The Many Flavors of Unix

In the beginning there was Multics.

"MULTiplexed Information and Computing Service" was an attempt in the late

sixties by MIT, Bell Labs, and GE, amongst others, to create a time-sharing operating

system. It never did succeed, though Honeywell did bring out a commercial version. Ken

Thompson of Bell Labs was one of the developers associated with the project, and after the

attempt at Multics was given up, Thompson went on to write Unix (a pun on Multics) to play

games on a salvaged PDP-7. Dennis Ritchie, the inventor of C, is considered the

co-developer of Unix.

This was in 1969. In 1972-1974, Unix was completely

rewritten in C, making it the first portable OS. It’s this portability that led to

the deployment of Unix on a wide range of hardware imaginable. Rights to Unix, including

the source code and the name, rested with Bell Labs. Bell Labs, licensed the source code

to other companies, but not the name. They had to sell their product under a different

brand name. Though these flavors developed independently, there have been various attempts

at standardization, including AT&T’s attempts in the mid-eighties, and the later

day POSIX standards.

This attempt is to make you familiar with some of the

variants of Unix.

AIX

IBM’s version

of Unix. IBM’s version

of Unix.

BSD

The Berkeley System

Distribution. Unix was first developed for the DEC VAX and the PDP-11. The commercial

versions that evolved out of BSD include SunOS and Ultrix. Free BSD is a free

version of BSD Unix. The Berkeley System

Distribution. Unix was first developed for the DEC VAX and the PDP-11. The commercial

versions that evolved out of BSD include SunOS and Ultrix. Free BSD is a free

version of BSD Unix.

HP Unix

No surprises

here. HP’s version of Unix. No surprises

here. HP’s version of Unix.

Irix

The version of

Unix used in Silicon Graphics workstations and servers. Irix has a strong graphical

orientation. Silicon Graphics has recently started a line of workstations running Win NT.

Linux

The hottest

operating system today. Linux and the OpenSource model that it propagates has taken the

computing world by storm. For more on Linux see our March issue. The hottest

operating system today. Linux and the OpenSource model that it propagates has taken the

computing world by storm. For more on Linux see our March issue.

MacOS X

Pronounced OS

ten, this is Apple’s operating system, written specifically for the server.

Basically, this is BSD Unix 4.4 on top of the Mach kernel (3 and 4). OS X can be termed to

be Unix with the Mac interface. In fact, you’ll have the Unix command-line interface,

something you would probably not have even dreamt of as happening on a Mac. The OS is

expected to be POSIX compliant.

Minix

Developed by

professor Andrew S Tanenbaum as a lite version for students to use on a PC. Developed by

professor Andrew S Tanenbaum as a lite version for students to use on a PC.

NextStep

After Steve

Jobs left Apple, he started Next and developed an OS called NextStep, based on the Mach

kernel. After Steve

Jobs left Apple, he started Next and developed an OS called NextStep, based on the Mach

kernel.

SCO OpenServer

One of

the two versions of Unix currently being pushed by SCO (Santacruz Operations). OpenServer

is positioned for small and medium businesses.

Solaris

The current

version of Unix from Sun. It’s available on Sun’s own Sparc and UltraSparc

machines, as well as on Intel platforms.

True64Unix

Originally,

called Digital Unix. Subsequent to Compaq’s takeover of Digital, it was renamed

True64 Unix. Originally,

called Digital Unix. Subsequent to Compaq’s takeover of Digital, it was renamed

True64 Unix.

UnixWare

SCO’s

Unix for enterprises. SCO’s

Unix for enterprises.

Xenix

Microsoft-licensed Unix from Bell Labs to develop it for the x86 family of processors.

Microsoft didn’t sell Xenix to end-users, preferring to sell it to OEMs like SCO and

Intel instead. SCO’s version of Xenix was the most popular of the lot. Xenix never

did really catch on, and its usage has almost died.