailbox: Trash"

    - by endolith
    Every time I start Thunderbird, I get this error: The current operation on 'Trash' did not succeed. The mail server for account [email protected] responded: [NONEXISTENT] Unknown Mailbox: Trash (now in authenticated state) (Failure). I've figured out that it goes away if I create folders in my Gmail accounts called "[Imap]/Trash" and "[Imap]/Sent", but why are these necessary? Even if I tell Thunderbird to unsubscribe from them, it still notices when I remove the labels and starts popping up this error again. One account also complains if I remove the "Sent Items" label.

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