This document preserves the original release notes for Linux kernel version 0.01, the first public release by Linus Torvalds in 1991. These notes provide historical context on the early design decisions and limitations of what would become the world’s most widely used operating system kernel. Contents The 0.01 distribution included: linux-0.01.tar.Z — kernel source code…
NFS squashes root access to an anonymous user (typically nobody) by default as a security measure. When a client connects as root, the server remaps that user to an unprivileged account, preventing root from having unrestricted access to exported shares. This can cause permission issues if your application genuinely requires root-level file operations. Using no_root_squash…
When you try to unmount a filesystem, Linux sometimes refuses with a “device is busy” error. This safety mechanism prevents data loss when processes are actively using the filesystem. But there are legitimate cases where you need to force an unmount: a dead NFS server, a failed USB device, or a hung mount that won’t…
When an NFS server goes down or becomes unreachable, client mounts can end up in a “Stale NFS file handle” state. Standard umount and umount -f commands fail, leaving you stuck with an unusable mount point and no clean way to recover without rebooting. The solution is to use umount -l (lazy unmount), which immediately…
On a Linux system, you often need to let regular users mount and unmount specific devices without requiring sudo or the root password. This is common for external drives, USB devices, or secondary internal disks. There are several approaches, each with different security and usability tradeoffs. Using /etc/fstab with the user Option The simplest approach…
Attaching storage to a running Xen DomU without rebooting is straightforward using the xl toolstack. This is useful when you need to add capacity, attach backup storage, or provision new volumes without downtime. Basic Disk Attachment To attach a logical volume or physical disk to a running DomU, use xl block-attach on Dom0: xl block-attach…
There are times when you need direct access to a DomU’s disk from Dom0—for recovery, backup, or maintenance. This is straightforward with Xen’s block device tools, though the commands have evolved depending on your Xen version. Attaching the Disk The method depends on which Xen toolstack you’re using. With xl (Xen 4.1+, recommended): xl block-attach…
When you try to unmount a filesystem with umount, Linux may report “device is busy.” This is a safety mechanism — the kernel blocks unmounting when processes or kernel threads are actively accessing the partition or holding open files on it. Forcing an unmount without understanding what’s using the filesystem risks data corruption and data…
The /etc/fstab file defines how Linux mounts filesystems at boot and controls mounting behavior for both the system and individual users. Understanding its format and options is essential for reliable storage management. File Format and Fields Each line in /etc/fstab represents one filesystem. Fields are separated by whitespace (tabs or spaces), and lines beginning with…
Shrinking an ext4 filesystem on LVM is riskier than expanding—it requires the filesystem offline and careful size planning. The operation can take hours on large volumes, and mistakes can destroy data. This guide walks through the safe path with verification at each step. Prerequisites Before starting: Backup everything. A full backup of the data being…
LVM abstracts physical storage into logical volumes, letting you resize filesystems online, add drives transparently, and manage capacity without downtime. This guide covers the most common task: extending a mounted ext4 filesystem when you need more space. Prerequisites Online extension requires the resize_inode option enabled on your ext4 filesystem. Check this first: tune2fs -l /dev/vg/lv_home…
A Fedora Live USB lets you boot directly into a Fedora environment without modifying your hard drive. You can use it to test Fedora, troubleshoot your system, or perform a fresh installation. This guide covers modern tools and workflows for creating bootable USB media. Back up any data on your USB stick first — the…
On Fedora/RHEL-based systems: dnf install ecryptfs-utils On Debian/Ubuntu: apt-get install ecryptfs-utils Load the kernel module modprobe ecryptfs To ensure the module loads automatically on boot, add it to /etc/modules-load.d/: echo “ecryptfs” | sudo tee /etc/modules-load.d/ecryptfs.conf Create directories You’ll need two directories: one for encrypted storage (.private) and one as the mount point (private). The .private…
ISO images are sector-by-sector copies of optical media stored as binary files. They’re useful for archiving DVDs or creating portable copies without keeping physical disks around. On Linux, several tools can accomplish this—dd is the simplest, but modern alternatives offer better features. Using dd to Create an ISO Image The most straightforward approach uses dd:…
Mounting an ISO on Linux requires a loop device. Modern systems support this directly with mount: sudo mount -o loop /path/to/image.iso /mnt/mount-point Or use the -t iso9660 option for explicit filesystem specification: sudo mount -t iso9660 -o loop /path/to/image.iso /mnt/mount-point To unmount: sudo umount /mnt/mount-point For temporary mounts that don’t require persistence across reboots, consider…