Unit 7 Assignment 1: Video Summary 5 BIOS is the first program activated during boot. This instruction set is permanent. Power-on self test checks basic system hardware, checks memory, and assigns system resources. The startup BIOS also checks CMOS settings. This is not permanent because it comes from RAM so it may be changed. BIOS and CMOS are different. BIOS is stored in ROM and permanent. CMOS is stored in RAM and volatile. CMOS settings are not lost during power outage because the CMOS battery provide power while shutdown. A common system of low battery is a slow clock. The system will still reboot if you clear the checksum error. The bootstrap loader runs POST, which checks CMOS, which reads MBR, which finds active partition, which loads the 1st OS file. To make changes to the BIOS by changing the Motherboard or flash the BIOS. BIOS is Firmware not hardware, or software. EEPROM stands for Electronically erasable programmable ROM. New BIOS lets you download a copy of new BIOS firmware from the manufacturer’s website. You can run BIOS flash installer. There are four system resources IRQ, I/O addresses, Memory Addresses, and DMA. IRQ is the interrupt request. It’s the communication channel from the hardware device to the CPU. IO address stands for Input/Output address and it’s the Hardware devices assigned address. The CPU sends instructions to address and the Device listens for address. The IO address is similar to device name. CPU communicates with the hard drive by using the hard drive’s I/O address. The hard drive listens for the address. Each hardware is assigned memory addresses. DMA has a direct communication channel between devices and system memory. It does not require CPU and not all devices use DMA. Sound cards and joysticks use DMA which reduces response time. Memory addresses are the instructions and work stored. You can see system resource assignments in system information and in device manager. You can use the device manager to troubleshoot hardware and resolve resource conflicts.