主题：请教个问题 -- 猫元帅

首先，图形界面（GUI）和鼠标是Mac的首创。

微软和IBM开始一起搞OS/2.搞到一半分了手。后来IBM推OS/2,微软推Winnt 3.X.后来不长时间，微软开始win9x和Winnt 4.0。Windows 1.x/2.x因该在Os/2之前。

Windows 1.0是1985年就推出了，而OS/2 1.0是在1987年12月才推出的！

NT象VMS多些还是象Unix多些？严格的说，都不太像。当时学OS的时候，讨论过这个问题。他们在设计思想上就有很大的不同。

[B]NT and UNIX[/B] 
NT's roots extend back to 1977 and Digital Equipment's release of VMS 1.0. Many core members of the future NT design team left Digital in 1988 to join Microsoft, which released NT's first version, Windows NT 3.1, in 1993. Thus, NT and UNIX have been evolving since the mid-1970s, and trends in academic OS research have influenced each OS. In addition, both OSs have similar design goals: portability, extensibility, and the ability to run on computers ranging from desktop PCs to departmental servers.

Internally, NT is similar to VMS, but how closely do NT's capabilities and features match those of UNIX? Shedding light on this question is difficult, because even the top three UNIX market share leaders--Solaris, HP/UX, and AIX--are in many ways as different from one another as each is from NT. Thus, there is no definitive "UNIX" to compare with NT. Therefore, I'll use traditional or prevalent UNIX features and implementations for each UNIX subsystem in the following comparison of NT and UNIX. I'll draw from the market leaders and three other UNIX variants: Linux, BSD 4.4, and Digital UNIX. 

Unix结构

NT结构

The OS architecture of most versions of UNIX is similar to that of NT. Figure 1 and Figure 2 show the UNIX and NT architectures, respectively. (To explore NT's architecture in depth, see "Windows NT Architecture, Part 1," March 1998 and "Windows NT Architecture, Part 2," April 1998.) Both OS architectures have two modes of operation: user mode and kernel mode. Familiar applications such as word processors and database programs execute in user mode. User mode is nonprivileged, which means that the system restricts programs operating in user mode from directly accessing hardware or resources belonging to other programs. Most of the OS code executes in kernel mode. Kernel mode is privileged, which means that code running in kernel mode can access hardware and resources belonging to any application, with few limitations.

A major difference between UNIX's and NT's architecture is that UNIX does not incorporate its windowing system--the subsystem that manages GUI resources for applications--into kernel mode, as does NT 4.0. Instead, the UNIX windowing system is an add-on user-mode application that its developers wrote using publicly defined UNIX APIs; consequently, third-party products can replace UNIX's windowing system. However, the majority of the UNIX community has adopted MIT's X-Windows as a de facto, if not official, graphical interface standard. Before NT 4.0, the NT windowing system was a user-mode implementation, but Microsoft found that the performance of graphics-intensive applications improved when the windowing system operated in kernel mode.

Another difference between the OS architectures is that UNIX applications can call kernel functions, or system calls, directly. In NT, applications call APIs that the OS environment to which they are coded (DOS, Windows 3.x, OS/2, POSIX) exports. A kernel system-call interface provides APIs for managing processes, memory, and files. The NT system-call interface, called the Native API, is hidden from programmers and largely undocumented. The number of UNIX system calls is roughly equal to the number of Native APIs, around 200 to 300. The API that UNIX applications write to is the UNIX system-call interface, whereas the API that the majority of NT applications write to is the Win32 API, which translates many Win32 APIs to Native APIs.

In the following comparison of NT and UNIX subsystems, I'll contrast the way each OS names internal resources, implements processes and threads, and manages virtual and physical memory. I'll also compare and contrast UNIX's and NT's security model, file-system data caching, networking architecture, and extensibility.
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如果感兴趣的话，我就说完！