Tech
Cracking a long-standing weakness in a classic algorithm for programming reconfigurable chips
Researchers from EPFL, AMD, and the University of Novi Sad have uncovered a long-standing inefficiency in the algorithm that programs millions of reconfigurable chips used worldwide, a discovery that could reshape how future generations of these are designed and programmed.
Many industries, including telecoms, automotive, aerospace and particle physics rely on a special breed of chip called the Field-Programmable Gate Array (FPGA). Unlike traditional chips, FPGAs can be reconfigured almost endlessly, making them invaluable in fast-moving fields where designing a custom chip would take years and cost a fortune. But this flexibility comes with a catch: FPGA efficiency depends heavily on the software used to program them.
Since the late 1990s, an algorithm known as PathFinder has been the backbone of FPGA routing. Its job: connecting thousands of tiny circuit components without creating overlaps.
For decades, it worked so well that it became the standard. However, as circuits grew larger, engineers began encountering frustrating slowdowns and occasional outright failures. Designs that should have worked were often labeled “unroutable.”
Now, with colleagues from the University of Novi Sad and the technology company AMD, researchers from the Parallel Systems Architecture Laboratory (PARSA) in the School of Computer and Communication Sciences have come one step closer to untangling the inner workings of this classic algorithm.
In their paper, which received the Best Paper Award at the 33rd IEEE International Symposium on Field-Programmable Custom Computing Machines, they revealed why these failures happen and how PathFinder’s limits can be overcome.
Cracks in the algorithm
“In fact, it’s not surprising that PathFinder sometimes fails,” explained Shashwat Shrivastava, Ph.D. student with PARSA and first author of the paper.
“Very early on, researchers showed that the problem behind FPGA routing is extremely hard. Later, the creators of the original algorithm, together with a few collaborators, found cases where PathFinder would never succeed—but they noted such cases wouldn’t appear in practice.”
For decades, it seemed they were correct—PathFinder worked surprisingly well.
“PathFinder worked so well, in fact, that when it failed, people rarely questioned the algorithm. Instead of venturing inside to see what was going on, they tweaked its parameters, modified circuits, or switched to larger FPGAs,” added Stefan Nikolić, an EPFL alumnus and now a professor at the University of Novi Sad.
“Part of the reason for this is that it is rather difficult to understand what PathFinder is actually doing on examples of practical importance. Modern circuits are so large that their signals form veritable on-chip jungles.”
Enter the forest
“So, we really needed to look at the individual trees in that jungle,” continued Shrivastava, “and I really mean trees. Each signal—a connection that carries information between circuit components—must reach multiple destinations without overlapping other signals. FPGA routing is essentially about building one tree for each signal on the chip.”
While working on another project that relied on PathFinder, the team kept seeing results that defied intuition. At first, they blamed external factors, not the algorithm itself. Eventually, they realized they needed controlled examples: small, tricky cases where a solution definitely existed, and in which PathFinder should succeed.
“We needed real, practical examples, and lots of them, to understand what was really going on,” Shrivastava explains. “So, we built a framework to automatically extract small, hard problems from real circuits. Watching how PathFinder struggled with these helped us uncover issues that had remained hidden for a very long time.”
Power in partnership
“This breakthrough would have been much harder without industry support,” said Mirjana Stojilović, Shrivastava’s Ph.D. advisor. “From the start, we collaborated with Chirag Ravishankar and Dinesh Gaitonde from AMD. They helped us model FPGAs as close as possible to commercial devices, ensuring our findings had real-world impact.”
Once the framework was ready, things moved quickly. The team found that PathFinder often built routing trees larger than necessary, increasing the risk of overlaps. The problem came from the order in which it created and added new branches to the trees.
“In retrospect, this is intuitive, but somehow it went largely unnoticed for many years,” Shrivastava said. “Our first solution was simple: try different orders and pick the one that results in the smallest tree. Experimentally, it worked surprisingly well.”
The team is now exploring more scalable solutions. “I am especially proud that Summer@EPFL interns have been contributing significantly. One of them, Sun Tanaka, is also a co-author of the paper,” added Stojilović.
“Our discovery could reshape how millions of FPGAs are programmed and influence the design of future generations of these reconfigurable chips.”
More information:
Shashwat Shrivastava et al, Guaranteed Yet Hard to Find: Uncovering FPGA Routing Convergence Paradox, 2025 IEEE 33rd Annual International Symposium on Field-Programmable Custom Computing Machines (FCCM) (2025). DOI: 10.1109/fccm62733.2025.00060
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For airlines to run critical operations on networks that are set up and run for them, removing the complexity and cost of managing connectivity themselves, air industry tech firm SITA has launched a new network solution designed to support the demands of complex airport and transport environments.
With around 2,500 customers, SITA technology supports more than 1,000 airports and more than 19,600 aircraft worldwide. The company said that it also helps more than 70 governments “strike the balance between secure borders and seamless journeys” and connects 45-50% of the industry’s data exchange to enable complex global networks to operate smoothly and reliably.
As part of the latter aim, the SITA Campus Network, powered by HPE Aruba Networking, aims to offer a managed network service covering more than 150 countries wherein SITA takes care of the design, procurement, shipping, installation, configuration and support for all devices involved. Boasting a low total cost of ownership (TCO), SITA is proposing “one of the most competitive” fully managed local area network/wireless local area network (LAN/WLAN) available in the industry.
Explaining the rationale for the launch, SITA noted that managing networks across multiple locations, devices and suppliers is complex and costly. Furthermore, it said that when networks are fragmented, performance suffers and disruptions can spread quickly.
SITA Campus Network is attributed with being able to remove this burden by delivering a fully managed network across wired and wireless environments. The campus network is claimed to combine “robust” connectivity with centralised, cloud-based management to ensure consistent, reliable performance across airport campuses and other large transport hubs.
Designed for high-density environments such as terminals, hangars and airline operations centres, the solution is said to support large volumes of users and devices without compromising performance, even during peak demand. By integrating HPE technology into its managed service, SITA’s customers get a network that is centrally operated by SITA while retaining the flexibility to use different technologies and vendors.
Available in more than 145 countries, with 24/7 operational support, SITA assured that by reducing the need for costly hardware and simplifying operations the network lowers both upfront investment and ongoing costs. Its pay-as-you-go model allows customers to scale usage up or down based on demand, with rapid deployment across locations.
This is said to reduce the need for on-site support, spare equipment and recurring training, freeing up IT teams to focus on higher-value activities. Where needed, the campus network connects to SITA’s global wide-area network services. This connectivity links more than 600 airports worldwide.
As is the norm with other leading networking solutions, the SITA Campus Network uses AI to improve visibility across the network, detect issues earlier and automate troubleshooting, helping reduce downtime. It also provides centralised management, allowing infrastructure and devices to be monitored and controlled across both on-site systems and remote environments.
Martin Smillie SITA senior vice-president of communications and data exchange, said integrating diverse systems and devices across airport environments is becoming more complex as operations become more connected: “At the same time, expectations on performance, resilience and security continue to rise. With SITA Campus Network powered by Aruba, we take on that complexity. We deliver a network that is set up, run and continuously optimised, so our customers can focus on keeping operations moving while maintaining control across increasingly demanding environments.”
Sujai Hajela, executive vice-president and general manager for enterprise campus and branch at HPE, added: “Airports and airlines have to support thousands of staff, passengers and mission critical systems across terminals, gates and airside areas – and any network issue shows up immediately as delays and frustration.
“SITA Campus Network powered by HPE Aruba Networking is built on our secure, AI-native technology to deliver a self-driving network that spots and fixes problems in real time, often before anyone notices, so operations keep moving and passengers stay connected.”
Tech
Chinese hackers using compromised networks to spy on Western companies, says Five Eyes | Computer Weekly
China-linked hackers are using networks of vulnerable internet-connected devices, including home routers, printers and smart devices, as cover to mount espionage and hacking operations.
The technique is now used by the majority of China-linked hackers as a way to obscure hacking and espionage attacks launched against organisations in the West.
The UK’s National Cyber Security Centre (NCSC) and national agencies in nine other countries have warned today that Chinese-linked groups are now leveraging networks of infected devices “at scale” to target critical sectors globally and steal sensitive data.
According to an advisory issued by the Five Eyes intelligence-sharing alliance – comprising the UK, the US, Canada, Australia and New Zealand – and 10 other countries, Chinese groups are exploiting security vulnerabilities in unpatched internet devices to create networks to use as a staging post to launch further attacks.
“We know that China’s intelligence and military agencies now display an eye-watering level of sophistication in their cyber operations,” said NCSC chief Richard Horne in a speech at its CyberUK conference in Glasgow.
Covert networks hide ‘indicators of compromise’
The agencies warn that the Chinese tactics are making it difficult for organisations to detect and attribute malicious attacks on their computer networks using traditional “indicators of compromise”.
Chinese groups, for example, could use a UK-based infected device as a staging post to hack into a UK-based company, meaning that blocking non-UK IP addresses no longer provides a defence for overseas attacks.
They advise companies to adopt “adaptive, intelligence-driven measures” to better mitigate the risks, including monitoring traffic from internet-connected devices, virtual private networks (VPNs) and remote access devices to identify suspicious traffic.
Chinese-linked groups are able to evade detection by exploiting low-cost networks of infected devices that can rapidly be reconfigured so that traditional static IP block lists are no longer effective.
The networks are used for each phase of a cyber attack, from reconnaissance and malware delivery, to command and control and data exfiltration against targets of espionage and offensive cyber operations, according to the advisory.
Covert networks behind major hacking operations
Covert networks of compromised devices have been used by the Chinese state-sponsored group Volt Typhoon to pre-position for future attacks on critical national infrastructure (CNI).
The group has targeted communications, energy, transport and water services in the US, and has been able to maintain covert access to critical IT systems for five years or more.
It used a network of vulnerable Cisco and NetGear routers, which were no longer supported by the manufacturers and were no longer receiving updates of security patches.
Another Chinese group, Flax Typhoon, has used a covert network of 260,000 compromised devices, including routers, firewalls, webcams and CCTV cameras, to conduct cyber espionage against targets in multiple countries.
Hacking as a service
Chinese hacking groups have a choice of covert networks, each with potentially hundreds of thousands of endpoints, which frequently change, making it more difficult for companies targeted to block attacks, according to the advisory.
Chinese information security companies have maintained networks of infected devices, available as a service for Chinese-linked hacking groups.
Chinese company Integrity Technology Group controlled a network known as Raptor Train, which infected more than 200,000 devices worldwide in 2024.
Companies advised to take countermeasures
The NCSC advises companies to map internet-connected devices in their organisation and corporate VPNs, so they can understand which traffic is legitimate.
They should also introduce multifactor authentication (MFA) when employees use remote connections to dial into business networks.
Larger organisations can profile incoming connections based on operating systems, time zones, and the organisation’s systems configurations to identify legitimate traffic.
The Five Eyes and the NCSC advise the most at-risk organisations to actively track Chinese advanced persistent threats (APTs), using threat reports supplied by the NCSC to create dynamic block lists and rules to detect incoming threats.
“In recent years, we have seen a deliberate shift in cyber groups based in China utilising these networks to hide their malicious activity in an attempt to avoid accountability,” said Paul Chichester, NCSC director of operations. “We call on organisations to act now to better defend their critical assets.”
Chirp reinvented the wheel—or at least one type, the yoga wheel. Chirp Wheels are effective in relieving upper and lower back pain, sciatica, and tension headaches. WIRED contributor Hannah Singleton has said the Chirp Wheel XR-3 Pack has even helped undo her tech neck and alleviate her brain fog.
Recently, the wellness brand has expanded beyond its flagship wheels into recovery gear. The lineup now includes powered rolling massagers (which I’ve been using a lot lately for back pain relief), TENS units, and even a full massage table (Chirp Contour) that I’m currently testing (stay tuned for the full review). Where Chirp stands out from heavyweights like Hyperice and Therabody is in its simplicity and value. The products tend to focus on doing one thing well rather than piling on features you may never use. Chirp promos and discounts run frequently on the Chirp website, and we have Chirp discount codes, so you can get an even better deal on recovery gear that’s already reasonably priced.
Save up to 67% on Chirp Products With Daily Deals
I like checking Chirp’s Daily Deals page because the exclusive offers rotate frequently, and you can save as much as 67%. I’ve spotted the Chirp Wheel XR 3-Pack on there, but you’ll also find different versions of the wheel, along with storage accessories. Some wheels skip the pressure-point nodes, which can feel better if you’re focusing on improving spinal mobility and flexibility rather than digging into stubborn knots. If the Chirp RPM Mini pops up at a special discount, it’s worth considering for your first purchase. It’s essentially an electric roller that kneads muscles more gently than most percussive massage guns; it also comes with a carrying case, so you can toss it in a bag and take it with you.
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Spend $99 or more, and Chirp will throw in a complimentary Chirp Wheel+ Deep Tissue 2-Pack, which retails for $75. The bundle includes two wheels: a 6-inch Deep Tissue Wheel designed for larger muscle groups and a 4-inch Focus Wheel meant to target trigger points in the neck and other small areas. You’ll need to sign up for the email newsletter to claim the freebie before adding it to your order.
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Chirp customers receive free shipping on U.S. orders over $75, and the perk stacks with the brand’s daily deals and most codes. If you time it right, you can shave a decent chunk off the final price. No promo code at checkout required.
Chirp Discount Code: Select Customers Can Get 15% Off
Chirp offers a 15% discount to certain groups through an online verification process. That includes: active-duty military personnel, veterans, and their dependents; first responders and law enforcement officers; medical professionals and healthcare workers; and teachers and academic administrators at any grade level.
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