Cloning and forking are often confused because both create copies of a repository. But they operate in different places and serve different purposes. A clone is a local copy on your computer, created with git clone. A fork is a server-side copy on your GitHub account, created with the “Fork” button. The distinction matters because…
A local Git repository is an island. Commits accumulate in the .git directory, branches are created and merged, but none of it is visible to anyone else until the repository is connected to a remote. git remote establishes that connection, and git push transmits the commits across it. For a new project, this is a…
An array that is created and forgotten is a liability. Drives fail, sectors go bad, and arrays silently degrade into a state where a second failure means total data loss. Managing an mdadm array is not about reacting to catastrophe—it is about routine monitoring, deliberate failure testing, and a recovery procedure that you have practiced…
The previous chapter established the theory of RAID levels. This chapter translates that theory into practice. mdadm is the userspace tool that communicates with the Linux kernel’s multiple device (md) driver to assemble physical block devices into a logical RAID array. The command syntax is dense—a single invocation can specify the array name, RAID level,…
Redundant Array of Independent Disks—RAID—is not a backup strategy. It is a method of combining multiple physical drives into a single logical unit to achieve one of three goals: increased performance, increased fault tolerance, or both. The LFCS exam expects you to understand the trade-offs between the common RAID levels and to recognize which level…
The previous chapter introduced the decision to run a repair. This chapter covers the tools themselves. e2fsck and xfs_repair are not interchangeable frontends for the same operation. They operate on different filesystem architectures, accept different flags, and enforce different preconditions. e2fsck assumes the filesystem may be dirty and performs a multi-pass check that can rebuild…
Filesystem corruption is not a theoretical concern. A sudden power loss, a failing disk, or an unclean shutdown can leave metadata in an inconsistent state—inodes marked as allocated with no directory entry, blocks claimed by multiple files, or a superblock that no longer matches reality. The fsck family of tools exists to detect and repair…
The standard library’s TcpStream and UdpSocket abstract away the network layer. They handle IP headers, checksums, and routing. But when you need to craft a custom protocol, implement a diagnostic tool, or build a userspace TCP/IP stack, that abstraction becomes a barrier. Raw sockets bypass the kernel’s network stack, giving you direct access to the…
Traditional deserialization reads a byte buffer, parses its contents, and allocates new memory to reconstruct the data structure. Zero-copy deserialization skips that final step: the byte buffer is laid out so that it already is the in-memory representation, and the program simply casts a pointer into the buffer and reads fields directly. Rust’s type system…
Rust’s standard library provides the Future trait, the Waker type, and the Context that ties them together. It does not provide an executor. Every async runtime in the ecosystem—Tokio, async-std, smol, and every educational implementation—builds these missing pieces from the same primitives. Understanding this architecture is not academic. When a future hangs, when a task…