DARPA

satellite launch

You won’t believe it, but the creation of the Internet is connected with the first space satellite launched by the USSR in 1957. And this is not a conspiracy, but the official version of the emergence of the Internet. Here is how it was.

In 1957, the Soviet Union overtook the United States in launching the first satellite, which was a serious blow to the national prestige of the Americans. In response to the events, Congress declared that this should not happen again, and in 1958 the DARPA organization was created .

Defense Advanced Research Projects Agency , or DARPA - US Department of Defense Advanced Research Projects Agency. This organization was funded by the US Department of Defense, but did not conduct research on its own, but issued grants for projects of interest to them.

DARPA was tasked with keeping US military technology cutting edge. DARPA exists independently of conventional military research institutions and reports directly to the leadership of the Department of Defense.

DARPA employs only two hundred people, but its budget is several billion dollars. The organization funds several hundred research projects that may be useful to the US Department of Defense.

These numbers are approximate because DARPA focuses on short-term programs (two to four years) run by small, hand-picked groups of contracting companies.

Initially called ARPA, it was renamed DARPA (with the word Defense added) in 1972, then back to ARPA in 1993, and finally back to DARPA on March 11, 1996.

DARPA was responsible for funding the university's development of the ARPANET (from which the Internet later emerged), as well as Unix-BSD (the Berkeley UNIX system) and the TCP/IP protocol stack. The organization currently sponsors the development of robotic vehicles, among other things.

ARPANET

At the height of the Cold War, the United States wanted a network that could even survive a nuclear war. The telephone networks that existed then did not provide the necessary reliability and fault tolerance. With the loss of critical nodes, the telephone network disintegrated into independent fragments.

To oversee this problem, a special department was created in the ARPA organization, the Office of Information Processing Methods. And the very development of the network was entrusted to a group of four universities:

• University of California Los Angeles
• Stanford Research Center
• University of Utah
• UC Santa Barbara

The research part started in 1969. The equipment at that time was very primitive, so a large number of different elements had to be used to transfer data: hardware, services, programs, and the like ... It was necessary to standardize their interaction.

The military also wanted such a system to support the most advanced data transfer protocols out of the box: telnet and ftp.

As a result, scientists decided to break the data transfer logic into as many as 7 logical levels, each of which was built on top of the previous one. We will cover this in more detail in the next lecture.

The universities participating in its development were chosen as the first nodes of the ARPANET. Later, they were joined by other technological institutions and, finally, the military.

In just six months, the first working version was developed. The first test of the technology took place on October 29, 1969 at 21:00 . The network consisted of two terminals, which had to be as far apart as possible in order to test the system in maximum modes.

The first terminal was located at the University of California, and the second - at a distance of as much as 600 km from it, at Stanford University. The terminals used 16-bit Honeywell DDP-316 minicomputers with 12 KB of RAM. DS-0 digital subscriber lines with a capacity of 56 kbps were leased from the telephone company AT&T.

The experiment was to send the word login over the network. It didn't work the first time, something went wrong. But a few hours later the experiment was repeated, and it was successful: the recipient saw the word login on his monitor.

After a successful experiment, the network began to develop quantitatively and qualitatively. More and more universities began to connect to it, the software improved, the hardware was standardized. But the network was mostly used by scientists.

In 1973, European universities began to connect to the network - it became truly international. In 1977, there were as many as 111 computers (servers) on the network. And already in 1983, out of 4,000 computers that were located throughout the United States, satellite communications were established with Hawaii and Europe.

TCP/IP

With few exceptions, early computers were connected directly to terminals and used by individual users, usually in the same building or room. Such networks became known as local area networks ( LANs ). Networks that go beyond local, that is, wide area networks ( WANs ), emerged in the 1950s and were introduced in the 1960s.

Very often, local networks were developed by employees of technical universities and laboratories for their internal needs. They had their own (sometimes analog) data transfer protocols, and in most cases they were not compatible with each other.

However, in 1972, a protocol stack called TCP/IP was created by a group of developers led by Vinton Cerf. It was versatile and suitable for both the WAN and multiple LANs.

In July 1976, Vint Cerf and Bob Kahn demonstrated for the first time data transmission using TCP over three different networks. The package traveled along the following route: San Francisco - London - University of Southern California. By the end of its journey, the package had traveled 150,000 km without losing a single bit.

In 1978, Cerf, Jon Postel, and Danny Cohan decided to split the then-current TCP protocol into two distinct functions: TCP and IP (Internet Protocol).

TCP was responsible for breaking down the message into small packets, datagrams, and putting them together at the final destination. IP was responsible for transmitting individual datagrams with receive control.

This is how the modern Internet protocol was born. And on January 1, 1983, ARPANET switched to a new protocol. This day is considered to be the official date of birth of the Internet .

UNIX/BSD

Another brainchild of DARPA is the BSD-UNIX operating system. This is a whole family of operating systems that goes back to distributions of the University of Berkeley. It all started with the UNIX operating system.

In fact, UNIX was developed in the bowels of AT&T, the technological leader of its time. But after being recognized as a monopolist, they were banned from developing a commercial version of their operating system, UNIX.

UNIX was very good, and there were already many programs for it, so clones of UNIX began to appear en masse, built on the same principles and supporting work with its programs. Such operating systems are called Unix-like . These clones included:

• BSD Unix
• GNU/Linux
• macOS
• MINIX
• FreeBSD

The BSD family of operating systems includes: NetBSD, FreeBSD , OpenBSD , ClosedBSD, MirBSD, DragonFly BSD, PC-BSD, GhostBSD, DesktopBSD, SunOS, TrueBSD, Frenzy, Ultrix and partly XNU ( macOS kernel , iOS , tvOS , watchOS , CarPlay, Darwin).

Yes, yes, the MacOS and iOS operating system also have a BSD-UNIX operating system under the hood. These are the pies.

Wherever you dig, you will find UNIX:

• Android has Linux under the hood, based on UNIX
• iPhone running iOS based on FreeBSD
• MacBook running macOS based on FreeBSD
• Almost any server is Linux, and it has UNIX under the hood

Routers, smart refrigerators, SmartTVs - everything under the hood somehow has the good old UNIX.