The metafamily of graphical operating systems developed, marketed, and sold by Microsoft offers what kind of help to musicians?
software for singing training
Winsingad
WinSingad is a Microsoft Windows based software for singing training.
Microsoft Windows
Microsoft Windows, or simply Windows, is a metafamily of graphical operating systems developed, marketed, and sold by Microsoft.
 It consists of several families of operating systems, each of which cater to a certain sector of the computing industry with the OS typically associated with IBM PC compatible architecture.
 Active Windows families include Windows NT and Windows Embedded; these may encompass subfamilies, e.g. Windows Embedded Compact (Windows CE) or Windows Server.
 Defunct Windows families include Windows 9x, Windows Mobile and Windows Phone.
MacOS
macOS (pronounced ; previously Mac OS X and later OS X) is the current series of Unix-based graphical operating systems developed and marketed by Apple Inc. designed to run on Apple's Macintosh computers ("Macs").
 It has been preinstalled on all Macs since 2002.
 Within the market of desktop, laptop and home computers, and by web usage, it is the second most widely used desktop OS after Microsoft Windows. Macintosh operating systems
The family of Macintosh operating systems developed by Apple Inc. includes the graphical user interface-based operating systems it has designed for use with its Macintosh series of personal computers since 1984, as well as the related system software it once created for compatible third-party systems. Windows 98
Windows 98 (codenamed Memphis while in development) is a graphical operating system by Microsoft.
 It is the second major release in the Windows 9x line of operating systems and the successor to Windows 95.
 It was released to manufacturing on May 15, 1998 and to retail on June 25, 1998. MS-DOS
MS-DOS ( ; acronym for "Microsoft Disk Operating System") is a discontinued operating system for x86-based personal computers mostly developed by Microsoft.
 Collectively, MS-DOS, its rebranding as IBM PC DOS, and some operating systems attempting to be compatible with MS-DOS, are sometimes referred to as "DOS" (which is also the generic acronym for disk operating system).
 MS-DOS was the main operating system for IBM PC compatible personal computers during the 1980s and the early 1990s, when it was gradually superseded by operating systems offering a graphical user interface (GUI), in various generations of the graphical Microsoft Windows operating system. EPOC (operating system)
EPOC is a discontinued family of graphical operating systems developed by Psion for portable devices, primarily PDAs.
 EPOC came from epoch, the beginning of an era, but was backfitted by the engineers to "Electronic Piece Of Cheese".
 It was succeeded by Symbian in 1998. Windows NT 4.0
Windows NT 4.0 is a preemptively multitasked graphical operating system, designed to work with either uniprocessor or symmetric multi-processor computers.
 It was part of Microsoft's Windows NT family of operating systems and was released to manufacturing on 31 July 1996.
 It is a 32-bit operating system available in both workstation and server editions with a graphical environment similar to that of Windows 95. Advanced Comprehensive Operating System
Advanced Comprehensive Operating System is a family of mainframe computer operating systems developed by NEC for the Japanese market.
 It consists of three systems, based on the General Comprehensive Operating System family developed by General Electric, Honeywell, and Bull.
 Two of these systems, ACOS-2 (based on GCOS 4) and ACOS-4 (based on GCOS 7) are still sold, although only ACOS-4 is under active development.
 ACOS-6 (based on GCOS 8) is an obsolete high-end mainframe platform, which ceased active development in the early 2000s. Usage share of desktop operating systems
The usage share of desktop operating systems is the percentage of the operating systems (OS) used in computers (approximately market share) with so-called (retronym) desktop operating system, that also run on e.g. laptops. Originally the only computers running those operating systems, where desktop computers, while with the introduction of so-called new class of mobile operating systems, desktop got to be the part of the name of the former class of OSes.
 The computers running these OSes have the desktop metaphor style of GUI, unlike the mobile OSes.
 See also usage share of operating systems for breakdown of the share of desktop, mobile (and other styles of) operating systems, separately, and share of those all operating systems as part of across classes.