Overview, An Incredible Journey
From the beginning of electronic communication with the telegraph in 1833 to the present, it has all happened in 181 years. The pace of technological advancements has been accelerating at what seems like an exponential rate. It is hard to believe that when I was born in 1944, TV was just a nascent technology, vinyl records were still 78 RPM, long-distance travel was via train, and transatlantic trips were via ship.
The record, a vinyl one, had a 100-year run while the CD, first pressed in 1982, has already been replaced, mostly by solid-state devices and smartphones via the Internet. And the Internet has gone from a glimmer in a few scientists' eyes to a trillion-dollar business in a little over 30 years.
Communication speed has gone from the teletype at 75 bits per second (bps) in the 1960s to gigabits per second (Gbs) speeds today. When the Internet was born in the late 1960s, it ran at 1,200 bps and today the Internet backbone using fiber optic cable and transmission protocols like SONET (Synchronous Optical Networking) and ATM (Asynchronous Transfer Mode) hits over 400 Gbs. This incredible speed improvement has made music and video on demand possible over the Internet as well as telephone and data that supports the financial and business communities around the world.
This phenomenal growth is due to the development of the transistor, integrated circuits and the microcomputer. Without these technologies packet switching networks, which are at the heart of the Internet,it would not be possible. The development of packet-switching-time-domain-multiplexing required the speed of the microcomputer. The old circuit switching technology of the telephone companies just was not viable for a worldwide data communication grid.
The following timeline highlights some of what I believe were the seminal breakthroughs of the last century and a half.
Timeline of Electronic Communications
- 1833 Telegraph: Carl Friedrich Gauss and Wilhelm Weber, Göttingen Germany.
- 1837 Morse Code and Telegraph in the USA: Samuel Morse.
- 1867 First Successful and Modern Typewriter: American, Sholes.
- 1876 Telephons: Alexander Graham Bell.
- 1877 Phonograph: Thomas Edison - with a wax cylinder as recording medium.
- 1887 Gramophone: Emile Berliner - a system of recording which could be used over and over.
- 1888 Kodak Roll Film: George Eastman.
- 1894 Wireless Telegaphy: Guglielmo Marconi.
- 1902 First Transatlanic Radio: Guglielmo Marconi - from Cornwall to Newfoundland.
- 1906 Electronic Amplifying Tube or Triode: Lee Deforest - this allowed all electronic signals to be amplified thus improving electronic communications
- 1923 The Television or Iconoscope (cathode-ray tube): Vladimir Kosma Zworykin - first television camera.
- 1939 Scheduled Television Broadcasts.
- 1944 Barton Phillips born April 11.
Computers: put into public service - government owned - the age of Information Science begins.
The Colossus: Bletchley Park England was used at the end of World War II to break encrypted German messages. Ten Colossi were in use by the end of the war.
- 1948 Transistor: invented at Bell Labs - enabling the miniaturization of electronic devices.
- 1948-1950 Cable TV and Subscription TV Services.
- 1950-1961 Development of T-1 Transmition Lines: Bell Labs.
- 1951 Computers are First Sold Commercially.
- 1952 CERN ("Conseil Européen pour la Recherche Nucléaire" or European Organization for Nuclear Research) founded in Switzerland.
- 1958 Integrated Circuits: enabling the further miniaturization of electronic devices and computers.
- 1960 Packet Switching: Paul Baran, Donald Davies and Leonard Kleinrock.
- 1961 Host-based Email CTTS Systems (Compatible Time-Sharing System. Big Main Fraims)
- 1964 Barton Phillips Graduates from UCLA and Enters the Air Force.
- DARPA (Defense Advanced Research Projects Agency) commissioned a study of decentralized switching systems.
- First demonstration net between MIT's Lincoln Lab and System Development Corporation in California (1200 bits/sec).
- ARPANET (Advanced Research Projects Agency Network) the first Internet started. Backbone running at 50 Kbits/sec.
- Request for Comments (RFC) started
- 1970 Barton Phillips Returns to US from the Air Force
- The Computer floppy disk Invented.
- The Microprocessor Invented. Three projects delivered a microprocessor at about the same time: Garrett AiResearch's Central Air Data Computer (CAD8), Texas Instruments' TMS 1000 (September), and Intel's 4004 (November).
- 1972 Ray Tomlinson Invented Network Email and the '@' Sign.
- 1974 TCP/IP (Transmission Control Program/Internet Protical RFC 675. Vinton Cerf, Yogen Dalal and Carl Sunshine).
- Barton Phillips Bought the KIM 1 6502 Computer kit: Hex keypad, 7 segment display, 1K RAM, 8K ROM.
- The S100 Bus Altair 8800 with the Intel 8080 processor became available along with the IMSAI 8080.
- March: X.25 Network standard approved.
- 1977 April: Barton Phillips Purchased the Apple I Home Computer also 6502 based. The Apple I had 4 or 8 Kbytes of RAM and Integer Basic in ROM. It also had a casset tape interface for reading and writing data via a casset player.
- October: Barton Phillips joins Micropolis Corp. a floppy disk manufacturer. Between 1978 and 1983 Barton wrote disk OS, Basic Interpreter, Assembler/Linker and Editor for the Micropolis products. In 1983 Micropolis stopped marketing its OS.
- 1978 X.25 provided the first international and commercial packet switching network, the "International Packet Switched Service" (IPSS).
- 1979 First Cellular Phone Communication Network Started in Japan.
- 1980 Tim Berners-Lee at CERN in Switzerland developed ENQUIRE a hypertext program. He also created HTML (Hyper Text Markup Language).
- 1981 IBM PC first sold using the Intel 8088.
- SMTP (Simple Mail Transport Protical) RFC 821.
- April: Sony Records presses first CD (Compact Disk)
- Ethernet, which was introduced in 1980 was standardized IEEE 802.3.
- Time magazines names the computer as Machine of the Year.
- Number of network hosts breaks 1,000
- Apple Macintosh released.
- IBM PC AT released using Intel 80286 (integrated memory management and floating point)
- ARPANET backbone via T-1 at 1.5 Mbits/sec.
- POP1 (Post Office Protical 1) RFC 918.
- IMAP (Internet Mail Access Protocol) was designed by Mark Crispin RFC 1064.
- SGML (Standard Generalized Markup Language) ISO 8879:1986.
- 1987 Number of network hosts breaks 10,000
- ADSL (Asymmetric Digital Subscriber Line) patented.
- POP3 RFC 1081 (the current standard)
- Tim Berners-Lee coined World Wide Web or WWW again at CERN.
- NSFNet takes over from ARPANET and becomes the principal internetwork backbone.
- Number of network hosts breaks 100,000
- HTTP (Hyper Text Transport Protical),
- HTML (Hyper Text Markup Protical), first server (CERN httpd) and the first browser all created by Tim Berners-Lee and Robert Cailliau all running on a NeXT computer.
- Nicola Pellow created a browser that could run on almost all computers called the "Line Mode Browser".
- URL of first website: http://info.cern.ch
- January: first HTTP server outside of CERN was activated.
- Comercial restriction on Internet lifted.
- ANSNet Backbone via T-3 at 45 Mbits/sec.
- April: Erwise browser first graphical browser available for systems other than the NeXT computer.
- Number of network hosts breaks 1,000,000
- WWW (World Wide Web).
January: 50 web servers in the world.
October: 500 web servers in the world.
- Mosaic web browser released by National Center for Supercomputing Applications (NCSA) at the University of Illinois at Urbana-Champaign (UIUC), led by Marc Andreessen. Funding for Mosaic came from the "High-Performance Computing and Communications Initiative", a funding program initiated by then Senator Al Gore's "High Performance Computing and Communication Act" of 1991 also known as the Gore Bill.
- June: Cello by Thomas R. Bruce was the first browser for Microsoft Windows.
- August: The NCSA released Mac Mosaic and WinMosaic.
- CIDR (Classless Inter-Domain Routing) blocks introduced to replace Classful network (A, B, C) design.
- WWW (World Wide Web).
- Private sector assumes responsibility for the Internet. Backbone via ATM at 145 Mbits/sec
- April: Netscape founder by Mark Andreessen and James H. Clark. Netscape Navigator born.
- Amazon founded.
- NFSNet backbone service decomissioned.
- HTML 2.0 published as IETF RFC 1866.
- 1996 Cable Internet. Rogers Communications introduced the first cable modem service
January: Google started as a research project by Larry Page and Sergey Brin at Stanford University.
- 1997 HTML 3.2 published as a W3C Recommendation.
- September: Google incorporated.
- HTML 4.0 published as a W3C Recommendation.
- 1999-2001 "Dot-Com" Boom, then bust.
- 2000 Apple Computer releases Mac OS X a Unix look-alike operating system.
- 2001 January: Wikipedia launched.
- February: Facebook launched.
- Internet traffic breaks one exabyte per month
- 2005 YouTube launched.
- SONET OC768 40 Gbit/sec optical fiber.
Theoretical Limit to fiber optical cable is one terabit or one trillion bits per second.
- Apple Computer switches from PowerPC processor to Intel thus obsoleting millions of systems in businesses and schools.
- SONET OC768 40 Gbit/sec optical fiber.
- January: HTML5 was published as a Working Draft by the W3C.
- October 23: AT&T announced the completion of upgrades to OC-768 on 80,000 fiber-optic wave-length miles of their IP/MPLS (Multiprotocol Label Switching) backbone network.
- IPv6 deployment starts (Summer Olympic Games via IPv6). Work on IPv6 started in the late 1990s when it became clear the IPv4's 4 billion addresses were not going to be enough.
- 2010 Internet traffic breaks 21 exabytes per month.
- December: W3C designated HTML5 as a Candidate Recommendation.
- NEC Corp. broke an ultra long-haul Internet speed record when it successfully transmitted data at 1.15 terabits/sec over 6,213 miles.
- IPv4 exhaustion imminent (4 billion addresses).
- 2013 The National Security Agency (NSA) is revealed to have secretly collected exabytes (1x1018 or 100,000 terabyte disk drives) worth of US and foreign citizens' data.
- 2014 The W3C (World Wide Web Consortium) plans to finalize the HTML 5 standard by July.
- 2016 It is estimated that Internet traffic will reach 1.3 zettabytes per year. About 3.4 billion Internet users.
- 2017 Cisco Systems estimates that by 2020 Internet traffic will reach 2.3 ZB per year.
Transmition Speed Timeline
- Mid-1960: Early ARPANET 1200-2400 bits/sec
- 1970's: ARPANET 50 Kbits/sec.
- Mid-1980's: LAN (Local Area Network: Ethernet, Token Ring) 10 Mbits/sec.
WAN (Wide Area Network: modems, T-1) 300-2400 bits/sec to 1.5 Mbits/sec.
- 1990's: WAN (T-1, ADSL, T-3, ATM) 1.5 Mbits/sec to 145 Mbits/sec. ADSL: downstream: 200-400 Mbits/sec, upstream: 384 Kbits/sec to 20 Mbits/sec.
- 2000's: WAN (SONET-OC-192) 10 Gbits/sec.
- 201x: WAN (SONET-OC-768) 40 Gbits/sec.
In 2000 there were just under 150 million dial-up subscriptions in the 34 OECD (Organization for Economic Co-operation and Development) countries and fewer than 20 million broadband subscriptions.
By 2004, broadband had grown and dial-up had declined so the number of subscriptions were roughly equal at 130 million each.
In 2010, in the OECD countries, over 90% of the Internet access subscriptions used broadband, which had grown to more than 300 million subscriptions, and dial-up subscriptions had declined to fewer than 30 million.
Making the Connections
The ARPANET, predecessor to the Internet, started with an inspiring vision of a "galactic" network, practical theory about packet switching, and a suite of standardized protocols. But none of this would have mattered if there hadn't also been a way to make and maintain connections.
In 1966-67 Lincoln Labs in Lexington, Massachusetts, and SDR in Santa Monica, California, got a grant from the DOD to begin research on linking computers across the continent. Larry Roberts, describing this work, explains:
"Convinced that it was a worthwhile goal, we set up a test network to see where the problems would be. Since computer time-sharing experiments at MIT and Dartmouth had demonstrated that it was possible to link different computer users to a single computer, the cross-country experiment built on this advance."
(i.e. Once timesharing was possible, the linking of remote computers was also possible.) Roberts reports that there was no trouble linking dissimilar computers. The problems, he claims, were with the telephone lines across the continent, i.e. that the throughput was inadequate to accomplish their goals.
The first ARPANET link was established between the University of California, Los Angeles (UCLA) and the Stanford Research Institute at 22:30 hours on October 29, 1969
Packet switching resolved many of the issues identified during the pre-ARPANET, time-sharing experiments. But higher-speed phone circuits also helped. The first wide area network (WAN) demonstrated in 1965 among computers at MIT's Lincoln Lab, ARPA's facilities, and the System Development Corporation in California utilized dedicated 1200 bps circuits. Four years later, when the ARPANET began operating, 50 Kbps circuits were used. But it wasn't until 1984 that ARPANET traffic levels were such that it became more cost effective to lease T1 lines (1.5 Mbps) than to continue using multiple 50 Kbps lines.
In the late 1960s and early 1970s, there were a number of separate nascent networks developed by states, universities and governments: NPL, Merit Network, CYCLADES, X.25. The problem with all those different networks was that they all "spoke" different languages/protocols, thus internet-working was difficult if not impossible.
In 1973 Vinton Cerf, the developer of the existing ARPANET Network Control Program (NCP) protocol, joined Robert E. Kahn to work on open-architecture interconnection models with the goal of designing the next protocol generation for the ARPANET. This was TCP/IP.
By the summer of 1973 Kahn and Cerf had worked out a fundamental reformulation in which the differences between network protocols were hidden by using a common internetwork protocol, and instead of the network being responsible for reliability, as in the ARPANET, the hosts became responsible. Cerf credits Hubert Zimmermann and Louis Pouzin, designer of the CYCLADES network, with important influences on this design.
Circuit Switching vs. Packet Switching:
Circuit switching is a method which sets up a limited number of dedicated connections of constant bit rate and constant delay between nodes for exclusive use during the communication session. It is a methodology of implementing a telecommunications network in which two network nodes establish a dedicated communications channel (circuit) through the network before the nodes may communicate. The circuit guarantees the full bandwidth of the channel and remains connected for the duration of the communication session. The circuit functions as if the nodes were physically connected as with an electrical circuit.
Packet switching divides the data to be transmitted into packets transmitted through the network independently. In packet switching, instead of being dedicated to one communication session at a time, network links are shared by packets from multiple competing communication sessions, resulting in the loss of the quality of service guarantees that are provided by circuit switching.
Packet switching also imposes overhead burdens because each packet must have information that delimits the packet. In TCP/IP the IP header comes first and is used to direct the packets from the source to the destination and identify the type of service being provided. The IP header is like a letter's envelope which contains an address and a return address. The TCP header comes after the IP header and contains information about the transmission including endpoint ports, sequencing information and the data. The data may (and usually does) have other headers that describe the specific service, for example HTTP, IMAP, POP3, FTP etc.
When a webpage is transmitted from the server to the client, there are usually many TCP/IP packets of data involved. Those packets that represent the webpage may take different routes to get to the final destination and may in fact arrive at the destination out of order. It is the information in the TCP header that allows the client (destination) to reassemble the webpage from the many packets correctly.
A good analogy is the Post Office. If we were going to send a large manuscript in chapters as they were completed, we would put the manuscript chapters into envelopes and address the envelopes with the destination address and the return address. We would also include information in the envelope describing the sequence of the chapters. The envelope is the IP header and the information inside the envelope is the TCP header and data. We need the TCP type of information in the envelope because as we all know, letters can be received out of sequence and therefore we need some information to let us know how to reassemble the manuscript.
Bits Bytes Binary Hex
Modern Digital Computers think in binary: ones and zeros. We have used the phrase "bits per second" or bps a lot in this history. In communication a bit is generally thought of as a one or a zero. Depending on the encoding scheme used in the communication stream, eight bits may represent a character or byte. I say may because different encoding schemes can use more than eight bits in order to cope with transmission phenomenons. So when we say that an early teletype ran at a rate of 75 bits per second (bps) that means that it typed about nine characters a second.
A byte is eight binary digits. For example, the number seven decimal in binary is 0111. The decimal number fifteen (15) is 1111 in binary. The decimal number sixteen is 0001,0000 in binary and takes up two bytes while fifteen takes only one byte. As I said in the previous paragraph, we usually think of a byte as being eight bits.
So what is HEX? HEX stands for hexadecimal which is a number system with a base of sixteen. The first sixteen hexadecimal numbers are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F. The number sixteen decimal is 10 HEX. Computer engineers use HEX because it works well with binary. For example, the number 47 decimal is 0010,1111 binary and 2F HEX. Binary is powers of two so the binary two bytes shown are (128)(64)(32)(16),(8)(4)(2)(1). 0010,1111 is then 32+8+4+2+1 or 47 decimal. Do you see the relation between binary and HEX? The HEX number 2F represents two bytes in binary 0010 (2) and 1111 (F). Each HEX digit is a byte. As you can see binary converts easily into HEX but not easily into decimal. Other number bases that have been popular are base 8 (octal) and base 12 (duodecimal) to a much lesser extent.
From Tim Berners-Lee's first message (web page):
"The World Wide Web (WWW) project aims to allow all links to be made to any information anywhere. [...] The WWW project was started to allow high energy physicists to share data, news, and documentation. We are very interested in spreading the web to other areas, and having gateway servers for other data. Collaborators welcome!"
|6502 CPU||KIM 1||Apple I|
|8080 CPU||S100 Board||IMSAI 8080|