"The US nuclear weapons force still uses a 1970s-era computer system and floppy disks, a government report has revealed.
The report said taxpayers spent $61bn (£41bn) a year on maintaining ageing technologies.
It said that was three times more than the investment on modern IT systems.
The report said that the Department of Defence systems that co-ordinated intercontinental ballistic missiles, nuclear bombers and tanker support aircraft "runs on an IBM Series-1 Computer - a 1970s computing system - and uses eight-inch floppy disks".
"This system remains in use because, in short, it still works," Pentagon spokeswoman Lt Col Valerie Henderson told the AFP news agency.
"However, to address obsolescence concerns, the floppy drives are scheduled to be replaced with secure digital devices by the end of 2017."
She added: "Modernisation across the entire Nuclear Command, Control, and Communications enterprise remains ongoing."
The report said that the Pentagon was planning to fully replace the system by the end of 2020.
According to the report, the US treasury also needed to upgrade its systems, which it said was using "assembly language code - a computer language initially used in the 1950s and typically tied to the hardware for which it was developed"."
Image above: "
Added: NOAA systems, pages 55, 56 of GAO report: NOAA's national and global climate data are used to make multi-trillion dollar bets.
"NWSTG still lacks full backup capability for 26 percent of its functions." This won't change until at least 2017: "According to officials, a detailed project plan to rearchitecture NWSTG is now being carried out and is scheduled to replace the NWSTG in early fiscal year 2017."
"The National Weather Service Telecommunication Gateway (NWSTG) system is operated by the National Oceanic and Atmospheric Administration, a component of the Department of Commerce. It is the nation’s hub for the collection and distribution of weather data and products and provides national and global real-time exchange services using automated communications resources to collect and distribute a wide variety of environmental data such as observations, analysis, and forecast products. Thousands of customers worldwide use data distributed by the NWSTG.
Concerns with the system had been increasing because the investment faced risks and challenges associated with an aging and unsupportable infrastructure, limited backup capability, and un-scalable architecture to support future data volume collection and dissemination.
In 2013, the agency upgraded its hardware and software to Power7 IBM servers and Unix operating systems (as depicted in the figure [below]); however, NWSTG still lacks full backup capability for 26 percent of its functions."
Above, NOAA IBM servers and UNIX operating systems, via GAO. p. 56 of report