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In the early 90s, Apple teamed up with IBM to create Star Trek, a version of System 7 for the IBM PC.

All this made Windows 95 more responsive and more stable than Windows 3.1.Īpple had tried several times to create a new operating system to replace the outdated Mac OS, but all of them had ended in failure. It determined which tasks had priority and assigned resources to them. The computer would dynamically assign resources and RAM to each program. It was backwards compatible with most DOS and 16-bit Windows programs, but it used preemptive multitasking for 32-bit Windows programs.

It was essentially a combined DOS and Windows. This was no worse than Windows 3.1, but Windows 95 trumped it. When a single program crashed, so did the whole operating system.

OS InstabilityĪdding multitasking to the Mac OS in this way made it much less stable. The computer could only allocate contiguous portions of memory to a program, and memory could eventually become fragmented (like a hard drive).īy contrast, Windows 95 supported dynamic memory allocation, which didn’t require contiguous blocks of memory and allowed the OS to allocate more memory to a program as it needed it. Each program would request a fixed amount of memory when it was launched, and the OS would dedicate all of the resources the program requested. Adding multitasking to the single-tasking Mac OS was a clever hack devised by Andy Hertzfeld in 1985, and it had been fully integrated into System 7.Īnother difference between Windows and the Mac OS is that the Mac used static memory allocation. With cooperative multitasking, each program controls how much processor time it uses before handing off control to the next program. Instead, the Mac OS used cooperative multitasking. With preemptive multitasking, the operating system controls how much processor time is allocated to each program. Like all versions of the Mac OS prior to Mac OS X, System 7 didn’t have preemptive multitasking. Apple was confident that users would still be attracted to the Mac because of its interface – but also worried that Windows’ multitasking environment would put Mac OS 7.5 to shame. In 1995, Microsoft was busy promoting the latest release of Windows, Windows 95.