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57-563: Instead of the instruction set architecture being implemented in hardware, or translated by specialized hardware, the Crusoe runs a software abstraction layer, or a virtual machine , known as the Code Morphing Software (CMS). The CMS translates machine code instructions received from programs into native instructions for the microprocessor. In this way, the Crusoe can emulate other instruction set architectures (ISAs). This

114-468: A high-level programming language (compared to the low-level ISA abstraction of the system VM). Process VMs are implemented using an interpreter ; performance comparable to compiled programming languages can be achieved by the use of just-in-time compilation . This type of VM has become popular with the Java programming language , which is implemented using the Java virtual machine . Other examples include

171-683: A virtual machine ( VM ) is the virtualization or emulation of a computer system . Virtual machines are based on computer architectures and provide the functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination of the two. Virtual machines differ and are organized by their function, shown here: Some virtual machine emulators, such as QEMU and video game console emulators , are designed to also emulate (or "virtually imitate") different system architectures, thus allowing execution of software applications and operating systems written for another CPU or architecture. OS-level virtualization allows

228-508: A 220 nm process. It has a 96k L1 cache (64 KB instruction and 32 KB data) and no L2 cache. The TM3120/TM3200 has an integrated SDRAM memory controller and a PCI interface. It measures 77 mm and uses a 1.5 V power supply, dissipating less than 1.5 W of power (typically). The TM5400 differs from the TM3120/TM3200 with the inclusion of a 128K of L1 Cache(with the addition of 32 KB data cache) as well as

285-465: A 54% smaller 399 pin FC-OBGA package rather than the ceramic 479 BGA package used previously. Clock speed remains the same between 667 and 1000 MHz. Transmeta was a fabless semiconductor company, without the facilities to fabricate their designs. Instead, both processors were fabricated by IBM Microelectronics , the semiconductor business of International Business Machines (IBM). IBM fabricated

342-478: A nested guest virtual machine does not need to be homogeneous with its host virtual machine; for example, application virtualization can be deployed within a virtual machine created by using hardware virtualization . Nested virtualization becomes more necessary as widespread operating systems gain built-in hypervisor functionality, which in a virtualized environment can be used only if the surrounding hypervisor supports nested virtualization; for example, Windows 7

399-431: A normal application inside a host OS and supports a single process. It is created when that process is started and destroyed when it exits. Its purpose is to provide a platform -independent programming environment that abstracts away details of the underlying hardware or operating system and allows a program to execute in the same way on any platform. A process VM provides a high-level abstraction – that of

456-495: A particular architecture does not provide hardware support required for nested virtualization, various software techniques are employed to enable it. Over time, more architectures gain required hardware support; for example, since the Haswell microarchitecture (announced in 2013), Intel started to include VMCS shadowing as a technology that accelerates nested virtualization. Fabless manufacturing Fabless manufacturing

513-673: A popular approach to implementing early microcomputer software, including Tiny BASIC and adventure games, from one-off implementations such as Pyramid 2000 to a general-purpose engine like Infocom 's z-machine , which Graham Nelson argues is "possibly the most portable virtual machine ever created". Significant advances occurred in the implementation of Smalltalk -80, particularly the Deutsch/Schiffmann implementation which pushed just-in-time (JIT) compilation forward as an implementation approach that uses process virtual machine. Later notable Smalltalk VMs were VisualWorks ,

570-471: A set of conditions can be executed simultaneously and are combined to form a 64- or 128-bit molecule containing two or four atoms , respectively. In the event that there are not enough instructions to fill a molecule, the software inserts NOPs as padding to fill out empty slots. This is required in all VLIW architectures and is criticised for being inefficient, which is why there are molecules of two separate lengths. The Crusoe performs in software some of

627-451: A specific programming language, but are embedded in an existing language; typically such a system provides bindings for several languages (e.g., C and Fortran ). Examples are Parallel Virtual Machine (PVM) and Message Passing Interface (MPI). Both system virtual machines and process virtual machines date to the 1960s and remain areas of active development. System virtual machines grew out of time-sharing , as notably implemented in

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684-513: A standard CDC Aerospace Computer and was used in the Spy in the Sky Satellites in addition to other classified satellite programs. GIM was reluctant to proceed with the next phase of the program, which it deemed to be too technically challenging. The GIM engineers who had worked on the project were encouraged by CDC to form their own company to provide five new custom circuits. This resulted in

741-607: A system virtual machine can be considered a generalization of the concept of virtual memory that historically preceded it. IBM's CP/CMS , the first systems to allow full virtualization , implemented time sharing by providing each user with a single-user operating system, the Conversational Monitor System (CMS). Unlike virtual memory, a system virtual machine entitled the user to write privileged instructions in their code. This approach had certain advantages, such as adding input/output devices not allowed by

798-493: Is also used to implement the "guest" environments, and applications running in a given "guest" environment view it as a stand-alone system. The pioneer implementation was FreeBSD jails ; other examples include Docker , Solaris Containers , OpenVZ , Linux-VServer , LXC , AIX Workload Partitions , Parallels Virtuozzo Containers, and iCore Virtual Accounts. A snapshot is a state of a virtual machine, and generally its storage devices, at an exact point in time. A snapshot enables

855-463: Is an example of such snapshots. Restoring a snapshot consists of discarding or disregarding all overlay layers that are added after that snapshot, and directing all new changes to a new overlay. The snapshots described above can be moved to another host machine with its own hypervisor; when the VM is temporarily stopped, snapshotted, moved, and then resumed on the new host, this is known as migration. If

912-548: Is capable of running Windows XP applications inside a built-in virtual machine. Furthermore, moving already existing virtualized environments into a cloud, following the Infrastructure as a Service (IaaS) approach, is much more complicated if the destination IaaS platform does not support nested virtualization. The way nested virtualization can be implemented on a particular computer architecture depends on supported hardware-assisted virtualization capabilities. If

969-477: Is the design and sale of hardware devices and semiconductor chips while outsourcing their fabrication (or fab ) to a specialized manufacturer called a semiconductor foundry . These foundries are typically, but not exclusively, located in the United States , China , and Taiwan . Fabless companies can benefit from lower capital costs while concentrating their research and development resources on

1026-531: Is used to allow the microprocessors to emulate the Intel x86 instruction set . The Crusoe is notable for its method of achieving x86 compatibility. Instead of the instruction set architecture being implemented in hardware, or translated by specialized hardware, the Crusoe runs a software abstraction layer, or a virtual machine , known as the Code Morphing Software (CMS). The CMS translates machine code instructions received from programs into native instructions for

1083-723: The CP-40 and SIMMON , which used full virtualization , and were early examples of hypervisors . The first widely available virtual machine architecture was the CP-67 /CMS (see History of CP/CMS for details). An important distinction was between using multiple virtual machines on one host system for time-sharing, as in M44/44X and CP-40, and using one virtual machine on a host system for prototyping, as in SIMMON. Emulators , with hardware emulation of earlier systems for compatibility, date back to

1140-582: The Compatible Time-Sharing System (CTSS). Time-sharing allowed multiple users to use a computer concurrently : each program appeared to have full access to the machine, but only one program was executed at the time, with the system switching between programs in time slices, saving and restoring state each time. This evolved into virtual machines, notably via IBM's research systems: the M44/44X , which used partial virtualization , and

1197-554: The IBM System/360 in 1963, while the software emulation (then-called "simulation") predates it. Process virtual machines arose originally as abstract platforms for an intermediate language used as the intermediate representation of a program by a compiler ; early examples date to around 1964 with the META II compiler-writing system using it for both syntax description and target code generation. A notable 1966 example

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1254-547: The Parrot virtual machine and the .NET Framework , which runs on a VM called the Common Language Runtime . All of them can serve as an abstraction layer for any computer language. A special case of process VMs are systems that abstract over the communication mechanisms of a (potentially heterogeneous) computer cluster . Such a VM does not consist of a single process, but one process per physical machine in

1311-592: The Squeak Virtual Machine , and Strongtalk . A related language that produced a lot of virtual machine innovation was the Self programming language, which pioneered adaptive optimization and generational garbage collection . These techniques proved commercially successful in 1999 in the HotSpot Java virtual machine. Other innovations include a register-based virtual machine, to better match

1368-402: The 'host', and the virtual machine emulated on that machine is generally referred to as the 'guest'. A host can emulate several guests, each of which can emulate different operating systems and hardware platforms. The desire to run multiple operating systems was the initial motive for virtual machines, so as to allow time-sharing among several single-tasking operating systems. In some respects,

1425-538: The Crusoe in a 0.18 μm CMOS process with five levels of copper interconnect . The Crusoe processor supports MMX but not SSE . As of 2022, most browsers on Windows and Linux, and some other programs, need SSE or SSE2 support; therefore, that software will no longer run on the Crusoe platform. For example, Firefox dropped support for systems without SSE2 in 2017, although K-Meleon could run without SSE on Windows XP. The Efficeon processor added support for SSE and SSE2. Virtual machine In computing ,

1482-540: The Crusoe processor was smaller and cheaper than the corresponding Intel processor. The Crusoe was initially available in two forms: the TM3120 (later called TM3200) for embedded applications and the TM5400 for low-power personal computing. Both were based on the same architecture but differed in clock frequency and peripheral support. The TM3120/TM3200 were manufactured in speeds of 333(TM3120 only) 366 and, 400 MHz using

1539-643: The IBM CP-40 and CP-67 , predecessors of the VM family. Examples outside the mainframe field include Parallels Workstation , Parallels Desktop for Mac , VirtualBox , Virtual Iron , Oracle VM , Virtual PC , Virtual Server , Hyper-V , VMware Fusion , VMware Workstation , VMware Server (discontinued, formerly called GSX Server), VMware ESXi , QEMU , Adeos , Mac-on-Linux, Win4BSD, Win4Lin Pro , and Egenera vBlade technology. In hardware-assisted virtualization,

1596-568: The ICs. These parts were given the designation LSI3201, LSI3202, LSI3203, LSI3204 and LSI3205. Another successful space program completed by LSI/CSI was the upgrade to class S of a Standard Brushless DC Motor Commutator/Controller Chip, LS7262, which was implemented in satellites. In 1994, Jodi Shelton , along with a half a dozen CEOs of fabless companies, established the Fabless Semiconductor Association (FSA) to promote

1653-550: The TM5400 and TM5600 operated at clock frequencies of 500–700 MHz. The TM5500/TM5800 are die shrunk versions of the TM5400/5600 Built on a TSMC 130 nm process at clock frequencies of 667-1000 MHz. Embedded versions rated for 10 years of continuous use were marketed as Crusoe SE (for Special Embedded) TM55E/TM58E respectively at clock frequencies of 667-993 MHz. The TM5700/TM5900 removes SDRAM support for its integrated memory controller and now comes in

1710-445: The VM continues operation from the last-known coherent state, rather than the current state, based on whatever materials the backup server was last provided with. Nested virtualization refers to the ability of running a virtual machine within another, having this general concept extendable to an arbitrary depth. In other words, nested virtualization refers to running one or more hypervisors inside another hypervisor. The nature of

1767-457: The VM for a location on its physical disk are transparently translated into an operation on the corresponding file. Once such a translation layer is present, however, it is possible to intercept the operations and send them to different files, depending on various criteria. Every time a snapshot is taken, a new file is created, and used as an overlay for its predecessors. New data is written to the topmost overlay; reading existing data, however, needs

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1824-545: The addition of DDR memory support, 256 KB unified L2 cache and LongRun power reduction technology manufactured using a smaller 180 nm process. It measures 73 mm and uses a 1.10 V (f = 25%) and 1.6 V (f = 100%) power supply, dissipating 0.5–1.5 W typically and a maximum of 6 W. Later the TM5600 was introduced as a higher end offering to the TM5400 with double the L2 cache (512 KB vs 256 KB). Both

1881-433: The assembly and testing of their own chips. As with most technology-intensive industries, the silicon manufacturing process presents high barriers to entry into the market, especially for small start-up companies. But integrated device manufacturers (IDMs) had excess production capacity. This presented an opportunity for smaller companies, relying on IDMs, to design but not manufacture silicon. These conditions underlay

1938-466: The birth of the fabless business model . Engineers at new companies began designing and selling integrated circuits (ICs) without owning a fabrication plant. Simultaneously, the foundry industry was established by Dr. Morris Chang with the founding of Taiwan Semiconductor Manufacturing Corporation (TSMC). Foundries became the cornerstone of the fabless model, providing a non-competitive manufacturing partner for fabless companies. The co-founders of

1995-449: The cluster. They are designed to ease the task of programming concurrent applications by letting the programmer focus on algorithms rather than the communication mechanisms provided by the interconnect and the OS. They do not hide the fact that communication takes place, and as such do not attempt to present the cluster as a single machine. Unlike other process VMs, these systems do not provide

2052-411: The developmental stage, so it runs inside a sandbox . Virtual machines have other advantages for operating system development and may include improved debugging access and faster reboots. Multiple VMs running their own guest operating system are frequently engaged for server consolidation. A process VM, sometimes called an application virtual machine , or Managed Runtime Environment (MRE), runs as

2109-420: The end market. Some fabless companies and pure play foundries (like TSMC ) may offer integrated-circuit design services to third parties. Prior to the 1980s, the semiconductor industry was vertically integrated . Semiconductor companies owned and operated their own silicon-wafer fabrication facilities and developed their own process technology for manufacturing their chips. These companies also carried out

2166-780: The fabless business-model globally. In December 2007, the FSA transitioned to the GSA, the Global Semiconductor Alliance . The organizational transition reflected the role FSA had played as a global organization that collaborated with other organizations to co-host international events. The fabless manufacturing model has been further validated by the conversion of major IDMs to a completely fabless model, including (for example) Conexant Systems , Semtech , and most recently, LSI Logic . Today most major IDMs including Apple Inc. , Infineon and Cypress Semiconductor have adopted

2223-463: The first fabless semiconductor company, LSI Computer Systems, Inc. (LSI/CSI) LSI/CSI, worked together at General Instrument Microelectronics (GIM) in the 1960s. In 1969 GIM was hired to develop three full custom CPU circuits for Control Data Corporation (CDC). These CPU ICs operated at 5 MHz (state of the art at the time) and were incorporated in the CDC Computer 469. The Computer 469 became

2280-455: The following: CDC's Aerospace Computer 469 weighed one pound, consumed a total of 10 watts and ran at 5 MHz. CDC ran a parallel program, developing a chipset of eight similar parts that were to operate at 2.5 MHz with the identical environmental and Class S requirements. CDC had initial difficulties with this project, but eventually awarded another contract to LSI/CSI to manage the processing, inspection, visuals, assembly, and testing of

2337-452: The formation of LSI Computer Systems, Inc. (LSI/CSI) in 1969. The new chips were power-efficient random logic circuits with extremely high circuit densities. These new circuits also operated at 5 MHz. These devices were designated LSI0101, LSI0102, LSI0103, LSI0104, and LSI0105 and were manufactured in compact 40-pin metal flat packs with 0.050 inches (1.3 mm) spacing. In creating the fabless semiconductor industry, LSI/CSI had to do

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2394-436: The functionality traditionally implemented in hardware (e.g. instruction re-ordering), resulting in simpler hardware with fewer transistors . The relative simplicity of the hardware means that Crusoe consumes less power (and therefore generates less heat) than other x86-compatible microprocessors running at the same frequency. A 700 MHz Crusoe ran x86 programs at the speed of a 500 MHz Pentium III x86 processor, although

2451-931: The hardware provides architectural support that facilitates building a virtual machine monitor and allows guest OSes to be run in isolation. Hardware-assisted virtualization was first introduced on the IBM System/370 in 1972, for use with VM/370 , the first virtual machine operating system offered by IBM as an official product. In 2005 and 2006, Intel and AMD provided additional hardware to support virtualization. Sun Microsystems (now Oracle Corporation ) added similar features in their UltraSPARC T-Series processors in 2005. Examples of virtualization platforms adapted to such hardware include KVM , VMware Workstation , VMware Fusion , Hyper-V , Windows Virtual PC , Xen , Parallels Desktop for Mac , Oracle VM Server for SPARC , VirtualBox and Parallels Workstation . In 2006, first-generation 32- and 64-bit x86 hardware support

2508-493: The microprocessor. In this way, the Crusoe can emulate other instruction set architectures (ISAs). This is used to allow the microprocessors to emulate the Intel x86 instruction set . In theory, it is possible for the CMS to be modified to emulate other ISAs. Transmeta demonstrated Crusoe executing Java bytecode by translating the bytecodes into instructions in its native instruction set. The addition of an abstraction layer between

2565-416: The older snapshots are kept in sync regularly, this operation can be quite fast, and allow the VM to provide uninterrupted service while its prior physical host is, for example, taken down for physical maintenance. Similar to the migration mechanism described above, failover allows the VM to continue operations if the host fails. Generally it occurs if the migration has stopped working. However, in this case,

2622-486: The overlay hierarchy to be scanned, resulting in accessing the most recent version. Thus, the entire stack of snapshots is virtually a single coherent disk; in that sense, creating snapshots works similarly to the incremental backup technique. Other components of a virtual machine can also be included in a snapshot, such as the contents of its random-access memory (RAM), BIOS settings, or its configuration settings. " Save state " feature in video game console emulators

2679-421: The resources of a computer to be partitioned via the kernel . The terms are not universally interchangeable. A "virtual machine" was originally defined by Popek and Goldberg as "an efficient, isolated duplicate of a real computer machine." Current use includes virtual machines that have no direct correspondence to any real hardware. The physical, "real-world" hardware running the VM is generally referred to as

2736-440: The same computer (e.g., Windows , Linux , or prior versions of an operating system) to support future software. The use of virtual machines to support separate guest operating systems is popular in regard to embedded systems . A typical use would be to run a real-time operating system simultaneously with a preferred complex operating system, such as Linux or Windows. Another use would be for novel and unproven software still in

2793-453: The same physical page by a technique termed kernel same-page merging (KSM). This is especially useful for read-only pages, such as those holding code segments, which is the case for multiple virtual machines running the same or similar software, software libraries, web servers, middleware components, etc. The guest operating systems do not need to be compliant with the host hardware, thus making it possible to run different operating systems on

2850-415: The standard system. As technology evolves virtual memory for purposes of virtualization, new systems of memory overcommitment may be applied to manage memory sharing among multiple virtual machines on one computer operating system. It may be possible to share memory pages that have identical contents among multiple virtual machines that run on the same physical machine, what may result in mapping them to

2907-520: The underlying hardware, rather than a stack-based virtual machine, which is a closer match for the programming language; in 1995, this was pioneered by the Dis virtual machine for the Limbo language. In full virtualization, the virtual machine simulates enough hardware to allow an unmodified "guest" OS (one designed for the same instruction set ) to be run in isolation. This approach was pioneered in 1966 with

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2964-429: The virtual machine's state at the time of the snapshot to be restored later, effectively undoing any changes that occurred afterwards. This capability is useful as a backup technique, for example, prior to performing a risky operation. Virtual machines frequently use virtual disks for their storage; in a very simple example, a 10- gigabyte hard disk drive is simulated with a 10-gigabyte flat file . Any requests by

3021-660: The virtual machine, notably in UCSD Pascal (1978); this influenced later interpreters, notably the Java virtual machine (JVM). Another early example was SNOBOL4 (1967), which was written in the SNOBOL Implementation Language (SIL), an assembly language for a virtual machine, which was then targeted to physical machines by transpiling to their native assembler via a macro assembler . Macros have since fallen out of favor, however, so this approach has been less influential. Process virtual machines were

3078-658: The x86 instruction stream and the hardware means that the hardware architecture can change without breaking compatibility, just by modifying the CMS. For example, Transmeta Efficeon — a second-generation Transmeta design — has a 256-bit-wide VLIW core versus the 128-bit core of the Crusoe. Efficeon also supports SSE instructions. The Crusoe is a VLIW microprocessor that executes bundles of instructions, termed molecules by Transmeta. Each molecule contains multiple instructions, termed atoms . The Code Morphing Software translates x86 instructions into native instructions. The native instructions are 32 bits long. Instructions that meet

3135-427: Was found to rarely offer performance advantages over software virtualization. In OS-level virtualization, a physical server is virtualized at the operating system level, enabling multiple isolated and secure virtualized servers to run on a single physical server. The "guest" operating system environments share the same running instance of the operating system as the host system. Thus, the same operating system kernel

3192-479: Was popularized around 1970 by Pascal , notably in the Pascal-P system (1973) and Pascal-S compiler (1975), in which it was termed p-code and the resulting machine as a p-code machine . This has been influential, and virtual machines in this sense have been often generally called p-code machines. In addition to being an intermediate language, Pascal p-code was also executed directly by an interpreter implementing

3249-548: Was the O-code machine , a virtual machine that executes O-code (object code) emitted by the front end of the BCPL compiler. This abstraction allowed the compiler to be easily ported to a new architecture by implementing a new back end that took the existing O-code and compiled it to machine code for the underlying physical machine. The Euler language used a similar design, with the intermediate language named P (portable). This

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