Comparison of operating system kernels

A kernel is the core component of every computer operating system. While kernels are highly technical in nature, and may be hidden from the user under many layers of software and applications, they do have distinguishing or characteristic features, such as computer architecture, design goals, as well as the more practical features that they provide. A direct comparison of operating system kernels can highlight these design choices, and provide insight into different niches and the evolving technology of kernels.

Comparison criterion

The following tables compare general and technical information for a number of widely used and currently available operating system kernels. Please see the individual products' articles for further information.

Even though there is a large number and variety of available Linux distributions, all of these kernels are grouped under a single entry in these tables, due to differences being of the patch level. See comparison of Linux distributions for a detailed comparison. For Linux distributions that have highly modified kernels, for example Real-time computing kernels, they should be listed separately. There are also a wide variety of minor BSD operating systems, many of which can be found at Comparison of BSD operating systems.

The tables specifically do not include subjective viewpoints on the merits of each kernel or operating system. For this kind of information, please see operating system advocacy.

Overview comparison

The major contemporary general-purpose kernels are shown in comparison. Only an overview of the technical features is detailed.

Kernel name	Used in	Creator	Executable format (also see section below)	Type	Integrated firewall	SMP support	Multiple architecture support (also see section below).	Multitasking
Agnix
Amiga Exec	Amiga OS	Commodore International/Carl Sassenrath	HUNK	microkernel (atypical)
Amiga Exec SG (2nd Generation)	Amiga OS 4.0	Hyperion Entertainment under license of Amiga Inc.	ELF (Can run 68000 code Hunk)	microkernel (atypical)
DragonFly BSD kernel	DragonFly BSD	Matt Dillon	ELF, others - platform dependent	hybrid	IPFilter, Ipfirewall, PF
FreeBSD kernel	FreeBSD Debian GNU/kFreeBSD Gentoo/FreeBSD	The FreeBSD Project	ELF, others - platform dependent	monolithic	IPFilter, Ipfirewall, PF
GNU Hurd	Bee GNU/Hurd Debian GNU/Hurd	GNU Project/Free Software Foundation	ELF	microkernel
GNU Mach		GNU Project/Free Software Foundation		microkernel
Inferno kernel	Inferno	Bell Labs / Vita Nuova Holdings		virtual machine
L4	L4	Jochen Liedtke		microkernel
Linux kernel	Linux	Linus Torvalds	ELF, others	monolithic	netfilter/ iptables
Mach		Carnegie Mellon University		microkernel
Minix 3	Minix 3	Andrew S. Tanenbaum	a.out	microkernel
MkLinux		OSF Research Institute and Apple Computer		microkernel
NetBSD kernel	NetBSD Debian GNU/NetBSD	The NetBSD Project	ELF, others - platform dependent	monolithic	IPFilter PF
NetWare kernel	Novell NetWare	Novell	NLM	hybrid
OpenBSD kernel	OpenBSD	OpenBSD developers	ELF, others - platform dependent	monolithic	PF
Plan 9 kernel	Plan 9 from Bell Labs	Bell Labs		hybrid	ipmux
SunOS kernel	SunOS	Sun Microsystems	a.out	monolithic
Solaris kernel	Solaris Operating System, Nexenta OS	Sun Microsystems	ELF (32-bit only until Solaris 7)	monolithic	IPFilter
Trix		Massachusetts Institute of Technology		monolithic
Windows NT kernel	Windows NT, 2000, XP, 2003, Vista	Microsoft	PE, others?	hybrid
XNU (Darwin kernel)	Mac OS X OpenDarwin GNU/Darwin	Apple Computer	Mach-O	hybrid	Ipfirewall
SPARTAN kernel (HelenOS kernel)	HelenOS	Jakub Jermar	ELF	microkernel
Kernel name	Used in	Creator	Executable format (also see section below)	Type	Integrated firewall	SMP support	Multiple architecture support (also see section below).	Multitasking

Binary format support

A comparison of OS support for different binary formats (executables):

Kernel Name	a.out	ECOFF	ELF	FDPIC ELF binaries (mmu less)	flat binaries (superH)	HUNK	Mach-O	Misc (wrapper based, like interpreters)	PE	SOM (PA-RISC, HP-UX)
Amiga Exec
Linux kernel
Solaris kernel
Windows NT kernel
XNU

File system support

Physical file systems:

Kernel	Acorn ADFS	Amiga FFS	BeFS	BFS	cramfs	EFS	ext2	ext3	ext4	FAT	FreeVxFS	HFS	HFS+	HPFS	ISO 9660	JFFS	JFFS2	JFS	Minix fs	NSS	NTFS	OCFS	QNX4 FS	System V FS	UDF	UFS	XFS	ZFS
Linux kernel			read only			read only					read only										limited write			write support?
NetWare kernel
Solaris kernel
Windows NT kernel
XNU																					limited write							read only

Supported CPU architectures

kernel	68k	DEC Alpha	ARM	HP PA-RISC	IA-64	MIPS	PowerPC	PowerPC 970	System/ 390	SuperH	SPARC 32-bit	SPARC 64-bit	x86	x86-64
Linux kernel
DragonFly BSD kernel
FreeBSD kernel
NetBSD kernel
NetWare kernel
OpenBSD kernel
Solaris kernel
Windows NT kernel		NT 5.0 RC1 and below only				NT 4.0 and below only	NT 3.51 and NT 4.0 only
XNU
SPARTAN kernel								In Progress

See also

• Comparison of open source operating systems
• Comparison of Linux distributions
• Comparison of BSD operating systems
• Comparison of Windows versions
• List of operating systems
• Comparison of file systems
• Comparison of operating systems
• Operating system advocacy
• Comparison of Windows and Linux
• XvsXP

Footnotes