Lecture 1: UNIX HISTORY

Prof. Guntis Bārzdiņš

Course homepage

http://www.ltn.lv/~guntis/unix/index.html Course requirements Lecture slides Assignments, home works Grades – in Moodle Video lectures: http://students.mii.lu.lv/Lekcijas/OperetajsistemaUNIX/

Kristaps Džonsons

Technical questions: guntis@latnet.lv

The uniqueness of UNIX

“Before Multics there was chaos, and afterwards, too” UNIX rose from the ashes of a multi-organizational (Bell Labs, MIT, GE) effort in

the early 1960s to develop a dependable timesharing operating system Multics The joint effort was not successful, but a few survivors from Bell Labs tried again

The features that made UNIX a hit from the start are: Multitasking capability Multiuser capability Portability Modular Structure Library of application software Work environment "of unusual simplicity, power, and elegance...."

Kenneth Thompson 1943 -- Born in New Orleans, Louisiana 1943-1960 - Navy brat moving every few years 1965-66 -- Graduates with B.S and M.S. degrees in electrical engineering from the

University of California at Berkeley 1966 -- Joins Bell Labs Computing Research Department, working on the Multics

project 1969 -- Develops UNIX* operating system 1970 -- Writes B language, precursor to Dennis Ritchie's C language 1971 -- Moves UNIX from the PDP-7 to the PDP-11 1973 -- Rewrites UNIX in Dennis Ritchie's C language 1973 -- Rewrites portions of UNIX to include Doug McIlroy's concept of pipes 1975-6 -- Visiting professor at the University of California, Berkeley 1980 -- "Belle," a chess-playing computer he developed with Joe H. Condon, wins the U.S.

and World Computing Chess Championships 1980 -- Elected to the U.S. National Academy of Engineering 1983 -- Named Bell Labs Fellow 1983 -- Receives with Dennis Ritchie the ACM Turing Award 1988 -- Visiting professor at the University of Sydney, Australia 1998 -- Awarded with Dennis Ritchie the National Medal of Technology for the

development of the UNIX system 2000 -- Retires from Bell Labs

Dennis M. Ritchie 1941 -- Born in Bronxville, N.Y. 1963 -- Graduates from Harvard University with a B.S. in Physics 1968 -- Receives from Harvard University a Ph.D. in mathematics 1967 -- Joins Bell Labs, following his father, Alistair E. Ritchie, who had a long career there 1968 -- Joins the Bell Labs team working on Multics, a joint effort of Bell Labs, MIT

and GE to develop a general computer operating system 1972 -- Creates C language 1989 -- Receives with Ken Thompson the NEC C&C Prize for significant contributions to

computer technology 1983 -- Named Bell Labs Fellow 1988 -- Elected to the U.S. National Academy of Engineering 1990 -- Appointed head, System Software Research Department in the Computer

Sciences Research Center at Bell Labs, Murray Hill, N.J. 1995 -- Heads the effort to create the Plan 9 operating system 1996 -- Heads the effort to create the Inferno(TM) operating system 1998 -- Awarded with Kenneth Thompson the U.S. National Medal of Technology for the

development of the UNIX system

Unixhistory

Unix versions

History of opensource UNIX

BSD (Berkley Software Distribution) Minix (Andrew Tannenbaum) GNU, GPL (Richard Stallman) Linux (Linus Torvalds) Darwin (Apple) Posix, Single Unix Specification, ISO/IEC 9945

Allows multiple interoperable Unix implementations

The History of BSD

1973 - Ken Thompson/Dennis Richie deliver a paper on UNIX

Dr. Bob Fabry from Berkeley attends and later obtains a copy of UNIX

UNIX is installed on several Berkeley PDP/11’s Ken Thompson takes a sabbatical at Berkeley, install

Version 6 on a PDP/11, and writes a Pascal compiler

The History of BSD

1977 - Bill Joy puts together 1st Berkeley Software Distribution (Version 1)

mid-1978 - 2BSD released with improved Pascal, termcap, vi (about 75 shipped)

1978 - Berkeley obtains a VAX-11/780 A copy of AT&T 32/V UNIX is installed - does not

take advantage of virtual memory

The History of BSD

1979 - VAX/BSD distribution assembled includes: virtual memory std 32/V utilities all BSD additions

Bill Joy ships about 100 tapes of 3BSD

The History of BSD

DARPA becomes interested in BSD wants to have common platform (reduced porting

costs on different h/w and os’s) desires distributed network UNIX chosen to solidify DARPA user base

1980 - DARPA grants Berkeley 18 month contract to add DARPA contractors features

The History of BSD

UNIX becomes a commercial AT&T product (System III and later System V)

AT&T/Berkeley work out BSD distribution license (user’s must buy AT&T license)

Oct. 1980 - 4BSD distribution includes: Pascal, Franz Lisp system, enhanced mail

June 1981 - 4.1BSD released includes: tuned up kernel, auto config (~400 shipped)

The History of BSD

DARPA happy with 4.1BSD, grants 2 yr contract with 5 times funding

Roadmap for future versions created: faster file system (Marshall McKusick) interprocess communication (Joy/Leffler IPC) networking support for ARPAnet (R.Gurwitz TCP/IP)

June 1982 - fast file system, TCP/IP, IPC operational Bill Joy joins SUN Microsystems.

The History of BSD

1983 - 4.2BSD is released over 1000 shipped - Very popular

1986 - 4.3BSD released w/ BSD TCP/IP stack AT&T did not have networking/fast file system.

These were later incorporated into System V using BSD code (which turned out to be a good thing)

1988 - 4.3BSD-Tahoe released (machine-independent)

The History of BSD

Up through the release of 4.3BSD-Tahoe, users were required to purchase an AT&T source license. AT&T continued to increase the license cost. PC vendors wanted the TCP/IP stack code, so this

was split out. 1989 - Networking Release 1

first freely distributed code form Berkeley (open source)

The History of BSD

early 1990 - 4.3BSD-Reno released virtual memory system from the MACH kernel SUN-compatible NFS

The History of BSD

1990 - Keith Bostic proposes having BSD become freely-distributed with most source code included Bostic pioneers the technique of mass net-based development

All UNIX utilities re-written from scratch Within 18 months, most lib’s/utilities rewritten

Karels, Bostic, and McKusick go through kernel, file-by-file rewriting 32/V code and removing it from the release

1991 - Networking Release 2 begins distribution Several open source groups form to continue the BSD work

The History of BSD

1992 - AT&T files suit against Berkeley Software Design Inc. (BSDi) BSDi heavily discounts source/binary products over System V AT&T suit alleges BSDi products contain USL code/trade

secrets Counter suit is filed in California

Berkeley and AT&T end up settling after it turned out AT&T had removed UC-Berkeley copyright notices out of the BSD code (TCP/IP and fast file system) it had incorporated years earlier

The History of BSD

BSD groups are formed to work together to maintain and enhance BSD NetBSD is focused on supporting as many platforms as

possible FreeBSD was formed a few months later and focuses on PC’s. OpenBSD is focused on improving the security of BSD

Today work continues on BSD through the NetBSD, FreeBSD and OpenBSD distributions. These are available via downloading over the internet

The History of BSD

Why BSD was so important allowed research environment to grow UNIX pioneered internet based open source development released programs with code or as code

Open source has attracted a lot of attention. Linux is probably the most well know about half of the utilities come from the BSD

distribution

GNU Project Richard Stallman goal 1985: a free Unix-like OS GNU GPL (General Public Licence)

freedom to run the program, for any purpose. freedom to modify the program to suit your needs.

To make this freedom effective in practice, you must have access to the source code, since making changes in a program without having the source code is exceedingly difficult.

freedom to redistribute copies, either gratis or for a fee. freedom to distribute modified versions of the program, so that the community can benefit

from your improvements. GNU/Linux ready by 1991

GNU – GPL utilities and Hurd kernel (Richard Stallman) Linux – GPL efficient Linux kernel (Linus Torvalds)

developed based on opensource mini-kernel architecture Minix (copyright Andrew Tannenbaum)

GPL vs BSD license

GNU GPL (General Public License) “You are free to make modifications and use them privately, without ever

releasing them.” “If you release the modified version to the public in some way, the GPL

requires you to make the modified source code available to the program's users, under the GPL.”

GNU LGPL (Lesser General Public License) Less restrictive

GNU licenses are long GPL v2 license – 14 000 characters

GPL vs BSD license

BSD license “Redistribution and use in source and binary forms, with or without modification, are permitted

provided that the following conditions are met:Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.Neither the name of the <ORGANIZATION> nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.”

BSD license is short and simple Total ~1400 characters

LinuxFrom: torvalds@klaava.Helsinki.FI (Linus Benedict Torvalds) Newsgroups: comp.os.minix Subject: Free minix-like kernel sources for 386-AT Message-ID: <1991Oct5.054106.4647@klaava.Helsinki.FI> Date: 5 Oct 91 05:41:06 GMT Organization: University of Helsinki

Do you pine for the nice days of minix-1.1, when men were men and wrote their own device drivers? Are you without a nice project and just dying to cut your teeth on a OS you can try to modify for your needs? Are you finding it frustrating when everything works on minix? No more all- nighters to get a nifty program working? Then this post might be just for you :-) As I mentioned a month(?) ago, I'm working on a free version of a minix-lookalike for AT-386 computers. It has finally reached the stage where it's even usable (though may not be depending on what you want), and I am willing to put out the sources for wider distribution. It is just version 0.02 (+1 (very small) patch already), but I've successfully run bash/gcc/gnu-make/gnu-sed/compress etc under it. Sources for this pet project of mine can be found at nic.funet.fi (128.214.6.100) in the directory /pub/OS/Linux. The directory also contains some README-file and a couple of binaries to work under linux (bash, update and gcc, what more can you ask for :-). Full kernel source is provided, as no minix code has been used. Library sources are only partially free, so that cannot be distributed currently. The system is able to compile "as-is" and has been known to work. Heh. Sources to the binaries (bash and gcc) can be found at the same place in /pub/gnu. ALERT! WARNING! NOTE! These sources still need minix-386 to be compiled (and gcc-1.40, possibly 1.37.1, haven't tested), and you need minix to set it up if you want to run it, so it is not yet a standalone system for those of you without minix. I'm working on it. You also need to be something of a hacker to set it up (?), so for those hoping for an alternative to minix-386, please ignore me. It is currently meant for hackers interested in operating systems and 386's with access to minix. The system needs an AT-compatible harddisk (IDE is fine) and EGA/VGA. If you are still interested, please ftp the README/RELNOTES, and/or mail me for additional info. I can (well, almost) hear you asking yourselves "why?". Hurd will be out in a year (or two, or next month, who knows), and I've already got minix. This is a program for hackers by a hacker. I've enjouyed doing it, and somebody might enjoy looking at it and even modifying it for their own needs. It is still small enough to understand, use and modify, and I'm looking forward to any comments you might have. I'm also interested in hearing from anybody who has written any of the utilities/library functions for minix. If your efforts are freely distributable (under copyright or even public domain), I'd like to hear from you, so I can add them to the system. I'm using Earl Chews estdio right now (thanks for a nice and working system Earl), and similar works will be very wellcome. Your (C)'s will of course be left intact. Drop me a line if you are willing to let me use your code. Linus PS. to PHIL NELSON! I'm unable to get through to you, and keep getting "forward error - strawberry unknown domain" or something.

From: torvalds@klaava.Helsinki.FI (Linus Benedict Torvalds) Newsgroups: comp.os.minix Subject: Free minix-like kernel sources for 386-AT Message-ID: <1991Oct5.054106.4647@klaava.Helsinki.FI> Date: 5 Oct 91 05:41:06 GMT Organization: University of Helsinki

Do you pine for the nice days of minix-1.1, when men were men and wrote their own device drivers? Are you without a nice project and just dying to cut your teeth on a OS you can try to modify for your needs? Are you finding it frustrating when everything works on minix? No more all- nighters to get a nifty program working? Then this post might be just for you :-) As I mentioned a month(?) ago, I'm working on a free version of a minix-lookalike for AT-386 computers. It has finally reached the stage where it's even usable (though may not be depending on what you want), and I am willing to put out the sources for wider distribution. It is just version 0.02 (+1 (very small) patch already), but I've successfully run bash/gcc/gnu-make/gnu-sed/compress etc under it. Sources for this pet project of mine can be found at nic.funet.fi (128.214.6.100) in the directory /pub/OS/Linux. The directory also contains some README-file and a couple of binaries to work under linux (bash, update and gcc, what more can you ask for :-). Full kernel source is provided, as no minix code has been used. Library sources are only partially free, so that cannot be distributed currently. The system is able to compile "as-is" and has been known to work. Heh. Sources to the binaries (bash and gcc) can be found at the same place in /pub/gnu. ALERT! WARNING! NOTE! These sources still need minix-386 to be compiled (and gcc-1.40, possibly 1.37.1, haven't tested), and you need minix to set it up if you want to run it, so it is not yet a standalone system for those of you without minix. I'm working on it. You also need to be something of a hacker to set it up (?), so for those hoping for an alternative to minix-386, please ignore me. It is currently meant for hackers interested in operating systems and 386's with access to minix. The system needs an AT-compatible harddisk (IDE is fine) and EGA/VGA. If you are still interested, please ftp the README/RELNOTES, and/or mail me for additional info. I can (well, almost) hear you asking yourselves "why?". Hurd will be out in a year (or two, or next month, who knows), and I've already got minix. This is a program for hackers by a hacker. I've enjouyed doing it, and somebody might enjoy looking at it and even modifying it for their own needs. It is still small enough to understand, use and modify, and I'm looking forward to any comments you might have. I'm also interested in hearing from anybody who has written any of the utilities/library functions for minix. If your efforts are freely distributable (under copyright or even public domain), I'd like to hear from you, so I can add them to the system. I'm using Earl Chews estdio right now (thanks for a nice and working system Earl), and similar works will be very wellcome. Your (C)'s will of course be left intact. Drop me a line if you are willing to let me use your code. Linus PS. to PHIL NELSON! I'm unable to get through to you, and keep getting "forward error - strawberry unknown domain" or something.

Linux is a clone of the operating system Unix, written from scratch by Linus Torvalds with assistance from a loosely-knit team of hackers across the Net.

It aims towards POSIX and Single UNIX Specification compliance

It has all the features you would expect in a modern fully-fledged Unix, including true multitasking, virtual memory, shared libraries, demand loading, shared copy-on-write executables, proper memory management, and TCP/IP networking

Based on Minix from Andrew S. Tannenbaum

Tannenbaum’scomments

about Linux

Thus, of course, Linus didn't sit down in a vacuum and suddenly type in the Linux source code. He had my book, was running MINIX, and undoubtedly knew the history (since it is in my book). But the code was his. The proof of this is that he messed the design up. MINIX is a nice, modular microkernel system, with the memory manager and file system running as user-space processes. This makes the system cleaner and more reliable than a big monolithic kernel and easier to debug and maintain, at a small price in performance, although even on a 4.77 MHz 8088 it booted in maybe 5 seconds (vs. a minute for Windows on hardware 500 times faster). Instead of writing a new file system and a new memory manager, which would have been easy, he rewrote the whole thing as a big monolithic kernel, complete with inline assembly code :-( . The first version of Linux was like a time machine. It went back to a system worse than what he already had on his desk. Of course, he was just a kid and didn't know better (although if he had paid better attention in class he should have), but producing a system that was fundamentally different from the base he started with seems pretty good proof that it was a redesign. I don't think he could have copied UNIX because he didn't have access to the UNIX source code, except maybe John Lions' book, which is about an earlier version of UNIX that does not resemble Linux so much.

Thus, of course, Linus didn't sit down in a vacuum and suddenly type in the Linux source code. He had my book, was running MINIX, and undoubtedly knew the history (since it is in my book). But the code was his. The proof of this is that he messed the design up. MINIX is a nice, modular microkernel system, with the memory manager and file system running as user-space processes. This makes the system cleaner and more reliable than a big monolithic kernel and easier to debug and maintain, at a small price in performance, although even on a 4.77 MHz 8088 it booted in maybe 5 seconds (vs. a minute for Windows on hardware 500 times faster). Instead of writing a new file system and a new memory manager, which would have been easy, he rewrote the whole thing as a big monolithic kernel, complete with inline assembly code :-( . The first version of Linux was like a time machine. It went back to a system worse than what he already had on his desk. Of course, he was just a kid and didn't know better (although if he had paid better attention in class he should have), but producing a system that was fundamentally different from the base he started with seems pretty good proof that it was a redesign. I don't think he could have copied UNIX because he didn't have access to the UNIX source code, except maybe John Lions' book, which is about an earlier version of UNIX that does not resemble Linux so much.

From: torvalds@klaava.Helsinki.FI (Linus Benedict Torvalds)Subject: Re: LINUX is obsoleteDate: 29 Jan 92 23:14:26 GMTOrganization: University of Helsinki Well, with a subject like this, I'm afraid I'll have to reply. Apologies to minix-users who have heard enough about linux anyway. I'dlike to be able to just "ignore the bait", but ... Time for someserious flamefesting! In article <12595@star.cs.vu.nl> ast@cs.vu.nl (Andy Tanenbaum) writes:>As most of you know, for me MINIX is a hobby, something that I do in the>evening when I get bored writing books and there are no major wars,>revolutions, or senate hearings being televised live on CNN. My real>job is a professor and researcher in the area of operating systems. You use this as an excuse for the limitations of minix? Sorry, but youloose: I've got more excuses than you have, and linux still beats thepants of minix in almost all areas. Not to mention the fact that mostof the good code for PC minix seems to have been written by Bruce Evans.

From: torvalds@klaava.Helsinki.FI (Linus Benedict Torvalds)Subject: Re: LINUX is obsoleteDate: 29 Jan 92 23:14:26 GMTOrganization: University of Helsinki Well, with a subject like this, I'm afraid I'll have to reply. Apologies to minix-users who have heard enough about linux anyway. I'dlike to be able to just "ignore the bait", but ... Time for someserious flamefesting! In article <12595@star.cs.vu.nl> ast@cs.vu.nl (Andy Tanenbaum) writes:>As most of you know, for me MINIX is a hobby, something that I do in the>evening when I get bored writing books and there are no major wars,>revolutions, or senate hearings being televised live on CNN. My real>job is a professor and researcher in the area of operating systems. You use this as an excuse for the limitations of minix? Sorry, but youloose: I've got more excuses than you have, and linux still beats thepants of minix in almost all areas. Not to mention the fact that mostof the good code for PC minix seems to have been written by Bruce Evans.

Popular GNU/Linux distributions

Debian (Ubuntu,...) RedHat / Fedora Suse Gentoo Knopix (loads from CD) Yellow Dog (PowerPC) Slackware etc.

RedHat / Fedora

RedHat Enterprise commercial, supported by RedHat, Inc.

Fedora (CentOS) free, open source, supported only by community

Easy installation, easy administration Package system RPM (RPM Package Manager) Good for beginners Customization may not be as easy

Gentoo

“The Gentoo philosophy is to allow this user to do what he or she wants to do, without getting in the way.”

Heart of a Gentoo system – package manager Portage Choose what features of a package you need Optimized for your processor type

Source packages called ebuilds Describes where to fetch source, how to compile, where to install Contains USE flags, which can be set to choose what features to compile in

Hard installation for beginners (everything done “by hand”)

SCO Lawsuits against Linux users

1979: SCO founded as The Santa Cruz Operation 1983: SCO delivers the first packaged UNIX System (called SCO® XENIX® System V) for

Intel® 8086 and 8088 processor-based PCs. 1995: SCO acquires UNIX System source technology business from Novell Corporation (which

had acquired it from AT&T's UNIX System Laboratories). 2001: Caldera Systems completes the acquisition of SCO's Server Software and Professional

Services Divisions, becoming Caldera International (Caldera) 2002: Caldera changes its name to The SCO Group (SCO), returning to the SCO brand 2003: SCO Files Lawsuit Against IBM (use of Linux) 2003: SCO Suspends Distribution of Linux Pending Intellectual Property Clarification 2003: The SCO Group Sends Open Letter to the Open Source Community 2003: SCO Ranked Number 75 Fastest Growing, North American Technology Company In

Deloitte Technology Fast 500 2003: SCO Announces New Initiatives to Enforce Intellectual Property Rights 2004: SCO Announces Worldwide Availability of SCO Intellectual Property License ($1300)

Popular *BSD distributions

NetBSD focused on supporting as many platforms as possible

FreeBSD focuses on PC’s.

OpenBSD focused on improving the security of BSD

Popular Commercial Unix versions

Solaris (Sun Microsystems) MacOS X (Apple) AIX (IBM) HP-UX (Hewlett Packard)