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• Time display and Cursor bug in Ubuntu 14.04 LTS

  - by user291774

  Just installed Ubuntu 14.04. Noticed the time in seconds speeds up then slows down to normal speed. The cursor for the keyboard has a strange rhythm; it stays normal, then slowly speeds up faster and faster till it looks like it's not blinking anymore, then goes back to normal and starts the process again. It almost seems like my whole operating system speeds up then slows down again. Even the hour circle that spins when it's loading starts slowly then it picks up speed till it spins so fast it looks like it's not even spinning. It interferes with video and the whole system. I have a Dell Vostro 3750 dual video cards and dual boot with Windows 7. Windows is running fine.

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• Particle system lifetimes in OpenGL ES 2

  - by user16547

  I don't know how to work with my particle's lifetimes. My design is simple: each particle has a position, a speed and a lifetime. At each frame, each particle should update its position like this: position.y = position.y + INCREMENT * speed.y However, I'm having difficulties in choosing my INCREMENT. If I set it to some sort of FRAME_COUNT, it looks fine until FRAME_COUNT has to be set back to 0. The effect will be that all particles start over at the same time, which I don't want to happen. I want my particles sort of live "independent" of each other. That's the reason I need a lifetime, but I don't know how to make use of it. I added a lifetime for each particle in the particle buffer, but I also need an individual increment that's updated on each frame, so that when PARTICLE_INCREMENT = PARTICLE_LIFETIME, each increment goes back to 0. How can I achieve something like that?

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• accessing webpages from terminal

  - by August

  Using Ubuntu 12.04 . I know two methods to access the web-pages through terminal . They are lynx & elinkswhen i have tried to use them to access web-pages from terminal i didn't felt any kind of speed improvements . I am not sure whether its a usual thing or my speed (because its slow one ). so which way is the best to access the web-page terminal browsers or GUI browsers? and what else more i can get/lost from text terminals ?

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• Can my computer run Ubuntu? [duplicate]

  - by Harry B

  This question already has an answer here: How do I find out which version and derivative of Ubuntu is right for my hardware in terms of minimal system requirements? 2 answers Just want to check if my computer can run Ubuntu. It is an old IBM ThinkPad, so here are the basic stats I could find: IBM 28832ZU Processor Intel(R) Celeron(R) M processor 1300MHz Processor Speed 1.27 GHz Memory (RAM) 2048 MB Operating System Microsoft Windows XP Professional Operating System Version 5.1.2600 Intel Extreme Graphics 2M And here is some info pulled from the graphics panel NTEL(R) EXTREME GRAPHICS 2 FOR MOBILE REPORT Report Date: 06/28/2013 Report Time[hr:mm:ss]: 17:53:20 Driver Version: 6.14.10.3943 Operating System: Windows NT* 5.1.2600 Service Pack 2 Default Language: English DirectX* Version: 9.0 Physical Memory: 2038 MB Min. Graphics Memory: 8 MB Max. Graphics Memory: 64 MB Graphics Memory in use: 7 MB Processor: x86 family 6 Model 9 Stepping 5 Processor Speed: 1296 MHZ Device Revision: 2 Output Devices Connected to Graphics Accelerator * Active Notebook Displays:1

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• Webcast: Extreme Analytics Without Limits

  - by Rob Reynolds

  Event Date: November 8, 2012 Event Time: 1 p.m. PT / 4 p.m. ET If you are a current Oracle Business Intelligence Applications customer, or thinking about implementing the BI Apps, please join us for this Webcast to learn how the combination of Oracle Exalytics In- Memory Machine and Oracle’s market leading analytic applications enables you to go beyond the traditional boundaries of data analysis and get the insight you need from massive volumes of data – all at the speed of thought. See how you can benefit from running your analytic applications on Oracle Exalytics to: Lower TCO Improve Operational Decision Making and Enhance Competitive Advantage Deliver Speed-of-thought Analysis – Anytime, Anywhere Click here to register.

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• How to calculate shot angle and velocity to hit a moving target?

  - by Guen

  I am developing a 2D Android game and I am making an aiming algorithm for AI projectiles to hit enemies either following a path, or free moving. At the moment it just calculates where the target will be after a distance and fires a projectile to meet it at that distance. Of course this means varying the projectile speed to meet the target. Does anyone have any tips for a simple-ish algorithm (optimal-ish) to calculate when the projectile needs to fire and where it needs to aim if it can only travel at a constant velocity? Say the projectile goes twice the speed of the target? The only way I can think of involves searching and seems quite large.

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• Generate Unique Abstract Backgrounds with Ablaze

  - by Jason Fitzpatrick

  If you want custom and unique backgrounds without having to code your own image-generating engine, Ablaze makes it simple (and fun) to create abstract images. You can customize a wide array of options in Ablaze including the base shape (ring, horizontal line, or random), number of particles, distance each particle travels, and the speed (if you increase the speed range you get more distinct lines and if you decrease it you get smoother smokier shapes). You can also seed the design with a color palette pulled from any image you provide (the sample above was seeded with a Wonder Woman comic panel). Tweak and reset the pattern generation as much as you want; when you create an abstract image worthy of your desktop just click the save button to grab a copy of it in PNG format. Ablaze [via Flowing Data] How To Create a Customized Windows 7 Installation Disc With Integrated Updates How to Get Pro Features in Windows Home Versions with Third Party Tools HTG Explains: Is ReadyBoost Worth Using?

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• Object array updates one instance repeatedly [on hold]

  - by MGN001

  I'm making a 2D shooter, and the player object holds an array of bullets that represent how many shots the player can have on screen at once. At least, this is what I'm trying for. What's happening is that each time any of the objects in the array is called, it seems to update a single object in memory. So, if I fire and then fire again, the object "starts over" from where I shot from and moves twice as fast. I've spent weeks trying to fix this and I've managed nothing. Hopefully another pair of eyes will see something I've missed. Player.cpp #include "Player.h" const int startLives = 3; const int maxHealth = 2; const float speed = 1; const int maxVelocity = 500; const int topBound = WINDOW_HEIGHT / 5 * 3; const int slowRate = 500; const int accRate = 1000; const int maxBullets = 5; const float spriteWidth = 99; const float spriteHeight = 75; const Vector2f startPosition = { (WINDOW_WIDTH / 2) - (spriteWidth / 2), (WINDOW_HEIGHT / 4 * 3) - (spriteHeight / 2) }; Bullet bullets[maxBullets]; Bullet * bulletPointers[maxBullets]; SDL_Texture * playerHealthy; SDL_Texture * playerDamaged; SDL_Texture * currentSprite; SDL_Rect * rect; Vector2f position; Vector2f velocity; int Health; int Lives; Player::Player() { rect = new SDL_Rect(); } Player::~Player() { SDL_DestroyTexture(playerHealthy); SDL_DestroyTexture(playerDamaged); SDL_DestroyTexture(currentSprite); rect = NULL; } void Player::Initialize(SDL_Renderer * renderer) { SDL_Surface * temp; temp = IMG_Load(".\\Sprites\\player.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } playerHealthy = SDL_CreateTextureFromSurface(renderer, temp); temp = IMG_Load(".\\Sprites\\playerDamaged.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } playerDamaged = SDL_CreateTextureFromSurface(renderer, temp); temp = IMG_Load(".\\Sprites\\laserGreen.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } SDL_Texture * bullet = SDL_CreateTextureFromSurface(renderer, temp); temp = IMG_Load(".\\Sprites\\laserGreenShot.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } SDL_Texture * explosion = SDL_CreateTextureFromSurface(renderer, temp); for (int i = 0; i < maxBullets; i++) { bullets[i].Initialize(renderer, bullet, explosion); bulletPointers[i] = NULL; } temp = NULL; rect->h = spriteHeight; rect->w = spriteWidth; Reset(); } void Player::Update(Input input, float deltaTime) { if (abs(velocity.x) < slowRate * deltaTime) { velocity.x = 0; } else if (velocity.x > 0) { velocity.x -= slowRate * deltaTime; } else if (velocity.x < 0) { velocity.x += slowRate * deltaTime; } if (abs(velocity.y) < slowRate * deltaTime) { velocity.y = 0; } if (velocity.y > 0) { velocity.y -= slowRate * deltaTime; } else if (velocity.y < 0) { velocity.y += slowRate * deltaTime; } if (Health <= 0) { --Lives; Spawn(); } velocity.x += UnitVector(input.InputNew.movement).x * accRate * deltaTime; velocity.y += UnitVector(input.InputNew.movement).y * accRate * deltaTime; if (Magnitude(velocity) > maxVelocity) { velocity.x = UnitVector(velocity).x * maxVelocity; velocity.y = UnitVector(velocity).y * maxVelocity; } position.x += velocity.x * deltaTime * speed; position.y += velocity.y * deltaTime * speed; if (input.InputNew.JumpLeft && !input.InputOld.JumpLeft) { position.x -= spriteWidth; } if (input.InputNew.JumpRight && !input.InputOld.JumpRight) { position.x += spriteWidth; } Boundaries(); rect->x = position.x; rect->y = position.y; if (input.InputNew.Fire && !input.InputOld.Fire) { Fire(); } for (int i = 0; i < maxBullets; ++i) { if (bulletPointers[i] != NULL) { bullets[i].Update(deltaTime); if (bullets[i].getPosition().y < -33) { bulletPointers[i] = NULL; } } } } void Player::Draw(SDL_Renderer * renderer) { for (int i = 0; i < maxBullets; ++i) { if (bulletPointers[i] != NULL) { bullets[i].Draw(renderer); } } SDL_RenderCopy(renderer, currentSprite, NULL, rect); } void Player::Spawn() { position = startPosition; Health = maxHealth; currentSprite = playerHealthy; rect->x = position.x; rect->y = position.y; } void Player::Boundaries() { if (position.x < 0) { position.x = 0; velocity.x *= -1; } else if (position.x > WINDOW_WIDTH - spriteWidth) { position.x = WINDOW_WIDTH - spriteWidth; velocity.x *= -1; } if (position.y < topBound) { position.y = topBound; velocity.y *= -1; } else if (position.y > WINDOW_HEIGHT - spriteHeight) { position.y = WINDOW_HEIGHT - spriteHeight; velocity.y *= -1; } } int Player::getLives() { return Lives; } void Player::Reset() { Lives = startLives; Spawn(); } void Player::Fire() { for (int i = 0; i < maxBullets; ++i) { if (bulletPointers[i] == NULL) { bulletPointers[i] = &bullets[i]; bullets[i].Fire(position,velocity.x/2); break; } } } Bullet.cpp #include "Bullet.h" const int speed = 500; Vector2f bulletVelocity; float ExplosionMax = 0.5f; float ExplosionTimer; const Vector2f fireOffset = { 45.5f, 10.0f }; const Vector2f explosionOffset = { 23.5f, -27.0f }; const Vector2i bulletSize = { 9, 33 }; const Vector2i explosionSize = { 56, 54 }; Vector2f bulletPosition; SDL_Texture * bulletSprite; SDL_Texture * explosionSprite; SDL_Texture * bulletCurrentSprite; SDL_Rect * bulletRect; Bullet::Bullet() { } Bullet::~Bullet() { } void Bullet::Initialize(SDL_Renderer * renderer, SDL_Texture * bullet, SDL_Texture * explosion) { bulletSprite = bullet; explosionSprite = explosion; bulletRect = new SDL_Rect(); } void Bullet::Update(float deltaTime) { bulletPosition.y -= bulletVelocity.y * deltaTime; bulletPosition.x += bulletVelocity.x * deltaTime; bulletRect->x = static_cast<int>(bulletPosition.x); bulletRect->y = static_cast<int>(bulletPosition.y); } void Bullet::Draw(SDL_Renderer * renderer) { SDL_RenderCopy(renderer, bulletCurrentSprite, NULL, bulletRect); } void Bullet::Fire(Vector2f pos, float xSpeed) { bulletPosition.x = pos.x + fireOffset.x; bulletPosition.y = pos.y + fireOffset.y; bulletVelocity.x = xSpeed; bulletVelocity.y = speed; bulletCurrentSprite = bulletSprite; bulletRect->h = bulletSize.y; bulletRect->w = bulletSize.x; bulletRect->x = static_cast<int>(bulletPosition.x); bulletRect->y = static_cast<int>(bulletPosition.y); } Vector2f Bullet::getPosition() { return bulletPosition; } void Bullet::Hit() { bulletCurrentSprite = explosionSprite; bulletVelocity = { 0.0f, 0.0f }; ExplosionTimer = ExplosionMax; bulletPosition.x += explosionOffset.x; bulletPosition.y += explosionOffset.y; bulletRect->w = explosionSize.x; bulletRect->h = explosionSize.y; }

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• Does low latency code sometimes have to be "ugly"?

  - by user997112

  (This is mainly aimed at those who have specific knowledge of low latency systems, to avoid people just answering with unsubstantiated opinions). Do you feel there is a trade-off between writing "nice" object orientated code and writing very fast low latency code? For instance, avoiding virtual functions in C++/the overhead of polymorphism etc- re-writing code which looks nasty, but is very fast etc? It stands to reason- who cares if it looks ugly (so long as its maintainable)- if you need speed, you need speed? I would be interested to hear from people who have worked in such areas.

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• Brocade Gives Ethernet, Storage Networking Switches a Boost

  Brocade gives speed and density boosts to its Ethernet and data storage switches as its rivalry with Cisco heats up.

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• Monday at Oracle OpenWorld 2012 - Must See Session: “Using the Right Tools, Techniques, and Technologies for Integration Projects”

  - by Lionel Dubreuil

  Don’t miss this “CON8669 - Using the Right Tools, Techniques, and Technologies for Integration Projects“ session with Timothy Hall - Sr. Director, Oracle: Date: Monday, Oct 1, Time: 3:15 PM - 4:15 PM Location: Moscone South - 308 Every integration project brings its own unique set of challenges. There are many tools and techniques to choose from. How do you ensure that you have a means of consistently and repeatedly making decisions about which tools, techniques, and technologies are used? In working with many customers around the globe, Oracle has developed a set of criteria to help evaluate a variety of common integration questions. This session explores these criteria and how they have been further organized into decision trees that offer a repeatable means for ensuring that project teams are given the same guidance from project to project. Using these techniques, the presentation shows how you can reduce risk and speed productivity for your projects Objectives for this session are to: Discuss common questions that arise at the start of integration projects Review various decision criteria and approaches for getting to a consistent set of answers Explore how these techniques can be used to reduce risk and speed productivity

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• Monday at Oracle OpenWorld 2012 - Must See Session: “Using the Right Tools, Techniques, and Technologies for Integration Projects”

  - by Lionel Dubreuil

  Don’t miss this “CON8669 - Using the Right Tools, Techniques, and Technologies for Integration Projects“ session with Timothy Hall - Sr. Director, Oracle: Date: Monday, Oct 1, Time: 3:15 PM - 4:15 PM Location: Moscone South - 308 Every integration project brings its own unique set of challenges. There are many tools and techniques to choose from. How do you ensure that you have a means of consistently and repeatedly making decisions about which tools, techniques, and technologies are used? In working with many customers around the globe, Oracle has developed a set of criteria to help evaluate a variety of common integration questions. This session explores these criteria and how they have been further organized into decision trees that offer a repeatable means for ensuring that project teams are given the same guidance from project to project. Using these techniques, the presentation shows how you can reduce risk and speed productivity for your projects Objectives for this session are to: Discuss common questions that arise at the start of integration projects Review various decision criteria and approaches for getting to a consistent set of answers Explore how these techniques can be used to reduce risk and speed productivity

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• Fix Slow Browsing &amp;#151; and More &amp;#151; With OpenDNS

  OpenDNS gives your small business&#146;s Internet connection an extra dose of speed, security and control.

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• FreeBSD performance tuning. Sysctls, loader.conf, kernel

  - by SaveTheRbtz

  I wanted to share knowledge of tuning FreeBSD via sysctl.conf/loader.conf/KENCONF. It was initially based on Igor Sysoev's (author of nginx) presentation about FreeBSD tuning up to 100,000-200,000 active connections. Tunings are for FreeBSD-CURRENT. Since 7.2 amd64 some of them are tuned well by default. Prior 7.0 some of them are boot only (set via /boot/loader.conf) or does not exist at all. sysctl.conf: # No zero mapping feature # May break wine # (There are also reports about broken samba3) #security.bsd.map_at_zero=0 # If you have really busy webserver with apache13 you may run out of processes #kern.maxproc=10000 # Same for servers with apache2 / Pound #kern.threads.max_threads_per_proc=4096 # Max. backlog size kern.ipc.somaxconn=4096 # Shared memory // 7.2+ can use shared memory > 2Gb kern.ipc.shmmax=2147483648 # Sockets kern.ipc.maxsockets=204800 # Can cause this on older kernels: # http://old.nabble.com/Significant-performance-regression-for-increased-maxsockbuf-on-8.0-RELEASE-tt26745981.html#a26745981 ) kern.ipc.maxsockbuf=10485760 # Mbuf 2k clusters (on amd64 7.2+ 25600 is default) # For such high value vm.kmem_size must be increased to 3G kern.ipc.nmbclusters=262144 # Jumbo pagesize(_SC_PAGESIZE) clusters # Used as general packet storage for jumbo frames # can be monitored via `netstat -m` #kern.ipc.nmbjumbop=262144 # Jumbo 9k/16k clusters # If you are using them #kern.ipc.nmbjumbo9=65536 #kern.ipc.nmbjumbo16=32768 # For lower latency you can decrease scheduler's maximum time slice # default: stathz/10 (~ 13) #kern.sched.slice=1 # Increase max command-line length showed in `ps` (e.g for Tomcat/Java) # Default is PAGE_SIZE / 16 or 256 on x86 # This avoids commands to be presented as [executable] in `ps` # For more info see: http://www.freebsd.org/cgi/query-pr.cgi?pr=120749 kern.ps_arg_cache_limit=4096 # Every socket is a file, so increase them kern.maxfiles=204800 kern.maxfilesperproc=200000 kern.maxvnodes=200000 # On some systems HPET is almost 2 times faster than default ACPI-fast # Useful on systems with lots of clock_gettime / gettimeofday calls # See http://old.nabble.com/ACPI-fast-default-timecounter,-but-HPET-83--faster-td23248172.html # After revision 222222 HPET became default: http://svnweb.freebsd.org/base?view=revision&revision=222222 kern.timecounter.hardware=HPET # Small receive space, only usable on http-server, on file server this # should be increased to 65535 or even more #net.inet.tcp.recvspace=8192 # This is useful on Fat-Long-Pipes #net.inet.tcp.recvbuf_max=10485760 #net.inet.tcp.recvbuf_inc=65535 # Small send space is useful for http servers that serve small files # Autotuned since 7.x net.inet.tcp.sendspace=16384 # This is useful on Fat-Long-Pipes #net.inet.tcp.sendbuf_max=10485760 #net.inet.tcp.sendbuf_inc=65535 # Turn off receive autotuning # You can play with it. #net.inet.tcp.recvbuf_auto=0 #net.inet.tcp.sendbuf_auto=0 # This should be enabled if you going to use big spaces (>64k) # Also timestamp field is useful when using syncookies net.inet.tcp.rfc1323=1 # Turn this off on high-speed, lossless connections (LAN 1Gbit+) # If you set it there is no need in TCP_NODELAY sockopt (see man tcp) net.inet.tcp.delayed_ack=0 # This feature is useful if you are serving data over modems, Gigabit Ethernet, # or even high speed WAN links (or any other link with a high bandwidth delay product), # especially if you are also using window scaling or have configured a large send window. # Automatically disables on small RTT ( http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/tcp_subr.c?#rev1.237 ) # This sysctl was removed in 10-CURRENT: # See: http://www.mail-archive.com/[email protected]/msg06178.html #net.inet.tcp.inflight.enable=0 # TCP slowstart algorithm tunings # We assuming we have very fast clients #net.inet.tcp.slowstart_flightsize=100 #net.inet.tcp.local_slowstart_flightsize=100 # Disable randomizing of ports to avoid false RST # Before usage check SA here www.bsdcan.org/2006/papers/ImprovingTCPIP.pdf # (it's also says that port randomization auto-disables at some conn.rates, but I didn't checked it thou) #net.inet.ip.portrange.randomized=0 # Increase portrange # For outgoing connections only. Good for seed-boxes and ftp servers. net.inet.ip.portrange.first=1024 net.inet.ip.portrange.last=65535 # # stops route cache degregation during a high-bandwidth flood # http://www.freebsd.org/doc/en/books/handbook/securing-freebsd.html #net.inet.ip.rtexpire=2 net.inet.ip.rtminexpire=2 net.inet.ip.rtmaxcache=1024 # Security net.inet.ip.redirect=0 net.inet.ip.sourceroute=0 net.inet.ip.accept_sourceroute=0 net.inet.icmp.maskrepl=0 net.inet.icmp.log_redirect=0 net.inet.icmp.drop_redirect=1 net.inet.tcp.drop_synfin=1 # # There is also good example of sysctl.conf with comments: # http://www.thern.org/projects/sysctl.conf # # icmp may NOT rst, helpful for those pesky spoofed # icmp/udp floods that end up taking up your outgoing # bandwidth/ifqueue due to all that outgoing RST traffic. # #net.inet.tcp.icmp_may_rst=0 # Security net.inet.udp.blackhole=1 net.inet.tcp.blackhole=2 # IPv6 Security # For more info see http://www.fosslc.org/drupal/content/security-implications-ipv6 # Disable Node info replies # To see this vulnerability in action run `ping6 -a sglAac ::1` or `ping6 -w ::1` on unprotected node net.inet6.icmp6.nodeinfo=0 # Turn on IPv6 privacy extensions # For more info see proposal http://unix.derkeiler.com/Mailing-Lists/FreeBSD/net/2008-06/msg00103.html net.inet6.ip6.use_tempaddr=1 net.inet6.ip6.prefer_tempaddr=1 # Disable ICMP redirect net.inet6.icmp6.rediraccept=0 # Disable acceptation of RA and auto linklocal generation if you don't use them #net.inet6.ip6.accept_rtadv=0 #net.inet6.ip6.auto_linklocal=0 # Increases default TTL, sometimes useful # Default is 64 net.inet.ip.ttl=128 # Lessen max segment life to conserve resources # ACK waiting time in miliseconds # (default: 30000. RFC from 1979 recommends 120000) net.inet.tcp.msl=5000 # Max bumber of timewait sockets net.inet.tcp.maxtcptw=200000 # Don't use tw on local connections # As of 15 Apr 2009. Igor Sysoev says that nolocaltimewait has some buggy realization. # So disable it or now till get fixed #net.inet.tcp.nolocaltimewait=1 # FIN_WAIT_2 state fast recycle net.inet.tcp.fast_finwait2_recycle=1 # Time before tcp keepalive probe is sent # default is 2 hours (7200000) #net.inet.tcp.keepidle=60000 # Should be increased until net.inet.ip.intr_queue_drops is zero net.inet.ip.intr_queue_maxlen=4096 # Interrupt handling via multiple CPU, but with context switch. # You can play with it. Default is 1; #net.isr.direct=0 # This is for routers only #net.inet.ip.forwarding=1 #net.inet.ip.fastforwarding=1 # This speed ups dummynet when channel isn't saturated net.inet.ip.dummynet.io_fast=1 # Increase dummynet(4) hash #net.inet.ip.dummynet.hash_size=2048 #net.inet.ip.dummynet.max_chain_len # Should be increased when you have A LOT of files on server # (Increase until vfs.ufs.dirhash_mem becomes lower) vfs.ufs.dirhash_maxmem=67108864 # Note from commit http://svn.freebsd.org/base/head@211031 : # For systems with RAID volumes and/or virtualization envirnments, where # read performance is very important, increasing this sysctl tunable to 32 # or even more will demonstratively yield additional performance benefits. vfs.read_max=32 # Explicit Congestion Notification (see http://en.wikipedia.org/wiki/Explicit_Congestion_Notification) net.inet.tcp.ecn.enable=1 # Flowtable - flow caching mechanism # Useful for routers #net.inet.flowtable.enable=1 #net.inet.flowtable.nmbflows=65535 # Extreme polling tuning #kern.polling.burst_max=1000 #kern.polling.each_burst=1000 #kern.polling.reg_frac=100 #kern.polling.user_frac=1 #kern.polling.idle_poll=0 # IPFW dynamic rules and timeouts tuning # Increase dyn_buckets till net.inet.ip.fw.curr_dyn_buckets is lower net.inet.ip.fw.dyn_buckets=65536 net.inet.ip.fw.dyn_max=65536 net.inet.ip.fw.dyn_ack_lifetime=120 net.inet.ip.fw.dyn_syn_lifetime=10 net.inet.ip.fw.dyn_fin_lifetime=2 net.inet.ip.fw.dyn_short_lifetime=10 # Make packets pass firewall only once when using dummynet # i.e. packets going thru pipe are passing out from firewall with accept #net.inet.ip.fw.one_pass=1 # shm_use_phys Wires all shared pages, making them unswappable # Use this to lessen Virtual Memory Manager's work when using Shared Mem. # Useful for databases #kern.ipc.shm_use_phys=1 # ZFS # Enable prefetch. Useful for sequential load type i.e fileserver. # FreeBSD sets vfs.zfs.prefetch_disable to 1 on any i386 systems and # on any amd64 systems with less than 4GB of avaiable memory # For additional info check this nabble thread http://old.nabble.com/Samba-read-speed-performance-tuning-td27964534.html #vfs.zfs.prefetch_disable=0 # On highload servers you may notice following message in dmesg: # "Approaching the limit on PV entries, consider increasing either the # vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable" vm.pmap.shpgperproc=2048 loader.conf: # Accept filters for data, http and DNS requests # Useful when your software uses select() instead of kevent/kqueue or when you under DDoS # DNS accf available on 8.0+ accf_data_load="YES" accf_http_load="YES" accf_dns_load="YES" # Async IO system calls aio_load="YES" # Linux specific devices in /dev # As for 8.1 it only /dev/full #lindev_load="YES" # Adds NCQ support in FreeBSD # WARNING! all ad[0-9]+ devices will be renamed to ada[0-9]+ # 8.0+ only #ahci_load="YES" #siis_load="YES" # FreeBSD 8.2+ # New Congestion Control for FreeBSD # http://caia.swin.edu.au/urp/newtcp/tools/cc_chd-readme-0.1.txt # http://www.ietf.org/proceedings/78/slides/iccrg-5.pdf # Initial merge commit message http://www.mail-archive.com/[email protected]/msg31410.html #cc_chd_load="YES" # Increase kernel memory size to 3G. # # Use ONLY if you have KVA_PAGES in kernel configuration, and you have more than 3G RAM # Otherwise panic will happen on next reboot! # # It's required for high buffer sizes: kern.ipc.nmbjumbop, kern.ipc.nmbclusters, etc # Useful on highload stateful firewalls, proxies or ZFS fileservers # (FreeBSD 7.2+ amd64 users: Check that current value is lower!) #vm.kmem_size="3G" # If your server has lots of swap (>4Gb) you should increase following value # according to http://lists.freebsd.org/pipermail/freebsd-hackers/2009-October/029616.html # Otherwise you'll be getting errors # "kernel: swap zone exhausted, increase kern.maxswzone" # kern.maxswzone="256M" # Older versions of FreeBSD can't tune maxfiles on the fly #kern.maxfiles="200000" # Useful for databases # Sets maximum data size to 1G # (FreeBSD 7.2+ amd64 users: Check that current value is lower!) #kern.maxdsiz="1G" # Maximum buffer size(vfs.maxbufspace) # You can check current one via vfs.bufspace # Should be lowered/upped depending on server's load-type # Usually decreased to preserve kmem # (default is 10% of mem) #kern.maxbcache="512M" # Sendfile buffers # For i386 only #kern.ipc.nsfbufs=10240 # FreeBSD 9+ # HPET "legacy route" support. It should allow HPET to work per-CPU # See http://www.mail-archive.com/[email protected]/msg03603.html #hint.atrtc.0.clock=0 #hint.attimer.0.clock=0 #hint.hpet.0.legacy_route=1 # syncache Hash table tuning net.inet.tcp.syncache.hashsize=1024 net.inet.tcp.syncache.bucketlimit=512 net.inet.tcp.syncache.cachelimit=65536 # Increased hostcache # Later host cache can be viewed via net.inet.tcp.hostcache.list hidden sysctl # Very useful for it's RTT RTTVAR # Must be power of two net.inet.tcp.hostcache.hashsize=65536 # hashsize * bucketlimit (which is 30 by default) # It allocates 255Mb (1966080*136) of RAM net.inet.tcp.hostcache.cachelimit=1966080 # TCP control-block Hash table tuning net.inet.tcp.tcbhashsize=4096 # Disable ipfw deny all # Should be uncommented when there is a chance that # kernel and ipfw binary may be out-of sync on next reboot #net.inet.ip.fw.default_to_accept=1 # # SIFTR (Statistical Information For TCP Research) is a kernel module that # logs a range of statistics on active TCP connections to a log file. # See prerelease notes http://groups.google.com/group/mailing.freebsd.current/browse_thread/thread/b4c18be6cdce76e4 # and man 4 sitfr #siftr_load="YES" # Enable superpages, for 7.2+ only # Also read http://lists.freebsd.org/pipermail/freebsd-hackers/2009-November/030094.html vm.pmap.pg_ps_enabled=1 # Usefull if you are using Intel-Gigabit NIC #hw.em.rxd=4096 #hw.em.txd=4096 #hw.em.rx_process_limit="-1" # Also if you have ALOT interrupts on NIC - play with following parameters # NOTE: You should set them for every NIC #dev.em.0.rx_int_delay: 250 #dev.em.0.tx_int_delay: 250 #dev.em.0.rx_abs_int_delay: 250 #dev.em.0.tx_abs_int_delay: 250 # There is also multithreaded version of em/igb drivers can be found here: # http://people.yandex-team.ru/~wawa/ # # for additional em monitoring and statistics use # sysctl dev.em.0.stats=1 ; dmesg # sysctl dev.em.0.debug=1 ; dmesg # Also after r209242 (-CURRENT) there is a separate sysctl for each stat variable; # Same tunings for igb #hw.igb.rxd=4096 #hw.igb.txd=4096 #hw.igb.rx_process_limit=100 # Some useful netisr tunables. See sysctl net.isr #net.isr.maxthreads=4 #net.isr.defaultqlimit=4096 #net.isr.maxqlimit: 10240 # Bind netisr threads to CPUs #net.isr.bindthreads=1 # # FreeBSD 9.x+ # Increase interface send queue length # See commit message http://svn.freebsd.org/viewvc/base?view=revision&revision=207554 #net.link.ifqmaxlen=1024 # Nicer boot logo =) loader_logo="beastie" And finally here is KERNCONF: # Just some of them, see also # cat /sys/{i386,amd64,}/conf/NOTES # This one useful only on i386 #options KVA_PAGES=512 # You can play with HZ in environments with high interrupt rate (default is 1000) # 100 is for my notebook to prolong it's battery life #options HZ=100 # Polling is goot on network loads with high packet rates and low-end NICs # NB! Do not enable it if you want more than one netisr thread #options DEVICE_POLLING # Eliminate datacopy on socket read-write # To take advantage with zero copy sockets you should have an MTU >= 4k # This req. is only for receiving data. # Read more in man zero_copy_sockets # Also this epic thread on kernel trap: # http://kerneltrap.org/node/6506 # Here Linus says that "anybody that does it that way (FreeBSD) is totally incompetent" #options ZERO_COPY_SOCKETS # Support TCP sign. Used for IPSec options TCP_SIGNATURE # There was stackoverflow found in KAME IPSec stack: # See http://secunia.com/advisories/43995/ # For quick workaround you can use `ipfw add deny proto ipcomp` options IPSEC # This ones can be loaded as modules. They described in loader.conf section #options ACCEPT_FILTER_DATA #options ACCEPT_FILTER_HTTP # Adding ipfw, also can be loaded as modules options IPFIREWALL # On 8.1+ you can disable verbose to see blocked packets on ipfw0 interface. # Also there is no point in compiling verbose into the kernel, because # now there is net.inet.ip.fw.verbose tunable. #options IPFIREWALL_VERBOSE #options IPFIREWALL_VERBOSE_LIMIT=10 options IPFIREWALL_FORWARD # Adding kernel NAT options IPFIREWALL_NAT options LIBALIAS # Traffic shaping options DUMMYNET # Divert, i.e. for userspace NAT options IPDIVERT # This is for OpenBSD's pf firewall device pf device pflog # pf's QoS - ALTQ options ALTQ options ALTQ_CBQ # Class Bases Queuing (CBQ) options ALTQ_RED # Random Early Detection (RED) options ALTQ_RIO # RED In/Out options ALTQ_HFSC # Hierarchical Packet Scheduler (HFSC) options ALTQ_PRIQ # Priority Queuing (PRIQ) options ALTQ_NOPCC # Required for SMP build # Pretty console # Manual can be found here http://forums.freebsd.org/showthread.php?t=6134 #options VESA #options SC_PIXEL_MODE # Disable reboot on Ctrl Alt Del #options SC_DISABLE_REBOOT # Change normal|kernel messages color options SC_NORM_ATTR=(FG_GREEN|BG_BLACK) options SC_KERNEL_CONS_ATTR=(FG_YELLOW|BG_BLACK) # More scroll space options SC_HISTORY_SIZE=8192 # Adding hardware crypto device device crypto device cryptodev # Useful network interfaces device vlan device tap #Virtual Ethernet driver device gre #IP over IP tunneling device if_bridge #Bridge interface device pfsync #synchronization interface for PF device carp #Common Address Redundancy Protocol device enc #IPsec interface device lagg #Link aggregation interface device stf #IPv4-IPv6 port # Also for my notebook, but may be used with Opteron device amdtemp # Same for Intel processors device coretemp # man 4 cpuctl device cpuctl # CPU control pseudo-device # Support for ECMP. More than one route for destination # Works even with default route so one can use it as LB for two ISP # For now code is unstable and panics (panic: rtfree 2) on route deletions. #options RADIX_MPATH # Multicast routing #options MROUTING #options PIM # Debug & DTrace options KDB # Kernel debugger related code options KDB_TRACE # Print a stack trace for a panic options KDTRACE_FRAME # amd64-only(?) options KDTRACE_HOOKS # all architectures - enable general DTrace hooks #options DDB #options DDB_CTF # all architectures - kernel ELF linker loads CTF data # Adaptive spining in lockmgr (8.x+) # See http://www.mail-archive.com/[email protected]/msg10782.html options ADAPTIVE_LOCKMGRS # UTF-8 in console (8.x+) #options TEKEN_UTF8 # FreeBSD 8.1+ # Deadlock resolver thread # For additional information see http://www.mail-archive.com/[email protected]/msg18124.html # (FYI: "resolution" is panic so use with caution) #options DEADLKRES # Increase maximum size of Raw I/O and sendfile(2) readahead #options MAXPHYS=(1024*1024) #options MAXBSIZE=(1024*1024) # For scheduler debug enable following option. # Debug will be available via `kern.sched.stats` sysctl # For more information see http://svnweb.freebsd.org/base/head/sys/conf/NOTES?view=markup #options SCHED_STATS If you are tuning network for maximum performance you may wish to play with ifconfig options like: # You can list all capabilities via `ifconfig -m` ifconfig [-]rxcsum [-]txcsum [-]tso [-]lro mtu In case you've enabled DDB in kernel config, you should edit your /etc/ddb.conf and add something like this to enable automatic reboot (and textdump as bonus): script kdb.enter.panic=textdump set; capture on; show pcpu; bt; ps; alltrace; capture off; call doadump; reset script kdb.enter.default=textdump set; capture on; bt; ps; capture off; call doadump; reset And do not forget to add ddb_enable="YES" to /etc/rc.conf Since FreeBSD 9 you can select to enable/disable flowcontrol on your NIC: # See http://en.wikipedia.org/wiki/Ethernet_flow_control and # http://www.mail-archive.com/[email protected]/msg07927.html for additional info ifconfig bge0 media auto mediaopt flowcontrol PS. Also most of FreeBSD's limits can be monitored by # vmstat -z and # limits PPS. variety of network counters can be monitored via # netstat -s In FreeBSD-9 netstat's -Q option appeared, try following command to display netisr stats # netstat -Q PPPS. also see # man 7 tuning PPPPS. I wanted to thank FreeBSD community, especially author of nginx - Igor Sysoev, nginx-ru@ and FreeBSD-performance@ mailing lists for providing useful information about FreeBSD tuning. FreeBSD WIP * Whats cooking for FreeBSD 7? * Whats cooking for FreeBSD 8? * Whats cooking for FreeBSD 9? So here is the question: What tunings are you using on yours FreeBSD servers? You can also post your /etc/sysctl.conf, /boot/loader.conf, kernel options, etc with description of its' meaning (do not copy-paste from sysctl -d). Don't forget to specify server type (web, smb, gateway, etc) Let's share experience!

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• car race game collision condition.

  - by ashok patidar

  in this how can rotate car when it goes to collied with the track side. package { import flash.display.MovieClip; import flash.events.Event; import flash.events.KeyboardEvent; import flash.text.TextField; import flash.ui.Keyboard; import Math; /** * ... * @author Ashok */ public class F1race extends MovieClip { public var increment:Number = 0; //amount the car moves each frame public var posNeg:Number = 1; public var acceleration:Number = .05; //acceleration of the car, or the amount increment gets increased by. public var speed:Number = 0; //the speed of the car that will be displayed on screen public var maxSpeed:Number = 100; public var keyLeftPressed:Boolean; public var keyRightPressed:Boolean; public var keyUpPressed:Boolean; public var keyDownPressed:Boolean; public var spedometer:TextField = new TextField(); public var carRotation:Number ; public var txt_hit:TextField = new TextField(); public function F1race() { carRotation = carMC.rotation; trace(carMC.rotation); //addChild(spedometer); //spedometer.x = 0; //spedometer.y = 0; addChild(txt_hit); txt_hit.x = 0; txt_hit.y = 100; //rotation of the car addEventListener(Event.ENTER_FRAME, onEnterFrameFunction); stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressed,false); stage.addEventListener(KeyboardEvent.KEY_UP, keyReleased,false); carMC.addEventListener(Event.ENTER_FRAME, carOver_road) } public function carOver_road(event:Event):void { //trace(texture.hitTestPoint(carMC.x,carMC.y,true),"--"); /* if(!texture.hitTestPoint(carMC.x,carMC.y,true)) { txt_hit.text = "WRONG WAY"; if(increment!=0) { increment=1; } } else { txt_hit.text = ""; //increment++; }*/ if (roadless.hitTestPoint(carMC.x - carMC.width / 2, carMC.y,true)) { trace("left Hit" + carMC.rotation); //acceleration = .005; //if(carMC.rotation>90 || carMC.rotation>90 //carMC.rotation += 2; if ((carMC.rotation >= 90) && (carMC.rotation <= 180)) { carMC.rotation += 3; carMC.x += 3; } if ((carMC.rotation <= -90) && (carMC.rotation >= -180)) { carMC.rotation += 3; texture.y -= 3; } if ((carMC.rotation > -90) && (carMC.rotation <= -1)) { carMC.rotation += 3; texture.y -= 3; } if(increment<0) { increment += 1.5 * acceleration; } if(increment>0) { increment -= 1.5 * acceleration; } } if (roadless.hitTestPoint(carMC.x + carMC.width / 2, carMC.y,true)) { trace("left right"); //carMC.rotation -= 2; if(increment<0) { increment += 1.5 * acceleration; } if(increment>0) { increment -= 1.5 * acceleration; } } if (roadless.hitTestPoint(carMC.x, carMC.y- carMC.height / 2,true)) { trace("left right"); //carMC.rotation -= 2; if(increment<0) { increment += 1.5 * acceleration; } if(increment>0) { increment -= 1.5 * acceleration; } } if (roadless.hitTestPoint(carMC.x, carMC.y+ carMC.height / 2,true)) { trace("left right"); //carMC.rotation -= 2; if(increment<0) { increment += 1.5 * acceleration; } if(increment>0) { increment -= 1.5 * acceleration; } } if ((!roadless.hitTestPoint(carMC.x - carMC.width / 2, carMC.y, true)) && (!roadless.hitTestPoint(carMC.x, carMC.y- carMC.height / 2,true)) && (!roadless.hitTestPoint(carMC.x, carMC.y+ carMC.height / 2,true)) && (!roadless.hitTestPoint(carMC.x, carMC.y+ carMC.height / 2,true))) { //acceleration = .05; } } public function onEnterFrameFunction(events:Event):void { speed = Math.round((increment) * 5); spedometer.text = String(speed); if ((carMC.rotation < 180)&&(carMC.rotation >= 0)){ carRotation = carMC.rotation; posNeg = 1; } if ((carMC.rotation < 0)&&(carMC.rotation > -180)){ carRotation = -1 * carMC.rotation; posNeg = -1; } if (keyRightPressed) { carMC.rotation += .5 * increment; carMC.LWheel.rotation = 8; carMC.RWheel.rotation = 8; steering.gotoAndStop(2); } if (keyLeftPressed) { carMC.rotation -= .5 * increment; carMC.LWheel.rotation = -8; carMC.RWheel.rotation = -8; steering.gotoAndStop(3); } if (keyDownPressed) { steering.gotoAndStop(1); carMC.LWheel.rotation = 0; carMC.RWheel.rotation = 0; increment -= 0.5 * acceleration; texture.y -= ((90 - carRotation) / 90) * increment; roadless.y = texture.y; if (((carMC.rotation > 90)&&(carMC.rotation < 180))||((carMC.rotation < -90)&&(carMC.rotation > -180))) { texture.x += posNeg * (((((1 - (carRotation / 360)) * 360) - 180) / 90) * increment); roadless.x = texture.x; } if (((carMC.rotation <= 90)&&(carMC.rotation > 0))||((carMC.rotation >= -90)&&(carMC.rotation < -1))) { texture.x += posNeg * ((carRotation) / 90) * increment; roadless.x = texture.x; } increment -= 1 * acceleration; if ((Math.abs(speed)) < (Math.abs(maxSpeed))) { increment += acceleration; } if ((Math.abs(speed)) == (Math.abs(maxSpeed))) { trace("hello"); } } if (keyUpPressed) { steering.gotoAndStop(1); carMC.LWheel.rotation = 0; carMC.RWheel.rotation = 0; //trace(carMC.rotation); texture.y -= ((90 - carRotation) / 90) * increment; roadless.y = texture.y; if (((carMC.rotation > 90)&&(carMC.rotation < 180))||((carMC.rotation < -90)&&(carMC.rotation > -180))) { texture.x += posNeg * (((((1 - (carRotation / 360)) * 360) - 180) / 90) * increment); roadless.x = texture.x; } if (((carMC.rotation <= 90)&&(carMC.rotation > 0))||((carMC.rotation >= -90)&&(carMC.rotation < -1))) { texture.x += posNeg * ((carRotation) / 90) * increment; roadless.x = texture.x; } increment += 1 * acceleration; if ((Math.abs(speed)) < (Math.abs(maxSpeed))) { increment += acceleration; } } if ((!keyUpPressed) && (!keyDownPressed)){ /*if (increment > 0 && (!keyUpPressed)&& (!keyDownPressed)) { //texture.y -= ((90-carRotation)/90)*increment; increment -= 1.5 * acceleration; } if((increment==0)&&(!keyUpPressed)&& (!keyDownPressed)) { increment = 0; } if((increment<0)&&(!keyUpPressed)&& (!keyDownPressed)) { increment += 1.5 * acceleration; }*/ if (increment > 0) { increment -= 1.5 * acceleration; texture.y -= ((90 - carRotation) / 90) * increment; roadless.y = texture.y; if (((carMC.rotation > 90)&&(carMC.rotation < 180))||((carMC.rotation < -90)&&(carMC.rotation > -180))) { texture.x += posNeg * (((((1 - (carRotation / 360)) * 360) - 180) / 90) * increment); roadless.x = texture.x; } if (((carMC.rotation <= 90)&&(carMC.rotation > 0))||((carMC.rotation >= -90)&&(carMC.rotation < -1))) { texture.x += posNeg * ((carRotation) / 90) * increment; roadless.x = texture.x; } } if (increment == 0) { increment = 0; } if (increment < 0) { increment += 1.5 * acceleration; texture.y -= ((90 - carRotation) / 90) * increment; roadless.y = texture.y; if (((carMC.rotation > 90)&&(carMC.rotation < 180))||((carMC.rotation < -90)&&(carMC.rotation > -180))) { texture.x += posNeg * (((((1 - (carRotation / 360)) * 360) - 180) / 90) * increment); roadless.x = texture.x; } if (((carMC.rotation <= 90)&&(carMC.rotation > 0))||((carMC.rotation >= -90)&&(carMC.rotation < -1))) { texture.x += posNeg * ((carRotation) / 90) * increment; roadless.x = texture.x; } } } } public function keyPressed(event:KeyboardEvent):void { trace("keyPressed"); if (event.keyCode == Keyboard.LEFT) { keyLeftPressed = true; } if (event.keyCode == Keyboard.RIGHT) { keyRightPressed = true; } if (event.keyCode == Keyboard.UP) { keyUpPressed = true; } if (event.keyCode == Keyboard.DOWN) { keyDownPressed = true; } } public function keyReleased(event:KeyboardEvent):void { trace("keyReleased..."); //increment -= 1.5 * acceleration; //increment--; if (event.keyCode == Keyboard.LEFT) { keyLeftPressed = false; } if (event.keyCode == Keyboard.RIGHT) { keyRightPressed = false; } if (event.keyCode == Keyboard.UP) { keyUpPressed = false; } if (event.keyCode == Keyboard.DOWN) { keyDownPressed = false; } } } }

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• SQL SERVER – DMV – sys.dm_os_wait_stats Explanation – Wait Type – Day 3 of 28

  - by pinaldave

  The key Dynamic Management View (DMV) that helps us to understand wait stats is sys.dm_os_wait_stats; this DMV gives us all the information that we need to know regarding wait stats. However, the interpretation is left to us. This is a challenge as understanding wait stats can often be quite tricky. Anyway, we will cover few wait stats in one of the future articles. Today we will go over the basic understanding of the DMV. The Official Book OnLine Reference for DMV is over here: sys.dm_os_wait_stats. I suggest you all to refer this for all the accuracy. Following is a statement from the online book: “Specific types of wait times during query execution can indicate bottlenecks or stall points within the query. Similarly, high wait times, or wait counts server wide can indicate bottlenecks or hot spots in interaction query interactions within the server instance.” This is the statement which has inspired me to write this series. Let us first run the following statement from DMV. SELECT * FROM sys.dm_os_wait_stats ORDER BY wait_time_ms DESC GO Above statement will show us few of the columns. Here it is quick explanation of each of the column. wait_type – this is the name of the wait type. There can be three different kinds of wait types – resource, queue and external. waiting_tasks_count – this incremental counter is a good indication of frequent the wait is happening. If this number is very high, it is good indication for us to investigate that particular wait type. It is quite possible that the wait time is considerably low, but the frequency of the wait is much high. wait_time_ms – this is total wait accumulated for any type of wait. This is the total wait time and includes singal_wait_time_ms. max_wait_time_ms – this indicates the maximum wait type ever occurred for that particular wait type. Using this, one can estimate the intensity of the wait type in past. Again, it is not necessary that this max wait time will occur every time; so do not over invest yourself here. signal_wait_time_ms – this is the wait time when thread is marked as runnable and it gets to the running state. If the runnable queue is very long, you will find that this wait time becomes high. Additionally, please note that this DMV does not show current wait type or wait stats. This is cumulative view of the all the wait stats since server (instance) restarted or wait stats have been cleared. In future blog post, we will also cover two more DMVs which can be helpful to identify wait-related issues. ?sys.dm_os_waiting_tasks sys.dm_exec_requests Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• Big Data: Size isn’t everything

  - by Simon Elliston Ball

  Big Data has a big problem; it’s the word “Big”. These days, a quick Google search will uncover terabytes of negative opinion about the futility of relying on huge volumes of data to produce magical, meaningful insight. There are also many clichéd but correct assertions about the difficulties of correlation versus causation, in massive data sets. In reading some of these pieces, I begin to understand how climatologists must feel when people complain ironically about “global warming” during snowfall. Big Data has a name problem. There is a lot more to it than size. Shape, Speed, and…err…Veracity are also key elements (now I understand why Gartner and the gang went with V’s instead of S’s). The need to handle data of different shapes (Variety) is not new. Data developers have always had to mold strange-shaped data into our reporting systems, integrating with semi-structured sources, and even straying into full-text searching. However, what we lacked was an easy way to add semi-structured and unstructured data to our arsenal. New “Big Data” tools such as MongoDB, and other NoSQL (Not Only SQL) databases, or a graph database like Neo4J, fill this gap. Still, to many, they simply introduce noise to the clean signal that is their sensibly normalized data structures. What about speed (Velocity)? It’s not just high frequency trading that generates data faster than a single system can handle. Many other applications need to make trade-offs that traditional databases won’t, in order to cope with high data insert speeds, or to extract quickly the required information from data streams. Unfortunately, many people equate Big Data with the Hadoop platform, whose batch driven queries and job processing queues have little to do with “velocity”. StreamInsight, Esper and Tibco BusinessEvents are examples of Big Data tools designed to handle high-velocity data streams. Again, the name doesn’t do the discipline of Big Data any favors. Ultimately, though, does analyzing fast moving data produce insights as useful as the ones we get through a more considered approach, enabled by traditional BI? Finally, we have Veracity and Value. In many ways, these additions to the classic Volume, Velocity and Variety trio acknowledge the criticism that without high-quality data and genuinely valuable outputs then data, big or otherwise, is worthless. As a discipline, Big Data has recognized this, and data quality and cleaning tools are starting to appear to support it. Rather than simply decrying the irrelevance of Volume, we need as a profession to focus how to improve Veracity and Value. Perhaps we should just declare the ‘Big’ silent, embrace these new data tools and help develop better practices for their use, just as we did the good old RDBMS? What does Big Data mean to you? Which V gives your business the most pain, or the most value? Do you see these new tools as a useful addition to the BI toolbox, or are they just enabling a dangerous trend to find ghosts in the noise?

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• Using the Onboard VGA output with a PCIe video card. Both nVidia

  - by sebikul

  I have 2 video cards, one On board, a nVidia 6150SE nForce 430 and a PCIe nVidia GeForce GT 220 1GB DDR2 RAM I have already configured the PCIe card to use the dual monitor feature, using the VGA and HDMI ports, but now I want to add a third monitor, using the On board VGA port I have managed to enable the On board graphics processor, which is taking 400MB of ram, but I cant manage to use it, nvidia-settings does not detect it, like it's not usable (but is there) My questions are the following: How can I manage to get the On board VGA display to work together with the PCIe graphics card? If possible, how can I recover those 400 MB the on board card is taking (even without being used) or how can I get it to use the PCIe card available memory? System Details: Linux 2.6.35-28-generic i686 Ubuntu 10.10 (All updates installed) NVIDIA Driver Version: 260.19.06 (Official) If more info is needed please let me know. Here is the lspci output when the On board card is disabled: 00:00.0 RAM memory: nVidia Corporation MCP61 Memory Controller (rev a1) 00:01.0 ISA bridge: nVidia Corporation MCP61 LPC Bridge (rev a2) 00:01.1 SMBus: nVidia Corporation MCP61 SMBus (rev a2) 00:01.2 RAM memory: nVidia Corporation MCP61 Memory Controller (rev a2) 00:01.3 Co-processor: nVidia Corporation MCP61 SMU (rev a2) 00:02.0 USB Controller: nVidia Corporation MCP61 USB Controller (rev a3) 00:02.1 USB Controller: nVidia Corporation MCP61 USB Controller (rev a3) 00:04.0 PCI bridge: nVidia Corporation MCP61 PCI bridge (rev a1) 00:05.0 Audio device: nVidia Corporation MCP61 High Definition Audio (rev a2) 00:06.0 IDE interface: nVidia Corporation MCP61 IDE (rev a2) 00:07.0 Bridge: nVidia Corporation MCP61 Ethernet (rev a2) 00:08.0 IDE interface: nVidia Corporation MCP61 SATA Controller (rev a2) 00:09.0 PCI bridge: nVidia Corporation MCP61 PCI Express bridge (rev a2) 00:0b.0 PCI bridge: nVidia Corporation MCP61 PCI Express bridge (rev a2) 00:0c.0 PCI bridge: nVidia Corporation MCP61 PCI Express bridge (rev a2) 00:0d.0 VGA compatible controller: nVidia Corporation C61 [GeForce 6150SE nForce 430] (rev a2) 00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration 00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map 00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller 00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control 01:09.0 Ethernet controller: Intel Corporation 82557/8/9/0/1 Ethernet Pro 100 (rev 08) 02:00.0 VGA compatible controller: nVidia Corporation GT216 [GeForce GT 220] (rev a2) 02:00.1 Audio device: nVidia Corporation High Definition Audio Controller (rev a1) And this is when both are enabled: 00:00.0 RAM memory: nVidia Corporation MCP61 Memory Controller (rev a1) 00:01.0 ISA bridge: nVidia Corporation MCP61 LPC Bridge (rev a2) 00:01.1 SMBus: nVidia Corporation MCP61 SMBus (rev a2) 00:01.2 RAM memory: nVidia Corporation MCP61 Memory Controller (rev a2) 00:01.3 Co-processor: nVidia Corporation MCP61 SMU (rev a2) 00:02.0 USB Controller: nVidia Corporation MCP61 USB Controller (rev a3) 00:02.1 USB Controller: nVidia Corporation MCP61 USB Controller (rev a3) 00:04.0 PCI bridge: nVidia Corporation MCP61 PCI bridge (rev a1) 00:05.0 Audio device: nVidia Corporation MCP61 High Definition Audio (rev a2) 00:06.0 IDE interface: nVidia Corporation MCP61 IDE (rev a2) 00:07.0 Bridge: nVidia Corporation MCP61 Ethernet (rev a2) 00:08.0 IDE interface: nVidia Corporation MCP61 SATA Controller (rev a2) 00:09.0 PCI bridge: nVidia Corporation MCP61 PCI Express bridge (rev a2) 00:0b.0 PCI bridge: nVidia Corporation MCP61 PCI Express bridge (rev a2) 00:0c.0 PCI bridge: nVidia Corporation MCP61 PCI Express bridge (rev a2) 00:0d.0 VGA compatible controller: nVidia Corporation C61 [GeForce 6150SE nForce 430] (rev a2) 00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration 00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map 00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller 00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control 01:09.0 Ethernet controller: Intel Corporation 82557/8/9/0/1 Ethernet Pro 100 (rev 08) 02:00.0 VGA compatible controller: nVidia Corporation GT216 [GeForce GT 220] (rev a2) 02:00.1 Audio device: nVidia Corporation High Definition Audio Controller (rev a1) Output of lshw -class display: *-display description: VGA compatible controller product: GT216 [GeForce GT 220] vendor: nVidia Corporation physical id: 0 bus info: pci@0000:02:00.0 version: a2 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vga_controller bus_master cap_list rom configuration: driver=nvidia latency=0 resources: irq:18 memory:df000000-dfffffff memory:c0000000-cfffffff memory:da000000-dbffffff ioport:ef80(size=128) memory:def80000-deffffff *-display description: VGA compatible controller product: C61 [GeForce 6150SE nForce 430] vendor: nVidia Corporation physical id: d bus info: pci@0000:00:0d.0 version: a2 width: 64 bits clock: 66MHz capabilities: pm msi vga_controller bus_master cap_list rom configuration: driver=nvidia latency=0 resources: irq:22 memory:dd000000-ddffffff memory:b0000000-bfffffff memory:dc000000-dcffffff memory:deb40000-deb5ffff If what I'm looking for is not possible, please tell me, so I can disable the On board card and recover those 400MB of wasted RAM Thanks for your help!

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• How many bits for sequence number using Go-Back-N protocol.

  - by Mike

  Hi Everyone, I'm a regular over at Stack Overflow (Software developer) that is trying to get through a networking course. I got a homework problem I'd like to have a sanity check on. Here is what I got. Q: A 3000-km-long T1 trunk is used to transmit 64-byte frames using Go-Back-N protocol. If the propagation speed is 6 microseconds/km, how many bits should the sequence numbers be? My Answer: For this questions what we need to do is lay the base knowledge. What we are trying to find is the size of the largest sequence number we should us using Go-Back-N. To figure this out we need to figure out how many packets can fit into our link at a time and then subtract one from that number. This will ensure that we never have two packets with the same sequence number at the same time in the link. Length of link: 3,000km Speed: 6 microseconds / km Frame size: 64 bytes T1 transmission speed: 1544kb/s (http://ckp.made-it.com/t1234.html) Propagation time = 6 microseconds / km * 3000 km = 18,000 microseconds (18ms). Convert 1544kb to bytes = 1544 * 1024 = 1581056 bytes Transmission time = 64 bytes / 1581056bytes / second = 0.000040479 seconds (0.4ms) So then if we take the 18ms propagation time and divide it by the 0.4ms transmission time we will see that we are going to be able to stuff ( 18 / 0.4) 45 packets into the link at a time. That means that our sequence number should be 2 ^ 45 bits long! Am I going in the right direction with this? Thanks, Mike

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• Alternative to robocopy /MIR

  - by Robin Day

  We run a number of web apps that store a lot of local data in small xml files. One part of our backup / recovery strategy is to produce a local mirror of the file system via a VPN to the hosting centre. The VPN connection is only via a 12Mbps ADSL and whilst there are a lot of files and directories, the actual number of files that changes is quite small. Although the bandwidth is probably an issue, I'm seeing results such as the output below. The robocopy /MIR took 5 hours to run yet only 30 mins to actually perform the copy. Does anyone have any suggestions as to ways to improve this. The 5 hours is now bordering on too slow and if we can't find a way to speed this up then we're going to have to come up with a completely different solution. Total Copied Skipped Mismatch FAILED Extras Dirs : 17625 6618 11007 0 0 0 Files : 1112430 1223 1111207 0 0 0 Bytes : 57.451 g 192.25 m 57.263 g 0 0 0 Times : 5:01:23 0:35:55 0:00:00 4:25:27 Speed : 93509 Bytes/sec. Speed : 5.350 MegaBytes/min. Ended : Fri Apr 16 05:54:23 2010

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• iPod touch has extremely slow wifi, drops packets - only on my router

  - by mskfisher

  I just purchased an iPod Touch. I am having a lot of trouble with its speeds on my Tenda W311R, but it has no speed problems on my neighbor's Netgear router. It will connect and authenticate to my network, but the Speed Test app from speedtest.net shows rates near 20-50 kbps. If I run the speed test immediately after powering the iPod on, it will get speeds of 10-20 Mbps, like it should - but the speeds slow down to the kbps range abut 10-15 seconds afterward. I get the same behavior with encryption and without encryption, and regardless of N, G, or B compatibility settings in the router. I've tried rebooting the iPod and resetting the network settings, but it's still slow. I've tried pinging the iPod from another computer, and it shows about 40% packet loss: $ ping 192.168.0.111 PING 192.168.0.111 (192.168.0.111): 56 data bytes 64 bytes from 192.168.0.111: icmp_seq=0 ttl=64 time=14.188 ms 64 bytes from 192.168.0.111: icmp_seq=1 ttl=64 time=11.556 ms 64 bytes from 192.168.0.111: icmp_seq=2 ttl=64 time=5.675 ms 64 bytes from 192.168.0.111: icmp_seq=3 ttl=64 time=5.721 ms Request timeout for icmp_seq 4 64 bytes from 192.168.0.111: icmp_seq=5 ttl=64 time=6.491 ms Request timeout for icmp_seq 6 64 bytes from 192.168.0.111: icmp_seq=7 ttl=64 time=8.065 ms Request timeout for icmp_seq 8 Request timeout for icmp_seq 9 Request timeout for icmp_seq 10 64 bytes from 192.168.0.111: icmp_seq=11 ttl=64 time=9.605 ms Signal strength is good - I'm never more than 20 feet from my access point, and it exhibits the same behavior if I'm standing next to the router. It works just well enough to receive text, but videos don't work at all. App downloads are hit and miss. I've tweaked just about all of the settings I can see to tweak, and I'm at a loss. I have also been searching Google for the past three days, all to no avail. Any suggestions?

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• Max. Bandwidth Cannot be Reached

  - by Poyraz Sagtekin

  I have a question regarding the bandwidth usage. I don't think it's a very technical question but I really want to know the reason behind the problem. I'm having my education in one of my university's campuses. There is a 200mbps bandwidth availability for approx. 2100 students. Our main campus has 25,000 students and 2gbps bandwidth and there is no problem with the internet connection speed in main campus. However, in my campus, we are having difficulties with the internet connection speed. I went to IT department of my university and they've showed me some graphics about the bandwidth usage. The usage of the bandwidth has never reached 200mbps and it generally is around 130-140mbps. According to this information, maximum bandwidth is never made by the users but the browsing speed is not very convincing. What can be the problem? Maybe this is a silly question but I really want to know the reason. They told me that they've reached 180mbps before.

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• How to wire 20 computers and 20 phones and 1 server into LAN?

  - by John Smith

  I have currently 3 switches Two Netgear JFS524 with 24 slots, One Belkin with 16 slots. Server DSL Internet Router. Main question is how to connect switches together, two Netgear's are next to each other, yet one is about 100 feet away and holds about 5 computer and 5 phones. If i connect them with only 1 wire will that limit bandwidth? e.g. all 23 computers will be limited to speed of one CAT5e cable? If i connect switches with 2 cables will this give speed boost? What's the ideal scenario should i just move the third switch next to other two? Will the speed of computer connected to white switch be same as computer connected to top switch? Will moving white switch right next top switch and having 16 wires comming 100 feet instead of 1 wire comming 100 feet make it faster? EDIT 1: I actually have NETGEAR ProSafe GS105 Gigabit switch its only has 4 ports in it though, you think i can have use of it in current setup? Like connect all 3 switches and server into it and keep internet router and phone server on one of the slower switches EDIT 2: Everyone mention gigabit switches, but will they do any difference with 10/100 network cards? I then have to use gigabit cards in every computer too? I could in server perhaps, but users will be 10/100

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• USB keyboard stopped working in Ubuntu with error -71

  - by tapan

  I have a usb keyboard which was working perfectly till now (about a year since i have been regularly using ubuntu). It suddenly stopped working. It stopped working when I connected a USB HDD. Now the keyboard works randomly .. working for a while and then stops working for a longer time. Here is the dmesg output : [ 705.817076] usb 5-1: device not accepting address 8, error -71 [ 705.928032] usb 5-1: new low speed USB device using uhci_hcd and address 9 [ 706.336060] usb 5-1: device not accepting address 9, error -71 [ 706.448055] usb 5-1: new low speed USB device using uhci_hcd and address 10 [ 706.568044] usb 5-1: device descriptor read/64, error -71 [ 706.792049] usb 5-1: device descriptor read/64, error -71 [ 707.008060] usb 5-1: new low speed USB device using uhci_hcd and address 11 [ 707.128041] usb 5-1: device descriptor read/64, error -71 [ 707.352052] usb 5-1: device descriptor read/64, error -71 [ 707.456068] hub 5-0:1.0: unable to enumerate USB device on port 1 Based on the suggestions here i tried the following two things: echo -1 > /sys/module/usbcore/parameters/autosuspend echo Y > /sys/module/usbcore/parameters/old_scheme_first However, i am still facing the same problem. Can anyone help me out with this ? I'm using Ubuntu 10.04 Lucid Lynx.

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• Cisco Catalyst 3750 connected to Cisco ASA 5505 and dropping packets

  - by Bo102010

  (Cross posted from Super User per suggestion there) At the office, I have inherited a network that I am still trying to fully comprehend. I have a problem today with a new connection between: A port on a Cisco Catalyst 3750 [WS-C3750G-48TS-S running C3750-IPSERVICESK9-M version 12.2(53)SE1] A port on a Cisco ASA 5505 [ASA Software version 8.3(2)] The 3750 is home to a Vlan that has a few ports assigned to it. interface Vlan3 description Internal network (172.18.160.0/24) ip address 172.18.160.1 255.255.255.0 I have a host (outside of my control) that needs to be in this VLAN (i.e it must have an address 172.18.160.something/24) that also needs to access the Internet. To accomplish this, I ran a link from the Catalyst (Gi1/0/13) to the ASA (Ethernet 0/5). I configured the Catalyst port like so: interface GigabitEthernet1/0/13 description To ASA, 172.18.160.69 switchport access vlan 3 switchport mode access speed 100 duplex full I configured the ASA like so: interface Vlan1 nameif inside security-level 100 ip address 172.18.160.69 255.255.255.0 interface Ethernet0/5 speed 100 duplex full Then I plugged the host into Ethernet 0/4 on the ASA and instructed its owner to make its default gateway 172.18.160.69. I made a NAT rule in the ASA and set up some rules, and it's able to access the Internet without issue. However, I noticed that the Catalyst reports a ton of packets being dropped toward the ASA. Catalyst3750#show interfaces GigabitEthernet 1/0/13 | include counters|drops Last clearing of "show interface" counters 00:28:13 Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 136909347 This is a huge number of drops, since there's not much traffic on this VLAN at all. I tried these things: Make sure speed and duplex agree on both sides (100 Mbps / Full) Set no cdp enable on the Catalyst Gi10/13 Set no keepalive on the Catalyst Gi10/13 Checked for excessive CPU usage on both Checked for excessive traffic on both Am I missing something? Any help would be appreciated.

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