Take a look at FUSE: http://fuse.sourceforge.net/ This will allow you to write a filesystem without having to actually write a device driver. From there, I’d start with a single file. Basically create a file that’s (for example) 100MB in length, then write your routines to read and write from that file. Once you’re happy with … Read more
I’m not sure your list is quite correct. It depends on what you mean by a file system. If you mean a file system that is mountable in an operating system and usable by any application that reads and writes files using POSIX calls, then GridFS doesn’t really qualify. It is just how MongoDB stores … Read more
This is straight from Andrew Gerrand’s 10 things you (probably) don’t know about Go: var fs fileSystem = osFS{} type fileSystem interface { Open(name string) (file, error) Stat(name string) (os.FileInfo, error) } type file interface { io.Closer io.Reader io.ReaderAt io.Seeker Stat() (os.FileInfo, error) } // osFS implements fileSystem using the local disk. type osFS struct{} … Read more
What you’re doing seems perfectly OK, provided you’re using the POSIX “raw” IO syscalls such as read(), write(), lseek() and so forth. If you use C stdio (fread(), fwrite() and friends) or some other language runtime library which has its own userspace buffering, then the answer by “Tilo” is relevant, in that due to the … Read more
Most filesystems (but not all) use locking to guard concurrent access to the same file. The lock can be exclusive, so the first user to get the lock gets access – subsequent users get a “access denied” error. In your example scenario, user A will be able to read the file and gets the file … Read more
External fragmentation Total memory space is enough to satisfy a request or to reside a process in it, but it is not contiguous so it can not be used. Internal fragmentation Memory block assigned to process is bigger. Some portion of memory is left unused as it can not be used by another process.
The answer is in the mount(8) manual page as well: Use findmnt -o TARGET,PROPAGATION to see the current propagation flags. An example: $ findmnt -o TARGET,PROPAGATION /opt TARGET PROPAGATION /opt shared $ sudo mount -o bind /opt /mnt $ sudo mount –make-slave /opt $ findmnt -o TARGET,PROPAGATION /opt TARGET PROPAGATION /opt private,slave $ sudo umount … Read more
A journaling filesystem records changes to the filesystem before it actually performs them. In this way it is able to recover after a failure (e.g. power fail) with minimal loss of data. The Features section of Wikipedia’s comparison of filesystems gives which are journaled. Journaling does not give a performance boost. In fact, the journaling … Read more
Copied from http://technet.microsoft.com/en-us/library/cc750354.aspx What’s FAT? FAT may sound like a strange name for a file system, but it’s actually an acronym for File Allocation Table. Introduced in 1981, FAT is ancient in computer terms. Because of its age, most operating systems, including Microsoft Windows NT®, Windows 98, the Macintosh OS, and some versions of UNIX, … Read more
There is no need to create a loop device, you can simply use the file itself as a vdev: zpool create test /tank/test/zpool