Extended file attributes
# zpool create -m /data datapool c0t0d0: Create a pool with a different mount point than the default. # zpool create datapool raidz c3t0d0 c3t1d0 c3t2d0: Create RAID-Z vdev pool # zpool add datapool raidz c4t0d0 c4t1d0 c4t2d0: Add RAID-Z vdev to pool datapool # zpool create datapool raidz1 c0t0d0 c0t1d0 c0t2d0 c0t3d0 c0t4d0 c0t5d0: Create RAID. Oct 31, · David Both - David Both is an Open Source Software and GNU/Linux advocate, trainer, writer, and speaker who lives in Raleigh North Carolina. He is a strong proponent of and evangelist for the "Linux Philosophy." David has been in the IT industry for nearly 50 years. He has taught RHCE classes for Red Hat and has worked at MCI Worldcom, Cisco, and the State of North Carolina.
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I am using Ubuntu When I try to create a hard link for any directory, it fails. I can create 110 links for files inside file system boundary. I know the reason why we cannot create hardlinks for files beyond file system. I just creatr to know the reason behind this. A hard link to a directory can link to a parent of itself, which creates a file system loop.
For example, these commands could create a loop with the back link l :. Avoiding an infinite loop when traversing such a directory structure is somewhat difficult though for example POSIX requires aa to avoid this.
A file system with this kind of hard link is no longer a tree, because a tree must not, by definition, contain a loop. So it has two parent directories. There are infinitely many further paths of the file. They are the same in terms of their inode number of course. But if you do not explicitly expect loops, there is no reason to check for that. A directory hardlink can also point to a child directory, or a directory that is neither child nor parent of any depth.
In this case, a file that is a filesysem of the link would be replicated to two files, identified by two paths. Filesysem path that may contain softlinks and even soft linked directory loops is often used just to how to create a filesystem in solaris 10 and open a file.
It can be used as a normal, linear path. But there are other situations, when paths ccreate used to compare files. In this case, symbolic links in the path can be resolved first, converting it to a minimal filesyste, and commonly agreed upon representation creating a canonical path :.
This is possible, because the soft links can all be expanded to paths without the link. After doing that with all soft links in a path, the remaining path is part of a tree, where a path is always unambiguous.
A soft link cannot cause all the trouble because it is different from the links inside the filesystem. It can be distinguished from hard links, and resolved to a ro without symlinks if hoow. In some sense, adding symlinks does not alter the basic file system structure - it keeps it, but adds more structure like an application layer.
From man readlink :. You need to understand the difference between hard links and symlinks, and use each as appropriate. Each comes with its own set of advantages and disadvantages:. Hard links are especially useful in performing "copy on write" applications. They allow you to how to make canned vanilla frosting chocolate a backup hoa of a directory structure, while only using space for 01 files that change between two versions.
Note that the implementation must first break the link or modifications will apply to the original file, too! The command cp -al is especially useful in this regard. It makes a complete copy of a directory structure, where all the files are represented what chemically makes a carbon chain unsaturated hard links to the original files.
You can then proceed to update how to create a culturally safe environment in the structure after creating actual copies of ho these filesand only the files that you update will take up additional space. This is especially useful when maintaining multigenerational backups. This is very dangerous because most tools and programs will not be aware of the binding.
The reason hard-linking directories is not allowed is a little technical. Essentially, they break the file-system structure. You should generally not use hard links anyway.
Symbolic links allow most 110 the same functionality without causing problems e. Ubuntu Community Ask! Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams Collaborate and share knowledge with a private group. Create a free Team What is Teams? Jow more. Why are hard links not allowed for directories?
Ask Question. Asked 8 years, 6 months ago. Active 26 days ago. Viewed k times. Improve this question. Nischay Nischay 3, 2 2 gold badges 16 16 silver badges 22 22 bronze badges. Certainly, it filesywtem to work for the superuser in older versions of Unix. Yes, bad things could happen, but usually not.
As I recall, rmdir knew not to carry on deleting past a hard link. However, users could get confused and delete things in error. StevePitchers How can rmdir handle hard links in a special way? A hard link is just a normal link - but an additional one.
It is not even easy to find out whether an unusual extra links exist without extra recordings. Each node stores fiesystem number of hard links that point to it: the contents are filesustem released once there are no remaining links. So rmdir can tell whether the directory has links from other places. Recursive removal, rm -rmust be coded with care, to be sure it will act correctly even should there be errors like "permission denied".
I have done ln -F on directories and have it work. But you don't dare delete the directory afterwards for fear of 110 the file system. Add a comment. Active Oldest Votes. Directory hardlinks break the how to change kitchen countertops in multiple ways They allow you sollaris create loops A hard link to a directory can link to a parent of itself, which creates a file system loop.
They multiply files Files are identified by paths, crdate resolving symlinks. In this case, symbolic links in the path can be resolved first, converting howw to a minimaland commonly agreed upon representation creating a canonical path : How to replace a tv lamp is possible, because the soft links can all be expanded to paths without the link.
Improve this answer. James Youngman 4 4 bronze badges. Volker Siegel Volker Siegel Why can't a soft link do all this? Tanay Right, it could help the expanation to compare it to similar cases with soft links. Ill try. Exactly how does this pertain to only directories? The way I understand it, these problems are also a problem for fileaystem files too. Moreover, I see hardlinking as an easy way to change a given directory's permission to allow others inside, without having to cilesystem them inside the parent chain too.
Sounds very interesting! But I know nothing about what the issue is - can you give me a hint? Show 3 more comments. Each comes with its own set of solarix and disadvantages: Symlinks can: Point to fllesystem Point to non-existent objects Point to files and directories outside the same filesystem Hard links can: Keep the file that they reference from being deleted Hard links are especially useful in performing "copy on write" applications. This description of hard links is rather misleading.
It's basically true that hard links "keep the file that they reference from being deleted", but how to create a filesystem in solaris 10 just a side effect of hard links. It's certainly NOT true that you can create hard links in one directory, change fileystem "original" file, and then expect the hard links to somehow point to the old content.
In fact, the guiding truth of hard links is the fact that it's not tp link at all, at least not any more so than the original "file", which is just a name pointing to a file.
A hard link is simply another name pointing to the same file. The backup idea is good and I actually use that a lot, but I think users should be warned that changing a file will also change the backup. Heck, a symlink need not point to anything at all.
In fact, if you think about it, a directory can be used as a relational database and not contain any actual files at all. Show 2 more comments. Use with care not to wipe the src ; kachar Feb 17 '14 at I get: mount: unknown filesystem type 'bind' Wizek Feb 25 '16 at MatM same with Debian how to use window media player hanshenrik Dec 23 '17 at If you only need to mount for read, you can set permissions on the mount point and avoid the rm -rf problem.
Yaroslav Nikitenko 8 filesystek bronze badges.
Permissions on Unix-like systems are managed in three distinct scopes or classes. These scopes are known as user, group, and others.. When a file is created on a Unix-like system, its permissions are restricted by the umask of the process that created it.. Classes. Files and directories are owned by a user. The owner determines the file's user datingfuckdating.comct permissions apply to the owner. We would like to show you a description here but the site wont allow datingfuckdating.com more. Extended file attributes are file system features that enable users to associate computer files with metadata not interpreted by the filesystem, whereas regular attributes have a purpose strictly defined by the filesystem (such as permissions or records of creation and modification times). Unlike forks, which can usually be as large as the maximum file size, extended attributes are usually.
If you're fed up with Windows , Linux , or macOS , you'll want to know if there's a great alternative desktop operating system that's worth using. While there are no absolute definitive answers here everyone's use case is different, after all we've discovered ten distinct examples that fall outside the usual bounds.
Our list even includes a few true outsiders, independent operating systems built from the ground up which serve mainly to prove just how difficult it is to create an entire functioning OS without a large number of brains working on it. Everything here can be tested reasonably within a virtual machine , so if something grabs your interest don't hesitate to download and give it a try. ArcaOS is a bit OS that runs on the x86 processor architecture, so should be compatible with some particularly old PCs.
The personal edition includes 6-months support and maintenance, while the commercial edition includes one-year of priority support and maintenance. We're a bit sad that BeOS didn't take off.
A stylish multitasking OS that introduced a whole host of features that Windows, Linux and macOS would later adopt for their own, BeOS was a true multimedia innovator that left the market with a whimper when its rights were sold to Palm in The spirit of the closed source BeOS lives on in the form of Haiku, an open source re-implementation which began development immediately after Be's demise, and it has been in development since.
Built from the ground up but designed to be backward-compatible with its classic quarry, Haiku follows BeOS' lead in its entirely modular design, allowing different components of the OS to be developed concurrently. In fact, even the second beta release of its under-development branch was released almost two years after the previous one. It's worth playing with just for the cleanness of its desktop, and there are working web browsers and media players, although it's still rather experimental and many of the features of BeOS haven't quite been fully realized as yet.
Linux, as you may know, is a ground-up reinterpretation of UNIX. It's completely open source, uses no proprietary Windows code, yet ReactOS is designed to be and in some cases actually is compatible with Windows drivers and applications. Your mileage may vary it's certainly not going to play nice with high-end games or software, and ReactOS isn't quite up to the Windows 10 level yet.
It's currently aiming at full compatibility with Windows Server So it's clearly a bit behind the times, but ReactOS does have its uses. Incorporating parts of noted Windows emulator Wine, it runs LibreOffice, Firefox, Opera and more quite happily, and can even manage some earlier versions of popular commercial applications like Adobe Photoshop.
Furthermore, ReactOS now natively supports more file systems than all Windows versions combined. Given that it's free, it's certainly worth a test to see if any of your older business-critical applications are compatible setting up workstations without Windows licensing is a tempting prospect, although we can't vouch for its resistance to attacks. As its name suggests, FreeDOS is a fully-compatible but completely free and open source remake of DOS that can handle just about everything its proprietary counterpart can.
That does, of course, mean no multitasking, no protected mode, no GUI, but it'll run your games and can even manage Windows 3. As you might expect, it's not a static recreation of the final commercial DOS release in , and indeed hasn't been static since it first emerged in In fact, FreeDOS remains in active development, and features a number of integrated improvements compared to its rather archaic ancestor.
Instead of a traditional installation, the distro is designed to be installed in bootable USB flash drives. Wayne OS is available in two versions -- Free and Paid. The Free version is meant for all kinds of end-users.
To install it, simply download its compressed installer and then extract the executable installer from the archive and fire it up. This will bring up the Wayne OS installer. Select the version you want to install and then point the installer to the USB disk you want to install it on. Wait for the installer to download and copy the necessary files to the USB disk.
The only reason it's not called BSD Unix is because of the pesky trademark and licensing gremlin. The OS runs on its own kernel, and all of its key components have been developed as part of a single whole.
Linux, on the other hand, is just the kernel; the rest of it is supplied by third parties so it lacks BSD's overall coherency. While FreeBSD is a highly complete and very reliable operating system, it doesn't come with a graphical user interface by default.
This is where FuryBSD steps in. It delivers a much more usable FreeBSD using a combination of a familiar graphical desktop environment with some additional tools and functionalities. The latest release is based on FreeBSD Its list of supported hardware widened as it grew, and in Sun released the source code in the form of OpenSolaris, leading to advanced community development. And then Oracle purchased Sun, renamed the OS once more to Oracle Solaris, and decided to cease source releases, effectively closing the source once again.
Sometime after this move, the community took it upon themselves to maintain OpenSolaris. They decided to ditch its development tools and processes and created the OpenIndiana Hipster branch to modernize the OS.
Hipster is compiled with GCC instead of Sun Studio and follows a rolling release model and the release team puts out installable snapshots every six-months. What makes OpenIndiana OI approachable to new users is that it runs familiar apps on its desktop. It uses the Mate desktop along with its cache of tools as well as a handful of mainstream productivity apps such as Firefox, Thunderbird and Pidgin.
It boots in a flash and gives you access to a number of useful apps. The OS boots in a snap and gives you the option to either launch the installer or boot into a Live session.
The inclusion of a very capable partitioner in the installer is another pleasant surprise. The desktop is fairly simple to navigate and includes a handful of essential apps, plus handy administration and configuration utilities. Visopsys does a nice job of masquerading as a regular desktop, but it really is a very capable CS project and should be treated as such.
Nostalgic open source fans can still get their dose of Amiga-esque goodness through Icaros. First-time users should appreciate the fact that the OS is distributed as an installable live CD to whet their appetite.
Click on the eye icon in the panel to get an Applications menu, or on the filing cabinet to get a selection of manuals. It's worth noting that there have been a number of other operating systems that were previously popular but have since been discontinued.
One of the most famous of which is AmigaOS, used in Amiga personal computers during the 's and which had a reputation for solid stability. Much like its ancestor it's been developed with security and stability in mind for commercial applications.
We see the claim 'zero downtime' repeated all over the place, and while it's theoretically possible to lock up your hardware with the wrong application, this is something that could have been a real killer feature. Developed between and , AtheOS initially planned as a clone of AmigaOS but later following its own path was the work of a lone Norwegian programmer, Kurt Skauen. After Skauen abandoned the project, its GPL-licensed source code was picked up by the community and Syllable Desktop was born.
The majority of it is composed of unique code, although certain components have been pulled from the vast library of open source Linux programs; there's also a Server version, which is more traditionally Linux. Syllable's key selling point ignoring the fact that it's free is its speed and lightness. Slap this on a modern PC and you'll likely never have seen an OS so quick. Syllable does lack the ports that make other indie operating systems attractive, though it contains a number of native apps for web browsing, email, VNC and more.
We're not entirely positive that it's still active the last official update was some time in but if there's a very, very old PC you need to resurrect with reasonably modern system architecture, try this.
The development of SkyOS has sadly been halted, but it's still worth looking at as an example of an OS constructed from scratch. Developed initially as an open source project by coder Robert Szeleney, SkyOS was based on concepts gleaned from other platforms but didn't originally borrow their code.
That said, a few components are based on other packages there's no sense, for example, developing an entirely new compiler when GCC already exists, and the SkyFS filesystem is forked from OpenBFS. Later in its life, Szeleney appears to have experimented with a version of SkyOS built on top of a Linux kernel in an attempt to help with driver compatibility.
The source was closed midway through its life, and Szeleney continued development based on feedback from a popular paid public beta program. Unfortunately the struggle to keep up with ever-diversifying computing standards became too much for the lone coder, and development was halted in , with the most recent beta made publicly available in It's obviously incomplete, and not suitable for any kind of business environment, but as a curio to run within a VM it's very interesting.
Whether the extreme religious doctrine behind it interests you or not, TempleOS is an interesting example of a completely independent, unique OS. It's been made and maintained with extreme dedication by one man, Terry A. Davis, over the course of ten years. TempleOS programmed entirely using Davis' own language, the excellently named HolyC, which you also use to interact with its shell deliberately includes no networking and absolutely no hardware support beyond that which forms the core PC system.
So what's the point? TempleOS has been built from the ground up with what seems like no hang-ups on existing operating systems. The entire thing is hyperlinked, meaning you can quickly burrow down to the source of a program just as easily as you can find its dependencies, and it's super-quick; there's no paging, so the whole OS gets up and running within a second or two.
It's unlikely you'll be able to use TempleOS for anything solid, and Davis' well-documented mental health struggles haven't helped its standing in the community. But it includes a huge number of interesting ideas, particularly the blurring of the division between document and program, which could impact more traditional operating systems.
TechRadar pro IT insights for business. North America. Please deactivate your ad blocker in order to see our subscription offer. Reasons to avoid - For older PCs. Haiku The modular successor to BeOS. Reasons to avoid - Slow release schedule. Reasons to avoid - Still in the Alpha phase.
Reasons to avoid - No GUI or multitasking. Reasons to avoid - bit only - Poor hardware support. Reasons to avoid - No graphical package manager. Reasons to avoid - Rudimentary apps - No package manager. Visopsys The ultimate CS project.
Reasons to avoid - Limited hardware support - Sparse apps. Icaros Desktop. Reasons to avoid - No package manager - Esoteric installer. See more Computing news. Most Popular Most Shared.