The concept defines the sequential access mechanism for ordered sequences of characters stored in persistent storage, formalized through the abstraction of an iterator object that yields discrete elements upon demand without retaining the entire dataset in volatile memory. This theoretical framework relies on the principle of lazy evaluation within stream processing domains, where the internal state of the read operation advances incrementally to expose the next atomic unit of data while maintaining position integrity relative to the underlying byte offset. The mechanism operates strictly within the domain of computer science, specifically the subfield of input/output theory and resource management, distinguishing itself from bulk read/write operations by enforcing a stateful, single-pass traversal constraint that optimizes memory complexity to O(1) relative to file size.
Prerequisite chain context: requires File Object Read Method in Python.