Indiana University
University Information Technology Services
  
What are archived documents?
Login>>
Login

Login is for authorized groups (e.g., UITS, OVPIT, and TCC) that need access to specialized Knowledge Base documents. Otherwise, simply use the Knowledge Base without logging in.

Close

What is Mach?

Based on BSD, Mach began as a Unix-like operating system developed by Carnegie Mellon University (CMU). Conceived in 1985 as a research initiative, work on Mach continued at CMU until 1994. A number of organizations and corporations have continued to develop Mach, and several major operating systems are currently based on the Mach microkernel. Examples of these systems are listed below:

  • Apple's Mac OS X, which is based on NeXT's OPENSTEP operating system

  • OSF/1, developed by the Open Group and incorporated into a number of Unix implementations, notably Tru64 UNIX. The Open Group calls its Mach descendant Mk.

  • Tenon Intersystems' MachTen, a Unix implementation that runs on top of Mac OS

  • The GNU Hurd, which is intended as a replacement for the Unix kernel. For more information, see: http://www.gnu.org/software/hurd/

Part of Mach's popularity is due to the extremely portable nature of its microkernel. The original Mach operating system consisted of a version of BSD Unix running on top of the microkernel. Current Mach-based operating systems have completely replaced the original Unix with their own OS front-ends, but they all share a variant of the microkernel. The microkernel handles low-level functions such as memory and thread management, multi-processor support, and interprocess communication and I/O. Higher-level functions, however, are left to OS-specific servers. The microkernel and servers perform the functions traditional kernels normally perform: catching and handling system calls. However, with Mach, calls are never allowed to access the hardware directly; that is reserved for the microkernel itself. While this arrangement can dramatically ease portability, it occasionally affects performance and breaks older software.

Though Mach is no longer an active project, Carnegie Mellon maintains a useful Mach page with links to other resources: http://www.cs.cmu.edu/afs/cs.cmu.edu/project/mach/public/www/mach.html For a forum of discussion about Mach, see the newsgroup comp.os.mach .

This is document agjw in domain all.
Last modified on May 13, 2009.

Comments/Questions/Corrections

Use this form to offer suggestions, corrections, and additions to the Knowledge Base. We welcome your input!

If you are affiliated with Indiana University and would like assistance with a specific computing problem, please use the Ask a Consultant form, or contact your campus Support Center.

Contact Information

Note: We will reply to your comment at this address. If your message concerns a problem receiving email, please enter an alternate email address.