Migration & Rebasing

Migration & Rebasing — LinSys Software

LinSys Software’s migration and rebasing practice helped clients move existing Linux-based products to new kernel versions, new hardware platforms, or new toolchains. This work typically involved porting custom drivers, kernel patches, and userspace components across version boundaries while preserving product behavior.

Typical migration engagements

• Kernel version rebasing — moving a product from an older Linux kernel (2.4.x, 2.6.x) to a newer LTS branch, including porting any custom out-of-tree drivers and patches
• Architecture porting — bringing a product from one CPU architecture to another (e.g., PowerPC to ARM, x86 to MIPS)
• Toolchain migration — moving from older compilers (GCC 2.x, 3.x) to newer versions, including resolving deprecation warnings and ABI changes
• Distribution migration — moving a product from one Linux distribution base to another (e.g., custom build to Yocto, Buildroot to Debian-derivative)
• Userspace API migration — porting code across major library version boundaries (glibc, OpenSSL, etc.)

Why migration is hard

Linux kernel migrations are deceptively complex because the surface area is enormous. Beyond obvious things like API changes, real migrations have to account for subtle behavior changes in scheduler heuristics, memory management policies, filesystem semantics, and locking primitives. LinSys’s practice combined kernel expertise (often using KGDB for source-level analysis of behavior changes) with disciplined test methodology (in collaboration with the Testing & QA team) to make migrations predictable.

Modern context

The migration pattern is even more important in modern Linux work, where the kernel evolves rapidly (a major release every ~9 weeks) and out-of-tree code accumulates compatibility debt quickly. The principles LinSys applied — early identification of breaking changes, systematic test coverage of edge cases, gradual rebasing rather than big-bang upgrades — are still the canonical approach.

Related services

Migration work was typically the bridge between Product Maintenance (older codebase) and ongoing Software Development (new platform).

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