Sungju's Slow Life

Personal journal


  • What’s virtual address limit of 32bit/64bit Linux kernel?

    RHEL 5 code 32bit: include/asm-i386/processor.h /* * User space process size: 3GB (default). */ #define TASK_SIZE (PAGE_OFFSET) 64bit: include/asm-x86_64/processor.h /* * User space process size. 47bits minus one guard page. */ #define TASK_SIZE64 (0x800000000000UL – 4096) /* This decides where the kernel will search for a free chunk of vm * space during mmap’s. */… Continue reading

  • Personal memo for ‘Automatic NUMA Balancing’

    Automatic NUMA Balancing It is described in Documentation/sysctl/kernel.txt numa_balancing Enables/disables automatic page fault based NUMA memory balancing. Memory is moved automatically to nodes that access it often. Enables/disables automatic NUMA memory balancing. On NUMA machines, there is a performance penalty if remote memory is accessed by a CPU. When this feature is enabled the kernel… Continue reading

  • crash extension ‘pstree’

    ‘crash’ is useful tool to analyse system crashes or debugging in Linux system. It has many useful commands, but sometimes I wanted to get full picture of process list that was running at the time of crash. You can get process list with ‘ps’, but if you want to get hierarchical view, only ‘ps -p’… Continue reading

  • A small tool to manage my projects

    If you are working with only on language, it would be quite easy to manage your source code. But, as there are many different requirements and circumstances, we are facing to work with several different languages which come with different tool set. I’ve tried to keep my project under one directory, but still it’s quite… Continue reading

  • Build a OpenStack on VMware Fusion 5

    Cloud is a big trend in recent years and it will be bigger and bigger. Even though you want to join in this trend, it’s hard as it requires lots of machines to build and test it. Fortunately, these days virtualisation technique allows us to install virtual guest on top of another virtual quest. So,… Continue reading

  • Updated github viewer is available

    There was an issue with the GithubView for several months (Honestly speaking, almost a year). It failed to communicate with as the server changed Open API. I didn’t have time to fix this issue as I’m doing it only during my spare time and it was quite busy recently. But, here we are. A… Continue reading

  • Very very very very very simple boot up code.

    I think it’s 2003 or 2004 that I made this very simple booting code to demonstrate how OS starts. I paste the output here for the future reference. bootsec.asm ORG 0x7c00 jmp begin_boot bootmesg1 db “Press any to boot KERNEL…..” mesglen equ $ – bootmesg1 drive db 0 [BITS 16] print_mesg: mov ah, 0x13 mov… Continue reading

  • My new iPhone app

    I haven’t been quite active here recently. Mostly had been in SNS, but want to update what’s going on with my iPhone apps. Recently, I released a new iPhone app : EasyPhoto. It’s a photo taking app which provides several film effects. Still immature, but please try it:         I also… Continue reading

  • Github Client for iPhone is available now.

    I’m happy to announce that github client for iPhone is on AppStore now. You can download it from here. With this, you can view several repositories and changes in it. Of course, you can check your own repositories as well. Continue reading

  • My first iPhone App is on live now!

    Finally!!!! You can find details in >>>HERE!!!<<< Continue reading

  • Stack Exchange Client for iPhone

    As a developer/engineer, I spent quite some time on When I try to search something on google, it also forwarded me to This site has really great resources with very clear interface. There are also some other topics that cover with stackexchange API such as Gaming, Photography, and Cooking. So, I decided to… Continue reading

  • Test screenshot

    For the test purpose. Continue reading