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• problems mounting an external IDE drive via USB in ubuntu

  - by Roy Rico

  I am having a problem connecting a specific IDE drive to my linux box. It's an old drive which I just want to get about 3 GB of files off of. INFO I am trying to connect a 200GB IDE Maxtor Drive, internally and externally... externally: I am using an self powered USB IDE external drive enclosure which I have used to connect various drives, under ubuntu and windows, in the past. The other posts stated it coudl be a problem I think i may have formatted the /dev/sdc partition instead of /dev/sdc1 partition when i originally formatted the drive. internally: I only have one machine left that has an internal IDE interface, and it's got XP on it. I plugged this drive internally into this machine with windows XP and used the ext2/ext3 drivers to mount this drive, but some files have question marks (?) in the file names which is messing up my copy process in windows. I can't delete the files under windows. Ubuntu Linux will not install on my only remaining machine that has IDE controller. I have tried the suggestions in the questions below http://superuser.com/questions/88182/mount-an-external-drive-in-ubuntu http://superuser.com/questions/23210/ubuntu-fails-to-mount-usb-drive it looks like i can see the drive in /proc/partitions $ cat /proc/partitions major minor #blocks name 8 0 78125000 sda 8 1 74894998 sda1 8 2 1 sda2 8 5 3229033 sda5 8 16 199148544 sdb <-- could be my drive? but it's not listed under fdisk -l $ fdisk -l Disk /dev/sda: 80.0 GB, 80000000000 bytes 255 heads, 63 sectors/track, 9726 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0xd0f4738c Device Boot Start End Blocks Id System /dev/sda1 * 1 9324 74894998+ 83 Linux /dev/sda2 9325 9726 3229065 5 Extended /dev/sda5 9325 9726 3229033+ 82 Linux swap / Solaris and here is my log of /var/log/messages. with a bunch of weird output, can someone let me know what that weird output is? Mar 3 19:49:40 mala kernel: [687455.112029] usb 1-7: new high speed USB device using ehci_hcd and address 3 Mar 3 19:49:41 mala kernel: [687455.248576] usb 1-7: configuration #1 chosen from 1 choice Mar 3 19:49:41 mala kernel: [687455.267450] Initializing USB Mass Storage driver... Mar 3 19:49:41 mala kernel: [687455.269180] scsi4 : SCSI emulation for USB Mass Storage devices Mar 3 19:49:41 mala kernel: [687455.269410] usbcore: registered new interface driver usb-storage Mar 3 19:49:41 mala kernel: [687455.269416] USB Mass Storage support registered. Mar 3 19:49:46 mala kernel: [687460.270917] scsi 4:0:0:0: Direct-Access Maxtor 6 Y200P0 YAR4 PQ: 0 ANSI: 2 Mar 3 19:49:46 mala kernel: [687460.271485] sd 4:0:0:0: Attached scsi generic sg2 type 0 Mar 3 19:49:46 mala kernel: [687460.278858] sd 4:0:0:0: [sdb] 398297088 512-byte logical blocks: (203 GB/189 GiB) Mar 3 19:49:46 mala kernel: [687460.280866] sd 4:0:0:0: [sdb] Write Protect is off Mar 3 19:50:16 mala kernel: [687460.283784] sdb: Mar 3 19:50:16 mala kernel: [687491.112020] usb 1-7: reset high speed USB device using ehci_hcd and address 3 Mar 3 19:50:47 mala kernel: [687522.120030] usb 1-7: reset high speed USB device using ehci_hcd and address 3 Mar 3 19:51:18 mala kernel: [687553.112034] usb 1-7: reset high speed USB device using ehci_hcd and address 3 Mar 3 19:51:49 mala kernel: [687584.116025] usb 1-7: reset high speed USB device using ehci_hcd and address 3 Mar 3 19:52:02 mala kernel: [687596.170632] type=1505 audit(1267671122.035:31): operation="profile_replace" pid=8426 name=/usr/lib/cups/backend/cups-pdf Mar 3 19:52:02 mala kernel: [687596.171551] type=1505 audit(1267671122.035:32): operation="profile_replace" pid=8426 name=/usr/sbin/cupsd Mar 3 19:52:06 mala kernel: [687600.908056] async/0 D c08145c0 0 7655 2 0x00000000 Mar 3 19:52:06 mala kernel: [687600.908062] e5601d38 00000046 e5774000 c08145c0 e4c2a848 c08145c0 d203973a 0002713d Mar 3 19:52:06 mala kernel: [687600.908072] c08145c0 c08145c0 e4c2a848 c08145c0 00000000 0002713d c08145c0 f0a98c00 Mar 3 19:52:06 mala kernel: [687600.908079] e4c2a5b0 c20125c0 00000002 e5601d80 e5601d44 c056f3be e5601d78 e5601d4c Mar 3 19:52:06 mala kernel: [687600.908087] Call Trace: Mar 3 19:52:06 mala kernel: [687600.908099] [<c056f3be>] io_schedule+0x1e/0x30 Mar 3 19:52:06 mala kernel: [687600.908107] [<c01b2cf5>] sync_page+0x35/0x40 Mar 3 19:52:06 mala kernel: [687600.908111] [<c056f8f7>] __wait_on_bit_lock+0x47/0x90 Mar 3 19:52:06 mala kernel: [687600.908115] [<c01b2cc0>] ? sync_page+0x0/0x40 Mar 3 19:52:06 mala kernel: [687600.908121] [<c020f390>] ? blkdev_readpage+0x0/0x20 Mar 3 19:52:06 mala kernel: [687600.908125] [<c01b2ca9>] __lock_page+0x79/0x80 Mar 3 19:52:06 mala kernel: [687600.908130] [<c015c130>] ? wake_bit_function+0x0/0x50 Mar 3 19:52:06 mala kernel: [687600.908135] [<c01b459f>] read_cache_page_async+0xbf/0xd0 Mar 3 19:52:06 mala kernel: [687600.908139] [<c01b45c2>] read_cache_page+0x12/0x60 Mar 3 19:52:06 mala kernel: [687600.908144] [<c0232dca>] read_dev_sector+0x3a/0x80 Mar 3 19:52:06 mala kernel: [687600.908148] [<c0233d3e>] adfspart_check_ICS+0x1e/0x160 Mar 3 19:52:06 mala kernel: [687600.908152] [<c023339f>] ? disk_name+0xaf/0xc0 Mar 3 19:52:06 mala kernel: [687600.908157] [<c0233d20>] ? adfspart_check_ICS+0x0/0x160 Mar 3 19:52:06 mala kernel: [687600.908161] [<c02334de>] check_partition+0x10e/0x180 Mar 3 19:52:06 mala kernel: [687600.908165] [<c02335f6>] rescan_partitions+0xa6/0x330 Mar 3 19:52:06 mala kernel: [687600.908171] [<c0312472>] ? kobject_get+0x12/0x20 Mar 3 19:52:06 mala kernel: [687600.908175] [<c0312472>] ? kobject_get+0x12/0x20 Mar 3 19:52:06 mala kernel: [687600.908180] [<c039fc43>] ? get_device+0x13/0x20 Mar 3 19:52:06 mala kernel: [687600.908185] [<c03c263f>] ? sd_open+0x5f/0x1b0 Mar 3 19:52:06 mala kernel: [687600.908189] [<c020fda0>] __blkdev_get+0x140/0x310 Mar 3 19:52:06 mala kernel: [687600.908194] [<c020f0ac>] ? bdget+0xec/0x100 Mar 3 19:52:06 mala kernel: [687600.908198] [<c020ff7a>] blkdev_get+0xa/0x10 Mar 3 19:52:06 mala kernel: [687600.908202] [<c0232f30>] register_disk+0x120/0x140 Mar 3 19:52:06 mala kernel: [687600.908207] [<c0308b4d>] ? blk_register_region+0x2d/0x40 Mar 3 19:52:06 mala kernel: [687600.908211] [<c03084f0>] ? exact_match+0x0/0x10 Mar 3 19:52:06 mala kernel: [687600.908216] [<c0308cf0>] add_disk+0x80/0x140 Mar 3 19:52:06 mala kernel: [687600.908221] [<c03084f0>] ? exact_match+0x0/0x10 Mar 3 19:52:06 mala kernel: [687600.908225] [<c0308860>] ? exact_lock+0x0/0x20 Mar 3 19:52:06 mala kernel: [687600.908230] [<c03c53df>] sd_probe_async+0xff/0x1c0

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• problems mounting an external IDE drive via USB in ubuntu

  - by Roy Rico

  I am having a problem connecting a specific IDE drive to my linux box. It's an old drive which I just want to get about 3 GB of files off of. INFO I am trying to connect a 200GB IDE Maxtor Drive, internally and externally... externally: I am using an self powered USB IDE external drive enclosure which I have used to connect various drives, under ubuntu and windows, in the past. The other posts stated it coudl be a problem I think i may have formatted the /dev/sdc partition instead of /dev/sdc1 partition when i originally formatted the drive. internally: I only have one machine left that has an internal IDE interface, and it's got XP on it. I plugged this drive internally into this machine with windows XP and used the ext2/ext3 drivers to mount this drive, but some files have question marks (?) in the file names which is messing up my copy process in windows. I can't delete the files under windows. Ubuntu Linux will not install on my only remaining machine that has IDE controller. I have tried the suggestions in the questions below http://superuser.com/questions/88182/mount-an-external-drive-in-ubuntu http://superuser.com/questions/23210/ubuntu-fails-to-mount-usb-drive it looks like i can see the drive in /proc/partitions $ cat /proc/partitions major minor #blocks name 8 0 78125000 sda 8 1 74894998 sda1 8 2 1 sda2 8 5 3229033 sda5 8 16 199148544 sdb <-- could be my drive? but it's not listed under fdisk -l $ fdisk -l Disk /dev/sda: 80.0 GB, 80000000000 bytes 255 heads, 63 sectors/track, 9726 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0xd0f4738c Device Boot Start End Blocks Id System /dev/sda1 * 1 9324 74894998+ 83 Linux /dev/sda2 9325 9726 3229065 5 Extended /dev/sda5 9325 9726 3229033+ 82 Linux swap / Solaris and here is my log of /var/log/messages. with a bunch of weird output, can someone let me know what that weird output is? Mar 3 19:49:40 mala kernel: [687455.112029] usb 1-7: new high speed USB device using ehci_hcd and address 3 Mar 3 19:49:41 mala kernel: [687455.248576] usb 1-7: configuration #1 chosen from 1 choice Mar 3 19:49:41 mala kernel: [687455.267450] Initializing USB Mass Storage driver... Mar 3 19:49:41 mala kernel: [687455.269180] scsi4 : SCSI emulation for USB Mass Storage devices Mar 3 19:49:41 mala kernel: [687455.269410] usbcore: registered new interface driver usb-storage Mar 3 19:49:41 mala kernel: [687455.269416] USB Mass Storage support registered. Mar 3 19:49:46 mala kernel: [687460.270917] scsi 4:0:0:0: Direct-Access Maxtor 6 Y200P0 YAR4 PQ: 0 ANSI: 2 Mar 3 19:49:46 mala kernel: [687460.271485] sd 4:0:0:0: Attached scsi generic sg2 type 0 Mar 3 19:49:46 mala kernel: [687460.278858] sd 4:0:0:0: [sdb] 398297088 512-byte logical blocks: (203 GB/189 GiB) Mar 3 19:49:46 mala kernel: [687460.280866] sd 4:0:0:0: [sdb] Write Protect is off Mar 3 19:50:16 mala kernel: [687460.283784] sdb: Mar 3 19:50:16 mala kernel: [687491.112020] usb 1-7: reset high speed USB device using ehci_hcd and address 3 Mar 3 19:50:47 mala kernel: [687522.120030] usb 1-7: reset high speed USB device using ehci_hcd and address 3 Mar 3 19:51:18 mala kernel: [687553.112034] usb 1-7: reset high speed USB device using ehci_hcd and address 3 Mar 3 19:51:49 mala kernel: [687584.116025] usb 1-7: reset high speed USB device using ehci_hcd and address 3 Mar 3 19:52:02 mala kernel: [687596.170632] type=1505 audit(1267671122.035:31): operation="profile_replace" pid=8426 name=/usr/lib/cups/backend/cups-pdf Mar 3 19:52:02 mala kernel: [687596.171551] type=1505 audit(1267671122.035:32): operation="profile_replace" pid=8426 name=/usr/sbin/cupsd Mar 3 19:52:06 mala kernel: [687600.908056] async/0 D c08145c0 0 7655 2 0x00000000 Mar 3 19:52:06 mala kernel: [687600.908062] e5601d38 00000046 e5774000 c08145c0 e4c2a848 c08145c0 d203973a 0002713d Mar 3 19:52:06 mala kernel: [687600.908072] c08145c0 c08145c0 e4c2a848 c08145c0 00000000 0002713d c08145c0 f0a98c00 Mar 3 19:52:06 mala kernel: [687600.908079] e4c2a5b0 c20125c0 00000002 e5601d80 e5601d44 c056f3be e5601d78 e5601d4c Mar 3 19:52:06 mala kernel: [687600.908087] Call Trace: Mar 3 19:52:06 mala kernel: [687600.908099] [<c056f3be>] io_schedule+0x1e/0x30 Mar 3 19:52:06 mala kernel: [687600.908107] [<c01b2cf5>] sync_page+0x35/0x40 Mar 3 19:52:06 mala kernel: [687600.908111] [<c056f8f7>] __wait_on_bit_lock+0x47/0x90 Mar 3 19:52:06 mala kernel: [687600.908115] [<c01b2cc0>] ? sync_page+0x0/0x40 Mar 3 19:52:06 mala kernel: [687600.908121] [<c020f390>] ? blkdev_readpage+0x0/0x20 Mar 3 19:52:06 mala kernel: [687600.908125] [<c01b2ca9>] __lock_page+0x79/0x80 Mar 3 19:52:06 mala kernel: [687600.908130] [<c015c130>] ? wake_bit_function+0x0/0x50 Mar 3 19:52:06 mala kernel: [687600.908135] [<c01b459f>] read_cache_page_async+0xbf/0xd0 Mar 3 19:52:06 mala kernel: [687600.908139] [<c01b45c2>] read_cache_page+0x12/0x60 Mar 3 19:52:06 mala kernel: [687600.908144] [<c0232dca>] read_dev_sector+0x3a/0x80 Mar 3 19:52:06 mala kernel: [687600.908148] [<c0233d3e>] adfspart_check_ICS+0x1e/0x160 Mar 3 19:52:06 mala kernel: [687600.908152] [<c023339f>] ? disk_name+0xaf/0xc0 Mar 3 19:52:06 mala kernel: [687600.908157] [<c0233d20>] ? adfspart_check_ICS+0x0/0x160 Mar 3 19:52:06 mala kernel: [687600.908161] [<c02334de>] check_partition+0x10e/0x180 Mar 3 19:52:06 mala kernel: [687600.908165] [<c02335f6>] rescan_partitions+0xa6/0x330 Mar 3 19:52:06 mala kernel: [687600.908171] [<c0312472>] ? kobject_get+0x12/0x20 Mar 3 19:52:06 mala kernel: [687600.908175] [<c0312472>] ? kobject_get+0x12/0x20 Mar 3 19:52:06 mala kernel: [687600.908180] [<c039fc43>] ? get_device+0x13/0x20 Mar 3 19:52:06 mala kernel: [687600.908185] [<c03c263f>] ? sd_open+0x5f/0x1b0 Mar 3 19:52:06 mala kernel: [687600.908189] [<c020fda0>] __blkdev_get+0x140/0x310 Mar 3 19:52:06 mala kernel: [687600.908194] [<c020f0ac>] ? bdget+0xec/0x100 Mar 3 19:52:06 mala kernel: [687600.908198] [<c020ff7a>] blkdev_get+0xa/0x10 Mar 3 19:52:06 mala kernel: [687600.908202] [<c0232f30>] register_disk+0x120/0x140 Mar 3 19:52:06 mala kernel: [687600.908207] [<c0308b4d>] ? blk_register_region+0x2d/0x40 Mar 3 19:52:06 mala kernel: [687600.908211] [<c03084f0>] ? exact_match+0x0/0x10 Mar 3 19:52:06 mala kernel: [687600.908216] [<c0308cf0>] add_disk+0x80/0x140 Mar 3 19:52:06 mala kernel: [687600.908221] [<c03084f0>] ? exact_match+0x0/0x10 Mar 3 19:52:06 mala kernel: [687600.908225] [<c0308860>] ? exact_lock+0x0/0x20 Mar 3 19:52:06 mala kernel: [687600.908230] [<c03c53df>] sd_probe_async+0xff/0x1c0

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• I&rsquo;m sorry RPGs, it&rsquo;s not you, it&rsquo;s me: The birth of my game idea

  - by George Clingerman

  One of the things I’ve had to give up in order to have some development time at night is gaming. It’s something I refused to admit for years but I’ve just had to face the facts. I’m no longer a gamer. I just don’t have hours and hours of free time to pour into gaming and when I do have hours and hours of free time I want to pour them into game development. That doesn’t mean I don’t game at all! I play games pretty much every day. It just means I’ve moved more into the casual game realm. It’s all I have time for when juggling priorities in my life. That means that games like Gears of War 2 sit shrink wrapped on my shelf and although I popped Dragon Age into my Xbox 360 one time, I barely made it through the opening sequence and haven’t had time to sit down and play again. Instead I’m playing short games like Jamestown, Atom Zombie Smasher, Fortix or if I have time to jump in and play a few rounds maybe some Monday Night Combat or Team Fortress 2. These are games I can instantly get into and play for just a short period of time and then walk away. Breath of Death VII saved my life: Back in the day (way, way back in the day) I used to be a pretty big RPG fan. Not big by a lot of RPG gamers' standards (most of the RPGs RPG fans about I’ve never heard of) but I used to LOVE to play them on the NES, SNES and Genesis and considered that my genre. Final Fantasy, Shining in the Darkness, Bard’s Tale, Faxanadu, Shadowrun, Ultima, Dragon Warrior, Chrono Trigger, Phantasy Star, Shining Force and well the list could go on but those are the ones I remember off the top of my head. I loved playing RPGs and they were my games of choice. After my first son was born (this was just about 12 years ago), I tried to continue playing RPGs and purchased games like Baldur’s Gate I & II, Neverwinter Nights, Fable, then a few of the Final Fantasy’s then Kingdom Hearts. I kept buying these games and then only playing for about fifteen minutes and never getting back to them. I still loved RPGs but they just no longer fit into my life (I still haven’t accepted that since I still purchased Dragon Age II for some reason and convinced myself I’d find the time). Adding three more sons to the mix (that’s 4 total) didn’t help much to finding more RPG time (except for Breath of Death VII and other XBLIG RPG titles, thanks guys!) All work and no RPG: A few months ago as I was sitting thinking about the lack of RPGs in my life and talking to my wife about why I wish RPGs were different and easier for a dad like me to get into. She seemed like she was listening, so I started listing all the things that made them impossible for me to play. Here’s a short list I came up with. They take 15 billion hours to complete I have a few minutes at a time I can grab to play them if I want to have time to code. At that rate it would take me 9 trillion years to beat just one RPG. There’s such long spans of times between when I can play them I forget what I was even doing so I have to spend most of the playtime I have just figuring that out and then my play time is over. Repeat. I’ll never finish one and since it takes so long to get to the fun part in an RPG, I’m never having fun. RPGs aren’t fun if you don’t have hours to play them at a time. As you can see based on my science and math, RPGs aren’t fun for me any more. From there my brain started toying around with ideas of RPGs that would work for me. They would have to be a short RPG, you know one you could beat in a single play session. A dad sized play session. I started thinking, wouldn’t it be awesome if there was a fifteen minute RPG? That got me laughing and I took that as a good sign that it sounded fun and so I thought about it a little more. I immediately discarded the idea of doing a real RPG. I’m sure a short RPG like that could be done but it wasn’t the vibe that I had in my head. No this was going to be something that just had the core essence of an RPG. In reality what I’d be making would be more of an arcade style game. One with high scores and lots of crazy action on the screen. And that’s when it hit me. It would be a speed run RPG. That’s the basics of the game I’m working on.   The Elevator Pitch: It’s a 2D top down RPG themed arcade game focused on speed. It sounds like an RPG, smells like an RPG but it’s merely emulating an RPG. The game is focused on fun and mayhem in RPG form with players leveling up in seconds instead of hours and rushing to finish quests as quickly as possible because they’ve only got fifteen minutes before EVIL overtakes the world. If the player takes longer than fifteen minutes, it’s game over man. One to four player co-operative play to really see just how fast players can level up and beat the game. Gamers will compete on leaderboards for bragging rights for fastest 1, 2, 3, and 4 player speed runs, lowest leveled characters to beat the game, highest leveled characters to beat the game and so on. Times will be tracked for everything from how long a player sat distributing stats, equipping items, talking to NPCs to running around the level. These stats will be shown at the end of each quest/level so the players can work on improving their speed run for that part of the game next time around. It’s the perfect RPG for those of us who only have fifteen minutes of game time! Where I’m at: I’m still at the prototyping stage attempting to but all the basic framework pieces in place that will at minimum give me one level to rush through. I’ve been working on this prototype for about a month now though so I’m going to have to step it up a bit or I’m not going to get finished in time (remember I’ve only got 85 days left!) Lots of the game code is in place (although pretty sloppy) but I still can’t play through that first quest/level just yet. That’s my goal to finish up by the end of next Sunday (3/25/2012). You can all hold me to that and cheer me on or heckle me throughout the week. Either way that should help me stay a bit more motivated and focused. In my head this feels like it’s going to be a fun game so I’m looking forward to seeing how it actually plays!

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• Premature-Optimization and Performance Anxiety

  - by James Michael Hare

  While writing my post analyzing the new .NET 4 ConcurrentDictionary class (here), I fell into one of the classic blunders that I myself always love to warn about.  After analyzing the differences of time between a Dictionary with locking versus the new ConcurrentDictionary class, I noted that the ConcurrentDictionary was faster with read-heavy multi-threaded operations.  Then, I made the classic blunder of thinking that because the original Dictionary with locking was faster for those write-heavy uses, it was the best choice for those types of tasks.  In short, I fell into the premature-optimization anti-pattern. Basically, the premature-optimization anti-pattern is when a developer is coding very early for a perceived (whether rightly-or-wrongly) performance gain and sacrificing good design and maintainability in the process.  At best, the performance gains are usually negligible and at worst, can either negatively impact performance, or can degrade maintainability so much that time to market suffers or the code becomes very fragile due to the complexity. Keep in mind the distinction above.  I'm not talking about valid performance decisions.  There are decisions one should make when designing and writing an application that are valid performance decisions.  Examples of this are knowing the best data structures for a given situation (Dictionary versus List, for example) and choosing performance algorithms (linear search vs. binary search).  But these in my mind are macro optimizations.  The error is not in deciding to use a better data structure or algorithm, the anti-pattern as stated above is when you attempt to over-optimize early on in such a way that it sacrifices maintainability. In my case, I was actually considering trading the safety and maintainability gains of the ConcurrentDictionary (no locking required) for a slight performance gain by using the Dictionary with locking.  This would have been a mistake as I would be trading maintainability (ConcurrentDictionary requires no locking which helps readability) and safety (ConcurrentDictionary is safe for iteration even while being modified and you don't risk the developer locking incorrectly) -- and I fell for it even when I knew to watch out for it.  I think in my case, and it may be true for others as well, a large part of it was due to the time I was trained as a developer.  I began college in in the 90s when C and C++ was king and hardware speed and memory were still relatively priceless commodities and not to be squandered.  In those days, using a long instead of a short could waste precious resources, and as such, we were taught to try to minimize space and favor performance.  This is why in many cases such early code-bases were very hard to maintain.  I don't know how many times I heard back then to avoid too many function calls because of the overhead -- and in fact just last year I heard a new hire in the company where I work declare that she didn't want to refactor a long method because of function call overhead.  Now back then, that may have been a valid concern, but with today's modern hardware even if you're calling a trivial method in an extremely tight loop (which chances are the JIT compiler would optimize anyway) the results of removing method calls to speed up performance are negligible for the great majority of applications.  Now, obviously, there are those coding applications where speed is absolutely king (for example drivers, computer games, operating systems) where such sacrifices may be made.  But I would strongly advice against such optimization because of it's cost.  Many folks that are performing an optimization think it's always a win-win.  That they're simply adding speed to the application, what could possibly be wrong with that?  What they don't realize is the cost of their choice.  For every piece of straight-forward code that you obfuscate with performance enhancements, you risk the introduction of bugs in the long term technical debt of the application.  It will become so fragile over time that maintenance will become a nightmare.  I've seen such applications in places I have worked.  There are times I've seen applications where the designer was so obsessed with performance that they even designed their own memory management system for their application to try to squeeze out every ounce of performance.  Unfortunately, the application stability often suffers as a result and it is very difficult for anyone other than the original designer to maintain. I've even seen this recently where I heard a C++ developer bemoaning that in VS2010 the iterators are about twice as slow as they used to be because Microsoft added range checking (probably as part of the 0x standard implementation).  To me this was almost a joke.  Twice as slow sounds bad, but it almost never as bad as you think -- especially if you're gaining safety.  The only time twice is really that much slower is when once was too slow to begin with.  Think about it.  2 minutes is slow as a response time because 1 minute is slow.  But if an iterator takes 1 microsecond to move one position and a new, safer iterator takes 2 microseconds, this is trivial!  The only way you'd ever really notice this would be in iterating a collection just for the sake of iterating (i.e. no other operations).  To my mind, the added safety makes the extra time worth it. Always favor safety and maintainability when you can.  I know it can be a hard habit to break, especially if you started out your career early or in a language such as C where they are very performance conscious.  But in reality, these type of micro-optimizations only end up hurting you in the long run. Remember the two laws of optimization.  I'm not sure where I first heard these, but they are so true: For beginners: Do not optimize. For experts: Do not optimize yet. This is so true.  If you're a beginner, resist the urge to optimize at all costs.  And if you are an expert, delay that decision.  As long as you have chosen the right data structures and algorithms for your task, your performance will probably be more than sufficient.  Chances are it will be network, database, or disk hits that will be your slow-down, not your code.  As they say, 98% of your code's bottleneck is in 2% of your code so premature-optimization may add maintenance and safety debt that won't have any measurable impact.  Instead, code for maintainability and safety, and then, and only then, when you find a true bottleneck, then you should go back and optimize further.

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• The SPARC SuperCluster

  - by Karoly Vegh

  Oracle has been providing a lead in the Engineered Systems business for quite a while now, in accordance with the motto "Hardware and Software Engineered to Work Together." Indeed it is hard to find a better definition of these systems.  Allow me to summarize the idea. It is:  Build a compute platform optimized to run your technologies Develop application aware, intelligently caching storage components Take an impressively fast network technology interconnecting it with the compute nodes Tune the application to scale with the nodes to yet unseen performance Reduce the amount of data moving via compression Provide this all in a pre-integrated single product with a single-pane management interface All these ideas have been around in IT for quite some time now. The real Oracle advantage is adding the last one to put these all together. Oracle has built quite a portfolio of Engineered Systems, to run its technologies - and run those like they never ran before. In this post I'll focus on one of them that serves as a consolidation demigod, a multi-purpose engineered system.  As you probably have guessed, I am talking about the SPARC SuperCluster. It has many great features inherited from its predecessors, and it adds several new ones. Allow me to pick out and elaborate about some of the most interesting ones from a technological point of view.  I. It is the SPARC SuperCluster T4-4. That is, as compute nodes, it includes SPARC T4-4 servers that we learned to appreciate and respect for their features: The SPARC T4 CPUs: Each CPU has 8 cores, each core runs 8 threads. The SPARC T4-4 servers have 4 sockets. That is, a single compute node can in parallel, simultaneously  execute 256 threads. Now, a full-rack SPARC SuperCluster has 4 of these servers on board. Remember the keyword demigod.  While retaining the forerunner SPARC T3's exceptional throughput, the SPARC T4 CPUs raise the bar with single performance too - a humble 5x better one than their ancestors.  actually, the SPARC T4 CPU cores run in both single-threaded and multi-threaded mode, and switch between these two on-the-fly, fulfilling not only single-threaded OR multi-threaded applications' needs, but even mixed requirements (like in database workloads!). Data security, anyone? Every SPARC T4 CPU core has a built-in encryption engine, that is, encryption algorithms cast into silicon.  A PCI controller right on the chip for customers who need I/O performance.  Built-in, no-cost Virtualization:  Oracle VM for SPARC (the former LDoms or Logical Domains) is not a server-emulation virtualization technology but rather a serverpartitioning one, the hypervisor runs in the server firmware, and all the VMs' HW resources (I/O, CPU, memory) are accessed natively, without performance overhead.  This enables customers to run a number of Solaris 10 and Solaris 11 VMs separated, independent of each other within a physical server II. For Database performance, it includes Exadata Storage Cells - one of the main reasons why the Exadata Database Machine performs at diabolic speed. What makes them important? They provide DB backend storage for your Oracle Databases to run on the SPARC SuperCluster, that is what they are built and tuned for DB performance.  These storage cells are SQL-aware.  That is, if a SPARC T4 database compute node executes a query, it doesn't simply request tons of raw datablocks from the storage, filters the received data, and throws away most of it where the statement doesn't apply, but provides the SQL query to the storage node too. The storage cell software speaks SQL, that is, it is able to prefilter and through that transfer only the relevant data. With this, the traffic between database nodes and storage cells is reduced immensely. Less I/O is a good thing - as they say, all the CPUs of the world do one thing just as fast as any other - and that is waiting for I/O.  They don't only pre-filter, but also provide data preprocessing features - e.g. if a DB-node requests an aggregate of data, they can calculate it, and handover only the results, not the whole set. Again, less data to transfer.  They support the magical HCC, (Hybrid Columnar Compression). That is, data can be stored in a precompressed form on the storage. Less data to transfer.  Of course one can't simply rely on disks for performance, there is Flash Storage included there for caching.  III. The low latency, high-speed backbone network: InfiniBand, that interconnects all the members with: Real High Speed: 40 Gbit/s. Full Duplex, of course. Oh, and a really low latency.  RDMA. Remote Direct Memory Access. This technology allows the DB nodes to do exactly that. Remotely, directly placing SQL commands into the Memory of the storage cells. Dodging all the network-stack bottlenecks, avoiding overhead, placing requests directly into the process queue.  You can also run IP over InfiniBand if you please - that's the way the compute nodes can communicate with each other.  IV. Including a general-purpose storage too: the ZFSSA, which is a unified storage, providing NAS and SAN access too, with the following features:  NFS over RDMA over InfiniBand. Nothing is faster network-filesystem-wise.  All the ZFS features onboard, hybrid storage pools, compression, deduplication, snapshot, replication, NFS and CIFS shares Storageheads in a HA-Cluster configuration providing availability of the data  DTrace Live Analytics in a web-based Administration UI Being a general purpose application data storage for your non-database applications running on the SPARC SuperCluster over whichever protocol they prefer, easily replicating, snapshotting, cloning data for them.  There's a lot of great technology included in Oracle's SPARC SuperCluster, we have talked its interior through. As for external scalability: you can start with a half- of full- rack SPARC SuperCluster, and scale out to several racks - that is, stacking not separate full-rack SPARC SuperClusters, but extending always one large instance of the size of several full-racks. Yes, over InfiniBand network. Add racks as you grow.  What technologies shall run on it? SPARC SuperCluster is a general purpose scaleout consolidation/cloud environment. You can run Oracle Databases with RAC scaling, or Oracle Weblogic (end enjoy the SPARC T4's advantages to run Java). Remember, Oracle technologies have been integrated with the Oracle Engineered Systems - this is the Oracle on Oracle advantage. But you can run other software environments such as SAP if you please too. Run any application that runs on Oracle Solaris 10 or Solaris 11. Separate them in Virtual Machines, or even Oracle Solaris Zones, monitor and manage those from a central UI. Here the key takeaways once again: The SPARC SuperCluster: Is a pre-integrated Engineered System Contains SPARC T4-4 servers with built-in virtualization, cryptography, dynamic threading Contains the Exadata storage cells that intelligently offload the burden of the DB-nodes  Contains a highly available ZFS Storage Appliance, that provides SAN/NAS storage in a unified way Combines all these elements over a high-speed, low-latency backbone network implemented with InfiniBand Can grow from a single half-rack to several full-rack size Supports the consolidation of hundreds of applications To summarize: All these technologies are great by themselves, but the real value is like in every other Oracle Engineered System: Integration. All these technologies are tuned to perform together. Together they are way more than the sum of all - and a careful and actually very time consuming integration process is necessary to orchestrate all these for performance. The SPARC SuperCluster's goal is to enable infrastructure operations and offer a pre-integrated solution that can be architected and delivered in hours instead of months of evaluations and tests. The tedious and most importantly time and resource consuming part of the work - testing and evaluating - has been done.  Now go, provide services.   -- charlie  

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• How to configure TATA Photon+ EC1261 HUAWEI

  - by user3215

  I'm running ubuntu 10.04. I have a newly purchased TATA Photon+ Internet connection which supports Windows and Mac. On the Internet I found a article saying that it could be configured on Linux. I followed the steps to install it on Ubuntu from this link. I am still not able to get online, and need some help. Also, it is very slow, but I was told that I would see speeds up to 3.1MB. I dont have wvdial installed and cannot install it from apt as I'm not connected to internet Booting from windows I dowloaded "wvdial" .deb package and tried to install on ubuntu but it's ended with dependency problem. Automatically, don't know how, I got connected to internet only for once. Immediately I installed wvdial package after this I followed the tutorials(I could not browse and upload the files here) . From then it's showing that the device is connected in the network connections but no internet connection. Once I disable the device, it won't show as connected again and I'll have to restart my system. Sometimes the device itself not detected(wondering if there is any command to re-read the all devices). output of wvdialconf /etc/wvdial.cof: #wvdialconf /etc/wvdial.conf Editing `/etc/wvdial.conf'. Scanning your serial ports for a modem. ttyS0<*1>: ATQ0 V1 E1 -- failed with 2400 baud, next try: 9600 baud ttyS0<*1>: ATQ0 V1 E1 -- failed with 9600 baud, next try: 115200 baud ttyS0<*1>: ATQ0 V1 E1 -- and failed too at 115200, giving up. Modem Port Scan<*1>: S1 S2 S3 WvModem<*1>: Cannot get information for serial port. ttyUSB0<*1>: ATQ0 V1 E1 -- failed with 2400 baud, next try: 9600 baud ttyUSB0<*1>: ATQ0 V1 E1 -- failed with 9600 baud, next try: 9600 baud ttyUSB0<*1>: ATQ0 V1 E1 -- and failed too at 115200, giving up. WvModem<*1>: Cannot get information for serial port. ttyUSB1<*1>: ATQ0 V1 E1 -- failed with 2400 baud, next try: 9600 baud ttyUSB1<*1>: ATQ0 V1 E1 -- failed with 9600 baud, next try: 9600 baud ttyUSB1<*1>: ATQ0 V1 E1 -- and failed too at 115200, giving up. WvModem<*1>: Cannot get information for serial port. ttyUSB2<*1>: ATQ0 V1 E1 -- OK ttyUSB2<*1>: ATQ0 V1 E1 Z -- OK ttyUSB2<*1>: ATQ0 V1 E1 S0=0 -- OK ttyUSB2<*1>: ATQ0 V1 E1 S0=0 &C1 -- OK ttyUSB2<*1>: ATQ0 V1 E1 S0=0 &C1 &D2 -- OK ttyUSB2<*1>: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 -- OK ttyUSB2<*1>: Modem Identifier: ATI -- Manufacturer: +GMI: HUAWEI TECHNOLOGIES CO., LTD ttyUSB2<*1>: Speed 9600: AT -- OK ttyUSB2<*1>: Max speed is 9600; that should be safe. ttyUSB2<*1>: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 -- OK Found a modem on /dev/ttyUSB2. Modem configuration written to /etc/wvdial.conf. ttyUSB2<Info>: Speed 9600; init "ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0" output of wvdial: #wvdial --> WvDial: Internet dialer version 1.60 --> Cannot get information for serial port. --> Initializing modem. --> Sending: ATZ ATZ OK --> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0 OK --> Sending: AT+CRM=1 AT+CRM=1 OK --> Modem initialized. --> Sending: ATDT#777 --> Waiting for carrier. ATDT#777 CONNECT --> Carrier detected. Starting PPP immediately. --> Starting pppd at Sat Oct 16 15:30:47 2010 --> Pid of pppd: 5681 --> Using interface ppp0 --> pppd: (u;[08]@s;[08]`{;[08] --> pppd: (u;[08]@s;[08]`{;[08] --> pppd: (u;[08]@s;[08]`{;[08] --> pppd: (u;[08]@s;[08]`{;[08] --> pppd: (u;[08]@s;[08]`{;[08] --> pppd: (u;[08]@s;[08]`{;[08] --> local IP address 14.96.147.104 --> pppd: (u;[08]@s;[08]`{;[08] --> remote IP address 172.29.161.223 --> pppd: (u;[08]@s;[08]`{;[08] --> primary DNS address 121.40.152.90 --> pppd: (u;[08]@s;[08]`{;[08] --> secondary DNS address 121.40.152.100 --> pppd: (u;[08]@s;[08]`{;[08] Output of log message /var/log/messages: Oct 16 15:29:44 avyakta-desktop pppd[5119]: secondary DNS address 121.242.190.180 Oct 16 15:29:58 desktop pppd[5119]: Terminating on signal 15 Oct 16 15:29:58 desktop pppd[5119]: Connect time 0.3 minutes. Oct 16 15:29:58 desktop pppd[5119]: Sent 0 bytes, received 177 bytes. Oct 16 15:29:58 desktop pppd[5119]: Connection terminated. Oct 16 15:30:47 desktop pppd[5681]: pppd 2.4.5 started by root, uid 0 Oct 16 15:30:47 desktop pppd[5681]: Using interface ppp0 Oct 16 15:30:47 desktop pppd[5681]: Connect: ppp0 <--> /dev/ttyUSB2 Oct 16 15:30:47 desktop pppd[5681]: CHAP authentication succeeded Oct 16 15:30:47 desktop pppd[5681]: CHAP authentication succeeded Oct 16 15:30:48 desktop pppd[5681]: local IP address 14.96.147.104 Oct 16 15:30:48 desktop pppd[5681]: remote IP address 172.29.161.223 Oct 16 15:30:48 desktop pppd[5681]: primary DNS address 121.40.152.90 Oct 16 15:30:48 desktop pppd[5681]: secondary DNS address 121.40.152.100 EDIT 1 : I tried the following sudo stop network-manager sudo killall modem-manager sudo /usr/sbin/modem-manager --debug > ~/mm.log 2>&1 & sudo /usr/sbin/NetworkManager --no-daemon > ~/nm.log 2>&1 & Output of mm.log: #vim ~/mm.log: ** Message: Loaded plugin Option High-Speed ** Message: Loaded plugin Option ** Message: Loaded plugin Huawei ** Message: Loaded plugin Longcheer ** Message: Loaded plugin AnyData ** Message: Loaded plugin ZTE ** Message: Loaded plugin Ericsson MBM ** Message: Loaded plugin Sierra ** Message: Loaded plugin Generic ** Message: Loaded plugin Gobi ** Message: Loaded plugin Novatel ** Message: Loaded plugin Nokia ** Message: Loaded plugin MotoC Output of nm.log: #vim ~/nm.log: NetworkManager: <info> starting... NetworkManager: <info> modem-manager is now available NetworkManager: SCPlugin-Ifupdown: init! NetworkManager: SCPlugin-Ifupdown: update_system_hostname NetworkManager: SCPluginIfupdown: guessed connection type (eth0) = 802-3-ethernet NetworkManager: SCPlugin-Ifupdown: update_connection_setting_from_if_block: name:eth0, type:802-3-ethernet, id:Ifupdown (eth0), uuid: 681b428f-beaf-8932-dce4-678ed5bae28e NetworkManager: SCPlugin-Ifupdown: addresses count: 1 NetworkManager: SCPlugin-Ifupdown: No dns-nameserver configured in /etc/network/interfaces NetworkManager: nm-ifupdown-connection.c.119 - invalid connection read from /etc/network/interfaces: (1) addresses NetworkManager: SCPluginIfupdown: management mode: unmanaged NetworkManager: SCPlugin-Ifupdown: devices added (path: /sys/devices/pci0000:00/0000:00:14.4/0000:02:02.0/net/eth1, iface: eth1) NetworkManager: SCPlugin-Ifupdown: device added (path: /sys/devices/pci0000:00/0000:00:14.4/0000:02:02.0/net/eth1, iface: eth1): no ifupdown configuration found. NetworkManager: SCPlugin-Ifupdown: devices added (path: /sys/devices/virtual/net/lo, iface: lo) @

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• dialing on iphone/ipod touch not working with documented procedures

  - by dave

  I'm trying to set up an iphone app to the phone number of a various sports store using the tel:// url passing method- I am developing on an ipod touch- usually on the touch you see the error message "Unsupported URL - This URL wasn't loaded tel://99887766" when you try and dial a number. I cant get this message to appear on the simulator or the ipod touch. do I need to do some sort of fancy signing before the app will dial properly? I am using this code: [[UIApplication sharedApplication] openURL:[NSURL URLWithString:[NSString stringWithFormat:@"tel:%@", [selectedBar phoneNumber]]]]; and I've tried adding the slashes: [[UIApplication sharedApplication] openURL:[NSURL URLWithString:[NSString stringWithFormat:@"tel://%@", [selectedBar phoneNumber]]]]; but neither work. I have also tried this way: [[UIApplication application] openURL:[NSURL URLWithString:@"tel://99887766"]]; and this way: NSMutableString *phone = [[@"+ 12 34 567 89 01" mutableCopy] autorelease]; [phone replaceOccurrencesOfString:@" " withString:@"" options:NSLiteralSearch range:NSMakeRange(0, [phone length])]; [phone replaceOccurrencesOfString:@"(" withString:@"" options:NSLiteralSearch range:NSMakeRange(0, [phone length])]; [phone replaceOccurrencesOfString:@")" withString:@"" options:NSLiteralSearch range:NSMakeRange(0, [phone length])]; NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"tel:%@", phone]]; [[UIApplication sharedApplication] openURL:url]; No matter what i do i can't get any response from the simulator / ipod touch that it is dealing with a phone number- When I press the button associated with this code, it doesnt crash, it's like its processed it and decided not to do anything. i even put an NSLog(@"button called"); in just before the code to confirm the button was working, which it is.

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• Android - I can't make a widget clickable to launch an intent

  - by Daniele

  Hi all. I am new to Android development. I have developed a very simple widget that was meant to interact with the user via an ImageButton. What I am trying to do now is as follows. When a user taps the button (after adding the widget to their home screen), I want the phone to dial a certain telephone number. A sort of speed dial for your home screen. Unfortunately when I tap the button nothing happens. This is the body of my SpeedDialAppWidgetProvider.onUpdate method: Log.d("", "beginning of onUpdate"); final int N = appWidgetIds.length; for (int i=0; i<N; i++) { int appWidgetId = appWidgetIds[i]; Log.d("", "dealing with appWidgetId: " + appWidgetId); // Create an Intent to launch ExampleActivity Intent dialIntent = new Intent(Intent.ACTION_CALL, Uri.parse("tel:1234567")); PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, dialIntent, 0); Log.d("", "pendingIntent classname " + pendingIntent.getClass().getName()); // Get the layout for the App Widget and attach an on-click listener to the button RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.speed_dial_appwidget); remoteViews.setOnClickPendingIntent(R.id.dial_icon, pendingIntent); Log.d("", "remoteViews classname " + remoteViews.getClass().getName()); // Tell the AppWidgetManager to perform an update on the current App Widget appWidgetManager.updateAppWidget(appWidgetId, remoteViews); Log.d("", "end of onUpdate"); I can see the method is called and the result of the logging makes sense. The speed_dial_appwidget.xml file is like this: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" androidrientation="vertical" android:layout_width="wrap_content" android:layout_height="wrap_content" > <ImageButton id="@+id/dial_icon" android:src="@drawable/speed_dial" android:layout_width="wrap_content" android:layout_height="wrap_content"/> </LinearLayout> Can you please help me with this? Thanks in advance, Dan

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• error 734 the ppp link control protocal was terminated

  - by satheesh

  Hi, i want to connect my mobile internet to pc using bluetooth device. I installed blue soleil software in my pc. Steps: 1.I can able to pair my cellphone with pc bluetooth device. 2.I selected my device and select bluetooth dialup networking service. 3.It asks an alert "DUN connection with device?" in my mobile. 4.After Clicked "YES", connect bluetooth DUN connection window opens. 5.In that window there was a fields "User Name", "PassWord" which i leave empty and then in "Dial = 99**1#" and click Dial button. 6.After that it say "Registering your computer on the netwok.." and become fails. 7. The Error is as "error 734 the ppp link control protocal was terminated" The same procedure should be followed for Nokia 3110c it works fine.But in my samsung mobile c3053 it not connected also i am tryig with samsung corby pro BT3510 mobile . Is there any settings changes needed for samsung mobiles ? Can anyone help me ? Thanks in advance...........

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• trying to make an accordion menu from a list - jquery indexhibit

  - by orionrush

  Hello - Im teaching my self javascript & jquery so this might be a bit of a low brow question or entirely too much code for anyone to wade through, but Im hoping for some feedback. I have looked around and haven't found a thread that looks like it will deals neatly with my question. Im using the cms indexhibit (cant create a new tag!) and trying to create an accordion style menu from the menu list it generates. I basically have the behaviour Im after, modifying an existing bit of work but there are quite a few foibles, which are no doubt a conflict between the .click and .toggle and a confused use if statements. I basically want to start from scratch and redo this so I can a) learn from my mistakes b) understand what's happening. Im having trouble now because I dont know where to go from here, or how to trouble shoot it. Can anyone give me a quick analysis how the the script in the head of the document work together? Also any insight into the nature of the conflicts Im seeing and what approach might take to remedy them? If you were going to start afresh what would be your approach? Here is a test to see it in action (warts and all): http://stillstatic.nfshost.com/ This script goes into the document head: <script type='text/javascript'> //im not entirely clear as to what this achieves path = 'path/to/script/'; $(document).ready(function() { setTimeout('move_up()', 1); expandingMenu(0); expandingMenu(1); expandingMenu(2); expandingMenu(3); expandingMenu(4); //etc }); </script> the generated list: <ul> <li class='section-title active_menu'>blogs</li> <li><a class="active" href='#' onclick="do_click();">3</a></li> </ul> <ul> //this menu section dose not have a label: class .section-title <li><a href='#' onclick="do_click();">1</a></li> <li><a href='#' onclick="do_click();">2</a></li> </ul> <ul> //this menu section is not the 'active menu' this is achieved by the jquery script <li class='section-title'>writing</li> <li><a href='#' onclick="do_click();">4</a></li> <li><a href='#' onclick="do_click();">5</a></li> </ul> The meat of in an external script: function expandingMenu(num) { var speed = 500; var menu_title = $("#menu ul").eq(num).children(":first"); // ie. first child be the title with the class .section-title unless the user turned it off var menu_items = $("#menu ul").eq(num).children().filter(function (index) { return index 0; }); // ie. any li NOT in position 0, below li.section-title if (menu_items.is(".active") == true) { menu_title.addClass("active_menu"); //Add a class to the active list so we can style it. } if (menu_title.is(".section-title") == true){ // this if prevents interference with users who turn off the section titling if ((menu_items.is(".active") == false) && (menu_items.is(":visible")) ) { menu_items.hide(0);// first we hide the inactive exhibits } $('li').click(function (){ if ( (menu_title.is(":visible") == true) ){ menu_items.hide(speed); } if ( (menu_items.is(":hidden") == true ) && (('')) ){// ?! without this second condition things break down. . . menu_items.show(speed); } }) menu_title.css({cursor:"pointer"}).toggle( // add click functions + pointer to menu_title function () { menu_items.show(speed);//Open it up }, function () { // this function could even be empty but without the if things get weird if (menu_items.is(".xx")) menu_items.hide(speed); //Take the menu item off of active duty! } ) } }

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• lwjgl isKeyDown canceling out other keys

  - by AKrush95

  While trying to create a simple game where a square is manipulated via the keyboard keys, I have come across a small, rather irritating problem. I would like it to work so that when the opposite directional key is pressed, the character will stop; the character may move the other two directions while stopped in this situation. This works perfectly with LEFT and RIGHT held down; the player may move UP or DOWN. If UP and DOWN are held down, however, the player will not move, nor will Java recognize that the LEFT or RIGHT keys were pressed. import java.util.ArrayList; import java.util.Random; import org.lwjgl.*; import org.lwjgl.input.Keyboard; import org.lwjgl.opengl.*; import static org.lwjgl.opengl.GL11.*; public class Main { private Man p; private ArrayList<Integer> keysDown, keysUp; public Main() { try { Display.setDisplayMode(new DisplayMode(640, 480)); Display.setTitle("LWJGLHelloWorld"); Display.create(); } catch (LWJGLException e) { e.printStackTrace(); } p = new Man(0, 0); keysDown = new ArrayList<>(); keysUp = new ArrayList<>(); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(0, 640, 480, 0, 1, -1); glMatrixMode(GL_MODELVIEW); while (!Display.isCloseRequested()) { glClear(GL_COLOR_BUFFER_BIT); checkKeys(); p.draw(); Display.update(); Display.sync(60); } Display.destroy(); } public void checkKeys() { ArrayList<Integer> keys = new ArrayList<>(); keys.add(Keyboard.KEY_A); keys.add(Keyboard.KEY_D); keys.add(Keyboard.KEY_W); keys.add(Keyboard.KEY_S); for (int key : keys) { if (Keyboard.isKeyDown(key)) keysDown.add(key); else keysUp.add(key); } keysDown.removeAll(keysUp); keysUp = new ArrayList<>(); int speed = 4; int dx = 0; int dy = 0; if (keysDown.contains(keys.get(2))) { System.out.println("keyUP"); dy -= speed; } if (keysDown.contains(keys.get(3))) { System.out.println("keyDOWN"); dy += speed; } if (keysDown.contains(keys.get(0))) { System.out.println("keyLEFT"); dx -= speed; } if (keysDown.contains(keys.get(1))) { System.out.println("keyRIGHT"); dx += speed; } //if (keysDown.contains(keys.get(0)) && keysDown.contains(keys.get(1))) dx = 0; //if (keysDown.contains(keys.get(2)) && keysDown.contains(keys.get(3))) dy = 0; p.update(dx, dy); } public static void main(String[] args) { new Main(); } class Man { public int x, y, w, h; public float cR, cG, cB; public Man(int x, int y) { this.x = x; this.y = y; w = 50; h = 50; Random rand = new Random(); cR = rand.nextFloat(); cG = rand.nextFloat(); cB = rand.nextFloat(); } public void draw() { glColor3f(cR, cG, cB); glRecti(x, y, x+w, y+h); } public void update(int dx, int dy) { x += dx; y += dy; } } } That is the code that I am working with. In addition, I am unsure how to compile an executable jar that is using the lwjgl library in addition to slick-util.

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• bandwidth throttling C linux

  - by bob moch

  hi im currently creating a function to create a sleep time i can pause between packets for my port scanner im creating for personal/educational use for my home network. what im currently doing is opening /proc/net/dev and reading the 9th set of digits for the eth0 interface to find out the current packets being set and then reading it again and doing some math to figure out a delay to sleep between sending a packet to a port to identify it and fingerprint it. my problem is that no matter what throttle % i use it always seems to send the same rate of packets. i think its mainly my way of mathematically creating my sleep delay. edit:: dont mind the function declaration and the struct stuff all im doing is spawning this function in a thread and passing a pointer to a struct to the function, recreating the struct locally and then freeing the passed structs memory. void *bandwidthmonitor_cmd(void *param) { char cmdline[1024], *bytedata[19]; int i = 0, ii = 0; long long prevbytes = 0, currentbytes = 0, elapsedbytes = 0, byteusage = 0, maxthrottle = 0; command_struct bandwidth = *((command_struct *)param); free(param); //printf("speed: %d\n throttle: %d\n\n", UPLOAD_SPEED, bandwidth.throttle); maxthrottle = UPLOAD_SPEED * bandwidth.throttle / 100; //printf("max throttle:%lld\n", maxthrottle); FILE *f = fopen("/proc/net/dev", "r"); if(f != NULL) { while(1) { while(fgets(cmdline, sizeof(cmdline), f) != NULL) { cmdline[strlen(cmdline)] = '\0'; if(strncmp(cmdline, " eth0", 6) == 0) { bytedata[0] = strtok(cmdline, " "); while(bytedata[i] != NULL) { i++; bytedata[i] = strtok(NULL, " "); } bytedata[i + 1] = '\0'; currentbytes = atoi(bytedata[9]); } } i = 0; rewind(f); elapsedbytes = currentbytes - prevbytes; prevbytes = currentbytes; byteusage = 8 * (elapsedbytes / 1024); //printf("usage:%lld\n",byteusage); if(ii & 0x40) { SLEEP += (maxthrottle - byteusage) * -1.1;//-2.5; if(SLEEP < 0){ SLEEP = 0; } //printf("sleep:%d\n", SLEEP); } usleep(25000); ii++; } } return NULL; } SLEEP and UPLOAD_SPEED are global variables and UPLOAD_SPEED is in kb/s and generated via a speedtest function that gets the upload speed of my computer. this function is running inside a POSIX thread updating SLEEP which my threads doing the socket work grab to sleep by after every packet. as testing instead of only doing the ports i want to check i make it do all the ports over and over again so i can run dstat on a machine to check bandwidth and no matter what bandwidth.throttle is set to it always seems to generate the same amount of bandwidth to the dstat machine. the way i calculate how much i "should" throttle by is by finding the maximum throttle speed which is defined as maxthrottle = upload_speed * throttle / 100; for example if my upload speed was 1000kb/s and my throttle was 90 (90%) my max throttle would be 900kb/s from there it would find the current bytes sent from /proc/net/dev and then find my sleep time via incrementing or decrementing it via sleep += (maxthrottle - bytesysed) * -1.1; this should in theory increase or decrease the sleep time based on how many bytes used there are. the if(ii & 0x40) statement is just for some moderation control. it makes it so it only sets sleep to a new time every 30-40 iterations. final notes: the main problem is that the sleep timer does not seem to modify the speed of packets being set. or maybe its just my implementation because on a freshly restarted machine where /proc/net/dev has low numbers of bytes sent it seems to raise the sleep timer accordingly on my 60kb/s upload machine (ex if i set the throttle to 2 it will incline the sleep timer until network bandwidth out reaches the max bandwidth threshold, but when i try running it on a server which as been online forever it doesnt seem to work as nicely if at all. if anyone can suggest a new method of monitoring the network to adjust a sleep delay then let me know or if anyone sees a flaw in my code. thank you.

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• C#: A "Dumbed-Down" C++?

  - by James Michael Hare

  I was spending a lovely day this last weekend watching my sons play outside in one of the better weekends we've had here in Saint Louis for quite some time, and whilst watching them and making sure no limbs were broken or eyes poked out with sticks and other various potential injuries, I was perusing (in the correct sense of the word) this month's MSDN magazine to get a sense of the latest VS2010 features in both IDE and in languages. When I got to the back pages, I saw a wonderful article by David S. Platt entitled, "In Praise of Dumbing Down"  (msdn.microsoft.com/en-us/magazine/ee336129.aspx).  The title captivated me and I read it and found myself agreeing with it completely especially as it related to my first post on divorcing C++ as my favorite language. Unfortunately, as Mr. Platt mentions, the term dumbing-down has negative connotations, but is really and truly a good thing.  You are, in essence, taking something that is extremely complex and reducing it to something that is much easier to use and far less error prone.  Adding safeties to power tools and anti-kick mechanisms to chainsaws are in some sense "dumbing them down" to the common user -- but that also makes them safer and more accessible for the common user.  This was exactly my point with C++ and C#.  I did not mean to infer that C++ was not a useful or good language, but that in a very high percentage of cases, is too complex and error prone for the job at hand. Choosing the correct programming language for a job is a lot like choosing any other tool for a task.  For example: if I want to dig a French drain in my lawn, I can attempt to use a huge tractor-like backhoe and the job would be done far quicker than if I would dig it by hand.  I can't deny that the backhoe has the raw power and speed to perform.  But you also cannot deny that my chances of injury or chances of severing utility lines or other resources climb at an exponential rate inverse to the amount of training I may have on that machinery. Is C++ a powerful tool?  Oh yes, and it's great for those tasks where speed and performance are paramount.  But for most of us, it's the wrong tool.  And keep in mind, I say this even though I have 17 years of experience in using it and feel myself highly adept in utilizing its features both in the standard libraries, the STL, and in supplemental libraries such as BOOST.  Which, although greatly help with adding powerful features quickly, do very little to curb the relative dangers of the language. So, you may say, the fault is in the developer, that if the developer had some higher skills or if we only hired C++ experts this would not be an issue.  Now, I will concede there is some truth to this.  Obviously, the higher skilled C++ developers you hire the better the chance they will produce highly performant and error-free code.  However, what good is that to the average developer who cannot afford a full stable of C++ experts? That's my point with C#:  It's like a kinder, gentler C++.  It gives you nearly the same speed, and in many ways even more power than C++, and it gives you a much softer cushion for novices to fall against if they code less-than-optimally.  A bug is a bug, of course, in any language, but C# does a good job of hiding and taking on the task of handling almost all of the resource issues that make C++ so tricky.  For my money, C# is much more maintainable, more feature-rich, second only slightly in performance, faster to market, and -- last but not least -- safer and easier to use.  That's why, where I work, I much prefer to see the developers moving to C#.  The quantity of bugs is much lower, and we don't need to hire "experts" to achieve the same results since the language itself handles those resource pitfalls so prevalent in poorly written C++ code.  C++ will still have its place in the world, and I'm sure I'll still use it now and again where it is truly the correct tool for the job, but for nearly every other project C# is a wonderfully "dumbed-down" version of C++ -- in the very best sense -- and to me, that's the smart choice.

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• Fast Data - Big Data's achilles heel

  - by thegreeneman

  At OOW 2013 in Mark Hurd and Thomas Kurian's keynote, they discussed Oracle's Fast Data software solution stack and discussed a number of customers deploying Oracle's Big Data / Fast Data solutions and in particular Oracle's NoSQL Database.  Since that time, there have been a large number of request seeking clarification on how the Fast Data software stack works together to deliver on the promise of real-time Big Data solutions.   Fast Data is a software solution stack that deals with one aspect of Big Data, high velocity.   The software in the Fast Data solution stack involves 3 key pieces and their integration:  Oracle Event Processing, Oracle Coherence, Oracle NoSQL Database.   All three of these technologies address a high throughput, low latency data management requirement.   Oracle Event Processing enables continuous query to filter the Big Data fire hose, enable intelligent chained events to real-time service invocation and augments the data stream to provide Big Data enrichment. Extended SQL syntax allows the definition of sliding windows of time to allow SQL statements to look for triggers on events like breach of weighted moving average on a real-time data stream.    Oracle Coherence is a distributed, grid caching solution which is used to provide very low latency access to cached data when the data is too big to fit into a single process, so it is spread around in a grid architecture to provide memory latency speed access.  It also has some special capabilities to deploy remote behavioral execution for "near data" processing.   The Oracle NoSQL Database is designed to ingest simple key-value data at a controlled throughput rate while providing data redundancy in a cluster to facilitate highly concurrent low latency reads.  For example, when large sensor networks are generating data that need to be captured while analysts are simultaneously extracting the data using range based queries for upstream analytics.  Another example might be storing cookies from user web sessions for ultra low latency user profile management, also leveraging that data using holistic MapReduce operations with your Hadoop cluster to do segmented site analysis.  Understand how NoSQL plays a critical role in Big Data capture and enrichment while simultaneously providing a low latency and scalable data management infrastructure thru clustered, always on, parallel processing in a shared nothing architecture. Learn how easily a NoSQL cluster can be deployed to provide essential services in industry specific Fast Data solutions. See these technologies work together in a demonstration highlighting the salient features of these Fast Data enabling technologies in a location based personalization service. The question then becomes how do these things work together to deliver an end to end Fast Data solution.  The answer is that while different applications will exhibit unique requirements that may drive the need for one or the other of these technologies, often when it comes to Big Data you may need to use them together.   You may have the need for the memory latencies of the Coherence cache, but just have too much data to cache, so you use a combination of Coherence and Oracle NoSQL to handle extreme speed cache overflow and retrieval.   Here is a great reference to how these two technologies are integrated and work together.  Coherence & Oracle NoSQL Database.   On the stream processing side, it is similar as with the Coherence case.  As your sliding windows get larger, holding all the data in the stream can become difficult and out of band data may need to be offloaded into persistent storage.  OEP needs an extreme speed database like Oracle NoSQL Database to help it continue to perform for the real time loop while dealing with persistent spill in the data stream.  Here is a great resource to learn more about how OEP and Oracle NoSQL Database are integrated and work together.  OEP & Oracle NoSQL Database.

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• Problem with sprite direction and rotation

  - by user2236165

  I have a sprite called Tool that moves with a speed represented as a float and in a direction represented as a Vector2. When I click the mouse on the screen the sprite change its direction and starts to move towards the mouseclick. In addition to that I rotate the sprite so that it is facing in the direction it is heading. However, when I add a camera that is suppose to follow the sprite so that the sprite is always centered on the screen, the sprite won't move in the given direction and the rotation isn't accurate anymore. This only happens when I add the Camera.View in the spriteBatch.Begin(). I was hoping anyone could maybe shed a light on what I am missing in my code, that would be highly appreciated. Here is the camera class i use: public class Camera { private const float zoomUpperLimit = 1.5f; private const float zoomLowerLimit = 0.1f; private float _zoom; private Vector2 _pos; private int ViewportWidth, ViewportHeight; #region Properties public float Zoom { get { return _zoom; } set { _zoom = value; if (_zoom < zoomLowerLimit) _zoom = zoomLowerLimit; if (_zoom > zoomUpperLimit) _zoom = zoomUpperLimit; } } public Rectangle Viewport { get { int width = (int)((ViewportWidth / _zoom)); int height = (int)((ViewportHeight / _zoom)); return new Rectangle((int)(_pos.X - width / 2), (int)(_pos.Y - height / 2), width, height); } } public void Move(Vector2 amount) { _pos += amount; } public Vector2 Position { get { return _pos; } set { _pos = value; } } public Matrix View { get { return Matrix.CreateTranslation(new Vector3(-_pos.X, -_pos.Y, 0)) * Matrix.CreateScale(new Vector3(Zoom, Zoom, 1)) * Matrix.CreateTranslation(new Vector3(ViewportWidth * 0.5f, ViewportHeight * 0.5f, 0)); } } #endregion public Camera(Viewport viewport, float initialZoom) { _zoom = initialZoom; _pos = Vector2.Zero; ViewportWidth = viewport.Width; ViewportHeight = viewport.Height; } } And here is my Update and Draw-method: protected override void Update (GameTime gameTime) { float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds; TouchCollection touchCollection = TouchPanel.GetState (); foreach (TouchLocation tl in touchCollection) { if (tl.State == TouchLocationState.Pressed || tl.State == TouchLocationState.Moved) { //direction the tool shall move towards direction = touchCollection [0].Position - toolPos; if (direction != Vector2.Zero) { direction.Normalize (); } //change the direction the tool is moving and find the rotationangle the texture must rotate to point in given direction toolPos += (direction * speed * elapsed); RotationAngle = (float)Math.Atan2 (direction.Y, direction.X); } } if (direction != Vector2.Zero) { direction.Normalize (); } //move tool in given direction toolPos += (direction * speed * elapsed); //change cameracentre to the tools position Camera.Position = toolPos; base.Update (gameTime); } protected override void Draw (GameTime gameTime) { graphics.GraphicsDevice.Clear (Color.Blue); spriteBatch.Begin (SpriteSortMode.BackToFront, BlendState.AlphaBlend, null, null, null, null, Camera.View); spriteBatch.Draw (tool, new Vector2 (toolPos.X, toolPos.Y), null, Color.White, RotationAngle, originOfToolTexture, 1, SpriteEffects.None, 1); spriteBatch.End (); base.Draw (gameTime); }

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• Single player 'pong' game

  - by Jam

  I am just starting out learning pygame and livewires, and I'm trying to make a single-player pong game, where you just hit the ball, and it bounces around until it passes your paddle (located on the left side of the screen and controlled by the mouse), which makes you lose. I have the basic code, but the ball doesn't stay on the screen, it just flickers and doesn't remain constant. Also, the paddle does not move with the mouse. I'm sure I'm missing something simple, but I just can't figure it out. Help please! Here's what I have: from livewires import games import random games.init(screen_width=640, screen_height=480, fps=50) class Paddle(games.Sprite): image=games.load_image("paddle.bmp") def __init__(self, x=10): super(Paddle, self).__init__(image=Paddle.image, y=games.mouse.y, left=10) self.score=games.Text(value=0, size=25, top=5, right=games.screen.width - 10) games.screen.add(self.score) def update(self): self.y=games.mouse.y if self.top<0: self.top=0 if self.bottom>games.screen.height: self.bottom=games.screen.height self.check_collide() def check_collide(self): for ball in self.overlapping_sprites: self.score.value+=1 ball.handle_collide() class Ball(games.Sprite): image=games.load_image("ball.bmp") speed=5 def __init__(self, x=90, y=90): super(Ball, self).__init__(image=Ball.image, x=x, y=y, dx=Ball.speed, dy=Ball.speed) def update(self): if self.right>games.screen.width: self.dx=-self.dx if self.bottom>games.screen.height or self.top<0: self.dy=-self.dy if self.left<0: self.end_game() self.destroy() def handle_collide(self): self.dx=-self.dx def end_game(self): end_message=games.Message(value="Game Over", size=90, x=games.screen.width/2, y=games.screen.height/2, lifetime=250, after_death=games.screen.quit) games.screen.add(end_message) def main(): background_image=games.load_image("background.bmp", transparent=False) games.screen.background=background_image paddle_image=games.load_image("paddle.bmp") the_paddle=games.Sprite(image=paddle_image, x=10, y=games.mouse.y) games.screen.add(the_paddle) ball_image=games.load_image("ball.bmp") the_ball=games.Sprite(image=ball_image, x=630, y=200, dx=2, dy=2) games.screen.add(the_ball) games.mouse.is_visible=False games.screen.event_grab=True games.screen.mainloop() main()

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• Single-player pong game

  - by Jam

  I am just starting out learning pygame and livewires, and I'm trying to make a single-player pong game, where you just hit the ball, and it bounces around until it passes your paddle (located on the left side of the screen and controlled by the mouse), which makes you lose. However, I keep getting the error: "Cannot have more than on Screen object", which I can find no references to online really, and I can't make sense of it. I want to eventually make the game more complicated, but I need to make it work first. Help please! Here's the code so far: from livewires import games games.init(screen_width=640, screen_height=480, fps=50) class Paddle(games.Sprite): image=games.load_image("paddle.bmp") def __init__(self): super(Paddle, self).__init__(image=Paddle.image, y=games.mouse.y, left=0) self.score=games.Text(value=0, size=25, top=5, right=games.screen.width-10) games.screen.add(self.score) def update(self): self.y=games.mouse.y self.check_collide() def check_collide(self): for ball in self.overlapping_sprites: self.score.value+=1 self.score.right=games.screen.width-10 ball.handle_collide() class Ball(games.Sprite): image=games.load_image("ball.bmp") speed=1 def __init__(self, x, y=90): super(Ball, self).__init__(image=Ball.image, x=x, y=y, dx=Ball.speed, dy=Ball.speed) def update(self): if self.left<0: self.end_game() self.destroy() def handle_collide(self): if self.right>games.screen.width: self.dx=-self.dx if self.bottom>games.screen.height or self.top<0: self.dy=-self.dy def ball_destroy(self): self.destroy() def main(): background_image=games.load_image("background.bmp", transparent=False) games.screen.background=background_image the_ball=Ball() games.screen.add(the_ball) the_paddle=Paddle() games.screen.add(the_paddle) games.mouse.is_visible=False games.screen.event_grab=True games.screen.mainloop() main()

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• Opengl Iphone SDK: How to tell if you're touching an object on screen?

  - by TheGambler

  First is my touchesBegan function and then the struct that stores the values for my object. I have an array of these objects and I'm trying to figure out when I touch the screen if I'm touching an object on the screen. I don't know if I need to do this by iterating through all my objects and figure out if I'm touching an object that way or maybe there is an easier more efficient way. How is this usually handled? -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{ [super touchesEnded:touches withEvent:event]; UITouch* touch = ([touches count] == 1 ? [touches anyObject] : nil); CGRect bounds = [self bounds]; CGPoint location = [touch locationInView:self]; location.y = bounds.size.height - location.y; float xTouched = location.x/20 - 8 + ((int)location.x % 20)/20; float yTouched = location.y/20 - 12 + ((int)location.y % 20)/20; } typedef struct object_tag // Create A Structure Called Object { int tex; // Integer Used To Select Our Texture float x; // X Position float y; // Y Position float z; // Z Position float yi; // Y Increase Speed (Fall Speed) float spinz; // Z Axis Spin float spinzi; // Z Axis Spin Speed float flap; // Flapping Triangles :) float fi; // Flap Direction (Increase Value) } object;

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• How close can I get C# to the performance of C++ for small intensive tasks?

  - by SLC

  I was thinking about the speed difference of C++ to C# being mostly about C# compiling to byte-code that is taken in by the JIT compiler (is that correct?) and all the checks C# does. I notice that it is possible to turn a lot of these functions off, both in the compile options, and possibly through using the unsafe keyword as unsafe code is not verifiable by the common language runtime. Therefore if you were to write a simple console application in both languages, that flipped an imaginary coin an infinite number of times and displayed the results to the screen every 10,000 or so iterations, how much speed difference would there be? I chose this because it's a very simple program. I'd like to test this but I don't know C++ or have the tools to compile it. This is my C# version though: static void Main(string[] args) { unsafe { Random rnd = new Random(); int heads = 0, tails = 0; while (true) { if (rnd.NextDouble() > 0.5) heads++; else tails++; if ((heads + tails) % 1000000 == 0) Console.WriteLine("Heads: {0} Tails: {1}", heads, tails); } } } Is the difference enough to warrant deliberately compiling sections of code "unsafe" or into DLLs that do not have some of the compile options like overflow checking enabled? Or does it go the other way, where it would be beneficial to compile sections in C++? I'm sure interop speed comes into play too then. To avoid subjectivity, I reiterate the specific parts of this question as: Does C# have a performance boost from using unsafe code? Do the compile options such as disabling overflow checking boost performance, and do they affect unsafe code? Would the program above be faster in C++ or negligably different? Is it worth compiling long intensive number-crunching tasks in a language such as C++ or using /unsafe for a bonus? Less subjectively, could I complete an intensive operation faster by doing this?

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• jQuery Collapse (with cookies), default open instead of closed?

  - by Christian

  Hi. I've got a jQuery snippet which basically allows a user to toggle a div, open or closed - their preference is saved in a cookie. (function($) { $.fn.extend({ collapse: function(options) { var defaults = { inactive : "inactive", active : "active", head : ".trigger", group : ".wrap-me-up", speed : 300, cookie : "collapse" }; // Set a cookie counter so we dont get name collisions var op = $.extend(defaults, options); cookie_counter = 0; return this.each(function() { // Increment cookie name counter cookie_counter++; var obj = $(this), sections = obj.find(op.head).addClass(op.inactive), panel = obj.find(op.group).hide(), l = sections.length, cookie = op.cookie + "_" + cookie_counter; // Look for existing cookies for (c=0;c<=l;c++) { var cvalue = $.cookie(cookie + c); if ( cvalue == 'open' + c ) { panel.eq(c).show(); panel.eq(c).prev().removeClass(op.inactive).addClass(op.active); }; }; sections.click(function(e) { e.preventDefault(); var num = sections.index(this); var cookieName = cookie + num; var ul = $(this).next(op.group); // If item is open, slide up if($(this).hasClass(op.active)) { ul.slideUp(op.speed); $(this).removeClass(op.active).addClass(op.inactive); $.cookie(cookieName, null, { path: '/', expires: 10 }); return } // Else slide down ul.slideDown(op.speed); $(this).addClass(op.active).removeClass(op.inactive); var cookieValue = 'open' + num; $.cookie(cookieName, cookieValue, { path: '/', expires: 10 }); }); }); } }); })(jQuery); Demo: http://christianbullock.com/demo/ I'm just wondering how I can display the list open as default, and have the div collapse when the header is clicked? Many thanks. Christian.

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• An Ideal Keyboard Layout for Programming

  - by Jon Purdy

  I often hear complaints that programming languages that make heavy use of symbols for brevity, most notably C and C++ (I'm not going to touch APL), are difficult to type because they require frequent use of the shift key. A year or two ago, I got tired of it myself, downloaded Microsoft's Keyboard Layout Creator, made a few changes to my layout, and have not once looked back. The speed difference is astounding; with these few simple changes I am able to type C++ code around 30% faster, depending of course on how hairy it is; best of all, my typing speed in ordinary running text is not compromised. My questions are these: what alternate keyboard layouts have existed for programming, which have gained popularity, are any of them still in modern use, do you personally use any altered layout, and how can my layout be further optimised? I made the following changes to a standard QWERTY layout. (I don't use Dvorak, but there is a programmer Dvorak layout worth mentioning.) Swap numbers with symbols in the top row, because long or repeated literal numbers are typically replaced with named constants; Swap backquote with tilde, because backquotes are rare in many languages but destructors are common in C++; Swap minus with underscore, because underscores are common in identifiers; Swap curly braces with square brackets, because blocks are more common than subscripts; and Swap double quote with single quote, because strings are more common than character literals. I suspect this last is probably going to be the most controversial, as it interferes the most with running text by requiring use of shift to type common contractions. This layout has significantly increased my typing speed in C++, C, Java, and Perl, and somewhat increased it in LISP and Python.

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• How to interpolate in MatLab

  - by G Sam

  I have a 1x1 Matrix of points which specifies speed of a drive with respect to time. This speed changes throughout the operation; which means that the difference between two points is changing. To give you an example: M = [1; 2; 3; 5; 7; 9; 11; 15; 19]. (Only that this is a 892x1 matrix) I want to make this matrix twice as long (so changing the relative speed per timestep), while retaining the way the speeds change. Eg: M' = [1; 1.5; 2; 2.5; 3; 4; 5; 6; 7; 8; 9; 10; 11; 13; 15; 17; 19]. Is there an easy way to do this in MatLab? So far I have tried upsampling (which fills the time step with zeros); interp (which fills it with low-pass interpolation. Thanks!

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• Android ArrayList<Location> passing between activities

  - by squixy

  I have simple class Track, which stores information about route: import java.io.Serializable; import java.util.ArrayList; import java.util.Date; import android.location.Location; public class Track implements Serializable { private static final long serialVersionUID = -5317697499269650204L; private Date date; private String name; private int time; private double distance, speed; private ArrayList<Location> route; public Track(String name, int time, double distance, ArrayList<Location> route) { this.date = new Date(); this.name = name; this.time = time; this.distance = distance; this.speed = distance / (time / 3600.); this.route = route; } public String getDate() { return String.format("Date: %1$td-%1$tb-%1$tY%nTime: %1$tH:%1$tM:%1$tS", date); } public String getName() { return name; } public int getTime() { return time; } public double getDistance() { return distance; } public float getSpeed() { return (float) speed; } public ArrayList<Location> getRoute() { return route; } @Override public String toString() { return String.format("Name: %s%nDate: %2$td-%2$tb-%2$tY%nTime: %2$tH:%2$tM:%2$tS", name, date); } } And I'm passing it from one activity to another: Intent showTrackIntent = new Intent(TabSavedActivity.this, ShowTrackActivity.class); showTrackIntent.putExtra("track", adapter.getItem(position)); startActivity(showTrackIntent); Where (Track object is element on ListView). I get error during passing Track object: java.lang.RuntimeException: Parcelable encountered IOException writing serializable object (name = classes.Track) What is happening?

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• Auditing front end performance on web application

  - by user1018494

  I am currently trying to performance tune the UI of a company web application. The application is only ever going to be accessed by staff, so the speed of the connection between the server and client will always be considerably more than if it was on the internet. I have been using performance auditing tools such as Y Slow! and Google Chrome's profiling tool to try and highlight areas that are worth targeting for investigation. However, these tools are written with the internet in mind. For example, the current suggestions from a Google Chrome audit of the application suggests is as follows: Network Utilization Combine external CSS (Red warning) Combine external JavaScript (Red warning) Enable gzip compression (Red warning) Leverage browser caching (Red warning) Leverage proxy caching (Amber warning) Minimise cookie size (Amber warning) Parallelize downloads across hostnames (Amber warning) Serve static content from a cookieless domain (Amber warning) Web Page Performance Remove unused CSS rules (Amber warning) Use normal CSS property names instead of vendor-prefixed ones (Amber warning) Are any of these bits of advice totally redundant given the connection speed and usage pattern? The users will be using the application frequently throughout the day, so it doesn't matter if the initial hit is large (when they first visit the page and build their cache) so long as a minimal amount of work is done on future page views. For example, is it worth the effort of combining all of our CSS and JavaScript files? It may speed up the initial page view, but how much of a difference will it really make on subsequent page views throughout the working day? I've tried searching for this but all I keep coming up with is the standard internet facing performance advice. Any advice on what to focus my performance tweaking efforts on in this scenario, or other auditing tool recommendations, would be much appreciated.

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• Dynamically loading external HTML in a div using Java Script

  - by user354051

  I have prepared some demo examples for the topic. There is page name "changelog.html" here: http://pantheon-studios.in/test/jquery/changelog.html This is working fine if loaded directly. I am trying to load this page dynamically into: http://pantheon-studios.in/test/jquery/index.html Here changelog.html doesn't behaving as expected. I think the init script on changelog.html is not getting executed or something else is happening when loading it dynamically. Like wise I do have couple of other pages using various jQuery and other java scripts plugins. Some of those needs initialization like animatedcollapse.js in the above example, and couple of them doesn't need initialization, you can directly call the script and go. I also gave a try using: jQuery.getScript("anim.js") after dynamically loading "changelog.html" but doesn't work. The "anim.js" contains animatedcollapse.addDiv('cat', 'fade=0,speed=400,group=pets,hide=1'); animatedcollapse.addDiv('dog', 'fade=0,speed=400,group=pets,hide=1'); animatedcollapse.addDiv('rabbit', 'fade=0,speed=400,group=pets,hide=1'); animatedcollapse.init(); I would really appreciate is some one point me out the right direction. I am completely new to web programming so please have some patience with me. Thanks

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