Process and thread are two basic concepts of operating system, but they are a bit abstract which cannot be  mastered easily.There is an analogy which explains these concepts very well.1. The kernel of the computer is CPU, it handles all the computing tasks, it's like a factory and will run all the time.2. Assume there is power limitation for the factory, it can only supply to one unit once,i.e, when one unit is working, other units must stop and wait. The meaning behind this is that each CPU can handle only one task at once.3. Process likes the unit in the factory, it represents the singl...

Some people ask a file is being written by one process and they want to check this process, but they cannot find the process even with sof.This question is very common and there are many solutions, here we introduce a straightforward method. In Linux, each file will be stored on one device and of course there will be a relative inode, then we can use vfs.write to know who is writing the inode on one specified device continuously. Luckily there is inodewatch.stp in the installation package of systemtap, it locates at /usr/local/share/doc/systemtap/examples/io. It is used foe above.Let take a lo...

The core Perl community—if you care to draw lines around a group ofpeople who use Perl seriously and call that a community—is like manyother core F/OSS communities. Real work happens on mailing lists and IRC. Iunsubscribed from several mailing lists and deliberately spent as little timeon IRC as possible this year, for various uninteresting reasons. (I haven'teven made it to the Portland Perl Mongersmeetings for several months.)While that's been good for my productivity, it's also produced aninteresting s...