We Need to Talk!


Staff member
We Need to Talk!
- The CPU needs some method to talk to the devices to tell them what to do.
- The devices need some way to send data to, and receive data from the CPU
- We need to expand our logical model from the CPU chapter.

- At least Sandy Bridge processor and current motherboard.
- 32/64-bit replacement for BIOS, Allows use of 3 TB+ drives without partitioning it down, Good topic for an internet search some rainy saturday.

Different motherboards have different keyboard controllers.
We need specific code to talk to the controller.
- We need a place to store this specific proframming and the proframming for other devices (optical drive, floppy, etc.)

- Use a ROM chip
- Does not "forget" when power is removed. like ROM does
- Specific to motherboard and devices on it, Read only, code does not change, Can hold lost of programs, like a "chapter book". Called "firmware"

System ROM
Holds all the support programming for basic devices, Is given a specific address space, or range of memory addresses for its code.

Basic Hardware
CPU, Mouse, Keyboard, Video card, RAM, Network card, Sound Card, Floppy drive, Hard Disk drive, Zip drive, USB port, CD-ROM drive.

Stored Information
- Stores access/write code for keyboard
- Stores access/write code for system speaker.
- Stores access/write code for other chips ( functions ) on motherboard.
- Doé not change (more on this in a moment)

Complimentary Metal Oxde Semiconductor - how it was made.
- Stores specific information about your system:
+ Amount of RAM present.
+ Type of hard disk drive
+ Date and Time
- Needs battery power to "remember" when power is off.

- All devices need BIOS code to interoperate with CPU. Some is stored directly in System BIOS chip, most is stored elsewhere.
- One of the functions of BIOS is to provide the CMOS setup Utility, or setup, which allows us to change CMOS data.