Oversimplified History of Computing
A mathematical statement can be illustrated with actual numbers, the numbers can be communicated and a community can arise. This allows the repeatable, verifiable statements which are the hallmark of mathematics and science. These kinds of statements have existed for thousands of years, and across multiple civilizations.
The earliest known tool for use in computation is the Sumerian abacus, and it was thought to have been invented in Babylon 2700–2300 BC. As early as 771 BC the south-pointing chariot was invented in China, the first known mechanism using a differential gear. In the 5th century BC in ancient India, the grammarian Pāṇini formulated the grammar of Sanskrit in 3959 rules known as the Ashtadhyayi which was highly systematized and technical. Panini used metarules, transformations and recursions. In the 3rd century BC, Archimedes used the mechanical principle of balance to calculate mathematical problems, such as the number of grains of sand in the universe (The sand reckoner), which also required a recursive notation for numbers (e.g., myriad mean).
The Antikythera mechanism is believed to be the earliest known mechanical analog computer. It was designed to calculate astronomical positions. It was discovered in 1901 in the Antikythera wreck off the Greek island of Antikythera, between Kythera and Crete, and has been dated to circa 100 BC.
John Napier discovered logarithms for computational purposes in the early 17th century, which led to Charles Babbage creating the “Difference Engine”, and the concept of the “Analytical Engine”, which was then taken by Ada Lovelace and turned into a program to calculate Bernoulli numbers which in essence was the first modern example of a series of instructions acting upon data which was dynamically set at runtime. Percy Ludgate then did this again but was unaware, wasnt even formally trained as a scientist or anything he was just dicking around at night was an accountant during the day.
Microprocessors & Personal Computers
A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circuitry required to perform the functions of a computer’s central processing unit. The integrated circuit is capable of interpreting and executing program instructions and performing arithmetic operations.
The microprocessor is a multipurpose, clock-driven, register-based, digital integrated circuit that accepts binary data as input, processes it according to instructions stored in its memory, and provides results (also in binary form) as output. Microprocessors contain both combinational logic and sequential digital logic, and operate on numbers and symbols represented in the binary number system.
Before microprocessors, computers had to be build using racks of circuit boards with a lot of integrated circuits, which were typically based on Transistor-Transistor Logic, meaning the transistors perform both the logic and the amplification, using one transistor for each purpose. The alternative options include but are not limited to Resistor-Transistor Logic, or Diode-Transistor Logic.
MOSFET
The metal–oxide–silicon field-effect transistor (MOSFET), also known as the MOS transistor, was invented by Mohamed Atalla and Dawon Kahng at Bell Labs in 1959. It was the first truly compact transistor that could be miniaturised and mass-produced for a wide range of uses.
The Silicon Gate Technology was the world’s first commercial MOS self-aligned-gate process technology. Before this technology, the control gate of the MOS transistor was made with aluminum instead of polycrystalline silicon. Aluminum-gate MOS transistors were three to four times slower, consumed twice as much silicon area, had higher leakage current and lower reliability compared with silicon-gate transistors. Faggin created the silicon gate technology in 1968 while working in the R&D Laboratories of Fairchild Semiconductor in Palo Alto, CA. He also designed and built the world’s first commercial integrated circuit using the silicon gate technology: the Fairchild 3708 - an 8-bit analog multiplexer with decoding logic. The first 3708 was fabricated in July 1968 and demonstrated a substantially improved performance over its metal-gate counterpart (called the 3705) and became commercially available in October 1968.
In 1968, almost all the integrated circuits sold used bipolar transistors. Bipolar transistors were about 100 times faster than MOS transistors but consumed much more power, required more silicon area, and used a much more complicated and costly manufacturing process. MOS technology was considered by most practitioners of the time promising but inadequate, with little chance of supplanting the bipolar technology. With the advent of the silicon gate technology, however, MOS technology, in less than 10 years, replaced bipolar technology as the vehicle of choice for complex integrated circuits.
This led to the development of the first single-chip microprocessor, the Intel 4004. The Intel 4004 was developed as a single-chip microprocessor from 1969 to 1970, led by Intel’s Federico Faggin, Marcian Hoff, and Stanley Mazor, and Busicom’s Masatoshi Shima. The chip was mainly designed and realized by Faggin, with his silicon-gate MOS technology. The microprocessor led to the microcomputer revolution, with the development of the microcomputer, which would later be called the personal computer. At this point early microprocessors, such as the Intel 8008 and Intel 8080, were 8-bit. Texas Instruments released the first fully 16-bit microprocessor, the TMS9900 processor, in June 1976.
Internet & The Next Evolutions
The first recorded description of the social interactions that could be enabled through networking was a series of memos written by J.C.R. Licklider of MIT in August 1962 discussing his “Galactic Network” concept. He envisioned a globally interconnected set of computers through which everyone could quickly access data and programs from any site. In spirit, the concept was very much like the Internet of today. Licklider was the first head of the computer research program at DARPA, starting in October 1962. While at DARPA he convinced his successors at DARPA, Ivan Sutherland, Bob Taylor, and MIT researcher Lawrence G. Roberts, of the importance of this networking concept. Leonard Kleinrock at MIT published the first paper on packet switching theory in July 1961 and the first book on the subject in 1964. Kleinrock convinced Roberts of the theoretical feasibility of communications using packets rather than circuits, which was a major step along the path towards computer networking. The other key step was to make the computers talk together. To explore this, in 1965 working with Thomas Merrill, Roberts connected the TX-2 computer in Mass. to the Q-32 in California with a low speed dial-up telephone line creating the first (however small) wide-area computer network ever built. The result of this experiment was the realization that the time-shared computers could work well together, running programs and retrieving data as necessary on the remote machine, but that the circuit switched telephone system was totally inadequate for the job. Kleinrock’s conviction of the need for packet switching was confirmed.
ARPANET
In late 1966 Roberts went to DARPA to develop the computer network concept and quickly put together his plan for the “ARPANET”, publishing it in 1967. At the conference where he presented the paper, there was also a paper on a packet network concept from the UK by Donald Davies and Roger Scantlebury of NPL. Scantlebury told Roberts about the NPL work as well as that of Paul Baran and others at RAND. The RAND group had written a paper on packet switching networks for secure voice in the military in 1964. It happened that the work at MIT (1961-1967), at RAND (1962-1965), and at NPL (1964-1967) had all proceeded in parallel without any of the researchers knowing about the other work. The word “packet” was adopted from the work at NPL and the proposed line speed to be used in the ARPANET design was upgraded from 2.4 kbps to 50 kbps.
In August 1968, after Roberts and the DARPA funded community had refined the overall structure and specifications for the ARPANET, an RFQ was released by DARPA for the development of one of the key components, the packet switches called Interface Message Processors (IMP’s). The RFQ was won in December 1968 by a group headed by Frank Heart at Bolt Beranek and Newman (BBN). As the BBN team worked on the IMP’s with Bob Kahn playing a major role in the overall ARPANET architectural design, the network topology and economics were designed and optimized by Roberts working with Howard Frank and his team at Network Analysis Corporation, and the network measurement system was prepared by Kleinrock’s team at UCLA.
Due to Kleinrock’s early development of packet switching theory and his focus on analysis, design and measurement, his Network Measurement Center at UCLA was selected to be the first node on the ARPANET. All this came together in September 1969 when BBN installed the first IMP at UCLA and the first host computer was connected. Doug Engelbart’s project on “Augmentation of Human Intellect” (which included NLS, an early hypertext system) at Stanford Research Institute (SRI) provided a second node. SRI supported the Network Information Center, led by Elizabeth (Jake) Feinler and including functions such as maintaining tables of host name to address mapping as well as a directory of the RFC’s.
One month later, when SRI was connected to the ARPANET, the first host-to-host message was sent from Kleinrock’s laboratory to SRI. Two more nodes were added at UC Santa Barbara and University of Utah. These last two nodes incorporated application visualization projects, with Glen Culler and Burton Fried at UCSB investigating methods for display of mathematical functions using storage displays to deal with the problem of refresh over the net, and Robert Taylor and Ivan Sutherland at Utah investigating methods of 3-D representations over the net. Thus, by the end of 1969, four host computers were connected together into the initial ARPANET, and the budding Internet was off the ground. Even at this early stage, it should be noted that the networking research incorporated both work on the underlying network and work on how to utilize the network. This tradition continues to this day.
Computers were added quickly to the ARPANET during the following years, and work proceeded on completing a functionally complete Host-to-Host protocol and other network software. In December 1970 the Network Working Group (NWG) working under S. Crocker finished the initial ARPANET Host-to-Host protocol, called the Network Control Protocol (NCP). As the ARPANET sites completed implementing NCP during the period 1971-1972, the network users finally could begin to develop applications.
In October 1972, Kahn organized a large, very successful demonstration of the ARPANET at the International Computer Communication Conference (ICCC). This was the first public demonstration of this new network technology to the public. It was also in 1972 that the initial “hot” application, electronic mail, was introduced. In March Ray Tomlinson at BBN wrote the basic email message send and read software, motivated by the need of the ARPANET developers for an easy coordination mechanism. In July, Roberts expanded its utility by writing the first email utility program to list, selectively read, file, forward, and respond to messages. From there email took off as the largest network application for over a decade. This was a harbinger of the kind of activity we see on the World Wide Web today, namely, the enormous growth of all kinds of “people-to-people” traffic.
The original ARPANET was based on the idea that there would be multiple independent networks of rather arbitrary design, beginning with the ARPANET as the pioneering packet switching network, but soon to include packet satellite networks, ground-based packet radio networks and other networks. The Internet as we now know it embodies a key underlying technical idea, namely that of open architecture networking. In this approach, the choice of any individual network technology was not dictated by a particular network architecture but rather could be selected freely by a provider and made to interwork with the other networks through a meta-level “Internetworking Architecture”. Up until that time there was only one general method for federating networks. This was the traditional circuit switching method where networks would interconnect at the circuit level, passing individual bits on a synchronous basis along a portion of an end-to-end circuit between a pair of end locations. Recall that Kleinrock had shown in 1961 that packet switching was a more efficient switching method. Along with packet switching, special purpose interconnection arrangements between networks were another possibility. While there were other limited ways to interconnect different networks, they required that one be used as a component of the other, rather than acting as a peer of the other in offering end-to-end service.
TCP Standardization
In an open-architecture network, the individual networks may be separately designed and developed and each may have its own unique interface which it may offer to users and/or other providers. including other Internet providers. Each network can be designed in accordance with the specific environment and user requirements of that network. There are generally no constraints on the types of network that can be included or on their geographic scope, although certain pragmatic considerations will dictate what makes sense to offer.
The idea of open-architecture networking was first introduced by Kahn shortly after having arrived at DARPA in 1972. This work was originally part of the packet radio program, but subsequently became a separate program in its own right. At the time, the program was called “Internetting”. Key to making the packet radio system work was a reliable end-end protocol that could maintain effective communication in the face of jamming and other radio interference, or withstand intermittent blackout such as caused by being in a tunnel or blocked by the local terrain. Kahn first contemplated developing a protocol local only to the packet radio network, since that would avoid having to deal with the multitude of different operating systems, and continuing to use NCP.
However, NCP did not have the ability to address networks (and machines) further downstream than a destination IMP on the ARPANET and thus some change to NCP would also be required. (The assumption was that the ARPANET was not changeable in this regard). NCP relied on ARPANET to provide end-to-end reliability. If any packets were lost, the protocol (and presumably any applications it supported) would come to a grinding halt. In this model NCP had no end-end host error control, since the ARPANET was to be the only network in existence and it would be so reliable that no error control would be required on the part of the hosts. Thus, Kahn decided to develop a new version of the protocol which could meet the needs of an open-architecture network environment. This protocol would eventually be called the Transmission Control Protocol/Internet Protocol (TCP/IP). While NCP tended to act like a device driver, the new protocol would be more like a communications protocol.
Four ground rules were critical to Kahn’s early thinking:
- Each distinct network would have to stand on its own and no internal changes could be required to any such network to connect it to the Internet.
- Communications would be on a best effort basis. If a packet didn’t make it to the final destination, it would shortly be retransmitted from the source.
- Black boxes would be used to connect the networks; these would later be called gateways and routers. There would be no information retained by the gateways about the individual flows of packets passing through them, thereby keeping them simple and avoiding complicated adaptation and recovery from various failure modes.
- There would be no global control at the operations level.
Kahn began work on a communications-oriented set of operating system principles while at BBN and documented some of his early thoughts in an internal BBN memorandum entitled “Communications Principles for Operating Systems“. At this point he realized it would be necessary to learn the implementation details of each operating system to have a chance to embed any new protocols in an efficient way. Thus, in the spring of 1973, after starting the internetting effort, he asked Vint Cerf (then at Stanford) to work with him on the detailed design of the protocol. Cerf had been intimately involved in the original NCP design and development and already had the knowledge about interfacing to existing operating systems. So armed with Kahn’s architectural approach to the communications side and with Cerf’s NCP experience, they teamed up to spell out the details of what became TCP/IP.
The give and take was highly productive and the first written version of the resulting approach was distributed as INWG#39 at a special meeting of the International Network Working Group (INWG) at Sussex University in September 1973. Subsequently a refined version was published in 19747. The INWG was created at the October 1972 International Computer Communications Conference organized by Bob Kahn, et al, and Cerf was invited to chair this group.
Some basic approaches emerged from this collaboration between Kahn and Cerf:
- Communication between two processes would logically consist of a very long stream of bytes (they called them octets). The position of any octet in the stream would be used to identify it.
- Flow control would be done by using sliding windows and acknowledgments (acks). The destination could select when to acknowledge and each ack returned would be cumulative for all packets received to that point.
- It was left open as to exactly how the source and destination would agree on the parameters of the windowing to be used. Defaults were used initially.
- Although Ethernet was under development at Xerox PARC at that time, the proliferation of LANs were not envisioned at the time, much less PCs and workstations. The original model was national level networks like ARPANET of which only a relatively small number were expected to exist. Thus a 32 bit IP address was used of which the first 8 bits signified the network and the remaining 24 bits designated the host on that network. This assumption, that 256 networks would be sufficient for the foreseeable future, was clearly in need of reconsideration when LANs began to appear in the late 1970s.
The original Cerf/Kahn paper on the Internet described one protocol, called TCP, which provided all the transport and forwarding services in the Internet. Kahn had intended that the TCP protocol support a range of transport services, from the totally reliable sequenced delivery of data (virtual circuit model) to a datagram service in which the application made direct use of the underlying network service, which might imply occasional lost, corrupted or reordered packets. However, the initial effort to implement TCP resulted in a version that only allowed for virtual circuits. This model worked fine for file transfer and remote login applications, but some of the early work on advanced network applications, in particular packet voice in the 1970s, made clear that in some cases packet losses should not be corrected by TCP, but should be left to the application to deal with. This led to a reorganization of the original TCP into two protocols, the simple IP which provided only for addressing and forwarding of individual packets, and the separate TCP, which was concerned with service features such as flow control and recovery from lost packets. For those applications that did not want the services of TCP, an alternative called the User Datagram Protocol (UDP) was added in order to provide direct access to the basic service of IP.
A major initial motivation for both the ARPANET and the Internet was resource sharing – for example allowing users on the packet radio networks to access the time sharing systems attached to the ARPANET. Connecting the two together was far more economical that duplicating these very expensive computers. However, while file transfer and remote login (Telnet) were very important applications, electronic mail has probably had the most significant impact of the innovations from that era. Email provided a new model of how people could communicate with each other, and changed the nature of collaboration, first in the building of the Internet itself (as is discussed below) and later for much of society.
There were other applications proposed in the early days of the Internet, including packet based voice communication (the precursor of Internet telephony), various models of file and disk sharing, and early “worm” programs that showed the concept of agents (and, of course, viruses). A key concept of the Internet is that it was not designed for just one application, but as a general infrastructure on which new applications could be conceived, as illustrated later by the emergence of the World Wide Web. It is the general purpose nature of the service provided by TCP and IP that makes this possible.
TCP/IP was adopted as a defense standard three years earlier in 1980. This enabled defense to begin sharing in the DARPA Internet technology base and led directly to the eventual partitioning of the military and non- military communities. By 1983, ARPANET was being used by a significant number of defense R&D and operational organizations. The transition of ARPANET from NCP to TCP/IP permitted it to be split into a MILNET supporting operational requirements and an ARPANET supporting research needs.
By 1985, Internet was already well established as a technology supporting a broad community of researchers and developers, and was beginning to be used by other communities for daily computer communications. Electronic mail was being used broadly across several communities, often with different systems, but interconnection between different mail systems was demonstrating the utility of broad based electronic communications between people.
Getting to Scale
At the same time that the Internet technology was being experimentally validated and widely used amongst a subset of computer science researchers, other networks and networking technologies were being pursued. The usefulness of computer networking – especially electronic mail – demonstrated by DARPA and Department of Defense contractors on the ARPANET was not lost on other communities and disciplines, so that by the mid-1970s computer networks had begun to spring up wherever funding could be found for the purpose. The U.S. Department of Energy (DoE) established MFENet for its researchers in Magnetic Fusion Energy, whereupon DoE’s High Energy Physicists responded by building HEPNet. NASA Space Physicists followed with SPAN, and Rick Adrion, David Farber, and Larry Landweber established CSNET for the (academic and industrial) Computer Science community with an initial grant from the U.S. National Science Foundation (NSF). AT&T’s free-wheeling dissemination of the UNIX computer operating system spawned USENET, based on UNIX’ built-in UUCP communication protocols, and in 1981 Ira Fuchs and Greydon Freeman devised BITNET, which linked academic mainframe computers in an “email as card images” paradigm.
With the exception of BITNET and USENET, these early networks (including ARPANET) were purpose-built – i.e., they were intended for, and largely restricted to, closed communities of scholars; there was hence little pressure for the individual networks to be compatible and, indeed, they largely they weren’t. In addition, alternate technologies were being pursued in the commercial sector, including XNS from Xerox, DECNet, and IBM’s SNA.8 It remained for the British JANET (1984) and U.S. NSFNET (1985) programs to explicitly announce their intent to serve the entire higher education community, regardless of discipline.
In 1985, Dennis Jennings came from Ireland to spend a year at NSF leading the NSFNET program. He worked with the community to help NSF make a critical decision – that TCP/IP would be mandatory for the NSFNET program. When Steve Wolff took over the NSFNET program in 1986, he recognized the need for a wide area networking infrastructure to support the general academic and research community, along with the need to develop a strategy for establishing such infrastructure on a basis ultimately independent of direct federal funding.
NSF also elected to support DARPA’s existing Internet organizational infrastructure, hierarchically arranged under the (then) Internet Activities Board (IAB). The public declaration of this choice was the joint authorship by the IAB’s Internet Engineering and Architecture Task Forces and by NSF’s Network Technical Advisory Group of RFC 985 (Requirements for Internet Gateways ), which formally ensured interoperability of DARPA’s and NSF’s pieces of the Internet.
In addition to the selection of TCP/IP for the NSFNET program, Federal agencies made and implemented several other policy decisions which shaped the Internet of today.
Federal agencies shared the cost of common infrastructure, such as trans-oceanic circuits. They also jointly supported “managed interconnection points” for interagency traffic; the Federal Internet Exchanges (FIX-E and FIX-W) built for this purpose served as models for the Network Access Points and “*IX” facilities that are prominent features of today’s Internet architecture.
To coordinate this sharing, the Federal Networking Council9 was formed. The FNC also cooperated with other international organizations, such as RARE in Europe, through the Coordinating Committee on Intercontinental Research Networking, CCIRN, to coordinate Internet support of the research community worldwide.
This sharing and cooperation between agencies on Internet-related issues had a long history. An unprecedented 1981 agreement between Farber, acting for CSNET and the NSF, and DARPA’s Kahn, permitted CSNET traffic to share ARPANET infrastructure on a statistical and no-metered-settlements basis. Subsequently, in a similar mode, the NSF encouraged its regional (initially academic) networks of the NSFNET to seek commercial, non-academic customers, expand their facilities to serve them, and exploit the resulting economies of scale to lower subscription costs for all.
On the NSFNET Backbone – the national-scale segment of the NSFNET – NSF enforced an “Acceptable Use Policy” (AUP) which prohibited Backbone usage for purposes “not in support of Research and Education.” The predictable (and intended) result of encouraging commercial network traffic at the local and regional level, while denying its access to national-scale transport, was to stimulate the emergence and/or growth of “private”, competitive, long-haul networks such as PSI, UUNET, ANS CO+RE, and (later) others. This process of privately-financed augmentation for commercial uses was thrashed out starting in 1988 in a series of NSF-initiated conferences at Harvard’s Kennedy School of Government on “The Commercialization and Privatization of the Internet” – and on the “com-priv” list on the net itself.
In 1988, a National Research Council committee, chaired by Kleinrock and with Kahn and Clark as members, produced a report commissioned by NSF titled “Towards a National Research Network”. This report was influential on then Senator Al Gore, and ushered in high speed networks that laid the networking foundation for the future internet.
In 1994, a National Research Council report, Entitled “Realizing The Information Future: The Internet and Beyond” was released, commissioned by NSF, in which a blueprint for the evolution of the “information superhighway” was articulated for the first time, and coined the meme phrase we know and love.
NSF’s privatization policy culminated in April, 1995, with the defunding of the NSFNET Backbone., which meant the funds recovered were (competitively) redistributed to regional networks to buy national-scale Internet connectivity from the now numerous, private, long-haul networks. So, essentially the opposite of the things we were just talking about like 2 seconds ago.
The backbone had made the transition from a network built from routers out of the research community (the “Fuzzball” routers from David Mills) to commercial equipment. In its 8 1/2 year lifetime, the Backbone had grown from six nodes with 56 kbps links to 21 nodes with multiple 45 Mbps links. It had seen the Internet grow to over 50,000 networks on all seven continents and outer space, with approximately 29,000 networks in the United States.
Such was the weight of the NSFNET program’s ecumenism and funding ($200 million from 1986 to 1995) – and the quality of the protocols themselves – that by 1990 when the ARPANET itself was finally decommissioned, TCP/IP had supplanted or marginalized most other wide-area computer network protocols worldwide.
