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Copland is an operating system developed by Apple for Macintosh computers between 1994 and 1996 but never commercially released. It was intended to be released with the name System 8, and later, Mac OS 8. Planned as a modern successor to the aging System 7, Copland introduced protected memory, preemptive multitasking, and several new underlying operating system features, while retaining compatibility with existing Mac applications. Copland's tentatively planned successor, codenamed Gershwin, was intended to add more advanced features such as application-level multithreading. Development officially began in March 1994. Over the next several years, previews of Copland garnered much press, introducing the Mac audience to operating system concepts such as object orientation, crash-proofing, and multitasking. In August 1995, David Nagel, a senior vice president, announced at Macworld Expo that Copland would be released in mid-1996. The following May, Gil Amelio stated that Copland was the primary focus of the company, aiming for a late-year release. Internally, however, the development effort was beset with problems due to dysfunctional corporate personnel and project management. Development milestones and developer release dates were missed repeatedly. Ellen Hancock was hired to get the project back on track, but quickly concluded it could never ship. In August 1996, it was announced that Copland was canceled and Apple would look outside the company for a new operating system. Among many choices, they selected NeXTSTEP and purchased NeXT in 1997 to obtain it. In the interim period, while NeXTSTEP was ported to the Mac, Apple released the much more legacy-oriented Mac OS 8 in 1997 based upon adding components from Copland, and Mac OS 9 in 1999 to transition forward. Mac OS X became Apple's next-generation operating system in 2001. The Copland development effort has been described as an example of feature creep. In 2008, PC World included Copland on a list of the biggest project failures in information technology (IT) history. Design Mac OS legacy The prehistory of Copland begins with an understanding of the Mac OS legacy, and its architectural problems to be solved. Launched in 1984, the Macintosh and its operating system were designed from the start as a single-user, single-tasking system, which allowed the hardware development to be greatly simplified. As a side effect of this single application model, the original Mac developers were able to take advantage of several compromising simplifications that allowed great improvements in performance, running even faster than the much more expensive Lisa. But this design also led to several problems for future expansion. By assuming only one program would be running at a time, the engineers were able to ignore the concept of reentrancy, which is the ability for a program (or code library) to be stopped at any point, asked to do something else, and then return to the original task. To be reentrant, any local data and state has to be stored out when another program calls the code, and if one does not require reentrancy, saving out the state can be skipped. In the case of QuickDraw for example, this means the system can store state information in the library, things like the current location of the window or the line style, knowing it would only change under control of the running program. Taking this one step further, the engineers left most of this state inside the application rather than in QuickDraw, thus eliminating the need to copy these data between the application and library, the program can make changes to these settings to its own internal storage and QuickDraw finds these data by looking for those values in known locations within the applications. This concept of sharing memory is a significant source of problems and crashes. If an application program writes incorrect data into these shared locations, it could cause QuickDraw to crash, thereby causing the computer to crash. Likewise, any problem in QuickDraw could cause it to overwrite data in the application, once again leading to crashes. In the case of a single-application operating system this was not a fatal limitation, because in that case a problem in either would require the application, or computer, to be restarted anyway. The other main issue was that early Macs lack a memory management unit (MMU), which precludes the possibility of several fundamental modern features. An MMU provides memory protection to ensure that programs cannot accidentally overwrite other program's memory, and provisions shared memory that allows data to be easily passed among libraries. Lacking shared memory, the API was instead written so the operating system and application shares all memory, which is what allows QuickDraw to examine the application's memory for settings like the line drawing mode or color. The Macintosh lacks multitasking but tries to fake it, and it insists on a complicated user interface but leaves much of the work up to the application. These are serious drawbacks, and it is difficult to imagine elegant repairs for them. These limits meant that supporting the multitasking of more than one program at a time would be difficult, without rewriting all of this operating system and application code. Yet doing so would mean the system would run unacceptably slow on existing hardware. Instead, Apple adopted a system known as MultiFinder in 1987, which keeps the running application in control of the computer, as before, but allows an application to be rapidly switched to another, normally simply by clicking on its window. Programs that are not in the foreground are periodically given short bits of time to run, but as before, the entire process is controlled by the applications, not the operating system. Because the operating system and applications all share one memory space, it is possible for a bug in any one of them to corrupt the entire operating system, and crash the machine. Under MultiFinder, any crash anywhere will crash all running programs. Running multiple applications potentially increases the chances of a crash, making the system potentially more fragile. Adding greatly to the severity of the problem is the patching mechanism used to add functions to the operating system, known as CDEVs and INITs or Control Panels and Extensions. Third party developers also make use of this mechanism to add features, including screensavers and a hierarchical Apple menu. Some of these third-party control panels became almost universal, like the popular After Dark screensaver package. Because there was no standard for use of these patches, it is not uncommon for several of these add-ons — including Apple's own additions to the OS — to use the same patches, and interfere with each other, leading to more crashing. Copland design Copland was designed to consist of the Mac OS on top of a microkernel named Nukernel, which would handle basic tasks such as application startup and.... Discover the Steve Copland popular books. Find the top 100 most popular Steve Copland books.