Group velocityThe group velocity of a wave is the velocity with which the overall envelope shape of the wave's amplitudes—known as the modulation or envelope of the wave—propagates through space. For example, if a stone is thrown into the middle of a very still pond, a circular pattern of waves with a quiescent center appears in the water, also known as a capillary wave. The expanding ring of waves is the wave group or wave packet, within which one can discern individual waves that travel faster than the group as a whole.
Phase velocityThe phase velocity of a wave is the rate at which the wave propagates in any medium. This is the velocity at which the phase of any one frequency component of the wave travels. For such a component, any given phase of the wave (for example, the crest) will appear to travel at the phase velocity. The phase velocity is given in terms of the wavelength λ (lambda) and time period T as Equivalently, in terms of the wave's angular frequency ω, which specifies angular change per unit of time, and wavenumber (or angular wave number) k, which represent the angular change per unit of space, To gain some basic intuition for this equation, we consider a propagating (cosine) wave A cos(kx − ωt).
64-bit computingIn computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit CPUs and ALUs are those that are based on processor registers, address buses, or data buses of that size. A computer that uses such a processor is a 64-bit computer. From the software perspective, 64-bit computing means the use of machine code with 64-bit virtual memory addresses.
X86-64x86-64 (also known as x64, x86_64, AMD64, and Intel 64) is a 64-bit version of the x86 instruction set, first released in 1999. It introduced two new modes of operation, 64-bit mode and compatibility mode, along with a new 4-level paging mode. With 64-bit mode and the new paging mode, it supports vastly larger amounts of virtual memory and physical memory than was possible on its 32-bit predecessors, allowing programs to store larger amounts of data in memory.
Windows 7Windows 7 is a major release of the Windows NT operating system developed by Microsoft. It was released to manufacturing on July 22, 2009, and became generally available on October 22, 2009. It is the successor to Windows Vista, released nearly three years earlier. Windows 7's server counterpart, Windows Server 2008 R2, was released at the same time. Windows 7 remained an operating system for use on personal computers, including home and business desktops, laptops, tablet PCs and media center PCs, and itself was replaced in November 2012 by Windows 8, the name spanning more than three years of the product.
Windows ServerWindows Server (formerly Windows NT Server) is a group of operating systems (OS) for servers that Microsoft has been developing since July 27, 1993. The first OS that was released for this platform is Windows NT 3.1 Advanced Server. With the release of Windows Server 2003, the brand name was changed to Windows Server. The latest release of Windows Server is Windows Server 2022, which was released in 2021. Microsoft's history of developing operating systems for servers goes back to Windows NT 3.1 Advanced Server.
Windows 98Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. The second operating system in the 9x line, it is the successor to Windows 95, and was released to manufacturing on May 15, 1998, and generally to retail on June 25, 1998. Like its predecessor, it is a hybrid 16-bit and 32-bit monolithic product with the boot stage based on MS-DOS. Windows 98 is a web-integrated operating system that bears numerous similarities to its predecessor.
Windows MobileWindows Mobile was a family of mobile operating systems developed by Microsoft for smartphones and personal digital assistants. Its origin dated back to Windows CE in 1996, though Windows Mobile itself first appeared in 2000 as Pocket PC 2000 which ran on Pocket PC PDAs. It was renamed "Windows Mobile" in 2003, at which point it came in several versions (similar to the desktop versions of Windows) and was aimed at business and enterprise consumers.
Plasma stabilityThe stability of a plasma is an important consideration in the study of plasma physics. When a system containing a plasma is at equilibrium, it is possible for certain parts of the plasma to be disturbed by small perturbative forces acting on it. The stability of the system determines if the perturbations will grow, oscillate, or be damped out. In many cases, a plasma can be treated as a fluid and its stability analyzed with magnetohydrodynamics (MHD).
Windows 8Windows 8 is a major release of the Windows NT operating system developed by Microsoft. It was released to manufacturing on August 1, 2012, and was made available for download via MSDN and TechNet on August 15, 2012. Nearly three months after its initial release, Windows 8 finally made its first retail appearance on October 26, 2012. Windows 8 is the first version of Microsoft Windows with a combination of 2D and 3D effects.
16-bit computing16-bit microcomputers are microcomputers that use 16-bit microprocessors. A 16-bit register can store 216 different values. The range of integer values that can be stored in 16 bits depends on the integer representation used. With the two most common representations, the range is 0 through 65,535 (216 − 1) for representation as an (unsigned) binary number, and −32,768 (−1 × 215) through 32,767 (215 − 1) for representation as two's complement. Since 216 is 65,536, a processor with 16-bit memory addresses can directly access 64 KB (65,536 bytes) of byte-addressable memory.
Windows SearchWindows Search (also known as Instant Search) is a content index desktop search platform by Microsoft introduced in Windows Vista as a replacement for both the previous Indexing Service of Windows 2000 and the optional MSN Desktop Search for Windows XP and Windows Server 2003, designed to facilitate local and remote queries for files and non-file items in compatible applications including Windows Explorer. It was developed after the postponement of WinFS and introduced to Windows constituents originally touted as benefits of that platform.
Microsoft WindowsMicrosoft Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for servers, and Windows IoT for embedded systems. Defunct Windows families include Windows 9x, Windows Mobile, and Windows Phone. The first version of Windows was released on November 20, 1985, as a graphical operating system shell for MS-DOS in response to the growing interest in graphical user interfaces (GUIs).
32-bit computingIn computer architecture, 32-bit computing refers to computer systems with a processor, memory, and other major system components that operate on data in 32-bit units. Compared to smaller bit widths, 32-bit computers can perform large calculations more efficiently and process more data per clock cycle. Typical 32-bit personal computers also have a 32-bit address bus, permitting up to 4 GB of RAM to be accessed, far more than previous generations of system architecture allowed.
Athlon 64The Athlon 64 is a ninth-generation, AMD64-architecture microprocessor produced by Advanced Micro Devices (AMD), released on September 23, 2003. It is the third processor to bear the name Athlon, and the immediate successor to the Athlon XP. The second processor (after the Opteron) to implement the AMD64 architecture and the first 64-bit processor targeted at the average consumer, it was AMD's primary consumer CPU, and primarily competed with Intel's Pentium 4, especially the Prescott and Cedar Mill core revisions.
IA-64IA-64 (Intel Itanium architecture) is the instruction set architecture (ISA) of the Itanium family of 64-bit Intel microprocessors. The basic ISA specification originated at Hewlett-Packard (HP), and was subsequently implemented by Intel in collaboration with HP. The first Itanium processor, codenamed Merced, was released in 2001. The Itanium architecture is based on explicit instruction-level parallelism, in which the compiler decides which instructions to execute in parallel.
MagnetohydrodynamicsMagnetohydrodynamics (MHD; also called magneto-fluid dynamics or hydromagnetics) is a model of electrically conducting fluids that treats all interpenetrating particle species together as a single continuous medium. It is primarily concerned with the low-frequency, large-scale, magnetic behavior in plasmas and liquid metals and has applications in numerous fields including geophysics, astrophysics, and engineering. The word magnetohydrodynamics is derived from magneto- meaning magnetic field, hydro- meaning water, and dynamics meaning movement.
Windows Server 2003Windows Server 2003, codenamed "Whistler Server", is the second version of Windows Server operating system produced by Microsoft. It is part of the Windows NT family of operating systems and was released to manufacturing on March 28, 2003 and generally available on April 24, 2003. Windows Server 2003 is the successor to the Server editions of Windows 2000 and the predecessor to Windows Server 2008. An updated version, Windows Server 2003 R2, was released to manufacturing on December 6, 2005.
Windows 3.1xWindows 3.1 is a major release of Microsoft Windows. It was released to manufacturing on April 6, 1992, as a successor to Windows 3.0. Like its predecessors, the Windows 3.1 series ran as a shell on top of MS-DOS. Codenamed Janus, Windows 3.1 introduced the TrueType font system as a competitor to Adobe Type Manager. Its multimedia was also expanded, and screensavers were introduced, alongside new software such as Windows Media Player and Sound Recorder. and Control Panel received tweaks, while Windows 3.
Windows PhoneWindows Phone (WP) is a discontinued family of mobile operating systems developed by Microsoft for smartphones as the replacement successor to Windows Mobile and Zune. Windows Phone featured a new user interface derived from the Metro design language. Unlike Windows Mobile, it was primarily aimed at the consumer market rather than the enterprise market. It was first launched in October 2010 with Windows Phone 7.
