Lecture №5 Memory Management in Embedded os introduction

Physical memory is composed o f two-dimensional arrays made up o f cells addressed by a unique row and column, in which each cell can store 1 bit. Again, the OS treats memory as one large one-dimensional array, called a memory map. Either a hardware component integrated in the master CPU or on the board does the conversion between logical and physical addresses (such as a memory management unit (MMU)), or it must be handled via the OS.

• Physical memory is composed o f two-dimensional arrays made up o f cells addressed by a unique row and column, in which each cell can store 1 bit. Again, the OS treats memory as one large one-dimensional array, called a memory map. Either a hardware component integrated in the master CPU or on the board does the conversion between logical and physical addresses (such as a memory management unit (MMU)), or it must be handled via the OS.

Dynamic Memory Allocation in Embedded Systems

the RTOS or the kernel typically uses the remaining physical memory for dynamic memory allocation. This memory area is called the heap. In general, a memory management facility maintains internal information for a heap in a reserved memory area called the control block. Typical internal information includes:

• the starting address of the physical memory block used for dynamic memory allocation,
• the overall size of this physical memory block, and
• the allocation table that indicates which memory areas are in use, which memory areas are free, and the size of each free region

Ko’pchilik o’rnatilgan qurilmalar(telefon, raqamli kamera, planshet) ixtiyoriy berilgan paytda parallel ravishda ishlay oladigan cheklangan sonli ilovalarga ega bo’lishadi, ammo bu qurilmalar kichik xajmdagi fizik xotiraga egadir. Bu esa o’z navbatida xotirani to’g’ri boshqarish kerakligidan dalolat beradi.

• Ko’pchilik o’rnatilgan qurilmalar(telefon, raqamli kamera, planshet) ixtiyoriy berilgan paytda parallel ravishda ishlay oladigan cheklangan sonli ilovalarga ega bo’lishadi, ammo bu qurilmalar kichik xajmdagi fizik xotiraga egadir. Bu esa o’z navbatida xotirani to’g’ri boshqarish kerakligidan dalolat beradi.
• Biz oldinroq aytganimizdek kernel(yadro) vazifalar orqali o’rnatilgan tizim doirasida dasturiy kodni boshqaradi. Boshqa mustaqil vazifalardan ximoya qilish uchun OT xavfsizlik tizimi mexanizmiga ega bo’lishi kerak. Bu va bundan boshqa funksiyalarga OT xotirani boshqarish komponenti javobgardir.