What happens when computers and cellphones suddenly stop working?

It's a question the world faced again Friday amid a widespread tech glitch that sowed worldwide chaos as airlines, hospitals, banks and other businesses ceased to function − all blamed on a botched software update from a little-known tech vendor. (Earlier this year, cellphones suddenly stopped working across the U.S., causing widespread disruptions.)

Experts have answers − however unsatisfying they may be.

Get used to tech outages. There are more serious issues looming. There are a few things you can do to prepare.

"I think we're getting a preview with this," said Avi Rubin, a cybersecurity expert and professor emeritus at Johns Hopkins University. "I have no doubt that this is going to happen again. The systems we use are vulnerable to it."

Our lives are so dependent on technology, internet

How can one malfunction cause so much chaos? When an operating system is so widely used in systems all over the world, it can reach into practically every industry.

The glitch meant computer screens across several industries flashed the dreaded "blue screen of death," which appears on Windows systems when there's a serious problem, usually requiring a skilled fix, Rubin said. The screens were seen in airports, transit centers and even Disneyland in France.

In some places, computers at grocery store checkout lanes flashed blue, disrupting daily shopping. Rubin said another way the glitches have real-world consequences is in hospitals, many of which canceled non-emergency procedures. Hospitals rely on electronic systems to dispense and track inventory medications and other supplies. Without a working system, the hospital can't function optimally. In an extreme situation, someone could die, Rubin said.

Many industries have done away with redundancies or backups in case the main operating system goes down, Rubin said: "I've spoken with hospital administrators who told me that they no longer have a way of functioning without the internet."

"This is a very, very uncomfortable illustration of the fragility of the world’s core internet infrastructure," Ciaran Martin, professor at Oxford University's Blavatnik School of Government and former head of the U.K. National Cyber Security Centre, told Reuters.

Cellphone, network issues can keep happening

Though CrowdStrike said Friday's outage wasn't the result of a cyberattack, digital security experts say the U.S. is vulnerable to one.

"My first thought when I first heard about this was, 'Oh my God, if this is what can happen when there's a software bug that's kind of by accident, imagine what a well-thought-out, well-funded attack could do?" Rubin said. "Our systems can't even withstand an accidental software error."

This year, cyberattacks have already affected water utilities across the country and car dealerships.

Communications outages are the norm, not the exception, Alyssa Provencio, professor at the University of Central Oklahoma, told USA TODAY earlier this year during the AT&T outage. They often follow natural disasters such as wildfires or hurricanes, said Provencio, who oversees the school's disaster management certificate program. And outages can last for days, weeks or months in an extreme event, she said.

Last summer, devastating wildfires that swept through Maui, Hawaii, and killed more than 100 people also caused widespread chaos and confusion when cell signals went out and people had a hard time figuring out what to do.

How can people prepare for disasters that cause outages?

Because we are so dependent on the technology that makes up an everyday part of our lives, it's important to have backup plans in place.

Experts suggest these tips to weather an outage caused by a glitch, natural disaster or even a cyberattack:

• Cash. It's a good idea to have cash on hand in case you can't use mobile payment options or ATMs are down, James Kendra, co-director of the Disaster Research Center at the University of Delaware, told USA TODAY.
• Paper copies of important documents. “One of the things that I stress to everybody is to have paper copies of all of your important documents,” he said. That means a printed-out bank statement so you have all your account numbers, a printed insurance statement, a phone bill and mortgage or rent documents so you have the numbers available you might typically go online to get.
• Landline. If you don't have a landline in a cell network outage, you might still be able to use your cell to send SMS text messages or use Wi-Fi to send messages or make calls.
• A radio. This is always a good thing to have to receive emergency updates, Provencio said, but if you don't have one in your home, chances are you do have one in your car.
• Other supplies. Learn more about packing a go-bag and gathering sheltering-in-place items

It's not always possible to prepare for a global outage such as the one we saw on Friday. But people can still lobby their elected representatives to push for more secure systems, Rubin said. They can also make sure they don't fall prey to smaller-scale attacks. Don't click on suspicious links or open files sent by someone you don't know, he said.

There is a way for businesses and companies to better protect themselves from disruptions because of outages or cyberattacks, he said. They can make sure they're not relying on a single operating system to carry out essential functions, so if there's a problem with one system – Windows in this case – they can switch to computers running Mac or Linux.

"Sometimes you have an incident that's serious but not catastrophic, and maybe that incident causes you to realize how vulnerable you are, and then to put in the effort to protect your systems more," Rubin said.

Contributing: Elizabeth Weise, USA TODAY; Reuters