Archive for August, 2009

  • The importance of experimental observation

    The importance of experimental observation

    There are a plethora of different theories and hypotheses put forward for pretty much every field of intellectual inquiry which includes the philosophical and metaphysical in addition to objective scientific study. It’s impractical to investigate them all simultaneously, as there are simply too many of...

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  • Broken gcalctool bit shift in OpenSolaris 2009.06

    Broken gcalctool bit shift in OpenSolaris 2009.06

    While working on some low-level OS code, I needed to juggle with some bit fields and it’s often useful to use the logical operations on OpenSolaris’ bundled calculator accessory. However, I thought I was going mad when I tried to shift left or right! Check...

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  • Windows ftp getting “425 Unable to build data connection”

    Windows ftp getting “425 Unable to build data connection”

    If you are using the command line ftp client within Windows and getting errors like these… 500 Illegal PORT command 425 Unable to build data connection: Connection refused Well, don’t worry – you’re in good company. This is probably one of the most commonly encountered...

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  • Detecting when a floppy disk is changed or missing

    Detecting when a floppy disk is changed or missing

    In a floppy disk controller device driver, we can check if a floppy disk has been changed or is missing by telling the controller to select the drive and switch it’s motor on, then checking if the DISK CHANGE bit is asserted in the Digital...

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  • Enabling paging vs. the GDT “wrap around” trick

    Enabling paging vs. the GDT “wrap around” trick

    When writing our standalone code for the OS nucleus or kernel, one of the first problems we have to deal with is the difference between our linked addresses (i.e. the load addresses defined by the linker) versus the actual address we are loaded at by...

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  • Creating VirtualBox (VDI) hard disk images on OpenSolaris

    Creating VirtualBox (VDI) hard disk images on OpenSolaris

    While testing my hobby OS nucleus (kernel) code, it is sometimes useful to be able to create disk images containing a file system and any files I need that I can then load into a virtual machine. One of the virtual hosts I like to...

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  • Freeing hidden space in the “System Volume Information” folder

    Freeing hidden space in the “System Volume Information” folder

    I was cleaning up an external USB drive that had a bunch of old data that I didn’t need any more. The drive was fine but had been used between a number of systems so I thought to do a quick “chkdsk” (this is an...

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