SimOS was a full system simulator, developed in the Stanford University

Stanford University

The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...

 in the late nineties in the research group of Mendel Rosenblum

Mendel Rosenblum

Mendel Rosenblum is an associate professor of Computer Science at Stanford University, and one of the co-founders of VMware. Since 2008 he is a Fellow of the Association for Computing Machinery "for contributions to reinventing virtual machines", and had previously received the ACM SIGOPS Mark...

. It was enabled to run IRIX

IRIX

IRIX is a computer operating system developed by Silicon Graphics, Inc. to run natively on their 32- and 64-bit MIPS architecture workstations and servers. It was based on UNIX System V with BSD extensions. IRIX was the first operating system to include the XFS file system.The last major version...

 5.3 on MIPS, and Unix variants (?) on Alpha.

SimOS-PPC

SimOS-PPC was forked from the original SimOS as IBM

IBM

International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

's internal project, running a modified AIX kernel and userland in an emulator, developed by Tom Keller and his team in the Austin lab of IBM. IBM used SimOS to facilitate development of new systems. The software used in this project is now publicly available for download for AIX 4.3 licensees.

Linux/SimOS

Linux/SimOS was "...a Linux operating system port to SimOS, which is a complete machine simulator from Stanford. The motivation for Linux/SimOS is to alleviate the limitations of SimOS, which only supports proprietary operating systems."

SimBCM

SimBCM is an open source full system simulator based on SimOS. It simulates BCM1250, a dual-core MIPS64 SOC of Broadcom

Broadcom

Broadcom Corporation is a fabless semiconductor company in the wireless and broadband communication business. The company is headquartered in Irvine, California, USA. Broadcom was founded by a professor-student pair Henry Samueli and Henry T. Nicholas III from the University of California, Los...

. The entire source code of SimBCM is distributed under GPL. It is capable of running the Linux kernel or the NICTA::Pistachio L4 microkernel.

Simics

The currently available commercial product, Virtutech

Virtutech

Virtutech was founded in 1998 as a spin-off from the Swedish Institute of Computer Science , in Stockholm, Sweden. In 2004, the headquarters was moved to San Jose, California, USA. The Stockholm site remains the company's R&D center. The company's main product is Simics software, used by teams of...

 Simics

Simics

Simics is a full-system simulator used to run unchanged production binaries of the target hardware at high-performance speeds. Simics was originally developed by the Swedish Institute of Computer Science , and then spun off to Virtutech for commercial development in 1998...

 was derived from the work of the Swedish Institute of Computer Science, and was originally developed to run a full system simulation of Solaris on SPARC platform. Simics was used by IBM to help develop AIX 6.1 on a simulation of the POWER6

POWER6

The POWER6 is a microprocessor developed by IBM that implemented the Power ISA v.2.03. When it became available in systems in 2007, it succeeded the POWER5+ as IBM's flagship Power microprocessor...

 hardware.

RSIM

RSIM was the "Rice Simulator for ILP Multiprocessors", developed at the Rice University in the late 1990s. It was able to run on Solaris, IRIX and HP-UX. The simulator is available under the University of Illinois/NCSA open source license agreement. The development is finished.

M5

Developed at the University of Michigan

University of Michigan

The University of Michigan is a public research university located in Ann Arbor, Michigan in the United States. It is the state's oldest university and the flagship campus of the University of Michigan...

, M5 simulates Alpha and SPARC hardware, with support for other architectures in progress.