QA

Questions and answers.

Prevent Chrome closing after closing the last tab

  How to prevent Chrome from closing itself after I close the last tab? This is a feature I want to have.   This is a feature I want to have. Last Tab Standing plugin plays the trick: https://chrome.google.com/webstore/detail/last-tab-standing/dlopnnfglheodcopccdllffcijjeenkj If the last tab is closed, this extension stops Chrome from closing and instead opens the New…

Installing Dropbox on Linux

How to install Dropbox on Linux ? Just follow Dropbox’s instruction here: https://www.dropbox.com/install?os=lnx A quick command for 64-bit Linux: $ cd ~ && wget -O – “https://www.dropbox.com/download?plat=lnx.x86_64” | tar xzf – Use the dropx CLI: http://www.dropboxwiki.com/Using_Dropbox_CLI Download dropbox.py: $ wget -O ~/bin/dropbox.py “https://www.dropbox.com/download?dl=packages/dropbox.py” Set the permissions: $ chmod +x ~/bin/dropbox.py Start Dropbox: $ dropbox.py start Status:…

Chrome does not work with ibus

Seems the input method on Linux (ibus) does not work well with Chrome. But other programs, e.g. thunderbird, has not problem with ibus at all. What’s wrong with Chrome or ibus? Check whether the “Qt IBus library and Qt input method plugin” is installed. If not, installing it and restarting ibus may help: # yum…

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Synchronizing home directories

Any good tools to synchronize home directories on Linux boxes? Many have several PC/laptops and consequently many home directories. There is home directory synchronizing problem. unison is a good tool to do this: http://www.cis.upenn.edu/~bcpierce/unison/download/releases/stable/unison-manual.html#rshmeth http://www.watzmann.net/blog/2009/02/my-homedirs-in-unison.html http://www.cis.upenn.edu/~bcpierce/papers/index.shtml#File%20Synchronization Useful script: $ unison -batch -ui text ./ /mnt/homebak/zma/ In text user interface, synchronizing two directories in batch mode…

Large-but-correctly-aligned-and-optimized code is faster than less-bytes-per-instruction/opcode-packed code

Is large-but-correctly-aligned-and-optimized code faster than less-bytes-per-instruction/opcode-packed code? Alex Ionescu mentioned in ros-dev mailing list: I’m not sure why you would want kernel code to be “smaller” instead of “faster” though — on modern processors for cases like interrupts and such, large-but-correctly-aligned-and-optimized code is faster than less-bytes-per-instruction/opcode-packed code. ie: mov eax, [foo] add eax, 1 mov…

SEEK_HOLE and SEEK_DATA: efficiently archive/copy large sparse files

How to efficiently archive a very large sparse file, say 1TB? The sparse file may contains a small amount of data, say 32MB. SEEK_HOLE and SEEK_DATA The SEEK_HOLE/SEEK_DATA functionalities play the trick and makes `tar` and `cp` handle the large sparse file very efficiently. `lseek` with `SEEK_HOLE` returns the offset of the start of the…

How to install the MATE fork of Gnome 2 on Fedora 17?

I miss Gnome 2. How to install the MATE fork of Gnome 2 on Fedora 17? MATE is already included into Fedora 17’s repository and is an official feature of Fedora 18. To install MATE on Fedora 17 # yum install @mate-desktop To install softwares usually needed: # yum install mate-media mate-screensaver mate-system-monitor mate-power-manager mate-utils…

Mmaping Memory Range Larger Than the Total Size of Physical Memory and Swap

In Linux, mmap() is a system call that is used to map a portion of a file or device into the memory of a process. This can be useful for a variety of purposes, such as memory-mapped I/O, shared memory, and virtual memory management. However, when mapping a large range of memory that is larger…

Managing LVM

Any tutorials or tips on how to manage LVM? LVM provides a flexible and easy way to management storage disks on Linux. It also provides a set of tools for management. Here are some tutorials and references for managing LVM: LVM man pages: https://www.systutorials.com/docs/linux/man/8-lvm/#lbAL Manage Disk Volume in Linux: http://www.hongkedavid.com/blog/disk_volume.html LVM with Xen: https://www.systutorials.com/b/linux/tag/lvm/ Remove missing phyiscal volumes…