Simics

Development began in 1991 at the Swedish Institute of Computer Science (SICS), where Peter S. Magnusson wrote the simulator for the institute's research on the Data Diffusion Machine, a cache-only memory architecture.^[1][4] Magnusson's first simulator, gsim, extended g88, a Motorola 88000 simulator by Robert Bedichek of the University of Washington, to model multiple processors with shared memory; SimICS, begun in 1993, was a from-scratch rewrite that replaced it.^[13][14] SimICS modelled a SPARC V8 processor and was developed to the point of booting and running unmodified Solaris images on a multiprocessor model.^[4][14] The name was a play on "Simulator from SICS".^[1] A simulation group formed around the project; by 1998 it comprised Magnus Christensson, Fredrik Larsson, Magnusson, Andreas Moestedt and Bengt Werner.^[4]

Research from this period included Partial Translation (1993), a technique for generating native code at run time inside an interpreter,^[15] and techniques for fast simulation of memory hierarchies.^[16] In 1997 the group booted an unmodified Solaris 2.6 on a simulated four-processor sun4m SPARCstation, directly from disk images taken from a real machine; the result was published at the 1998 USENIX Annual Technical Conference.^[13][1]

In 1998 the five members of the SICS simulation group founded Virtutech AB in Stockholm, the first spin-off company in SICS's history; SICS licensed the simulator's development and exploitation rights to the new company, and the product was launched in June 1998.^[4][1] Early customers included Sun Microsystems, Ericsson and Hewlett-Packard; David Yen, Sun's vice president and general manager of enterprise server products, called the group "one of the world's foremost research groups in system level simulation" and said that Sun had "worked with them for many years".^[4] Werner later recalled that although the tool had been pitched to industrial partners as a cache-analysis tool, it was quickly found to be most valuable for developing software that interacted with hardware, and that companies could not depend on a tool maintained by a research institute, which drove the decision to form a company.^[1]

In January 2001 AMD licensed Simics under the name "VirtuHammer", a simulator of its forthcoming 64-bit x86-64 "Hammer" processors that ran on ordinary 32-bit PCs, and delivered it to the software companies porting operating systems to the new architecture more than two years before the first Opteron shipped. SuSE ported Linux on it, Wasabi Systems ported NetBSD on it, and Microsoft used it to develop the x64 version of Windows: Dave Cutler, who led that effort, and Forrest Foltz developed the port on simulators alone, logging on to a desktop under simulation for the first time on October 25, 2001, and when AMD delivered the first x86-64 machine to Microsoft on February 7, 2002, the 64-bit build booted two hours later. Virtutech began selling the x86-64 model directly as Simics/x86-64 in 2002.^{[17][18][19][20][21][22][23][24][25][26][27][28]}

Simics was a finalist for the Best of COMDEX award in November 2001,^[29] and Simics 1.0 was released in February 2002.^[30] That year the Virtutech team published "Simics: A Full System Simulation Platform" in IEEE Computer, describing the architecture and calling Simics the first commercial full-system simulator.^[3] By 2003 the company reported Simics in use at some 300 universities,^[31] and by 2004 the simulator used just-in-time compilation and had demonstrated a simulated network of 1,000 machines.^[32]

Simics 3.0, released in March 2005, introduced "Hindsight", the ability to run a simulated system backwards.^[33] Later in 2005 IBM selected Simics for development of its POWER6 platform,^[34] and Iridium adopted it for satellite software development and testing;^[35] Wind River Systems became a customer in 2006.^[36] Simics 4.0, launched in 2008, added multithreaded simulation within a single process.^[37]

On February 5, 2010, Intel announced an agreement to acquire Virtutech, with the Simics product line placed in Intel's Wind River subsidiary.^[5][38] Wind River released Simics 4.4 in 2010, Simics 5 in 2015 and Simics 6 in 2019.^[39][40][41] In 2013 Intel devoted an issue of the Intel Technology Journal to Simics,^[42] and a textbook on development with Simics by Daniel Aarno and Jakob Engblom was published in 2014.^[43] Intel provides customers with Simics models of future platforms before hardware is available,^[44] and in 2021 released the Intel Simics Simulator as a free public download.^[2]