We're big fans of reusing old hardware here at XDA, from reusing the second-best Mac Pro chassis for a killer gaming PC, turning old PCs into servers, or, in some cases, still using the same old hardware from years past. But these are all deliberate choices, to reuse hardware so it doesn't end up in the landfill. Many companies and organizations don't have a choice, as some of their critical systems are running on legacy hardware and/or code that should have been retired decades ago. Let's take a look at some of the systems that you might be shocked to know are running on ancient hardware.

7 Trains

It seems floppy disks won't die

When you entrust your life to something like a commuter train, you have some expectation that the company running it is using the latest and greatest technology, with a control room that's all modern and full of flashing lights like in the movies. Well, that might have been true at the time the rail system was put in, but nowadays, those control rooms haven't aged well. Take San Francisco's Municipal Transportation Agency, whose Automatic Train Control System uses 5 1/4" floppy disks to run (via ArsTechnica). Only while the trains are inside the subway portions, mind you, as human operators are responsible while the trains are on surface tracks.

The agency is in the process of modernizing the system, which will cost a staggering $212 million to complete. When that's the average cost of upgrading complex systems that still run on legacy hardware, it's not hard to understand why companies are slow to transition, especially if the legacy systems are still functioning. San Francisco's ATCS is still functional, but those floppy disks won't last forever, and the coding knowledge needed to keep the legacy code going is getting harder to find.

6 Sales terminals

Many still use underpowered processors to run

Lately, in the US, you're more likely to see tablet-based sales terminals from Square or the other new breed of payment processors, but that isn't the case everywhere. Sales terminals can run on very low-spec hardware, and until fairly recently, most ran on x286 processors. Even going into the 2000s, payment terminals used low-powered embedded Intel processors, and some of those units are still in use today. These machines topped out at Pentiums running at 266Hz, running Windows CE.

The only reason new POS terminals were purchased and installed was the shift in who was responsible for preventing credit card fraud. Once the province of the card issuers and payment processors, the responsibility was recently shifted onto individual stores, which is a big part of why the US now has more secure cards with embedded chips. This shift hasn't completely replaced the legacy POS terminals, but they are finally on the way out.

5 The German Navy

Floppy disks are still used for many systems

The German Navy is still using floppy disks on some of its warships as part of the onboard data acquisition systems (via Tom's Hardware). These frigates were put into commission in the mid-90s, but they use 8-inch floppy disks in some vital systems. The Navy is in the process of replacing these with another system but hasn't yet decided exactly which system will replace the floppy disks while retaining the rest of the operational electronics.

If you're wondering if this is the only world power still using floppy disks in their military, it's very unlikely. The US had relied on the same 8-inch floppy disks until 2019 for the US Strategic Automated Command and Control System, and it's likely other military powers with aging arsenals are also using similar systems.

4 Governments

Security requirements often mean old code stays around

Governments worldwide are still using legacy systems and the legacy code bases from which they were created, and that isn't going to change any time soon. The sheer scale of the undertaking to modernize any of these sprawling agencies, like the IRS or the system for running background checks in the US, makes the replacement process complex, especially since the systems have to coexist for some time as new data is always being added.

Whether it's because of obsolete programming languages like COBOL, or modern systems built on top of legacy systems, so it's difficult to see where one ends and the other starts, the challenge of modernization is real. It's not just legacy code either, as obsolete hardware plays a part. It wasn't until mid-2024 that Japan managed to finally remove all floppy disk usage from its government, as it had a huge number of legacy regulations that required their use.

3 Banking

ATMs and legacy code abound in the banking industry

The banking sector is old-fashioned in many ways, and some of those include its heavy reliance on legacy systems. The databases and systems that are used to shift colossal amounts of money around the world are all aging, but it's not just the macro picture that's running code that's old enough to retire. ATMs are often an attack surface, even the newer ones that have NFC readers, because the chips or code that runs on them are full of issues and vulnerabilities that existed at the time the ATM was installed. That could be a decade ago or longer, and the criminals that like to attack ATMs have gotten increasingly sophisticated in that time. Plus, the mainframes and other systems that run the banking world were designed way before the mobile age, and they just can't keep up with the increasing strain of everyone having an internet-connected computer in their pocket.

2 Healthcare

Old databases and hardware are hard to modernize

Anyone who has dealt with a healthcare system lately knows it's slow and inefficient. That's firmly down to using legacy systems for health records, billing, and claims processing. The main problem standing in the way of modernization is that most of these systems are critical to keeping compliance with healthcare regulations, which also haven't been updated in some time. It's clear that the whole system needs an overhaul, from the decades-old databases that manage patient data to the systems that interface between doctors, nurses, and off-premises care providers so the patient's medical history is up to date and accessible by all.

1 Some Boeing 747 models

Yes, but only when they're on the ground

Before the invention of the USB drive, many computer systems still needed an easy way to be updated when in service. The humble floppy disk was yet again the tool of choice, and as we saw earlier, almost every form of moving vehicle used them. And still do, as some Boeing 747 models use a floppy drive to update the avionics systems that operate the plane while in the air. These updates have to be done monthly, for up-to-date information on airports, flight paths, runways, and more, and they usually need eight floppies or more. If you didn't grow up in the age of the floppy disk, just trust me when I say that's a long time spent waiting while the system copies the data off each disk.

Legacy tech is a real issue for many critical infrastructures, and it's only going to get worse

Whether it's outdated code bases that run in functionally dead coding languages, or hardware that we're shocked actually powers on today, legacy technologies are a real and present danger to the smooth operation of the world. Currently, critical infrastructure that enables the modern world runs on these technologies, and the process of creating replacements is slow. Passenger vehicles from boats, planes, and trains are all updated using floppy disks, old databases store personally identifying information insecurely, and many operating systems that consumers no longer use at home are still active in other devices we use every day. As time goes on, more systems will become legacies, and we could be marching toward some level of technological collapse as a result.