History of Modern Computing Section 6

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1 History of Modern Computing Section 6 David Pease Computer Engineering Department Jack Baskin School of Engineering

2 Lesson Outline The Internet The Free Software Movement The World Wide Web Modern Programming Languages Java JavaScript Perl Python Printing

3 The Internet NSFNet (1984) Established by National Science Foundation TCP/IP-based wide-area network Used to connect large supercomputing centers funded by NSF Operational by 1986 Since ARPANET and NSFNet both used TCP/IP, they were interoperable The two networks began to merge in mid-1980s Term Internet began to be used: Interoperable, interconnected, TCP/IP-based WAN New functionality was needed with rapid growth of Internet : Domain Name Services (DNS) Hierarchical routing architecture TCP/IP network spread to other continents CERNnet in Europe, Australia, etc. Initially, network was defense and research only Growth of backbone infrastructure from commercial enterprises and other government agencies subsumed ARPANET and NSFNet

4 The Free Software Movement Software in the 1950s and 1960s Often or usually free of cost Bundled with hardware by manufacturer Generally not portable to other computers Written by users and shared DECUS, SHARE, etc. Source code unusally available Could be improved and shared In the 1970s Rise of proprietary software and software copyrights Unbundling Software not free with hardware Software companies and products Sort utilities, tape management products, etc. Industry-specific proprietary applications Source code usually unavailable, or licensed with restrictions

5 The Free Software Movement Think free speech, not free beer. Richard Stallman and the FSF Stallman ( rms ) was a programmer at MIT AI lab in 1970s By the 1980s, rise of proprietary software threatened the MIT hacker culture he was part of (If interested, find Eric S. Raymond s web page on being a Hacker) Stallman felt software should be free to be modified, improved, shared In 1983, he announced the GNU project (g noo, a pun on new ) Founded the Free Software Foundation Took donations, hired programmers Created the Gnu Public License (GPL) and the copyleft concept GNU: GNU s Not Unix Goal is to implement a full, free operating system environment Modelled on UNIX, but not containing any UNIX code By 1990, the GNU system contsisted of GNU Emacs, GCC, GDB, libraries, shell and shell utilities Also used other open software: X-Windows, Tex Almost everything but an OS kernel Working on kernel called Hurd

The Free Software Movement Linux Linus Torvalds, Finnish computer scientist Attended University of Helsinki from 1988-1996 M.Sc.

program in assembler Kept extending it: Stand-alone (no OS needed), multiple threads, filesystem, etc. Eventually evolved into a POSIX-compliant OS kernel Version 0.

6 The Free Software Movement Linux Linus Torvalds, Finnish computer scientist Attended University of Helsinki from M.Sc. In CS in 1996 (Thesis: Linux, A Portable Operating System ) Originally used Minix A simple unix-like kernel written by Andrew Tanenbaum, for teaching In 1991, started writing a terminal emulator program in assembler Kept extending it: Stand-alone (no OS needed), multiple threads, filesystem, etc. Eventually evolved into a POSIX-compliant OS kernel Version 0.01 released (on Internet) September, 1991 Downloaded by 10s of people! - many of whom wanted to help Network administrator who provided access (via ftp) needed a name Picked Linus Minix => Linux Over time, hundred of volunteers helped write the Linux kernel People added features/components they wanted, or Worked on components that Linus needed help with Ended up with a very complete kernel for Intel processor Linus still (today) determines what is allowed into kernel Benevolent Dictator"

The Free Software Movement Tux Linux The Linux kernel was soon combined with tools from GNU project Bash shell and utilities, GCC compiler and libraries,

Created a complete, fully functional, free Unix-like OS environment Linux kernel also released under the GPL Picked Tux the penguin as a mascot Kernel has gone

7 The Free Software Movement Tux Linux The Linux kernel was soon combined with tools from GNU project Bash shell and utilities, GCC compiler and libraries, X-Windows, etc. Created a complete, fully functional, free Unix-like OS environment Linux kernel also released under the GPL Picked Tux the penguin as a mascot Kernel has gone through many revisions Current production is 2.6.nn Groups began packaging Linux Distributions for users Yaggdrasil (1994, 0.99 kernel) Red Hat, Slackware, SuSE, Debian, etc., etc. Other FS and OSS projects Free Software and Open Source Software not identical OpenOffice, WINE, hundreds of others See sourceforge.net

8 The World Wide Web Hypertext is not a new concept: Vannevar Bush: memex, 1930s Ted Nelson: Project Xanadu, 1960s Coined term hypertext Douglas Engelbart: NLS on-line System SRI, 1960s Internet information search and retrieval services Gopher, WAIS, Anonymous FTP Site List Tim Berners-Lee Began research at CERN in 1980 wanted to share research information Built prototype hypertext system called ENQUIRE In 1989, got idea to join hypertext with Internet

The World Wide Web Tim Berners-Lee (continued) Built first Web Server (named httpd) and browser/editor in 1990 On Next Cube > Introduced URL, HTTP, HTML Browser was named WorldWideWeb Shown to world

9 The World Wide Web Tim Berners-Lee (continued) Built first Web Server (named httpd) and browser/editor in 1990 On Next Cube > Introduced URL, HTTP, HTML Browser was named WorldWideWeb Shown to world in August, Announced as a free service from CERN in 1993 Berners-Lee Founded W3C at MIT in 1994 World Wide Web Consortium International Web standards oganization He now heads W3C

10 The World Wide Web A very early version of Berners-Lee's first web page: (

The World Wide Web National Center for Supercomputing Applications at UIUC, 1992 NCSA group heard about Tim Berners-Lee s work Downloaded ViolaWWW browser, connected to CERN over ARPANET Demonstrated

11 The World Wide Web National Center for Supercomputing Applications at UIUC, 1992 NCSA group heard about Tim Berners-Lee s work Downloaded ViolaWWW browser, connected to CERN over ARPANET Demonstrated early Web to group at NCSA Two students, Marc Andreessen and Eric Bina Began work on UNIX X-Windows browser Mosaic for X-Windows relased in February, 1993 Provided support for Graphics, Sound, Video Later added support for Forms Mosaic for Macintosh released soon after First cross-platform browser In 1994 commercial rights assigned to Spyglass, Inc. Technology licensed to others, including Microsoft (basis of IE)

The World Wide Web Marc Andreessen moved to California in 1993

Netscape Communications Released Netscape Communicator in 1994 (

standard until Microsoft bundled IE with Windows (the beginning of

12 The World Wide Web Marc Andreessen moved to California in 1993 (after graduation) With funding from SGI founder, started Mosaic Communications Corp. University of Illinois didn t like use of Mosaic so company became Netscape Communications Released Netscape Communicator in 1994 ( Mozilla ) 1995 IPO made Andreessen wealthy Netscape was de-facto standard until Microsoft bundled IE with Windows (the beginning of the Browser Wars ) Netscape code eventually released as Open Source project (GPL) Latest version of Netscape is Mozilla Firefox 3.5

13 Modern Programming Languages In 1980s, C and C++ became dominant For both operating systems and application software Unixes always written in C (including Linux) Windows written in C++ A good language for applications High-level enough for good productivity Efficient enough for good performance Access to low-level system function Many new languages developed in 1990s Fueled (both directly and indirectly) by the web, and by increasing system performance Many interpretive/scripting languages

Modern Programming Languages Java Invented by James Gosling at Sun Microsystems in 1991 To be used in embedded systems Called Oak, Green, eventually Java (a random word) Based on C/C++ syntax Simpler

14 Modern Programming Languages Java Invented by James Gosling at Sun Microsystems in 1991 To be used in embedded systems Called Oak, Green, eventually Java (a random word) Based on C/C++ syntax Simpler memory model, object model Released by Sun in 1995 Sun Java technology now open source De-facto standard controlled by Java Community Process Compiles to bytecode, runs in JVM (Virtual Machine) in Java Runtime Environment (JRE) WORA programs (write once run anywhere) Port JVM/JRE to target host system Very popular as server-side web page scripting language Web servers run Java Applets Except modern Microsoft IE (without an extra plug-in) Microsoft violated Java license agreement

15 Modern Programming Languages JavaScript Developed by Brendon Eich of Netscape First released in Netscape 2.0 in 1995 No real relation to Java Netscape wanted to take advantage of Java's popularity on the web with JavaScript's name Like Java, based on C-style syntax But many differences in syntax and semantics Primarily used for client-side web page scripting JavaScript runs in user's web browser Can react immediately to user actions Submitted to ECMA, now dialect of ECMAScript Microsoft JScript very similar, but not ECMA-compliant Key Web 2.0 technology, especially in AJAX Asynchronous JavaScript And XML Currently managed by Mozilla Foundation

16 Modern Programming Languages Perl Created by Larry Wall at NASA in 1987 Originally called Pearl, but that was already used General scripting language Similar to shell scripting Much more powerful Swiss Army chainsaw of programming languages Borrows from shell (sh), C, AWK, sed Powerful text processing, including regular expressions Perl 5 (current dialect) released in 1994 Comprehensive Perl Archive Network (CPAN), 1995 Repository for Perl modules ~17,000 by 7,000 authors One of the greatest strengths of the language for ($result = 1; $n > 0; $n--) { $result *= $n; }

17 Modern Programming Languages Python Created by Guido van Rossum (BFDL) at CWI (Nat'l Res. Inst. for Mathematics and Computer Science, Amsterdam) Holiday project (Dec. 89) to implement scripting language Based on ABC (from SETL), with aspects of Modula-3 Guido is a Monty Python's Flying Circus fan Less C-like than most modern languages Uses colon for blocks, which are indented Both for readability and program structure Has Modula-3 inspired module import capability Hundreds of modules for many purposes Insider's joke: import this prints the Python Koan Supports both structured and object-oriented programming Like Perl (and PHP), part of the LAMP tool set Linux, Apache, MySQL, [Perl,Python,PHP] result = n for i in range(1,n): result *= i

18 Modern Programming Languages Python Koan The Zen of Python, by Tim Peters Beautiful is better than ugly. Explicit is better than implicit. Simple is better than complex. Complex is better than complicated. Flat is better than nested. Sparse is better than dense. Readability counts. Special cases aren't special enough to break the rules. Although practicality beats purity. Errors should never pass silently. Unless explicitly silenced. In the face of ambiguity, refuse the temptation to guess. There should be one-- and preferably only one --obvious way to do it. Although that way may not be obvious at first unless you're Dutch. Now is better than never. Although never is often better than right now. If the implementation is hard to explain, it's a bad idea. If the implementation is easy to explain, it may be a good idea. Namespaces are one honking great idea -- let's do more of those!

1403) (1950s) Daisy-wheel (1970s) Non-formed characters Dot-matrix

19 Printing Common Printing Technologies Impact Fully-formed characters Chain, bar, etc. (e.g. 1403) (1950s) Daisy-wheel (1970s) Non-formed characters Dot-matrix (1970s) IBM 3800 Laser Printer (1976) Non-impact Laser: Large: Data Center Small: Office/Personal Inkjet (1970s) (1980s) (1970s-80s)

OOP and Scripting in Python

DIEE - Università degli Studi di Cagliari OOP and Scripting in Python Introduction Giuliano Armano DIEE Univ. di Cagliari Python Roots... Object Oriented Programming (C++, Modula-3, ABC, Icon) Scripting