Dead Operating Systems
Before I start, I would like to define a dead operating system as one on which
little or no further development is expected to be done. This could be for a variety
of reasons, such as the vendor not seeing further profitability of the OS, the replacement
of an OS by another OS (Like SunOS for Solaris), etc.
Unix family members
The Unix family is littered with many dead operating systems.
SunOS - Sun's BSD-family Unix, replaced by the SysV-family Solaris
Minix - A lightweight Unix for PCs, superceded by Linux
Xenix - An old Unix by Microsoft. Became SCO Unix
Unixware - An old Unix by Novell.
There are many others...
Windows
Windows was an operating environment by Microsoft, originally designed
by Microsoft as a stepping stone to MS OS/2. Replaced by NT and Win95,
Windows has failed to completely leave the computing scene, as several large
businesses have not followed the migration path that Microsoft has prepared.
The biggest problem that Windows had was that it had no networking capability
built-in.
AmigaOS is 32-bit, and runs on Motorola 680x0 and soon some other (not yet known) processor. AmigaOS is a preemptive
multitasker, with a GUI. Click here for more info, as
I personally have not used an Amiga for a long time and do not remember much about them. AmigaDOS, as AmigaOS
is often known, is not in any way related to the DOS entries at the top. The most common interface seen on an
Amiga is Workbench, the GUI.
DOS
Several DOS family members are dead, including all the "proper" DOSes
MS-DOS - Microsoft's DOS, probably the most widely-used DOS family member
PC-DOS - IBM's DOS
Caldera/DR-DOS - Caldera's multitasking DOS
Concurrent DOS - DRI's multitasking DOS
Multiuser DOS - A multiuser DOS by Digital Research
The descendants of MS-DOS that are still DOS (i.e. Win98 is derived from DOS but can't rightly be called a real DOS)
were 16-bit singletasking operating systems that ran on the 80x86 line of processors. Because they ran in that processor's real
mode, their native services could only provide access to 1 Megabyte of memory, which for various reasons only
left 640k of memory available to software. DOS assumed little about the hardware it ran on, and had a very
extensable design. Unfortunately, this design also made writing viruses for DOS to be incredibly easy, as DOS
could not protect its memory in any fashion.
OS/2 was a 32-bit, preemptively multitasking OS that ran on the Intel 80x86.
The father of Windows NT (and in a sense, Windows itself), OS/2 was born of
cooperation between Microsoft and IBM. Before the 2.0 release, Microsoft
withdrew from the project, leaving IBM to continue development. IBM continued
development for several years, and then in early 2000 announced that it was
dead (although no new versions had been released for several years before).
OS/2 placed a great deal of emphasis on customizability, and borrowed
liberally from Unix and DOS. Additionally, it's DOS emulation was quite good,
allowing it also to run Windows 3.1. During its midlife, OS/2 was a testing
ground for a number of IBM technologies, including built-in voice dictation
software, Java development tools, and various other things. Unfortunately,
OS/2 suffered greatly from poor 3rd party support, lack of support from
various divisions within IBM, and several long-lived architectural flaws.
BeOS was an OS for PowerPC and Intel systems. It was vaguely modeled after Unix in architecture, and had a fairly
attractive interface. It placed an emphasis on SMP and multimedia performace.
MacOS, previously known only as System, was the Operating System that came with older Apple Macintosh
computers. MacOS was a 32-bit, cooperative multitasking, easy to use operating system. It ran
on Motorola 680x0 processors, as well as the IBM/Motorola PowerPC processors.
It was replaced by the NeXTStep-derived MacOS X.
