Memory Basics
Understanding Linux Memory Architecture
Memory is a critical component in computer systems, serving as a temporary storage area for data and instructions. In Linux systems, memory management is complex and involves multiple layers of abstraction.
RAM Types and Characteristics
RAM Type |
Characteristics |
Access Speed |
SRAM |
Fastest, used in CPU cache |
Nanoseconds |
DRAM |
Standard main memory |
Microseconds |
DDR4/DDR5 |
Modern high-speed memory |
High bandwidth |
Memory Allocation Mechanisms
graph TD
A[Memory Request] --> B{Allocation Type}
B --> |Static| C[Compile-time Allocation]
B --> |Dynamic| D[Runtime Allocation]
D --> E[Heap Memory]
D --> F[Stack Memory]
Memory Allocation Example in C
#include <stdlib.h>
#include <stdio.h>
int main() {
// Dynamic memory allocation
int *dynamicArray = (int*)malloc(5 * sizeof(int));
if (dynamicArray == NULL) {
printf("Memory allocation failed\n");
return 1;
}
// Memory usage
for (int i = 0; i < 5; i++) {
dynamicArray[i] = i * 10;
}
// Memory deallocation
free(dynamicArray);
return 0;
}
This code demonstrates dynamic memory allocation using malloc()
, showcasing how Linux systems manage memory allocation and deallocation. The process involves requesting memory from the heap, using it, and then freeing it to prevent memory leaks.
Memory Management Principles
Linux uses virtual memory techniques to provide:
- Process isolation
- Memory protection
- Efficient memory utilization
- Swap space management
The kernel manages physical and virtual memory, mapping process memory spaces and handling memory requests dynamically.