Linux page cache explained: faster file reads, readahead, writeback and memory reclaim, with the cache-state checks needed for a meaningful benchmark.
Linux Page Cache — Why the Second Read Is Faster Read Post »
How ptrace powers strace and gdb: syscall stops, signal delivery, breakpoints, tracing overhead and the permissions behind Operation not permitted.
Linux signals explained: SIGTERM, SIGKILL, SIGCHLD, zombie processes, thread masks, safe handlers, SA_RESTART and EINTR.
Signals in Linux — SIGKILL, SIGTERM, SIGCHLD and the Anatomy of a Handler Read Post »
How Linux futexes support mutexes: userspace fast paths, FUTEX_WAIT and FUTEX_WAKE, contention, shared memory and the limits of syscall-based diagnosis.
mmap, read or pread? Demand paging, page cache, shared mappings, copy-on-write and SIGBUS risks, with practical guidance for fair comparisons.
mmap — When Memory-Mapped I/O Beats read() and write() Read Post »
Why RSS can stay high after free(): glibc arenas, tcache, fragmentation and mmap, and how to distinguish retained allocator memory from a leak.
malloc internals — Why free() Doesn’t Return Memory to the System Read Post »
awk as a language: records, fields, BEGIN/END, associative arrays, functions and a stateful parser. Choosing mawk, gawk or Python and measuring fairly.
awk as a Full Programming Language — Not Just {print $2} Read Post »
Before main(): ELF segments, ld.so, GOT/PLT and lazy binding. Inspecting dependencies and using LD_PRELOAD with an understanding of its limits.
ELF and Dynamic Linking — What Happens Before main() Runs Read Post »
Reading strace: errno, filters, descriptors, -f, -c, -T and -k. Distinguishing CPU time from waiting and understanding ptrace overhead.
strace as a Debugging Primitive — When the Stack Trace Lies Read Post »
Analyzing Linux segfaults: MMU, page faults, SIGSEGV, mappings and gdb core dumps. Null pointers, stack overflow and use-after-free without guesswork.
Anatomy of a Segfault — From MMU Through Kernel to gdb Core Dump Read Post »