During which phase does the computer perform a series of system checks stored in the ROM?

The phase during which the computer performs a series of system checks that are stored in the ROM is known as POST, or Power-On Self-Test. This is a critical process that occurs right after the computer is powered on but before the operating system loads. During POST, the system checks various hardware components such as RAM, the processor, disk drives, and video cards to ensure they are functioning correctly. If POST detects any issues, it will typically issue error codes or beeps that can help diagnose the problem.

The importance of POST lies in its role in ensuring that the hardware is ready for the operating system to take over. If there are no issues found during this test, the system will then proceed to initialize the bootloader and load the operating system. This process highlights the significance of checking hardware integrity as a foundational step in the boot-up sequence.