Engineering Challenges With Legacy Systems In Production

80% of SAP migrations are routine. It’s the other 20% that destroy your timeline — and your credibility. Here’s how I learned the difference the hard way. When I talk to system integrators or MSPs who do SAP migrations, the story’s always the same: “We’ve done this a dozen times.” “We have our own scripts.” “We’ve got a playbook.” And 80% of the time, they’re right. Standard migrations follow standard patterns. But it’s that last 20% - the edge cases, the brittle dependencies, the jobs nobody’s touched in 10 years - that turn a migration from smooth to painful. That’s what separates the professionals from the panicked. Here’s what I watch for when things start to crack: 1. Undocumented complexity Legacy systems have quirks nobody logged. Shared file systems. Custom batch jobs. Forgotten user exits. These things always surface mid-migration. 2. Data volumes that blow past estimates I’ve seen a “simple” 2TB system balloon during testing. Archiving was skipped. Logs piled up. And suddenly the 24-hour cutover became 72. 3. Tools that break when assumptions change Even the best platforms fail if they’re built for best-case scenarios. You need fallback plans, not just features. 4. Engineers without deep system context If your team only knows how to click through the UI — but not how to debug scripts or logs — one hiccup can turn into a showstopper. 5. Clients who don’t believe in enough dry runs This one’s fatal. No test (or lack there-of) = no timing/no tuning. And no timing/no tuning = no trust. The truth? Anyone can move systems when everything goes according to plan. But real-world migrations don’t run on rails — they run on resilience. That’s why at IT-Conductor Inc., we don’t just prepare for the 80%. We engineer for the 20%. Because one botched migration isn’t just a missed milestone. It’s a lost contract.

I was asked what changes you can make to legacy equipment to enhance reliability and better control process. I can only speak to things I have done and worked with other FAB owners on. First I change every bit of monitoring sensors etc. over to digital and install a translator to feed signals to the legacy controls. Next modify the gas management to modular with all currant components and digital MFC's again building and installing a translator for controls interface. Probably the most overlooked by everyone is the vacuum systems and controls. This is probably the simplest to update and greatly enhances reliability along with better process controls in many cases. This same methods I utilize in wets, diffusion and all other process systems. The goal is to increase reliability and allow better maintenance at lower cost. This also helps MTBF and MTTR because you are utilizing currant off the shelf commercial parts. This helps focus on obsolescing OEM parts sources. The OEM parts area is one where keeping legacy equipment running will require developing second source manufactures in the OEM's are not going to support. With todays technologies any items or software can be reverse engineered. I have noticed that the mind set of many process engineers and all most everyone in Asia having real issues when not utilizing original parts from when a system was originally manufactured. There is really no reason if you work with component manufactures on form fit function of parts. The signal translators or relatively simple and very reliable If you are going to keep utilizing legacy equipment then you have to start thinking about the reality of obsolescing parts and how they effect the overall performance of the FAB. Other industries have been doing these things for decades. Look at the B52 bomber which is 60+ years old and keeps getting updated. Legacy equipment is no deferent if you work at it.

How to tackle legacy system modernization at scale: How Booking(.)com tackled a legacy API that had gotten completely out of hand: The situation: A 14-year-old API in their Perl monolith had grown from handling simple app updates to managing 21 different features across 7 teams. Instead of a quick migration to Java, the team took a thoughtful approach to breaking down this complex system. Key insights from their successful modernization: 1. Map before you migrate. The team created visual diagrams to understand how 1,500 lines of code connected to various parts of their system. 2. Know your stakeholders. Using repository history, they identified every team dependent on the API and included them in the planning process. 3. Split strategically. They separated the system into focused services based on functionality and platform requirements, making it more maintainable. 4. Test thoroughly. When they encountered unexpected issues with marketing metrics, they used A/B testing to identify and fix problems without disrupting service. The biggest lesson? Modernizing legacy systems isn't just rushing to new technology. It's about understanding what you have and carefully restructuring it into something better. Follow Pratik Daga for daily informative posts on software engineering.

The legacy system documentation is a ticking time bomb. Hey y'all! Something's keeping me up at night: while everyone's drooling over the newest AI toys, millions of critical COBOL systems are running with documentation that's basically a hot mess of digital spaghetti. The documentation problem is REAL, folks. Most big companies have decades of system info scattered across random folders, personal drives, and (I'm not making this up) actual paper manuals locked in cabinets nobody can find keys for anymore. Why should we care? Because when your last COBOL expert retires next month, all that knowledge walks right out the door with them. And guess who's gonna be panicking when that mission-critical banking system crashes at 2 AM? Yep, you. Some facts that should make you sweat: • Most companies have ZERO actual documentation standards for legacy systems • Documentation is often older than most entry-level employees • New developers waste 60% of their time just trying to figure out how the darn system works • Critical knowledge exists only in the heads of people about to retireThe solution isn't fancy or trendy, but it works: get your documentation organized, people!Smart companies are doing some basic stuff that actually works: 1. Create a standard folder structure for ALL legacy documentation 2. Set up smart search capabilities (like Smart Folders) that can find any document across your entire system¹ 3. Use naming conventions that even new hires can understand 4. Make sure the right team members can access what they need 5. Create specific spaces for critical documents like system diagrams and emergency proceduresWill this problem get better or worse soon? My bet: it's gonna get much, much worse unless companies wake up and do something now. The good news? You don't need some expensive fancy solution. A well-organized folder system with decent search can turn your documentation chaos into something usable overnight. If you're running legacy systems without a documentation strategy, you're basically playing Russian roulette with your company's most important stuff. Don't be that person.

When you're explaining how one small system change impacts the entire architecture… Many legacy systems we are still relying on aren’t just “old.” They’re fragile, deeply embedded, and connected in ways that make untangling them feel impossible. Every quick fix, every workaround, and every “we’ll document that later” decision adds another layer of complexity. Rarely do we get the opportunity to start fresh with a new product architecture. When that chance comes, it’s critical to set up a system that isn’t just functional today but maintainable and adaptable for the future. ✅ Separation of Concerns – Keep modules clean, independent, and focused on their specific roles to prevent ripple effects from minor changes. ✅ Well-Defined APIs – Establish clear, stable interfaces so teams can innovate without breaking critical dependencies. ✅ Scalable Foundations – Build with maintenance and updates in mind, not just initial deployment. Because in the end, everything is connected—and the choices made today will shape how smoothly (or painfully) the system evolves over time. #SystemsThinking #SoftwareArchitecture #LegacySystems #TechDebt #APIDesign

In manufacturing, bad data creates big problems. If your decisions are based on bad data, your supply chain will suffer - especially in industries with millions of SKUs like electronics manufacturing and distribution. But the truth is, many suppliers rely on bad data…thanks to outdated, disconnected legacy systems. These systems often require manual processes that fail to track data in real-time, leaving companies with fragmented and inconsistent information. Add to that the chaos of acquisitions, where disorganized data - like scanned PDFs of part numbers - gets inherited and piles up. (I’ve even seen one of the biggest electronics companies in the world still using a scan of a typewritten data sheet.) Over time, this leads to a complete breakdown in visibility, making it nearly impossible to maintain a reliable database. The result? The same item might have multiple part numbers across systems, demand planning becomes a guessing game, unnecessary reorders happen, and stockouts leave teams scrambling. Of course, this isn’t a consequence of negligence or bad intentions - but one of bad data from legacy systems that aren’t built to prioritize accuracy and visibility. To fix this, companies need Integrated solutions that can clean up and centralize data, eliminate inefficiencies, and give businesses the clarity they need to operate smoothly. Because without accurate data, every other decision you make is at risk.