portable operating system proved to be the key to the success of UNIX. During the 1970s, UNIX evolved through the development work of programmers at Bell Labs and several universities, notably the University of California, at Berkeley. - When UNIX first started to be marketed commercially in the 1980s, it was used to run powerful network servers, not desktop computers. Today, there are dozens of different versions of UNIX, including the following: UNIX, in its various forms, continues to advance its position as the reliable, secure OS of choice for mission-critical applications that are crucial to the operation of a business or other organization. UNIX is also tightly integrated with TCP/IP. TCP/IP basically grew out of UNIX because of the need for LAN and WAN communications. The Sun Microsystems Solaris Operating Environment and its core OS, SunOS, is a high-performance, versatile, 64-bit implementation of UNIX. Solaris runs on a wide variety of computers, from Intel-based personal computers to powerful mainframes and supercomputers. Solaris is currently the most widely used version of UNIX in the world for large networks and Internet websites. Sun is also the developer of the "Write Once, Run Anywhere" Java technology. Despite the popularity of Microsoft Windows on corporate LANs, much of the Internet runs on powerful UNIX systems. Although UNIX is usually associated with expensive hardware and is no user friendly, recent developments, including the creation of Linux, have changed that image. Origins of Linux
In 1991, a Finnish student named Linus Torvalds began work on an operating system for an Intel 80386-based computer. Torvalds became frustrated with the state of desktop operating systems, such as DOS, and the expense and licensing issues associated with commercial UNIX. Torvalds set out to develop an operating system that was UNIX-like in its operation but used software code that was open and completely free of charge to all users. Torvald's work led to a world-wide collaborative effort to develop Linux, an open source operating system that looks and feels like UNIX. By the late 1990s, Linux had become a viable alternative to UNIX on servers and Windows on the desktop. The popularity of Linux on desktop PCs has also contributed to interest in using UNIX distributions, such as FreeBSD and Sun Solaris on the desktop. Versions of Linux can now run on almost any 32-bit processor, including the Intel 80386, Motorola 68000, Alpha, and PowerPC chips. As with UNIX, there are numerous versions of Linux. Some are free downloads from the web, and others are commercially distributed. The following are a few of the most popular versions of Linux: Linux is one of the most powerful and reliable operating systems in the world today. Because of this, Linux has already made inroads as a platform for power users and in the enterprise server arena. Linux is less often deployed as a corporate desktop operating system. Although graphical user interfaces (GUIs) are available to make Linux user-friendly, most beginning users find Linux more difficult to use than Mac OS or Windows. Currently, many companies, such as Red Hat, SuSE, Corel, and Caldera, are striving to make Linux a viable operating system for the desktop. - Application support must be considered when Linux is implemented on a desktop system. The number of business productivity applications is limited when compared to Windows. However, some vendors provide Windows emulation software, such as WABI and WINE, which enables many Windows applications to run on Linux. Additionally, companies such as Corel are making Linux versions of their office suites and other popular software packages. Networking with Linux
Recent distributions of Linux have networking components built in for connecting to a LAN, establishing a dialup connection to the Internet, or other remote network. In fact, TCP/IP is integrated into the Linux kernel instead of being implemented as a separate subsystem. Some advantages of Linux as a desktop operating system and network client include the following:
Content 6.1 Workstations and Servers 6.1.7 Apple Apple Macintosh computers were designed for easy networking in a peer-to-peer, workgroup situation. Network interfaces are included as part of the hardware and networking components are built into the Macintosh operating system. Ethernet and Token Ring network adapters are available for the Macintosh. The Macintosh, or Mac, is popular in many educational institutions and corporate graphics departments. Macs can be connected to one another in workgroups and can access AppleShare file servers. Macs can also be connected to PC LANs that include Microsoft, NetWare, or UNIX servers. Mac OS X (10)
The Macintosh operating system, Mac OS X, is sometimes referred to as Apple System 10. Some of the features of Mac OS X are in the GUI called Aqua. The Aqua GUI resembles a cross between Microsoft Windows XP and Linux X-windows GUI. Mac OS X is designed to provide features for the home computer, such as Internet browsing, video and photo editing, and games, while still providing features that offer powerful and customizable tools that IT professionals need in an operating system. The Mac OS X is fully compatible with older versions of the Mac operating systems. Mac OS X provides a new feature that allows for AppleTalk and Windows connectivity. The Mac OS X core operating system is called Darwin. Darwin is a UNIX-based, powerful system that provides stability and performance. These enhancements provide Mac OS X with support for protected memory, preemptive multitasking, advanced memory management, and symmetric multiprocessing. This makes Mac OS X a formidable competitor amongst operating systems.
Content 6.1 Workstations and Servers 6.1.8 Concept of service on servers Networking operating systems (NOSs) are designed to provide network processes to clients. Network services include the World Wide Web (WWW), file sharing, mail exchange, directory services, remote management, and print services. Remote management is a powerful service that allows administrators to configure networked systems that are miles apart. It is important to understand that these network processes are referred to as services in Windows 2000 and daemons in UNIX and Linux. Network processes all provide the same functions, but the way processes are loaded and interact with the NOS are different in each operating system. Depending on the NOS, some of these key network processes may be enabled during a default installation. Most popular network processes rely on the TCP/IP suite of protocols. Because TCP/IP is an open, well-known set of protocols, TCP/IP-based services are vulnerable to unauthorized scans and malicious attacks. Denial of service (DoS) attacks, computer viruses, and fast-spreading Internet worms have forced NOS designers to reconsider which network services are started automatically. Recent versions of popular NOSs, such as Windows 2000 and Red Hat Linux 7, restrict the number of network services that are on by default. When deploying a NOS, key network services will need to be enabled manually. When a user decides to print in a networked printing environment, the job is sent to the appropriate queue for the selected printer. Print queues stack the incoming print jobs and services them using a first-in, first-out (FIFO) order. When a job is added to the queue, it is placed at the end of