What is a linker script and why is it important in embedded development?

A linker script defines memory layout for embedded systems: memory regions (Flash address, size; RAM address, size), section placement (.text in Flash, .data initial values in Flash copied to RAM, .bss in RAM), stack and heap allocation, and entry point. It ensures code and data are placed at correct addresses for the hardware. Critical for: Reset vector location, peripheral memory-mapped addresses, bootloader/application separation, and memory protection configuration. Each MCU requires specific linker script matching its memory map.