Controlo de Hardware (Físico) de um sistema operativo

The Hardware Level of the operating system controls the use of physical system resources, such as the memory manager, process manager, disk drivers, etc.

This layer of an operating system is often called the kernel. The exact boundaries of what constitutes the kernel varies by OS and often includes portions of the Logical Layer.

kernels em uso

BSD: FreeBSD, ULTRIX

MACH: Digital UNIX , Mac OS X, MkLinux (PowerPC, Intel, and HP/PA), NeXT (2.5), Rhapsody

LINUX: LINUX

Proprietary: (NOTE: Each would be a different proprietary kernel) IRIX, Pyramid

Kernels por sistema operativo

Digital UNIX: Mach 2.5-based implementation of BSD 4.x

FreeBSD: BSD 4.4 + enhancements

IRIX: Proprietary. “SGI has put a lot of work into IRIX; it isn’t just someone else’s kernel with some bundled software on top. It also predates MACH or any other open unix standard by a number of years.” — Walter Roberson

LINUX: LINUX. “The Linux kernel was originally written by Linus Torvalds (hence the name “Linux”), and it maintained by a team of developers. The kernel itself is released under the GPL (GNU Public License).” —Rich Steiner

Mac OS X: Mach

NeXT: Mach 2.5-baseado na implementação do BSD 4.x

Netware: Proprietary.

Rhapsody: Mach 2.5 (with custom enhancements)

Número de bits

One area of operating system support is how many bits of address and data space it can deal with. Early microprocessors were typically four or eight bits, while early mainframes and minicomputers were typically eight or twelve bits. Modern mainframes and microcomputers are typically either 32 or 64 bits.

The biggest advantage of more bits is a larger addressable space, both more RAM and larger disk (or other) storage space.

The bit-ness of an operating system or even of application programs can greatly exceed that of the underlying hardware. Classic examples include multi-precision mathematics in science and engineering and large data space in graphics software.

The bit-ness of the hardware can exceed that of the operating system or application programs. This is generally not a problem. It can lead to inefficiencies in operand fetches or writes and in allocation of data storage space, although this is not normally the case as hardware generally keeps smaller bitsize operations in the instruction set.

A related situation is the running of old legacy software on modern hardware. This can lead to inefficiencies in both allocation of space and in fetch and write of operands. The typical solution is for an operating system to provide an environment for legacy software that recreates the expectations of the older software.

In general, the more bits an operating system can handle, the more ready it is for the upcoming demands of truely large graphics and database operations, as well as being able to smoothly scale many everyday processes to the size needed for a large scale operation (such as web servers handling huge amounts of traffic). Most modern operating systems are in the process of the changeover to 64-bit hardware.

64-bit OSs: BeOS, Digital UNIX, HP-UX, IRIX, LINUX (dependendo do processador), Mac OS X, Solaris, Sun-OS

32-bit OSs: Amiga , FreeBSD, LINUX (dependendo do processador), Macintosh, NeXT, OS/2, Pyramid, Rhapsody, Solaris, ULTRIX, Windows 95, Windows 98, Windows NT, Windows NT Server, Windows NT Server Enterprise Edition