CASE STUDY 1: Types of Systems in OS

· Batch Systems

Ex:
IBM 7090/94 IBSYS - IBSYS was the tape based operating system that IBM supplied with its IBM 7090 and IBM 7094 computers. A similar operating system (but with several significant differences), also called IBSYS, was provided with IBM 7040 and IBM 7044 computers. IBSYS was based on FORTRAN Monitor System (FMS) and SHARE Operating System.


IBSYS itself was really a basic monitor program, that read control card images placed between the decks of program and data cards of individual jobs. An IBSYS control card began with a "quot; in column 1, immediately followed by a Control Name that selected the various IBSYS utility programs needed to set up and run the job. These card deck images were read from magnetic tapes, prepared offline, not usually directly from the punched card reader.


· Interactive Systems

Ex:
Mac OS X (pronounced /ˈmæk ˌoʊ ˌɛs ˈtɛn/ mak oh es ten) - is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, Mac OS X has been included with all new Macintosh computer systems. It is the successor to Mac OS 9, released in 1999, the final release of the "classic" Mac OS, which had been Apple's primary operating system since 1984.


Mac OS X, whose X is the Roman numeral for 10 and is a prominent part of its brand identity, is a Unix-based graphical operating system, built on technologies developed at NeXT between the second half of the 1980s and Apple's purchase of the company in late 1996. From its sixth release Mac OS X v10.5 "Leopard" and onwards, every release of Mac OS X gained UNIX 03 certification while running on Intel processor.


The first version released was Mac OS X Server 1.0 in 1999, and a desktop-oriented version, Mac OS X v10.0 "Cheetah" followed on March 24, 2001. Releases of Mac OS X are named after big cats: for example, Mac OS X v10.6 is usually referred to by Apple and users as "Snow Leopard". The server edition, Mac OS X Server, is architecturally identical to its desktop counterpart, and includes tools to facilitate management of workgroups of Mac OS X machines, and to provide access to network services. These tools include a mail transfer agent, a Samba server, an LDAP server, a domain name server, and others. It is pre-loaded on Apple's Xserveserver hardware, but can be run on almost all of Apple's current selling computer models.


Apple also produces specialized versions of Mac OS X for use on its consumer devices. iOS, which is based off Mac OS X, runs on the iPhone, iPod Touch,iPad, and the 2nd generation Apple TV. An unnamed variant of Mac OS X powered the 1st generation Apple TV.


· Real-time Systems

Ex:
μnOS – it was the first 32bit Unix-like real-time operating system with real-time extensions. It was developed by Jeffery Goldberg, PhD. who left Bell Labs after using UNIX and became VP of engineering for (now defunct) Charles River Data Systems (CRDS). UNOS was written to capitalize on the first 32 bit microprocessor, the Motorola 68k CPUs. CRDS sold a UNOS based 68K system, and sold porting services and licenses to other manufacturers who had embedded cpu's.


· Hybrid Systems

Ex:
Windows XP is an operating system that was produced by Microsoft for use on personal computers, including home and business desktops, laptops, and media centers. It was first released in August 2001, and is the most popular version of Windows, based on installed user base. The name "XP" is short for "eXPerience."


Windows XP was the successor to both Windows 2000 and Windows Me, and was the first consumer-oriented operating system produced by Microsoft to be built on the Windows NT kernel and architecture. Windows XP was released for retail sale on October 25, 2001, and over 400 million copies were in use in January 2006, according to an estimate in that month by an IDC analyst. It was succeeded by Windows Vista, which was released to volume license customers on November 8, 2006, and worldwide to the general public on January 30, 2007. Direct OEM and retail sales of Windows XP ceased on June 30, 2008. Microsoft continued to sell Windows XP through their System Builders (smaller OEMs who sell assembled computers) program until January 31, 2009. XP may continue to be available as these sources run through their inventory or by purchasing Windows 7 Ultimate, Windows 7 Pro, Windows Vista Ultimate or Windows Vista Business, and then downgrading to Windows XP.


The most common editions of the operating system were Windows XP Home Edition, which was targeted at home users, and Windows XP Professional, which offered additional features such as support for Windows Server domains and two physical processors, and was targeted at power users, business and enterprise clients.Windows XP Media Center Edition has additional multimedia features enhancing the ability to record and watch TV shows, view DVD movies, and listen to music.Windows XP Tablet PC Edition was designed to run stylus applications built using the Tablet PC platform.


Windows XP was eventually released for two additional architectures, Windows XP 64-bit Edition for IA-64 (Itanium) processors and Windows XP Professional x64 Edition for x86-64. There is also Windows XP Embedded, a component version of the Windows XP Professional, and editions for specific markets such as Windows XP Starter Edition. By mid 2009, a manufacturer revealed the first Windows XP powered cellular telephone.


The NT-based versions of Windows, which are programmed in C, C++, and assembly, are known for their improved stability and efficiency over the 9x versions of Microsoft Windows. Windows XP presented a significantly redesigned graphical user interface, a change Microsoft promoted as more user-friendly than previous versions of Windows. A new software management facility called Side-by-Side Assembly was introduced to ameliorate the "DLL hell" that plagues 9x versions of Windows. It is also the first version of Windows to use product activation to combat illegal copying. Windows XP had also been criticized by some users for security vulnerabilities, tight integration of applications such as Internet Explorer 6 and Windows Media Player, and for aspects of its default user interface. Later versions with Service Pack 2, Service Pack 3, and Internet Explorer 8 addressed some of these concerns.


During development, the project was codenamed "Whistler", after Whistler, British Columbia, as many Microsoft employees skied at the Whistler-Blackcomb ski resort.


According to web analytics data generated by W3Schools, as of October 2010, Windows XP is the most widely used operating system for accessing the Internet in the world with a 48.9% market share, having peaked at 76.1% in January 2007.


· Embedded Systems

Ex:
Embedded Linux - is the use of Linux in embedded computer systems such as mobile phones, personal digital assistants, media players, set-top boxes, and other consumer electronics devices, networking equipment, machine control, industrial automation, navigation equipment and medical instruments. According to survey conducted by Venture Development Corporation, Linux was used by 18% of embedded engineers.


Linux has been ported to a variety of processors not always suited for use as the processor of desktop or server computers, such as various CPUs including ARM, AVR32, Blackfin, ETRAX CRIS, FR-V, H8300, IP7000 M32R, m68k, MIPS, mn10300, PowerPC, SuperH, or Xtensa processors, as an alternative to using a proprietary operating system and toolchain.


The advantages of embedded Linux over other embedded operating systems include no royalties or licensing fees, a stable kernel, a support base that is not restricted to the employees of a single software company, and the ability to modify and redistribute the source code. The disadvantages include a comparatively larger memory footprint (kernel and root filesystem), complexities of user mode and kernel mode memory access and complex device drivers framework.