Sharing a good answer from perplexity.ai about dynamic memory allocation (as opposed to static memory allocation).
Dynamic memory allocation is the process of assigning the memory space during the execution time (aka. the run time). (Static memory allocation is a process in which memory for variables and data structures is reserved at compile time, before the program runs.)
When was dynamic memory allocation first introduced and why?
Dynamic memory allocation was first introduced in the early days of the C programming language, which was developed in the early 1970s. The concept became fully established and standardized with the 7th Edition of Unix, released in 1979[1].
The introduction of dynamic memory allocation was driven by several key factors:
Flexibility: It allowed programs to request memory as needed at runtime, rather than having to pre-allocate all required memory at compile time[2].
Efficient resource use: Dynamic allocation enabled more efficient use of limited memory resources, as memory could be allocated and deallocated as needed during program execution[2].
Handling variable-sized data: It provided a solution for managing data structures whose size was not known until runtime, such as when reading data from user input or files[2].
Overcoming limitations: Dynamic allocation addressed limitations of static and automatic memory allocation, which required compile-time constant sizes and had restricted lifetimes[2].
Complex program needs: As programs became more complex, there was an increasing need for greater flexibility in memory management beyond what static and stack-based allocation could provide[2].
The introduction of dynamic memory allocation represented a significant advancement in programming capabilities, allowing for more sophisticated and flexible software design. However, it also introduced new challenges, such as the need to manually manage memory to prevent leaks and fragmentation[3].
Citations:
[1] https://patents.google.com/patent/US20110078404
[2] https://en.wikipedia.org/wiki/C_dynamic_memory_allocation
[3] https://en.wikipedia.org/wiki/Memory_management
[4] https://patents.google.com/patent/US20050268049A1/en
[5] https://stackoverflow.com/questions/49354528/c-when-do-objects-of-classes-allocated-dynamic-memory
[6] https://azrael.digipen.edu/~mmead/www/Courses/CS120/DynamicMemoryAllocation-1.html
[7] https://gamedev.stackexchange.com/questions/8206/dynamic-memory-allocation-and-memory-management
What problems did it lead to?
Dynamic memory allocation, introduced in the early 1970s with the C programming language, led to several significant problems:
Memory leaks: Programs could lose references to allocated memory, causing gradual resource exhaustion[1][5].
Fragmentation: Repeated allocation and deallocation could lead to memory fragmentation, making it difficult to find contiguous blocks of free memory[1][3].
Non-deterministic behavior: Allocation times became unpredictable, which is problematic for real-time systems[2][3].
Allocation failures: Programs could run out of memory unexpectedly, or fail to allocate due to fragmentation[1][2].
Dangling pointers: Improper deallocation could result in pointers referencing freed memory[1].
Performance overhead: Dynamic allocation functions have significant execution overhead[1].
Lack of reentrancy: Common implementations were not thread-safe, causing issues in multi-threaded systems[2].
Inefficient memory usage: Dynamic allocation could lead to wasted space and inefficient memory utilization[1][5].
Debugging complexity: Memory-related bugs became harder to identify and fix[5].
Security vulnerabilities: Improper memory management could lead to exploitable security flaws[5].
These issues are particularly problematic in embedded and real-time systems, where resources are constrained and predictable behavior is crucial[3][5].
Citations:
[1] https://electrical.codidact.com/posts/286121
[2] https://embeddedcomputing.com/technology/software-and-os/ides-application-programming/dynamic-memory-allocation-just-say-no
[3] https://www.design-reuse.com/articles/25090/dynamic-memory-allocation-fragmentation-c.html
[4] https://barrgroup.com/tech-talks/memory-allocation
[5] https://www.reddit.com/r/embedded/comments/u31pse/why_is_dynamic_memory_allocation_bad/
[6] https://stackoverflow.com/questions/72211874/what-is-the-practical-scenario-example-use-of-dynamic-memory-allocation-and-vect
[7] https://blog.jyotiprakash.org/basic-dynamic-memory-allocation-programming-questions
[8] https://docs.multiversx.com/developers/best-practices/the-dynamic-allocation-problem/
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