running costs - Page 215

Connecting 2 ubuntu machines as a LAN

- by Brendan Cutjar

Hi i am trying to connect 2 ubuntu computers as a LAN. In my current setup I have: One machine running ubuntu 11.10 with Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller While the other machine is running Ubuntu 12.04 with an Atheros Communications Inc AR8152 v1.1 Fast Ethernet The two machines are connected via a switch (Edimax ES-3205P). Unfortunately I still cannot connect the two machines together. Can somebody please show me what to do and how to go about solving this issue? Thank you ANSWERED All I had to do was set up both ip's maually, subnet mask to 255.255.255.0 and left blank both gateway and DNS.

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Run command in command prompt from Ruby application

- by Julian

I have a command-line Ruby application that uses Curses to create a GUI. This GUI is absolutely mangled by Windows' command prompt if the command prompt window is too small. The command prompt window can be resized in properties. However, I want to resize it programatically. Running this command in the command prompt (nothing to do with Ruby) will resize the command prompt window to desired variables. mode con:cols=120 lines=40 Can I do this purely in Ruby? Or, failing that (I suspect doing it purely in Ruby may be impossible) can my ruby application actually run that command and 'hit enter', and resize window it's running in?

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Linux router: ping doesn't route back

- by El Barto

I have a Debian box which I'm trying to set up as a router and an Ubuntu box which I'm using as a client. My problem is that when the Ubuntu client tries to ping a server on the Internet, all the packets are lost (though, as you can see below, they seem to go to the server and back without problem). I'm doing this in the Ubuntu Box: # ping -I eth1 my.remote-server.com PING my.remote-server.com (X.X.X.X) from 10.1.1.12 eth1: 56(84) bytes of data. ^C --- my.remote-server.com ping statistics --- 13 packets transmitted, 0 received, 100% packet loss, time 12094ms (I changed the name and IP of the remote server for privacy). From the Debian Router I see this: # tcpdump -i eth1 -qtln icmp tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes IP X.X.X.X > 10.1.1.12: ICMP echo reply, id 305, seq 7, length 64 IP 10.1.1.12 > X.X.X.X: ICMP echo request, id 305, seq 8, length 64 IP X.X.X.X > 10.1.1.12: ICMP echo reply, id 305, seq 8, length 64 IP 10.1.1.12 > X.X.X.X: ICMP echo request, id 305, seq 9, length 64 IP X.X.X.X > 10.1.1.12: ICMP echo reply, id 305, seq 9, length 64 IP 10.1.1.12 > X.X.X.X: ICMP echo request, id 305, seq 10, length 64 IP X.X.X.X > 10.1.1.12: ICMP echo reply, id 305, seq 10, length 64 IP 10.1.1.12 > X.X.X.X: ICMP echo request, id 305, seq 11, length 64 IP X.X.X.X > 10.1.1.12: ICMP echo reply, id 305, seq 11, length 64 ^C 9 packets captured 9 packets received by filter 0 packets dropped by kernel # tcpdump -i eth2 -qtln icmp tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth2, link-type EN10MB (Ethernet), capture size 65535 bytes IP 192.168.1.10 > X.X.X.X: ICMP echo request, id 360, seq 213, length 64 IP X.X.X.X > 192.168.1.10: ICMP echo reply, id 360, seq 213, length 64 IP 192.168.1.10 > X.X.X.X: ICMP echo request, id 360, seq 214, length 64 IP X.X.X.X > 192.168.1.10: ICMP echo reply, id 360, seq 214, length 64 IP 192.168.1.10 > X.X.X.X: ICMP echo request, id 360, seq 215, length 64 IP X.X.X.X > 192.168.1.10: ICMP echo reply, id 360, seq 215, length 64 IP 192.168.1.10 > X.X.X.X: ICMP echo request, id 360, seq 216, length 64 IP X.X.X.X > 192.168.1.10: ICMP echo reply, id 360, seq 216, length 64 IP 192.168.1.10 > X.X.X.X: ICMP echo request, id 360, seq 217, length 64 IP X.X.X.X > 192.168.1.10: ICMP echo reply, id 360, seq 217, length 64 ^C 10 packets captured 10 packets received by filter 0 packets dropped by kernel And at the remote server I see this: # tcpdump -i eth0 -qtln icmp tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes IP Y.Y.Y.Y > X.X.X.X: ICMP echo request, id 360, seq 1, length 64 IP X.X.X.X > Y.Y.Y.Y: ICMP echo reply, id 360, seq 1, length 64 IP Y.Y.Y.Y > X.X.X.X: ICMP echo request, id 360, seq 2, length 64 IP X.X.X.X > Y.Y.Y.Y: ICMP echo reply, id 360, seq 2, length 64 IP Y.Y.Y.Y > X.X.X.X: ICMP echo request, id 360, seq 3, length 64 IP X.X.X.X > Y.Y.Y.Y: ICMP echo reply, id 360, seq 3, length 64 IP Y.Y.Y.Y > X.X.X.X: ICMP echo request, id 360, seq 4, length 64 IP X.X.X.X > Y.Y.Y.Y: ICMP echo reply, id 360, seq 4, length 64 IP Y.Y.Y.Y > X.X.X.X: ICMP echo request, id 360, seq 5, length 64 IP X.X.X.X > Y.Y.Y.Y: ICMP echo reply, id 360, seq 5, length 64 IP Y.Y.Y.Y > X.X.X.X: ICMP echo request, id 360, seq 6, length 64 IP X.X.X.X > Y.Y.Y.Y: ICMP echo reply, id 360, seq 6, length 64 IP Y.Y.Y.Y > X.X.X.X: ICMP echo request, id 360, seq 7, length 64 IP X.X.X.X > Y.Y.Y.Y: ICMP echo reply, id 360, seq 7, length 64 IP Y.Y.Y.Y > X.X.X.X: ICMP echo request, id 360, seq 8, length 64 IP X.X.X.X > Y.Y.Y.Y: ICMP echo reply, id 360, seq 8, length 64 IP Y.Y.Y.Y > X.X.X.X: ICMP echo request, id 360, seq 9, length 64 IP X.X.X.X > Y.Y.Y.Y: ICMP echo reply, id 360, seq 9, length 64 18 packets captured 228 packets received by filter 92 packets dropped by kernel Here "X.X.X.X" is my remote server's IP and "Y.Y.Y.Y" is my local network's public IP. So, what I understand is that the ping packets are coming out of the Ubuntu box (10.1.1.12), to the router (10.1.1.1), from there to the next router (192.168.1.1) and reaching the remote server (X.X.X.X). Then they come back all the way to the Debian router, but they never reach the Ubuntu box back. What am I missing? Here's the Debian router setup: # ifconfig eth1 Link encap:Ethernet HWaddr 94:0c:6d:82:0d:98 inet addr:10.1.1.1 Bcast:10.1.1.255 Mask:255.255.255.0 inet6 addr: fe80::960c:6dff:fe82:d98/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:105761 errors:0 dropped:0 overruns:0 frame:0 TX packets:48944 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:40298768 (38.4 MiB) TX bytes:44831595 (42.7 MiB) Interrupt:19 Base address:0x6000 eth2 Link encap:Ethernet HWaddr 6c:f0:49:a4:47:38 inet addr:192.168.1.10 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::6ef0:49ff:fea4:4738/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:38335992 errors:0 dropped:0 overruns:0 frame:0 TX packets:37097705 errors:0 dropped:0 overruns:0 carrier:1 collisions:0 txqueuelen:1000 RX bytes:4260680226 (3.9 GiB) TX bytes:3759806551 (3.5 GiB) Interrupt:27 eth3 Link encap:Ethernet HWaddr 94:0c:6d:82:c8:72 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:20 Base address:0x2000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:3408 errors:0 dropped:0 overruns:0 frame:0 TX packets:3408 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:358445 (350.0 KiB) TX bytes:358445 (350.0 KiB) tun0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 inet addr:10.8.0.1 P-t-P:10.8.0.2 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1 RX packets:2767779 errors:0 dropped:0 overruns:0 frame:0 TX packets:1569477 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:100 RX bytes:3609469393 (3.3 GiB) TX bytes:96113978 (91.6 MiB) # route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 10.8.0.2 0.0.0.0 255.255.255.255 UH 0 0 0 tun0 127.0.0.1 0.0.0.0 255.255.255.255 UH 0 0 0 lo 10.8.0.0 10.8.0.2 255.255.255.0 UG 0 0 0 tun0 192.168.1.0 0.0.0.0 255.255.255.0 U 1 0 0 eth2 10.1.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth2 # arp -n # Note: Here I have changed all the different MACs except the ones corresponding to the Ubuntu box (on 10.1.1.12 and 192.168.1.12) Address HWtype HWaddress Flags Mask Iface 192.168.1.118 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.72 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.94 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.102 ether NN:NN:NN:NN:NN:NN C eth2 10.1.1.12 ether 00:1e:67:15:2b:f0 C eth1 192.168.1.86 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.2 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.61 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.64 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.116 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.91 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.52 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.93 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.87 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.92 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.100 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.40 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.53 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.1 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.83 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.89 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.12 ether 00:1e:67:15:2b:f1 C eth2 192.168.1.77 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.66 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.90 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.65 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.41 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.78 ether NN:NN:NN:NN:NN:NN C eth2 192.168.1.123 ether NN:NN:NN:NN:NN:NN C eth2 # iptables -L -n Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination # iptables -L -n -t nat Chain PREROUTING (policy ACCEPT) target prot opt source destination Chain POSTROUTING (policy ACCEPT) target prot opt source destination MASQUERADE all -- 10.1.1.0/24 !10.1.1.0/24 MASQUERADE all -- !10.1.1.0/24 10.1.1.0/24 Chain OUTPUT (policy ACCEPT) target prot opt source destination And here's the Ubuntu box: # ifconfig eth0 Link encap:Ethernet HWaddr 00:1e:67:15:2b:f1 inet addr:192.168.1.12 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::21e:67ff:fe15:2bf1/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:28785139 errors:0 dropped:0 overruns:0 frame:0 TX packets:19050735 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:32068182803 (32.0 GB) TX bytes:6061333280 (6.0 GB) Interrupt:16 Memory:b1a00000-b1a20000 eth1 Link encap:Ethernet HWaddr 00:1e:67:15:2b:f0 inet addr:10.1.1.12 Bcast:10.1.1.255 Mask:255.255.255.0 inet6 addr: fe80::21e:67ff:fe15:2bf0/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:285086 errors:0 dropped:0 overruns:0 frame:0 TX packets:12719 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:30817249 (30.8 MB) TX bytes:2153228 (2.1 MB) Interrupt:16 Memory:b1900000-b1920000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:86048 errors:0 dropped:0 overruns:0 frame:0 TX packets:86048 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:11426538 (11.4 MB) TX bytes:11426538 (11.4 MB) # route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth0 0.0.0.0 10.1.1.1 0.0.0.0 UG 100 0 0 eth1 10.1.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 10.8.0.0 192.168.1.10 255.255.255.0 UG 0 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0 192.168.1.0 0.0.0.0 255.255.255.0 U 1 0 0 eth0 # arp -n # Note: Here I have changed all the different MACs except the ones corresponding to the Debian box (on 10.1.1.1 and 192.168.1.10) Address HWtype HWaddress Flags Mask Iface 192.168.1.70 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.90 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.97 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.103 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.13 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.120 (incomplete) eth0 192.168.1.111 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.118 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.51 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.102 (incomplete) eth0 192.168.1.64 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.52 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.74 (incomplete) eth0 192.168.1.94 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.121 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.72 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.87 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.91 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.71 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.78 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.83 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.88 (incomplete) eth0 192.168.1.82 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.98 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.100 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.93 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.73 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.11 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.85 (incomplete) eth0 192.168.1.112 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.89 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.65 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.81 ether NN:NN:NN:NN:NN:NN C eth0 10.1.1.1 ether 94:0c:6d:82:0d:98 C eth1 192.168.1.53 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.116 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.61 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.10 ether 6c:f0:49:a4:47:38 C eth0 192.168.1.86 (incomplete) eth0 192.168.1.119 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.66 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.1 ether NN:NN:NN:NN:NN:NN C eth0 192.168.1.1 ether NN:NN:NN:NN:NN:NN C eth1 192.168.1.92 ether NN:NN:NN:NN:NN:NN C eth0 # iptables -L -n Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination # iptables -L -n -t nat Chain PREROUTING (policy ACCEPT) target prot opt source destination Chain INPUT (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination Chain POSTROUTING (policy ACCEPT) target prot opt source destination Edit: Following Patrick's suggestion, I did a tcpdump con the Ubuntu box and I see this: # tcpdump -i eth1 -qtln icmp tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes IP 10.1.1.12 > X.X.X.X: ICMP echo request, id 21967, seq 1, length 64 IP X.X.X.X > 10.1.1.12: ICMP echo reply, id 21967, seq 1, length 64 IP 10.1.1.12 > X.X.X.X: ICMP echo request, id 21967, seq 2, length 64 IP X.X.X.X > 10.1.1.12: ICMP echo reply, id 21967, seq 2, length 64 IP 10.1.1.12 > X.X.X.X: ICMP echo request, id 21967, seq 3, length 64 IP X.X.X.X > 10.1.1.12: ICMP echo reply, id 21967, seq 3, length 64 IP 10.1.1.12 > X.X.X.X: ICMP echo request, id 21967, seq 4, length 64 IP X.X.X.X > 10.1.1.12: ICMP echo reply, id 21967, seq 4, length 64 IP 10.1.1.12 > X.X.X.X: ICMP echo request, id 21967, seq 5, length 64 IP X.X.X.X > 10.1.1.12: ICMP echo reply, id 21967, seq 5, length 64 IP 10.1.1.12 > X.X.X.X: ICMP echo request, id 21967, seq 6, length 64 IP X.X.X.X > 10.1.1.12: ICMP echo reply, id 21967, seq 6, length 64 ^C 12 packets captured 12 packets received by filter 0 packets dropped by kernel So the question is: if all packets seem to be coming and going, why does ping report 100% packet loss?

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Set default browser to OPEN browser

- by dmeu

Hi I am switching constantly between browsers (three different at the moment). So i was also switching default browsers to open my mail / new links etc... I also saw that with the command sudo update-alternatives --config x-www-browser the browsers have different priorities. So I had the idea that it could be possible that the default browser could be the browser/s that is/are actually open and running! And if two are running, the one with higher priority is chosen. Unluckily I did not find anything.. Is this possible? Would be really great! cheers dmeu

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Automated deployment/installation of development tools

- by thegreendroid

My team is looking to automate installation/deployment of all of our development tools. The main driver for this is to ensure that everyone in the team has a consistent development environment setup and to also allow a new recruit to get up and running easily. By development environment I mean tools like SCM, toolchains, IDEs etc. and by consistent I mean everyone using the same version of compiler to build code (this is very important!). Here are a few of our requirements – Allow unattended (silent) install of our entire dev setup by running a single script Ability to deploy selective updates (new versions) for specific tools Ability to report which tools are installed and their specific version numbers Must work on Windows (Linux would be a bonus) Must be easy to maintain What are some of the tools that you've used to automate such a task?

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Unable to get screen signal after purge FGLRX

- by Boris

I thought that my ATI driver was not running well so I wanted to re-instal it completely. I did: sudo apt-get remove --purge fglrx* sudo apt-get remove --purge xserver-xorg-video-ati xserver-xorg-video-radeon and after a boot I wanted to intal the ATI driver BUT at the boot no more signal to my screen. Since, every time I turn on my PC it gets to purple screen and then screen shuts down ! Note that: Even if the screen is off, PC seems to be running almost well: I m still able to use my network to access data shared with NFS. Using live USB I have no screen problem. I tried to plug my screen on an alternative output but it did not work. I tried CTRL+ALT+F1 while being on purple screen but it does not do anything, screen shut down anyway. I m going to try the SHIFT thing and learn from blackscreen wiki...

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Safely deploying changes to production servers

- by oazabir

When you deploy incremental changes on a production server, which is running and live all the time, you some times see error messages like “Compiler Error Message: The Type ‘XXX’ exists in both…”. Sometimes you find Application_Start event not firing although you shipped a new class, dll or web.config. Sometimes you find static variables not getting initialized and so on. There are so many weird things happen on webservers when you incrementally deploy changes to the server and the server has been up and running for several weeks. So, I came up with a full proof house keeping steps that we always do whenever we deploy some incremental change to our websites. These steps ensure that the web sites are properly recycled , cached are cleared, all the data stored at Application level is initialized. First of all you should have multiple web servers behind load balancer. This way you can take one server our of the production traffic, do your deployment and house keeping tasks like restarting IIS, and then put it back. Then you can do it for the second server and so on. This ensures there’s no outage for customer. If you can do it reasonable fast, hopefully customers won’t notice discrepancy between the servers some having new code and some having old code. You should only do this when your changes aren’t drastic. For ex, you aren’t delivering a complete revamped UI. In that case, some users hitting server1 with latest UI will suddenly get a completely different experience and then on next page refresh, they might hit server2 with old code and get a totally different experience. This works for incremental non-dramatic changes only. During deployment you should follow these steps: Take server X out of load balancer so that it does not get any traffic. Stop all windows services on the server. Stop IIS. Delete the Temporary ASP.NET folders of all .NET versions incase you have multiple .NET versions running. You can follow this link. Deploy the changes. Flush any distributed cache you have, for ex, Velocity or Memcached. Start IIS. Start the windows services on the server. Warm up all websites by hitting major URLs on the websites. You should have some automated script to do this. You can use tinyget to hit some major URLs, especially pages that take a lot of time to compile. Read my post on keeping websites warm with zero coding. Put server X back to load balancer so that it starts receiving traffic. That’s it. It should give you a clean deployment and prevent unexpected errors. You should print these steps and hang on the desk of your deployment guys so that they never forget during deployment pressure.

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Run virtualbox in other X session

- by Valicek1

I'm running ubuntu on my laptop (host). Inside ubuntu, there is running one instance of virtualbox. (where is installed MS Windows). My idea is to run virtualbox in separate X session (something like multiuser). If it is not clear, i'll try to explain... When I want to visit tty1, I'll press CTRL+ALT+F1. To return to my Unity desktop, I'm gona use CTRL+ALT+F7... And here comes what I need. After pressing CTRL+ALT+F8 show fullscreen virtualbox windows system, just to switch as ttys.. I am using Ubuntu 14.10. I have wasted hours by using google to find some solution, but my biggest prolem is I cannot name the problem.

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Kendo UI Mobile with Knockout for Master-Detail Views

- by Steve Michelotti

Lately I’ve been playing with Kendo UI Mobile to build iPhone apps. It’s similar to jQuery Mobile in that they are both HTML5/JavaScript based frameworks for buildings mobile apps. The primary thing that drew me to investigate Kendo UI was its innate ability to adaptively render a native looking app based on detecting the device it’s currently running on. In other words, it will render to look like a native iPhone app if it’s running on an iPhone and it will render to look like a native Droid app if it’s running on a Droid. This is in contrast to jQuery Mobile which looks the same on all devices and, therefore, it can never quite look native for whatever device it’s running on. My first impressions of Kendo UI were great. Using HTML5 data-* attributes to define “roles” for UI elements is easy, the rendering looked great, and the basic navigation was simple and intuitive. However, I ran into major confusion when trying to figure out how to “correctly” build master-detail views. Since I was already very family with KnockoutJS, I set out to use that framework in conjunction with Kendo UI Mobile to build the following simple scenario: I wanted to have a simple “Task Manager” application where my first screen just showed a list of tasks like this: Then clicking on a specific task would navigate to a detail screen that would show all details of the specific task that was selected: Basic navigation between views in Kendo UI is simple. The href of an <a> tag just needs to specify a hash tag followed by the ID of the view to navigate to as shown in this jsFiddle (notice the href of the <a> tag matches the id of the second view): Direct link to jsFiddle: here. That is all well and good but the problem I encountered was: how to pass data between the views? Specifically, I need the detail view to display all the details of whichever task was selected. If I was doing this with my typical technique with KnockoutJS, I know exactly what I would do. First I would create a view model that had my collection of tasks and a property for the currently selected task like this: 1: function ViewModel() { 2: var self = this; 3: self.tasks = ko.observableArray(data); 4: self.selectedTask = ko.observable(null); 5: } Then I would bind my list of tasks to the unordered list - I would attach a “click” handler to each item (each <li> in the unordered list) so that it would select the “selectedTask” for the view model. The problem I found is this approach simply wouldn’t work for Kendo UI Mobile. It completely ignored the click handlers that I was trying to attach to the <a> tags – it just wanted to look at the href (at least that’s what I observed). But if I can’t intercept this, then *how* can I pass data or any context to the next view? The only thing I was able to find in the Kendo documentation is that you can pass query string arguments on the view name you’re specifying in the href. This enabled me to do the following: Specify the task ID in each href – something like this: <a href=”#taskDetail?id=3></a> Attach an “init method” (via the “data-show” attribute on the details view) that runs whenever the view is activated Inside this “init method”, grab the task ID passed from the query string to look up the item from my view model’s list of tasks in order to set the selected task I was able to get all that working with about 20 lines of JavaScript as shown in this jsFiddle. If you click on the Results tab, you can navigate between views and see the the detail screen is correctly binding to the selected item: Direct link to jsFiddle: here. With all that being done, I was very happy to get it working with the behavior I wanted. However, I have no idea if that is the “correct” way to do it or if there is a “better” way to do it. I know that Kendo UI comes with its own data binding framework but my preference is to be able to use (the well-documented) KnockoutJS since I’m already familiar with that framework rather than having to learn yet another new framework. While I think my solution above is probably “acceptable”, there are still a couple of things that bug me about it. First, it seems odd that I have to loop through my items to *find* my selected item based on the ID that was passed on the query string - normally, with Knockout I can just refer directly to my selected item from where it was used. Second, it didn’t feel exactly right that I had to rely on the “data-show” method of the details view to set my context – normally with Knockout, I could just attach a click handler to the <a> tag that was actually clicked by the user in order to set the “selected item.” I’m not sure if I’m being too picky. I know there are many people that have *way* more expertise in Kendo UI compared to me – I’d be curious to know if there are better ways to achieve the same results.

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Most Unprofessional Workplace

- by TehGrumpyCoder

I've worked lots of places in lots of roles: Delivery truck driver, Boilermaker, antenna rigger, Professional Musician, Electronic Technician, Electrical Engineer, and for most of my career: Software Turkey. I want to say this large company is the most unprofessional place I've ever worked, but then I think about other jobs such as TTI that stiffed us all for 10 months salary -- or had us work 2-1/2 years at 66% however you want to look at it, or maybe NeoPlanet with a cast from a bad sitcom running the show, I could go on, but I digress (as usual). So maybe this place isn't the *most* unprofessional, but the personnel rank up there. I'm in a small room off a factory. There are 3 managerial offices, and 36 common-folk of various skill-sets in a variety of single to quad cubicles. No matter where you sit though, because of the layout and location, you've got a hard wall as one wall of your cubicle. Because of that hard wall, everything echoes. I get off the phone, and the guy in the next cubicle makes a comment in response to my phone conversation... I hate that it can be heard and I hate that they do that! These people have no problem yelling from cube to cube to carry on running conversations some of which are actually work-related. There's a lady two cubes away that talks so loud I can clearly hear every phone conversation she has... all work-related but still... Then the one in the next cubicle must have been raised on a farm because there's only one volume setting: LOUD... "HEY MARGE, CAN I GET IN FOR A QUICK APPOINTMENT AFTER WORK TONIGHT?" ... sigh Also that cube is the 'party cube' so that's where all the candy, cake, donuts, and leftovers sits. Anything MzLoud brings in has to have a verbal recipe associated with it at least 10 times during the day, and of course at volume. I've had running conversations over the top of my cube from people in the next one on each side. The weird thing is... the boss sits with an open door closer to this whole fiasco than me. So I wear a pair of Bose noise-cancelling headphones, and crank up Kenny Burrell, Herb Ellis, Wes Montgomery, or Jimmy Smith to the point I can't hear the racket... what the heck, I already have a hearing loss from playing guitar.

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Windows Azure ASP.NET MVC 2 Role with Silverlight

- by GeekAgilistMercenary

I was working through some scenarios recently with Azure and Silverlight. I immediately decided a quick walk through for setting up a Silverlight Application running in an ASP.NET MVC 2 Application would be a cool project. This walk through I have Visual Studio 2010, Silverlight 4, and the Azure SDK all installed. If you need to download any of those go get em? now. Launch Visual Studio 2010 and start a new project. Click on the section for cloud templates as shown below. After you name the project, the dialog for what type of Windows Azure Cloud Service Role will display. I selected ASP.NET MVC 2 Web Role, which adds the MvcWebRole1 Project to the Cloud Service Solution. Since I selected the ASP.NET MVC 2 Project type, it immediately prompts for a unit test project. Because I just want to get everything running first, I will probably be unit testing the Silverlight and just using the MVC Project as a host for the Silverlight for now, and because I would prefer to just add the unit test project later, I am going to select no here. Once you've created the ASP.NET MVC 2 project to host the Silverlight, then create another new project. Select the Silverlight section under the Installed Templates in the Add New Project dialog. Then select Silverlight Application. The next dialog that comes up will inquire about using the existing ASP.NET MVC Application I just created, which I do want it to use that so I leave it checked. The options section however I do not want to check RIA Web Services, do not want a test page added to the project, and I want Silverlight debugging enabled so I leave that checked. Once those options are appropriately set, just click on OK and the Silverlight Project will be added to the overall solution. The next steps now are to get the Silverlight object appropriately embedded in the web page. First open up the Site.Master file in the ASP.NET MVC 2 Project located under the Veiws/Shared/ location. After you open the file review the content of the <header></header> section. In that section add another <contentplaceholder></contentplaceholder> tag as shown in the code snippet below. <head runat="server"> <title> <asp:ContentPlaceHolder ID="TitleContent" runat="server" /> </title> <link href="../../Content/Site.css" rel="stylesheet" type="text/css" /> <asp:ContentPlaceHolder ID="HeaderContent" runat="server" /> </head> I usually put it toward the bottom of the header section. It just seems the <title></title> should be on the top of the section and I like to keep it that way. Now open up the Index.aspx page under the ASP.NET MVC 2 Project located in the Views/Home/ directory. When you open up that file add a <asp:Content><asp:Content> tag as shown in the next snippet. <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> Home Page </asp:Content> <asp:Content ID=headerContent ContentPlaceHolderID=HeaderContent runat=server> </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <h2><%= Html.Encode(ViewData["Message"]) %></h2> <p> To learn more about ASP.NET MVC visit <a href="http://asp.net/mvc" title="ASP.NET MVC Website">http://asp.net/mvc</a>. </p> </asp:Content> In that center tag, I am now going to add what is needed to appropriately embed the Silverlight object into the page. The first thing I needed is a reference to the Silverlight.js file. <script type="text/javascript" src="Silverlight.js"></script> After that comes a bit of nitty gritty Javascript. I create another tag (and for those in the know, this is exactly like the generated code that is dumped into the *.html page generated with any Silverlight Project if you select to "add a test page that references the application". The complete Javascript is below. function onSilverlightError(sender, args) { var appSource = ""; if (sender != null && sender != 0) { appSource = sender.getHost().Source; } var errorType = args.ErrorType; var iErrorCode = args.ErrorCode; if (errorType == "ImageError" || errorType == "MediaError") { return; } var errMsg = "Unhandled Error in Silverlight Application " + appSource + "\n"; errMsg += "Code: " + iErrorCode + " \n"; errMsg += "Category: " + errorType + " \n"; errMsg += "Message: " + args.ErrorMessage + " \n"; if (errorType == "ParserError") { errMsg += "File: " + args.xamlFile + " \n"; errMsg += "Line: " + args.lineNumber + " \n"; errMsg += "Position: " + args.charPosition + " \n"; } else if (errorType == "RuntimeError") { if (args.lineNumber != 0) { errMsg += "Line: " + args.lineNumber + " \n"; errMsg += "Position: " + args.charPosition + " \n"; } errMsg += "MethodName: " + args.methodName + " \n"; } throw new Error(errMsg); } I literally, since it seems to work fine, just use what is populated in the automatically generated page. After getting the appropriate Javascript into place I put the actual Silverlight Object Embed code into the HTML itself. Just so I know the positioning and for final verification when running the application I insert the embed code just below the Index.aspx page message. As shown below. <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <h2> <%= Html.Encode(ViewData["Message"]) %></h2> <p> To learn more about ASP.NET MVC visit <a href="http://asp.net/mvc" title="ASP.NET MVC Website"> http://asp.net/mvc</a>. </p> <div id="silverlightControlHost"> <object data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%"> <param name="source" value="ClientBin/CloudySilverlight.xap" /> <param name="onError" value="onSilverlightError" /> <param name="background" value="white" /> <param name="minRuntimeVersion" value="4.0.50401.0" /> <param name="autoUpgrade" value="true" /> <a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=4.0.50401.0" style="text-decoration: none"> <img src="http://go.microsoft.com/fwlink/?LinkId=161376" alt="Get Microsoft Silverlight" style="border-style: none" /> </a> </object> <iframe id="_sl_historyFrame" style="visibility: hidden; height: 0px; width: 0px; border: 0px"></iframe> </div> </asp:Content> I then open up the Silverlight Project MainPage.xaml. Just to make it visibly obvious that the Silverlight Application is running in the page, I added a button as shown below. <UserControl x:Class="CloudySilverlight.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400"> <Grid x:Name="LayoutRoot" Background="White"> <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="48,40,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" /> </Grid> </UserControl> Just for kicks, I added a message box that would popup, just to show executing functionality also. private void button1_Click(object sender, RoutedEventArgs e) { MessageBox.Show("It runs in the cloud!"); } I then executed the ASP.NET MVC 2 and could see the Silverlight Application in page. With a quick click of the button, I got a message box. Success! Now the next step is getting the ASP.NET MVC 2 Project and Silverlight published to the cloud. As of Visual Studio 2010, Silverlight 4, and the latest Azure SDK, this is actually a ridiculously easy process. Navigate to the Azure Cloud Services web site. Once that is open go back in Visual Studio and right click on the cloud project and select publish. This will publish two files into a directory. Copy that directory so you can easily paste it into the Azure Cloud Services web site. You'll have to click on the application role in the cloud (I will have another blog entry soon about where, how, and best practices in the cloud). In the text boxes shown, select the application package file and the configuration file and place them in the appropriate text boxes. This is the part were it comes in handy to have copied the directory path of the file location. That way when you click on browser you can just paste that in, then hit enter. The two files will be listed and you can select the appropriate file. Once that is done, name the service deployment. Then click on publish. After a minute or so you will see the following screen. Now click on run. Once the MvcWebRole1 goes green (the little light symbol to the left of the status) click on the Web Site URL. Be patient during this process too, it could take a minute or two. The Silverlight application should again come up just like you ran it on your local machine. Once staging is up and running, click on the circular icon with two arrows to move staging to production. Once you are done make sure the green light is again go for the production deploy, then click on the Web Site URL to verify the site is working. At this point I had a successful development, staging, and production deployment. Thanks for reading, hope this was helpful. I have more Windows Azure and other cloud related material coming, so stay tuned. Original Entry

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Bastion unexpectedly exits when I move my cursor

- by user69358

I downloaded the Humble Indie Bundle V, mostly because my friend told me about how great Bastion was. When I first installed it, I was getting the seemingly common "black screen" error that most people got (fixed that half with this http://ubuntuforums.org/showthread.php?p=11992661). But I also have an error where every time I move my cursor, in any direction, any amount, the game closes instantly. I can use the keyboard no problem, but without fail, every time I move my mouse, it crashes. Does anyone know what might be causing this? Has anyone encountered anything like this before? I am worried it may be a hardware issue, but hoping someone might be able to help me out. I'm running Ubuntu 12.04 on a Dell Studio 1558. Graphics card is the stock Intel graphics card, running on 4 GB of RAM.

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Why is my Ubuntu system not using the correct kernel?

- by Brooks Moses

We're having a bit of confusion on a Ubuntu remote system -- /boot/grub/menu.lst suggests the system should boot into kernel 2.6.35-30-generic, but it is actually running kernel 2.6.32-27-generic. Where should I look to start figuring out why this is happening and how to fix it? Specifically, /boot/grub/menu.lst has default 0 and the first entry is title Ubuntu 10.10, kernel 2.6.35-30-generic uuid 67717ee3-cbf9-45d2-ae97-820256f4c4fd kernel /boot/vmlinuz-2.6.35-30-generic root=UUID=67717ee3-cbf9-45d2- ae97-820256f4c4fd ro quiet splash initrd /boot/initrd.img-2.6.35-30-generic Further, I've confirmed that /boot/vmlinuz-2.6.35-30-generic and /boot/initrd.img-2.6.35-30-generic exist and have appropriate permissions. Meanwhile, uname -a returns: $ uname -a Linux cuda2 2.6.32-27-generic #49-Ubuntu SMP Thu Dec 2 00:51:09 UTC 2010 x86_64 GNU/Linux Edit: I've also tried re-running update-grub, and rebooting; no luck. Here's the full menu.lst, as requested by a commenter: # menu.lst - See: grub(8), info grub, update-grub(8) # grub-install(8), grub-floppy(8), # grub-md5-crypt, /usr/share/doc/grub # and /usr/share/doc/grub-legacy-doc/. ## default num # Set the default entry to the entry number NUM. Numbering starts from 0, and # the entry number 0 is the default if the command is not used. # # You can specify 'saved' instead of a number. In this case, the default entry # is the entry saved with the command 'savedefault'. # WARNING: If you are using dmraid do not use 'savedefault' or your # array will desync and will not let you boot your system. default 0 ## timeout sec # Set a timeout, in SEC seconds, before automatically booting the default entry # (normally the first entry defined). timeout 3 ## hiddenmenu # Hides the menu by default (press ESC to see the menu) hiddenmenu # Pretty colours #color cyan/blue white/blue ## password ['--md5'] passwd # If used in the first section of a menu file, disable all interactive editing # control (menu entry editor and command-line) and entries protected by the # command 'lock' # e.g. password topsecret # password --md5 $1$gLhU0/$aW78kHK1QfV3P2b2znUoe/ # password topsecret # # examples # # title Windows 95/98/NT/2000 # root (hd0,0) # makeactive # chainloader +1 # # title Linux # root (hd0,1) # kernel /vmlinuz root=/dev/hda2 ro # # # Put static boot stanzas before and/or after AUTOMAGIC KERNEL LIST ### BEGIN AUTOMAGIC KERNELS LIST ## lines between the AUTOMAGIC KERNELS LIST markers will be modified ## by the debian update-grub script except for the default options below ## DO NOT UNCOMMENT THEM, Just edit them to your needs ## ## Start Default Options ## ## default kernel options ## default kernel options for automagic boot options ## If you want special options for specific kernels use kopt_x_y_z ## where x.y.z is kernel version. Minor versions can be omitted. ## e.g. kopt=root=/dev/hda1 ro ## kopt_2_6_8=root=/dev/hdc1 ro ## kopt_2_6_8_2_686=root=/dev/hdc2 ro # kopt=root=UUID=67717ee3-cbf9-45d2-ae97-820256f4c4fd ro ## default grub root device ## e.g. groot=(hd0,0) # groot=67717ee3-cbf9-45d2-ae97-820256f4c4fd ## should update-grub create alternative automagic boot options ## e.g. alternative=true ## alternative=false # alternative=true ## should update-grub lock alternative automagic boot options ## e.g. lockalternative=true ## lockalternative=false # lockalternative=false ## additional options to use with the default boot option, but not with the ## alternatives ## e.g. defoptions=vga=791 resume=/dev/hda5 # defoptions=quiet splash ## should update-grub lock old automagic boot options ## e.g. lockold=false ## lockold=true # lockold=false ## Xen hypervisor options to use with the default Xen boot option # xenhopt= ## Xen Linux kernel options to use with the default Xen boot option # xenkopt=console=tty0 ## altoption boot targets option ## multiple altoptions lines are allowed ## e.g. altoptions=(extra menu suffix) extra boot options ## altoptions=(recovery) single # altoptions=(recovery mode) single ## controls how many kernels should be put into the menu.lst ## only counts the first occurence of a kernel, not the ## alternative kernel options ## e.g. howmany=all ## howmany=7 # howmany=all ## specify if running in Xen domU or have grub detect automatically ## update-grub will ignore non-xen kernels when running in domU and vice versa ## e.g. indomU=detect ## indomU=true ## indomU=false # indomU=detect ## should update-grub create memtest86 boot option ## e.g. memtest86=true ## memtest86=false # memtest86=true ## should update-grub adjust the value of the default booted system ## can be true or false # updatedefaultentry=false ## should update-grub add savedefault to the default options ## can be true or false # savedefault=false ## ## End Default Options ## title Ubuntu 10.10, kernel 2.6.35-30-generic uuid 67717ee3-cbf9-45d2-ae97-820256f4c4fd kernel /boot/vmlinuz-2.6.35-30-generic root=UUID=67717ee3-cbf9-45d2-ae97-820256f4c4fd ro quiet splash initrd /boot/initrd.img-2.6.35-30-generic title Ubuntu 10.10, kernel 2.6.35-30-generic (recovery mode) uuid 67717ee3-cbf9-45d2-ae97-820256f4c4fd kernel /boot/vmlinuz-2.6.35-30-generic root=UUID=67717ee3-cbf9-45d2-ae97-820256f4c4fd ro single initrd /boot/initrd.img-2.6.35-30-generic title Ubuntu 10.10, kernel 2.6.32-32-server uuid 67717ee3-cbf9-45d2-ae97-820256f4c4fd kernel /boot/vmlinuz-2.6.32-32-server root=UUID=67717ee3-cbf9-45d2-ae97-820256f4c4fd ro quiet splash initrd /boot/initrd.img-2.6.32-32-server title Ubuntu 10.10, kernel 2.6.32-32-server (recovery mode) uuid 67717ee3-cbf9-45d2-ae97-820256f4c4fd kernel /boot/vmlinuz-2.6.32-32-server root=UUID=67717ee3-cbf9-45d2-ae97-820256f4c4fd ro single initrd /boot/initrd.img-2.6.32-32-server title Ubuntu 10.10, kernel 2.6.32-27-generic uuid 67717ee3-cbf9-45d2-ae97-820256f4c4fd kernel /boot/vmlinuz-2.6.32-27-generic root=UUID=67717ee3-cbf9-45d2-ae97-820256f4c4fd ro quiet splash initrd /boot/initrd.img-2.6.32-27-generic title Ubuntu 10.10, kernel 2.6.32-27-generic (recovery mode) uuid 67717ee3-cbf9-45d2-ae97-820256f4c4fd kernel /boot/vmlinuz-2.6.32-27-generic root=UUID=67717ee3-cbf9-45d2-ae97-820256f4c4fd ro single initrd /boot/initrd.img-2.6.32-27-generic title Chainload into GRUB 2 root 67717ee3-cbf9-45d2-ae97-820256f4c4fd kernel /boot/grub/core.img title Ubuntu 10.10, memtest86+ uuid 67717ee3-cbf9-45d2-ae97-820256f4c4fd kernel /boot/memtest86+.bin ### END DEBIAN AUTOMAGIC KERNELS LIST To add complication and joy to my life, this is a desktop machine in a remote datacenter; we don't have either local access or serial-console access. Suggestions?

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Rhythmbox is crashing on start

- by Kristal

I'm using ubuntu 10.10 and until about 3 days ago rhythmbox worked fine but now when I start it, it opens, then after 4 second it crashes. When running it from terminal I get this: ~$ rhythmbox (rhythmbox:27420): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed ** Message: pygobject_register_sinkfunc is deprecated (GstObject) (rhythmbox:27420): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed Segmentation fault and then rhythmbox closes. What to do? =\ Edit: Disabled most of the plugins and it's not crashing now, but i still get when running from terminal (rhythmbox:27420): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed ** Message: pygobject_register_sinkfunc is deprecated (GstObject) (rhythmbox:27420): GLib-GObject-CRITICAL **: g_object_unref: assertion `G_IS_OBJECT (object)' failed should I worry?

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Cost Comparison Hard Disk Drive to Solid State Drive on Price per Gigabyte - dispelling a myth!

- by tonyrogerson

It is often said that Hard Disk Drive storage is significantly cheaper per GiByte than Solid State Devices – this is wholly inaccurate within the database space. People need to look at the cost of the complete solution and not just a single component part in isolation to what is really required to meet the business requirement. Buying a single Hitachi Ultrastar 600GB 3.5” SAS 15Krpm hard disk drive will cost approximately £239.60 (http://scan.co.uk, 22nd March 2012) compared to an OCZ 600GB Z-Drive R4 CM84 PCIe costing £2,316.54 (http://scan.co.uk, 22nd March 2012); I’ve not included FusionIO ioDrive because there is no public pricing available for it – something I never understand and personally when companies do this I immediately think what are they hiding, luckily in FusionIO’s case the product is proven though is expensive compared to OCZ enterprise offerings. On the face of it the single 15Krpm hard disk has a price per GB of £0.39, the SSD £3.86; this is what you will see in the press and this is what sales people will use in comparing the two technologies – do not be fooled by this bullshit people! What is the requirement? The requirement is the database will have a static size of 400GB kept static through archiving so growth and trim will balance the database size, the client requires resilience, there will be several hundred call centre staff querying the database where queries will read a small amount of data but there will be no hot spot in the data so the randomness will come across the entire 400GB of the database, estimates predict that the IOps required will be approximately 4,000IOps at peak times, because it’s a call centre system the IO latency is important and must remain below 5ms per IO. The balance between read and write is 70% read, 30% write. The requirement is now defined and we have three of the most important pieces of the puzzle – space required, estimated IOps and maximum latency per IO. Something to consider with regard SQL Server; write activity requires synchronous IO to the storage media specifically the transaction log; that means the write thread will wait until the IO is completed and hardened off until the thread can continue execution, the requirement has stated that 30% of the system activity will be write so we can expect a high amount of synchronous activity. The hardware solution needs to be defined; two possible solutions: hard disk or solid state based; the real question now is how many hard disks are required to achieve the IO throughput, the latency and resilience, ditto for the solid state. Hard Drive solution On a test on an HP DL380, P410i controller using IOMeter against a single 15Krpm 146GB SAS drive, the throughput given on a transfer size of 8KiB against a 40GiB file on a freshly formatted disk where the partition is the only partition on the disk thus the 40GiB file is on the outer edge of the drive so more sectors can be read before head movement is required: For 100% sequential IO at a queue depth of 16 with 8 worker threads 43,537 IOps at an average latency of 2.93ms (340 MiB/s), for 100% random IO at the same queue depth and worker threads 3,733 IOps at an average latency of 34.06ms (34 MiB/s). The same test was done on the same disk but the test file was 130GiB: For 100% sequential IO at a queue depth of 16 with 8 worker threads 43,537 IOps at an average latency of 2.93ms (340 MiB/s), for 100% random IO at the same queue depth and worker threads 528 IOps at an average latency of 217.49ms (4 MiB/s). From the result it is clear random performance gets worse as the disk fills up – I’m currently writing an article on short stroking which will cover this in detail. Given the work load is random in nature looking at the random performance of the single drive when only 40 GiB of the 146 GB is used gives near the IOps required but the latency is way out. Luckily I have tested 6 x 15Krpm 146GB SAS 15Krpm drives in a RAID 0 using the same test methodology, for the same test above on a 130 GiB for each drive added the performance boost is near linear, for each drive added throughput goes up by 5 MiB/sec, IOps by 700 IOps and latency reducing nearly 50% per drive added (172 ms, 94 ms, 65 ms, 47 ms, 37 ms, 30 ms). This is because the same 130GiB is spread out more as you add drives 130 / 1, 130 / 2, 130 / 3 etc. so implicit short stroking is occurring because there is less file on each drive so less head movement required. The best latency is still 30 ms but we have the IOps required now, but that’s on a 130GiB file and not the 400GiB we need. Some reality check here: a) the drive randomness is more likely to be 50/50 and not a full 100% but the above has highlighted the effect randomness has on the drive and the more a drive fills with data the worse the effect. For argument sake let us assume that for the given workload we need 8 disks to do the job, for resilience reasons we will need 16 because we need to RAID 1+0 them in order to get the throughput and the resilience, RAID 5 would degrade performance. Cost for hard drives: 16 x £239.60 = £3,833.60 For the hard drives we will need disk controllers and a separate external disk array because the likelihood is that the server itself won’t take the drives, a quick spec off DELL for a PowerVault MD1220 which gives the dual pathing with 16 disks 146GB 15Krpm 2.5” disks is priced at £7,438.00, note its probably more once we had two controller cards to sit in the server in, racking etc. Minimum cost taking the DELL quote as an example is therefore: {Cost of Hardware} / {Storage Required} £7,438.60 / 400 = £18.595 per GB £18.59 per GiB is a far cry from the £0.39 we had been told by the salesman and the myth. Yes, the storage array is composed of 16 x 146 disks in RAID 10 (therefore 8 usable) giving an effective usable storage availability of 1168GB but the actual storage requirement is only 400 and the extra disks have had to be purchased to get the IOps up. Solid State Drive solution A single card significantly exceeds the IOps and latency required, for resilience two will be required. ( £2,316.54 * 2 ) / 400 = £11.58 per GB With the SSD solution only two PCIe sockets are required, no external disk units, no additional controllers, no redundant controllers etc. Conclusion I hope by showing you an example that the myth that hard disk drives are cheaper per GiB than Solid State has now been dispelled - £11.58 per GB for SSD compared to £18.59 for Hard Disk. I’ve not even touched on the running costs, compare the costs of running 18 hard disks, that’s a lot of heat and power compared to two PCIe cards!Just a quick note: I've left a fair amount of information out due to this being a blog! If in doubt, email me :)I'll also deal with the myth that SSD's wear out at a later date as well - that's just way over done still, yes, 5 years ago, but now - no.

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Securing iOS or Android Backend API

- by El Guapo

I have an application that I am writing for both iOS and Android; this application will be served by a ReSTFUL API running on a cluster of servers on "the internets". I am curious how the rest of the world is going about securing their APIs so only specific applications running on iOS or Android can use these APIs. I could go the same route as other OAuth providers by providing a key/secret combination (2-legged OAuth), however, what do I do if I ever have to change these keys??? Do I create a new key/secret for every person that downloads the app???

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Bumblebee - Poor performance with games

- by user106880

I have an Alienware M14x (GeForce 650m with Optimus) and got Bumblebee working correctly (trying to get ready for steam for linux :)). Also I'm running Ubuntu 12.10 with Unity. I get great framerates with glxgears and sauerbraten (a game on the repositories), but when I run games like Bastion and Splice, I get pretty terrible framerate, in fact worse than my integrated intel gpu. I have nvidia-current installed under ubuntu-x-swat/x-updates so it's driver version 310.xx. Also I forgot to add that I haven't been able to test other drivers because they seem to break glx (x can't load the glx module). I've been troubleshooting this for days now, and I'm very nearly out of ideas. Any hints on why only some games are running so poorly with bumblebee?

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11.04 radeon screen tearing oddity

- by Kevin Qiu

I have a mobility radeon 5850 running 11.04 and am running catalyst 11.10 drivers. I noticed that whenever I have two windows open, one of top of the other, scrolling results in minor screen tearing, usually around the border of the window on the bottom. When I minimize or close the bottom the tearing goes away. I have tear free desktop enabled and tried looking for this specific issue but couldn't find anyone else with it. It happens in both Unity and Classic. Is there any fix for this?

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Display resolution problem with Sony TV and Intel integrated graphics

- by user96195

I am trying to set the correct display resolution for my Sony TV (KDL-32V2000, native resolution 1366x768) connected via HDMI to my HTPC running Ubuntu 12.04. I have a Intel Core i3-530 and Intel mobo (DH57JG), so no proprietary graphics drivers. The problem is that I can't get the correct resolution to display on the TV. Initially I only had 1024x768 (or similar) as a maximum resolution, which was not displayed properly. I tried a few steps, including generating an xorg.conf (initially didn't have one) and adding the segment as described in this post regarding this particular TV. I couldn't get this to work, and at this stage have reverted to running without an xorg.conf. Another post suggested upgrading to kernel 3.5, which did give me a 1920x1080 resolution option. This results in the TV cutting off a fair bit of the edges of the screen. My Dell laptop with ATI drivers recognises the TV screen and works well via HDMI. Any idea how to proceed?

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How to change default boot with two Ubuntus?

- by d3vid

I currently have 11.10 and 12.04 Beta running side-by-side. Since installing the beta, I am presented with a GRUB2 menu every time I boot up, which selects 12.04 by default. (Aside: when the 11.10 kernel updated from 3.0.0-16 to 3.0.0-17 this option did not appear in the GRUB2 menu.) When I open Grub Customizer in 11.10, it shows 11.10 kernel 3.0.0-17 as the default, when I open Grub Customizer in 12.04, it shows 12.04 as the default. How can I change GRUB2 to pick the latest 11.10 kernel as the default? (Latest means that if 3.0.0-18 is released it will become the default, and so on.) And also stop displaying the menu (I only boot into the beta when I have something specific to test). Generic answers that apply to any two Ubuntus running side-by-side are preferred.

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Problem with apt-get [install, purge, autoremove, upgrade]

- by Ark

I am trying to install openvpn using apt-get, but I get an error during the process [As far as I understand the issue is with unattended-updates, which I could not upgrade due to apt-get porblem :/]. I cannot upgrade, install, autoremove or purge anything else [which I need to do since /boot is full. For upgrading I did update before trying].... Trace [on sudo apt-get autoremove]: 0 upgraded, 0 newly installed, 79 to remove and 421 not upgraded. 35 not fully installed or removed. Need to get 24.1 kB of archives. After this operation, 140 MB disk space will be freed. Do you want to continue [Y/n]? y Get:1 http://us.archive.ubuntu.com/ubuntu/ oneiric/main unattended-upgrades all 0.73ubuntu1 [24.1 kB] Fetched 24.1 kB in 0s (31.2 kB/s) Preconfiguring packages ... (Reading database ... 287206 files and directories currently installed.) Removing flashplugin-downloader:i386 ... Removing libasound2-plugins:i386 ... Removing libpulse0:i386 ... Removing libsndfile1:i386 ... Removing libvorbisenc2:i386 ... Removing libvorbis0a:i386 ... Processing triggers for libc-bin ... ldconfig deferred processing now taking place (Reading database ... 287174 files and directories currently installed.) Preparing to replace unattended-upgrades 0.73ubuntu1 (using .../unattended-upgrades_0.73ubuntu1_all.deb) ... Checking for running unattended-upgrades: Traceback (most recent call last): File "/usr/share/unattended-upgrades/unattended-upgrade-shutdown", line 27, in <module> import apt_pkg ImportError: No module named apt_pkg invoke-rc.d: initscript unattended-upgrades, action "stop" failed. dpkg: warning: subprocess old pre-removal script returned error exit status 1 dpkg - trying script from the new package instead ... Checking for running unattended-upgrades: Traceback (most recent call last): File "/usr/share/unattended-upgrades/unattended-upgrade-shutdown", line 27, in <module> import apt_pkg ImportError: No module named apt_pkg invoke-rc.d: initscript unattended-upgrades, action "stop" failed. dpkg: error processing /var/cache/apt/archives/unattended-upgrades_0.73ubuntu1_all.deb (--unpack): subprocess new pre-removal script returned error exit status 1 update-rc.d: warning: unattended-upgrades start runlevel arguments (2 3 4 5) do not match LSB Default-Start values (none) update-rc.d: warning: unattended-upgrades stop runlevel arguments (0 1 6) do not match LSB Default-Stop values (0 6) Checking for running unattended-upgrades: Traceback (most recent call last): File "/usr/share/unattended-upgrades/unattended-upgrade-shutdown", line 27, in <module> import apt_pkg ImportError: No module named apt_pkg invoke-rc.d: initscript unattended-upgrades, action "start" failed. dpkg: error while cleaning up: subprocess installed post-installation script returned error exit status 1 Errors were encountered while processing: /var/cache/apt/archives/unattended-upgrades_0.73ubuntu1_all.deb E: Sub-process /usr/bin/dpkg returned an error code (1) Maybe I missed something basic, but I would appreciate pointers on solving the issue. Thanks

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Two Wifi Icons in Panel [Solved]

- by Alex

I have the exact problem in 13.10 as this user Two Wifi indicators in panel. Here are some screenshots: Here are some screenshots from another user: http://ubuntuforums.org/showthread.php?t=2183020&p=12825563 ifconfig and iwconfig outputs $ ifconfig lo Link encap:Local Loopback inet addr:XXXXXX Mask:XXXXXXX inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:2243 errors:0 dropped:0 overruns:0 frame:0 TX packets:2243 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:209889 (209.8 KB) TX bytes:209889 (209.8 KB) wlan0 Link encap:Ethernet HWaddr XXXXXXXXX inet addr:XXXXXX Bcast:XXXXXXXX Mask:XXXXXXX inet6 addr: XXXXXXX Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:5925 errors:0 dropped:0 overruns:0 frame:0 TX packets:3361 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2951818 (2.9 MB) TX bytes:630579 (630.5 KB) $ iwconfig lo no wireless extensions. wlan0 IEEE 802.11abgn ESSID:"XXXXX" Mode:Managed Frequency:2.437 GHz Access Point: XXXXXXXX Bit Rate=72.2 Mb/s Tx-Power=15 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:on Link Quality=49/70 Signal level=-61 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:153 Invalid misc:472 Missed beacon:0

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How do I set a static DNS nameserver address on Ubuntu Server?

- by Aleks

I am trying statically to set DNS server addresses in my Ubuntu server running as virtual machine. I followed all recommendations on official Ubuntu support pages but I simply cannot get rid of my ISP's DNS servers set by DHCP. I assigned br0 interface on my host machine static IP address and eth0 on VM to use Google DNS and my own local DNS running on the second vm by setting it in /etc/network/interfaces. Tried to fiddle with head base and tail files in /etc/resolvconf/resolv.conf.d/ and tried to shuffle interface-order in /etc/resolvconf/interface-order but when I restarted network service I got the ISP's DNS addresses back every time. Is there a way that I can disable resolvconf and set up my resolv.conf file manually as I always did on Red Hat? Or at can you tell me which hook script keeps putting ISP DNSs in resolv.conf? My ISP don't allow me to change DHCP settings on my router so I cannot do it that way. Why is such a simple thing such as setting DNS servers got so complicated???

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Why is ubuntu so sluggish?

- by Evan

I have noticed the trend that ubuntu is getting increasingly slower with each release. It used to be much faster than windows, but now it is really much slower. I have an Asus G74Sx with an i7 processor, 8Gb of RAM, and an Nvidia Geforce GTX 560M graphics card. I am currently using ubuntu 12.10, but will probably be going back to 12.04. Ubuntu is running as the native operating system. There is really no reason for terminal to take more than 25 seconds to open. I love all of the stuff behind ubuntu, what it stands for and everything, but I need to at least be able to open gedit without waiting 3 minutes for it to open. Sorry if this sounds like a rant, but I would really like to know what is going on and if there is anything I can do to get Ubuntu running at a more appropriate speed.

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Want to Patch your Red Hat Linux Kernel Without Rebooting?

- by Lenz Grimmer

Patched Tube by Morten Liebach (CC BY 2.0) Are you running Red Hat Enterprise Linux? Take back your weekend and say goodbye to lengthy maintenance windows for kernel updates! With Ksplice, you can install kernel updates while the system is running. Stay secure and compliant without the hassle. To give you a taste of one of the many features that are included in Oracle Linux Premier Support, we now offer a free 30-day Ksplice trial for RHEL systems. Give it a try and bring your Linux kernel up to date without rebooting (not even once to install it)! For more information on this exciting technology, read Wim's OTN article on using Oracle Ksplice to update Oracle Linux systems without rebooting. Watch Waseem Daher (one of the Ksplice founders) telling you more about Ksplice zero downtime updates in this screencast "Zero Downtime OS Updates with Ksplice" - Lenz

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