Linux has more than what a modern day operating system should typically have. Let us look at some of them
Multitasking: Refers to multiple processes or tasks that execute on a single processor simultaneously without interfering with each other. To better understand, it can be said that, each process will be running independent of the other under the illusion that it is the only process running on the processor and has an exclusive access to all the services of the OS
Multiuser: Linux allows multiple users to use the system simultaneously under the illusion that each being the sole user
Multiplatform: Linux runs on most computers, laptops and platforms. Several projects are underway to port Linux on to other hardware configurations, truly speaks about its extensible nature. To my knowledge Linux runs on Alpha, Arm, AMD, Cyrix, Power PC, Mips, M68k, Intel, Sparc and many more, the list goes on.(//// to support 40 different architectures.!!)
Multiprocessor: Symmetric Multi-Processing (SMP), a computer architecture that provides faster performance by making multiple CPUs available to individual processes simultaneously .Linux has SMP support for Alpha, PowerPC, Intel, Sparc, and many more are underway.( SMP technology details along with the Intel Dual Core release).
Multithreading: It is the ability of the Operating System to execute different parts of a program, called threads, simultaneously. Linux has native kernel support for multiple independent threads of control within a single process memory space.
Customization: One of the greatest feature of Linux, is that it helps users to customize it to their requirements and likings. You can make it exactly the way you want and on the platform you want it to run so as to best utilize its services.
Security: Linux implements more security features to prevent intruders. Some of them include Files and File system security, Trojan Horses, Password Security and Encryption, Network Security, Kernel Security, Device Security, Host Security etc. It also enables you to create customized security features, thanks to its open nature.
Protection against Crashes : has memory protection between processes, so that one program can’t bring the whole system down.
Demand loads executables: Linux only reads from disk those parts of a program that are actually used.
Compatibility: It is mostly compatible with POSIX, System V, and BSD at the source level.
Open Source Nature: Complete source code, including the whole kernel, drivers, development tools and all user programs, are available and also freely distributable under GPL (GNU General Public License)
Filesystem Support: As Linux runs on almost every hardware platform, it must support all the filesystem types that are found on those systems, this is an important feature for any OS to co-exist with the other, so as to share data between them on the same system. Linux includes all modern day journaling filesystems and Windows compatible ones. Some of them are Ext2, Ext3, Fat16, Fat32, MS-DOS, AFF, NFS, NTFS, ISO, UPS, SysV etc.
Networking protocols: Protocols available in the latest development kernels include TCP, IPv4, IPv6, AX.25, X.25, IPX, DDP (Appletalk), Netrom, and others. Stable network protocols included in the stable kernels currently include TCP, IPv4, IPX, DDP, and AX.25
Different formats for executable files: Linux has support for many executable file formats. This helps Linux run executables, that are created on other platforms. Some of them include a.out, and elf32.
Small and Compact: Linux kernel image and complete root filesystem, including all basic system programs can fit in to just a 1.4MB floppy diskette.
Help through user communities: There is huge Linux community representations through chat rooms, mailing lists and discussion forums, who are ready to help you with your questions, fixes, updates, software patches and more, anytime and everytime. Moreover, these people are volunteers and don’t charge anything for helping you.
There is more to Linux than we could ever imagine.