Rest easy, people of Earth: The United States’ nuclear arsenal will no longer rely on a computer system that uses 8-inch floppy disks, in an update that the Defense Department has cast as a step into the future but which some observers might be surprised to learn was required at all.

The system, called Strategic Automated Command and Control System, or SACCS, “is still in use today but no longer uses floppy disks,” David Faggard, a spokesman for the Air Force Global Strike Command, which manages the Air Force portion of the arsenal, said in an e-mail. “Air Force Global Strike Command is committed to modernizing for the future.”

The update is part of a broader overhaul of U.S. atomic weapons that began under President Barack Obama and has continued under President Donald Trump. The move away from floppy disks was completed in June but was not widely reported at the time. It was reported last week by C4ISRNET, a website that covers military technology.

“The Air Force completed a replacement of the aging SACCS floppy drives with a highly secure solid-state digital storage solution in June,” Justin Oakes, a spokesman for the Eighth Air Force, said in an e-mail. “This replacement effort exponentially increased message storage capacity and operator response times for critical nuclear command and control message receipt and processing.”

The role of floppy disks in the command and control operations of the nation’s nuclear arsenal was highlighted in a 2016 report from the U.S. Government Accountability Office. It said the disks were used in a system that “coordinates the operational functions of the nation’s nuclear forces.”

The report said that the Strategic Automated Command and Control System ran on an IBM Series/1 computer — a piece of hardware that dates to the 1970s — and used 8-inch floppy disks to manage weapons like intercontinental ballistic missiles, nuclear bombers and tanker support aircraft.

The report warned that the Pentagon was one of several government agencies whose computer systems relied on “outdated software languages and hardware parts that are unsupported,” some of which were “at least 50 years old.”

It also cited aging or obsolete systems at the Treasury Department, the Justice Department, the Social Security Administration and the Department of Veterans Affairs.

But a “60 Minutes” report from 2014 pointed out a perhaps unexpected upside of relying on such old technology. Because the systems are not connected to the internet, they are exceptionally secure: Hackers can’t break into a floppy disk.

In a nod to the fact that some readers, even of dry government reports, may not know what a floppy disk is, the Government Accountability Office provided a photograph of two disks along with a description. “Introduced in the 1970s, the 8-inch floppy disk is a disk-based storage medium that holds 80 KB of data,” it said. “In comparison, a single modern flash drive can contain data from the equivalent of more than 3.2 million floppy disks.”

Tom Persky, who inventories and sells floppy disks at what may be one of the largest such companies left, FloppyDisk.com, said the disks are more widely used than one might expect, especially in industrial machines, aircraft, medical devices and complex hardware systems like those used by the world’s militaries. He said he thought it had been roughly five years since anyone had manufactured a new disk.

“A big industrial machine that is designed to last 30, 40 or 50 years and in fact does last 30, 40 or 50 years — do you throw it away because there is a new way to get information onto the machine?” he said.

Noting the advantages, he said, “We have an old technology that is not easily hackable, that is not expensive, that is extremely well understood, it is extremely stable, and as long as the bits of information you are trying to get into a machine are small, a floppy disk is a perfectly good and OK thing to use.”