Computer System Structure

Computer System Structure
Hardware Protection
DualMode Operation
I/O Protection
Hardware Address Protection
Memory Protection
Base register
Limit register
CPU Protection
Timer
Storage Hierarchy
Speed
Cost
Volatility
Caching
Storage Device Hierarchy
Storage Structure
Main memory
Secondary storage
Magnetic disks
I/O Structure
Synchronous I/O Structure
Asynchronous I/O Structure
Two I/O Methods
Interrupt Handling
The operating system preserves the state
of the CPU by storing registers and the
program counter.
Determines which type of interrupt has
occurred, either by:
polling, or
vectored interrupt system
Separate segments of code determine
what action should be taken for each type
of interrupt.
Computer-System
Operation
Each device controller has a local buffer
The CPU and device controllers can
execute concurrently
Each device controller is in charge of a
specific type of device
CPU moves data from/to main memory
to/from local buffers
I/O is from the device to local buffer of
controller
Device controller informs CPU that it has
finished its operation by causing an
interrupt
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