Linux is an operating system developed and released by Linus Torvalds in September 1991. It is an open-source Unix-like operating system.
Kernel
The kernel is the heart of an operating system. It serves as a bridge between a computer’s applications and hardware components. By acting as a gatekeeper, it manages memory and processor access. In addition, it helps optimize file systems and networking.
There are five significant layers in the kernel. Each layer has a different function. For instance, the highest level is responsible for software interface, while the lowest is machine oriented.
The kernel’s most crucial role is multitasking. Keeping several processes running at the same time requires careful monitoring and allocation of resources. However, if one method fails, the entire system can crash.
One of the significant challenges for the kernel is memory management. When a process demands more memory than the machine can provide, the kernel allocates extra space for the task.
Init
The Linux operating system uses init for initializing the system and starting processes. The init process is the grandparent of all other functions on the Linux system. Init also spawns daemons to perform various system tasks. In addition, it creates multiple networking stacks and other background processes required to run the system.
When the system boots, the kernel launches init and initializes the virtual devices associated with the file system. The init program reads an initial file, specifying the init system’s configuration. Init then runs start scripts with a start parameter and kills other hands with a stop parameter.
During boot, the init program also reads /etc/inittab, a configuration file describing each run level’s behavior. So, for example, a user could run the system in GUI or single-user mode.
Device management
A Linux operating system has several features that make it a viable choice for enterprises and consumers. Among them is its device management.
This term encompasses the plethora of administrative tools used to track and manage all hardware devices in a system. It may include storage, input, and output devices. Using device management can improve business processes, security, and troubleshooting.
The kernel also supports device drivers, which have a unique role in the operating system. These devices supervise data transmission between the main memory and peripheral unit. They can be built separately or as part of the kernel.
The Linux device model is a layer of abstraction that describes hardware resources and software components. It also covers the basics like power management, hot-pluggable devices, and integration with real hardware.
Memory management
Memory management under Linux is a multi-layered approach involving various components. The primary feature is the page allocator. This part allocates and frees physical memory.
A page is a non-overlapping region of contiguous memory. In addition, a page can be reused by other processes. However, the size of a page is dependent on the processor architecture.
Another component of memory management is the page cache. This is a cache of recently requested data. It helps to make data available faster. When a file is read, the kernel fills the page cache with the contents from the disk.
The kernel uses a page table to translate virtual and physical memory addresses. This is done by combining the page tables and address translation hardware.
Physical memory is a finite resource. Therefore, when a process requires access to a large portion of this memory, it must request an allocation from the kernel. At that time, the kernel will map the requested page to the process’s address space.
Security
Security is a critical part of operating systems, whether Windows, Linux, or any other OS. Unfortunately, cybercriminals have many ways to infect an OS with their malicious code.
The key is to use tools that are designed to secure your system. There are various programs, including OpenSSH, ClamAV, and Snort. You should also check the latest patches to ensure your security.
Linux is a relatively safe operating system, but it is not foolproof. Some of the vulnerabilities you may encounter in Linux are based on buffer overflows. These exploits allow an intruder to log into your system and access files. If you don’t protect your data, a cybercriminal can do anything with the compromised files.
SELinux is a mandatory access control system built into the Linux kernel. This system uses role-based access control to enforce your security policy.
