PC OSes are growing up. OS/2 and Windows NT are 32-bit flat-memory systems that run in protected mode, multitask preemptively, and support virtual memory--all classic mainframe features.
"A protected-mode OS is the key to robustness in PCs," says Roger Alford, president of Programmable Designs (Ann Arbor, MI). Carl Amdahl of NetFrame Systems (Milpitas, CA) concurs: "You have to be able to kill an application and have the OS stay alive and well."
Windows NT could have a very bright future as a general-purpose server OS because of several crucial architectural features. It was designed to be both a client and a server--in peer and client/server networking schemata--and is both a NOS (network operating system) and
an applications platform. It was also written to ride on a HAL (hardware abstraction layer), which hides the specifics of the machine behind a generalized interface. Because of HAL, NT has been successfully ported to a variety of systems built on x86, Alpha, PowerPC, and Mips processors. NT also supports SMP (symmetric multiprocessing), software- and hardware-implemented RAID, and performance monitoring.
OS/2 is available with support for SMP and will soon run on the PowerPC. NetWare support for SMP is expected to ship this summer. And the full gamut of high-end OS features--including 32-bitness, multitasking, SMP support, and management tools--has been available for years in SCO Unix, Novell's UnixWare, and Solaris for x86 and Interactive Unix from SunSoft.
Though NetWare's performance benefits from kernel-mode operation, its reliability suffers: The NOS is subject to crashing from conflicting NLMs (NetWare loadable modules). Fortunately, this isn't the problem it would be in a general-purpos
e OS, because end users typically don't load software onto servers. But NetWare must evolve task isolation and preemptive multitasking to become a credible application server, which is precisely what Novell plans to do in SuperNOS, a next-generation OS combining NetWare and UnixWare.
PC Software Gets More Potent
