A Brief History of UNIX
In 1969, development of a new operating system began at AT&T Bell Labs. It was called UNIX. UNIX was written in the CLanguage, with the exception of the kernel, which was written in AssemblyLanguage.
AT&T distributed UNIX to various organizations, including the University of California, Berkeley. Scientists there greatly modified UNIX and released their own distribution of UNIX called BSD (Berkley Software Design/Distribution). One of the additions was the TCP/IP protocol, which allowed networking capabilities.
Bell Labs also continued to modify their version of UNIX and finally released UNIX Version 7. After this, Bell Labs' version of UNIX became known as System I and, later, the final release as System V Release 4.
Between 1969 and present day, there have been a vast number of distributions, versions, and variations of UNIX, including IrixOs, XenixOs, GnuOs and LinuxOs (two names for the same thing, depending on whom you ask), AixOs, HpUxOs and many others. Today, the main UNIX variants are GnuOs/LinuxOs, BsdOs derivatives, and SolarisOs.