http://www.osxbook.com/blog A Systems Approach Tue, 17 Mar 2009 02:32:43 +0000 http://backend.userland.com/rss092 en The other day I came across this web page in which the author describes his experiment to create a tiny ELF executable that will run on Linux. The result: a 45-byte ELF executable that executes and returns a value. The executable is functionally equivalent to the one generated from compiling ... http://www.osxbook.com/blog/2009/03/15/crafting-a-tiny-mach-o-executable/ Suppose you have a Macintosh without a TPM. This, of course, is highly likely because only the first few x86-based Macintosh models had TPMs. Now suppose you really want to experiment with Trusted Computing or features of the TPM in general. Your needs could be development-related or they could ... http://www.osxbook.com/blog/2009/03/08/a-tpm-for-everyone/ I often hear users—and even developers, for that matter—grumbling about the fact that they are "required" to reboot their systems after installing or upgrading MacFUSE. I've even heard explanations that because MacFUSE "does something with the kernel," a reboot is necessary. Well, this whole rebooting-required thing is a myth. Lets ... http://www.osxbook.com/blog/2009/03/02/why-macfuse-installation-recommends-a-reboot/ The other day I needed to know within one of my experimental programs if the host x86 processor supports certain features. In many cases, the operating system provides interfaces that can answer such questions. Sometimes, the interfaces may not have the answer, or you may wish to avoid them for ... http://www.osxbook.com/blog/2009/03/02/retrieving-x86-processor-information/ The Apple Kernel Debug Kit comes with a kernel gdb macros file (kgmacros) that contains numerous macros useful during low-level development and analysis. One of the macros is showbootermemorymap, which dumps the physical memory map from EFI. The information in this map is very useful for certain types of development. Since ... http://www.osxbook.com/blog/2009/02/25/displaying-the-physical-memory-map/ XBinary is software that lets you add kernel-level support for executing arbitrary binary formats on Mac OS X. To read more about it and to download it, visit the XBinary page. http://www.osxbook.com/blog/2009/01/20/xbinary-extended-binary-format-support-for-mac-os-x/ By popular demand, I've "ported" AncientFS to Linux and FreeBSD. It was reasonably straightforward. Largely on purpose, AncientFS depends on the cross-platform interfaces of MacFUSE for the most part. Most people don't realize that MacFUSE is much more than a "Mac OS X implementation of the FUSE API." Of course, the ... http://www.osxbook.com/blog/2008/12/22/ancientfs-on-linux-and-freebsd/ Here are some extended notes on understanding, compiling, and using AncientFS, the file system I talked about in the previous blog post. http://www.osxbook.com/blog/2008/12/17/extended-notes-on-ancientfs/ There has been much buzz about new features and functionality in MacFUSE 2.0. Besides the MacFUSE 2.0 release, there are still more new and interesting things to be discussed in the realm of user-space file systems. As I described and briefly demonstrated during my recent talk at the Googleplex, I ... http://www.osxbook.com/blog/2008/12/16/more-user-space-file-system-goodies/ Mac OS X, like many other Unix-like operating systems, includes the "autofs" file system layer that make automatic on-demand mounting of remote resources possible. See the man page for automount(8) for more details. Such automatic mounting is orthogonal to and possible with MacFUSE. (NB: You will need MacFUSE 2.0 or above ... http://www.osxbook.com/blog/2008/12/11/a-note-on-automounting-macfuse-file-systems/ VeryBigFS is a trivial MacFUSE file system—about 60 lines of C code—that creates a huge volume with a huge file in it. "Huge" would be 512TB in this case. This is useful if you want to see how a program will deal with unusually large files. Since it is extremely unlikely ... http://www.osxbook.com/blog/2008/12/10/verybigfs-all-you-can-read/ It was a little over two years ago that I gave serious thought to making user-space file systems a reality on Mac OS X. The result of that work, MacFUSE, was introduced at the Macworld conference in January 2007. Since then, MacFUSE has come a long way. It's been used ... http://www.osxbook.com/blog/2008/12/08/macfuse-20-is-here/ Next Monday (December 8, 2008), there will be an open-to-all talk on MacFUSE at Google's Mountain View headquarters. Here is a more detailed announcement. http://www.osxbook.com/blog/2008/12/02/macfuse-talk-at-google/ A couple of weeks ago, I released HFSDebug 4. I've updated it to make HFSDebug's pathname processing a little more sophisticated. Depending on how (and how seriously) you use HFSDebug, knowing the details could be useful. When you specify a file system object to HFSDebug using a pathname, how HFSDebug will ... http://www.osxbook.com/blog/2008/11/24/a-note-on-pathname-processing-in-hfsdebug/ I wrote HFSDebug in early 2004. I initially made it available as a software tool to help understand fragmentation in HFS+ volumes, although it could also be used to analyze several implementation details of HFS+. Eventually, I extended HFSDebug to be able to analyze all on-disk aspects of HFS+, along ... http://www.osxbook.com/blog/2008/11/09/hfsdebug-40-and-new-hfs-features/ Earlier this year, I released GrabFS, a MacFUSE file system that shows "live" screenshots of Mac OS X applications. If you wish to understand how GrabFS works, you can now browse its source. Enjoy. http://www.osxbook.com/blog/2008/08/19/grabfs-source-code/