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Appendix H
Appendix H is the name of an infamous appendix in Pentium Processor Family Developer's Manual, Volume 3. This appendix contained reference to documentation only available under a legally binding NDA. This NDAed documentation described various new features introduced in the Pentium processor, notably Virtual Mode Extensions (VME) and 4 MB paging. VME added an additional feature to the existing virtual 8086 mode (which was introduced with the 80386 processor), and included optimized handling and delivery of interrupts to and from virtual machines by reducing the number of traps required. VME should not be confused with the later Intel VT virtualization technology aiming at full virtualization of the CPU, rather than just the 8086 mode. The appendix was referenced by the official chapters in the documentation, provoking irritation among the public who was not allowed to access the detailed descriptions. This started a movement with observers trying to reverse-engineer the inf ...
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Non-disclosure Agreement
A non-disclosure agreement (NDA) is a legal contract or part of a contract between at least two parties that outlines confidential material, knowledge, or information that the parties wish to share with one another for certain purposes, but wish to restrict access to. Doctor–patient confidentiality (physician–patient privilege), attorney–client privilege, priest–penitent privilege and bank–client confidentiality agreements are examples of NDAs, which are often not enshrined in a written contract between the parties. It is a contract through which the parties agree not to disclose any information covered by the agreement. An NDA creates a confidential relationship between the parties, typically to protect any type of confidential and proprietary information or trade secrets. As such, an NDA protects non-public business information. Like all contracts, they cannot be enforced if the contracted activities are illegal. NDAs are commonly signed when two companies, indi ...
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Virtual Mode Extensions
In the 80386 microprocessor and later, virtual 8086 mode (also called virtual real mode, V86-mode, or VM86) allows the execution of real mode applications that are incapable of running directly in protected mode while the processor is running a protected mode operating system. It is a hardware virtualization technique that allowed multiple 8086 processors to be emulated by the 386 chip. It emerged from the painful experiences with the 80286 protected mode, which by itself was not suitable to run concurrent real-mode applications well. John Crawford developed the Virtual Mode bit at the register set, paving the way to this environment. VM86 mode uses a segmentation scheme identical to that of real mode (for compatibility reasons), which creates 20-bit linear addresses in the same manner as 20-bit physical addresses are created in real mode, but are subject to protected mode's memory paging mechanism. Overview The virtual 8086 mode is a mode for a protected-mode task. Consequ ...
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Paging
In computer operating systems, memory paging is a memory management scheme by which a computer stores and retrieves data from secondary storage for use in main memory. In this scheme, the operating system retrieves data from secondary storage in same-size blocks called ''pages''. Paging is an important part of virtual memory implementations in modern operating systems, using secondary storage to let programs exceed the size of available physical memory. For simplicity, main memory is called "RAM" (an acronym of random-access memory) and secondary storage is called "disk" (a shorthand for hard disk drive, drum memory or solid-state drive, etc.), but as with many aspects of computing, the concepts are independent of the technology used. Depending on the memory model, paged memory functionality is usually hardwired into a CPU/MCU by using a Memory Management Unit (MMU) or Memory Protection Unit (MPU) and separately enabled by privileged system code in the operating system's ...
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Virtual 8086 Mode
In the 80386 microprocessor and later, virtual 8086 mode (also called virtual real mode, V86-mode, or VM86) allows the execution of real mode applications that are incapable of running directly in protected mode while the processor is running a protected mode operating system. It is a hardware virtualization technique that allowed multiple 8086 processors to be emulated by the 386 chip. It emerged from the painful experiences with the 80286 protected mode, which by itself was not suitable to run concurrent real-mode applications well. John Crawford developed the Virtual Mode bit at the register set, paving the way to this environment. VM86 mode uses a segmentation scheme identical to that of real mode (for compatibility reasons), which creates 20-bit linear addresses in the same manner as 20-bit physical addresses are created in real mode, but are subject to protected mode's memory paging mechanism. Overview The virtual 8086 mode is a mode for a protected-mode task. Conseq ...
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80386
The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistorsmit.edu—The Future of FPGAs
(Cornell) October 11, 2012
and were the of many s and high-end s of the time. As the original implementation of the

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Intel VT
x86 virtualization is the use of hardware-assisted virtualization capabilities on an x86/x86-64 CPU. In the late 1990s x86 virtualization was achieved by complex software techniques, necessary to compensate for the processor's lack of hardware-assisted virtualization capabilities while attaining reasonable performance. In 2005 and 2006, both Intel ( VT-x) and AMD (AMD-V) introduced limited hardware virtualization support that allowed simpler virtualization software but offered very few speed benefits. Greater hardware support, which allowed substantial speed improvements, came with later processor models. Software-based virtualization The following discussion focuses only on virtualization of the x86 architecture protected mode. In protected mode the operating system kernel runs at a higher privilege such as ring 0, and applications at a lower privilege such as ring 3. In software-based virtualization, a host OS has direct access to hardware while the guest OSs have limited a ...
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Christian Ludloff
Christians () are people who follow or adhere to Christianity, a Monotheism, monotheistic Abrahamic religion based on the life and teachings of Jesus in Christianity, Jesus Christ. The words ''Christ (title), Christ'' and ''Christian'' derive from the Koine Greek title ''Christós'' (Χριστός), a translation of the Biblical Hebrew term ''mashiach'' (מָשִׁיחַ) (usually rendered as ''messiah'' in English). While there are diverse interpretations of Christianity which sometimes conflict, they are united in believing that Jesus has a unique significance. The term ''Christian'' used as an adjective is descriptive of anything associated with Christianity or Christian churches, or in a proverbial sense "all that is noble, and good, and Christ-like." It does not have a meaning of 'of Christ' or 'related or pertaining to Christ'. According to a 2011 Pew Research Center survey, there were 2.2 billion Christians around the world in 2010, up from about 600 million in 1910. T ...
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Virtual 8086 Mode Enhancements
In the 80386 microprocessor and later, virtual 8086 mode (also called virtual real mode, V86-mode, or VM86) allows the execution of real mode applications that are incapable of running directly in protected mode while the processor is running a protected mode operating system. It is a hardware virtualization technique that allowed multiple 8086 processors to be emulated by the 386 chip. It emerged from the painful experiences with the 80286 protected mode, which by itself was not suitable to run concurrent real-mode applications well. John Crawford developed the Virtual Mode bit at the register set, paving the way to this environment. VM86 mode uses a segmentation scheme identical to that of real mode (for compatibility reasons), which creates 20-bit linear addresses in the same manner as 20-bit physical addresses are created in real mode, but are subject to protected mode's memory paging mechanism. Overview The virtual 8086 mode is a mode for a protected-mode task. Consequ ...
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VME (CONFIG
VME may refer to: Computing * ICL VME, (Virtual Machine Environment) a mainframe computer operating system developed by International Computers Limited * VMEbus, the ANSI/IEEE computer hardware bus standard * Virtual machine escape is the process of breaking out of a virtual machine and interacting with the host operating system * Virtual Mode Extensions, an undocumented extension of the Intel Pentium in v86 mode, "Virtual 8086 Mode Enhancements" in later Intel processors ** ''vme'', a flag in a modern x86 CPU indicating support of Virtual 8086 mode * VME (CONFIG.SYS directive), a configuration directive under OS/2 Other uses * V-me, a Spanish-language TV network in the United States * Voices Music & Entertainment Voices Music & Entertainment is a record label based in Oslo, Norway established in 1988 by Ketil Sveen and Dag Krogsvold. In the first years the company was a label focusing on signing and developing Norwegian rock acts. Since then the company ha ...
, a Norwegi ...
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QEMM
Quarterdeck Expanded Memory Manager (QEMM) is a memory manager produced by Quarterdeck Office Systems in the late 1980s through the late 1990s. It was the most popular third-party memory manager for the MS-DOS and other DOS operating systems. QEMM product ranges ;QRAM: A memory manager for Intel 80286 or higher CPUs. It supports Chips and Technologies chipsets. 2.02 added SHADOWRAM switch. QEXT correctly reallocates eXtended Memory Specification (XMS). It includes VIDRAM, Optimize, LOADHI from QEMM 6.02, Manifest 1.13. Earlier versions of QRAM also supported the older 8086 and 8088 CPUs. ;QEMM Game Edition: It is a version of QEMM that includes Quarterdeck GameRunner. Patches for regular QEMM do not work on QEMM Game Edition. ;QEMM MegaBundle: In the version shipped with Borland SideKick for Windows, it is a version with SideBar 1.00 (1994-08-22) and QEMM 7.5. ; DESQview 386: It includes DESQview and QEMM-386. Features/tools QEMM driver QEMM provides access to the ...
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