The fundamental purpose of mutual exclusion is to prevent several threads from altering a shared resource at the same time, avoiding race situations and data inconsistencies. If two threads attempt to update the same data at the same time, the outcome may be determined by the exact order of actions, resulting in unpredictable behavior and inconsistent data.
Assume two threads are attempting to update a shared bank account’s balance at the same time. If both read the current balance, make changes depending on that value, and then send it back, one update may overwrite the other, resulting in a damaged balance. Mutual exclusion prevents this by enabling only one thread to access the shared resource at any given time, ensuring that processes run smoothly and consistently.