What does the memory test that occurs at boot up do?
1. >>Counts RAM memory locations
2. Tests CPU burst speed
3. Counts HDD memory locations
4. Tests RAM refresh rate and speed
5. Tests HDD memory locations
6. Tests ROM memory locations
Explanation : During the Power-On Self-Test (POST) process at boot up, a PC checks the basic hardware before loading the operating system. One of the hardware tests performed is a physical memory (RAM) check. The system performs a write and a read to each memory location to make sure all memory locations are good. It also counts each location, sequentially, to make sure memory addresses map to contiguous (adjacent or physically consecutive) physical memory. The memory test does not test RAM refresh rate and speed. It only tries to write and then read from each cell. The test either passes or fails. If the memory test fails, the system doesn't know whether it is because the RAM refresh rate or read/write speed is wrong or because the memory cell is bad.
The memory test that occurs at boot up does not count or test hard disk drive (HDD) memory locations. It does not test Read-Only Memory (ROM) locations, although it performs a checksum (a simple count) to make sure the BIOS instructions are all there and intact. It performs a CMOS memory check to make sure the contents of CMOS have not changed (as can happen if the backup battery has gone bad).
POST does not test microprocessor (CPU) speed. It only checks to see if the CPU is present and working, and then resets it to begin executing the BIOS program.
Objective: Personal Computer Components
