History of UNIX Fergus Toolan Intelligent Information Retrieval Group University College Dublin

COMP2006, UNIX Operating Systems, January 26 th. 2 Administration Practical Attendance. Practical Web Site – Lecture Notes –Also available at web site.

COMP2006, UNIX Operating Systems, January 26 th. 3 Overview UNIX/LINUX/SOLARIS Motivations for the development of UNIX. History of the development Reasons for its success over the years Future developments for UNIX.

COMP2006, UNIX Operating Systems, January 26 th. 4 Flavours There are many ‘flavours’ of UNIX. UNIX / LINUX / SOLARIS /... UNIX stable scalable OS. Micro-kernel architecture.

COMP2006, UNIX Operating Systems, January 26 th. 5 Linux Originally a scaled down version of UNIX. Now a full OS in its own right. Developed by Linus Torvalds Based on MINIX created by Andrew Tanenbaum.

COMP2006, UNIX Operating Systems, January 26 th. 6 Solaris Sun Microsystems OS for the Sun machines. Derivative of UNIX. Can be off-putting for a UNIX/LINUX person as the commands are slightly different. However if you can use 1 you can use 3.

COMP2006, UNIX Operating Systems, January 26 th. 7 MULTICS In the mid 60’s all computers used batch processing systems An interactive “shell” was required by some people Multi-tasking, multi-user systems were necessary Bell Labs developed MULTICS in 1965.

COMP2006, UNIX Operating Systems, January 26 th. 8 MULTICS Bell Labs pulled out of the MULTICS project in Progress had been slow. Financial issues with the partners. Bell Labs allowed the continuation of the Operating Systems Group. Thompson/Ritchie develop UNIX.

COMP2006, UNIX Operating Systems, January 26 th. 9 Space Traveller Game written by Ritchie. FORTRAN code for the GECOS system Poor graphics on GECOS. Thompson had access to a PDP-7 with good graphics. No OS available to run the space traveller game.

COMP2006, UNIX Operating Systems, January 26 th. 10 Space Traveller UNIX developed to run Space Traveller. Based on a design Thompson and Ritchie had sketched out on paper. Included a file system, a process subsystem and a few basic utility programs The name UNIX was coined by Kernighan as a pun on MULTICS.

COMP2006, UNIX Operating Systems, January 26 th. 11 History 1969 can be seen as the birth of UNIX. However it was 1971 before it was implemented in an actual project in Bell. This was on a PDP-11. Application development then began in earnest for UNIX systems.

COMP2006, UNIX Operating Systems, January 26 th. 12 Application Development Thompson began to create a Fortran compiler in However it mutated to become a compiler for a derivative of BCPL. This language became known as B. It was interpreted. Ritchie created a compiled version. C was born!

COMP2006, UNIX Operating Systems, January 26 th. 13 Operating Systems In 1973 a momentous event occurred. Prior to this time all operating systems had been written in assembly languages. Hence hardware dependent. Difficult to program. Ritchie rewrote UNIX in C in High-Level language.

COMP2006, UNIX Operating Systems, January 26 th. 14 Distribution By 1977 was the year that UNIX was first ported to a non-PDP machine. This was a landmark achievement. UNIX is the first (and only??) truly portable OS. PC’s, Clusters, Mac, Crays,... In 1977 there were approximately 500 installations of UNIX in the world.

COMP2006, UNIX Operating Systems, January 26 th. 15 The split Up to the late 1970’s Bell Labs were the only people developing the UNIX system. Academic licences had meant that Universities were looking at it. The fact that the OS source code was freely available meant that anyone could edit. Countless people began to develop new utilities.

COMP2006, UNIX Operating Systems, January 26 th. 16 The Split When the University of California – Berkely got a copy of the UNIX OS they began to edit the kernel. This lead to the split. By 1983 there were two flavours of UNIX. –System V – the Bell labs version –BSD – Berkely Software Distribution

COMP2006, UNIX Operating Systems, January 26 th. 17 The Success of UNIX By ,000 installations were in place. Why did it succeed. –Written in a high-level language – slower but... –Simple UI – interactive shell, no batch –Primitives that allow complex programs to be built. –Hierarchical File System –Consistent format for files

COMP2006, UNIX Operating Systems, January 26 th. 18 Success of UNIX –Simple interface to peripheral devices – treats all as a file. –multi-user, multiprocess system. Each user can execute several processes at once. –Hides machine architecture. Cross platform programs could be developed.

COMP2006, UNIX Operating Systems, January 26 th During this period there was little major changes made to the system kernel. Both BSD and System V remained static. However many utilities programs were developed around the world for both systems. What would run on one would run on another.

COMP2006, UNIX Operating Systems, January 26 th. 20 Open Source UNIX was born in an era with little in the way of copy protection. Hence all code for UNIX was open source. This is beginning to change in some installations. Red-Hat Enterprise servers. However SUSE, Fedora, Debian are still open source.

COMP2006, UNIX Operating Systems, January 26 th. 21 Open Source What did it mean? –anyone could edit the OS. –Most were disasters –however some were incorporated into the system. –It involves rebuilding the kernel. –Most UNIX users have strange kernel configurations.

COMP2006, UNIX Operating Systems, January 26 th. 22 The birth of LINUX In 1991 Linus Torvalds a graduate student in Denmark developed a system as part of his PhD work which he called LINUX. It was a simpler variant of UNIX. It is now the third most popular operating systems in the world after Windows and Mac.

COMP2006, UNIX Operating Systems, January 26 th. 23 The birth of LINUX LINUX has been implemented on many platforms and for different tasks from standard desktop use to high-level servers. LINUX is more suited to desktop operations than UNIX which is mainly server level. The main reason is in the utilities that have been developed.

COMP2006, UNIX Operating Systems, January 26 th. 24 LINUX Utilities X-Windows. Movies, Games, Music,... Web Browsers, clients, Word Processing –including through star/open office the creation of Word, Excel, PPT etc.

COMP2006, UNIX Operating Systems, January 26 th. 25 The spread of UNIX In 2000 Apple made a major leap forward in terms of the spread of UNIX. For the OS-X operating system (the current standard macintosh operating system) Apple based it on Free BSD UNIX. This means that UNIX has proliferated.

COMP2006, UNIX Operating Systems, January 26 th. 26 For naive users it looks like the old mac OS. However underneath it is an installation of BSD 4.3 – I think!! This means that any application for Macintosh, UNIX or LINUX can be run on it. If we have source code even windows applications can be run on it.

COMP2006, UNIX Operating Systems, January 26 th. 27 The spread of LINUX Many distributions: Red Hat, Mandrake, Suse, Debian,.... Red Hat commercial company. Enterprise level services power many servers. Desktop ones available for free. Now from Fedora – Linux returns to Open Source.