EDS operated in 66 countries, with the largest numbers of employees in the cities of Detroit, Michigan, USA; Dallas-Fort Worth, Texas, USA; São Paulo, Brazil; Washington, D.C., USA; Toronto, Ontario, Canada; Rome and Milan, Italy; Paris, France; Adelaide, Australia; Philadelphia, Pennsylvania, USA; Sydney, Australia; Blackpool, UK; Sacramento, California, USA; Tyneside, UK; Madrid and Barcelona, Spain, Antwerp, Belgium and Frankfurt, Germany. Other major facilities were in Argentina, Australia, Belgium, Brazil, Canada, Egypt, Germany, Hungary, India, Dublin, Ireland, Israel, Italy, Mexico, Netherlands, New Zealand, South Africa, Spain and the United Kingdom.
EDS's Plano, Texas campus is located about 20 miles (30 km) north of downtown Dallas. The campus consists of 3,521,000 square feet (327,000 m²) of office and data center space on 270 acres (1.1 km²) of land. The campus included four Tier-IV data centers, a command center, four clusters of office buildings, a fitness center, a service station, four helipads and a hangar. It is the center of the 2,665 acre (11 km²) Legacy in Plano real estate development, which EDS built.
EDS established a number of Business alliances with other companies through its global alliance program. The company has three types of alliances: Agility Alliances, Solution Alliances, and Technology Alliances.
The EDS Agility Alliance has worked on a range of projects, notably its Agile Enterprise. Members of the EDS Agility Alliance include Cisco Systems, EMC Corporation, Cisco Systems, EMC Corporation, Microsoft, Oracle Corporation, SAP, Sun Microsystems, Symantec, and Xerox.
Most of EDS's clients were very large companies and governments that need services from a company of EDS's scale. EDS's largest clients included Rolls-Royce plc, General Motors, Bank of America, Arcandor, Kraft, United States Navy, the UK Ministry of Defence and Royal Dutch Shell although General Motors announced plans to move 90% of its IT work back in house over the next 3 to 5 years starting in 2012.
EDS formed the National Heritage Insurance Company in 1996. The creation of this subsidiary is to manage Medicare Part B services on behalf of the Medicare Part B services on behalf of the Centers for Medicare and Medicaid Services (CMS), formerly the Health Care Financing Administration (HCFA). NHIC handles call center, claims processing and payment, fraud investigations, physician enrollment etc. in many states of the US.
Another large EDS client is the United States Navy. In 2000, they won a contract for the creation of a US$9 billion Intranet linking the Navy and the Marine Corps, which was set to late 2006, but on March 24, 2006, was extended to 2010, adding $3 billion to the accumulated contract worth. This initiative is known as the Navy Marine Corps Intranet, or simply NMCI. In 2004, NMCI accounted for about 4% of EDS's revenue. NMCI has been called the largest private network in the world, with approximately 400,000 "seats". EDS provided the network, desktops, laptops, servers, telephones, video-conferencing, satellite transceivers, and overall management of the intranet.
Following on to the NMCI type of services, EDS in March 2005 won a US$4 billion contract with the UK Ministry of Defence to "consolidate numerous existing information networks into a single next-generation infrastructure ... The network will provide seamless interaction between headquarters, battlefield support and the front line, linking about 150,000 desktop terminals and 340,000 users in approximately 2,000 locations ..."
In February 2008 EDS signed a US$1.3 billion contract with the Infocomm Development Authority of Singapore, one of the largest IT projects ever undertaken in Asia. This agreement will help the Singapore government achieve a standard desktop, network and messaging/collaboration environment across its public sector by the end of fiscal year 2010.
In October 2008, the U.S. Defense Information Systems Agency (DISA) signed a US$111 million contract with EDS. Under this contract, EDS will: conduct worldwide security reviews, deliver certification and accreditation support, provide independent evaluation of United States Department of Defense security policies, and conduct security assessments on DOD operating systems, applications, databases, and networks. DOD and EDS have had a 13-year relationship of providing DISA with a wide range of infrastructure services, hardware and software through the DISA I-Assure and Encore contract vehicles.
Of historical significance, just prior to the overthrow of the Shah of Iran, EDS was the IT company that developed the Iranian social security information system. During the 1979 overthrow, several EDS employees were detained by the transitioning government of Iran, causing H. Ross Perot to undertake extraordinary clandestine measures to get these employees out of Iran. These events were recounted in Ken Follett's book On Wings of Eagles.