OS part I, , Part I Computer System Structures Department of Computer Engineering, PSUWannarat Suntiamorntut

OS part I, Department of Computer Engineering, PSUWannarat Suntiamorntut Computer - System Operating

OS part I, Department of Computer Engineering, PSUWannarat Suntiamorntut Computer - System Operating Steps Have an initial program to run (Bootstrap program) Boot Init Wait Ready interrupt

OS part I, Department of Computer Engineering, PSUWannarat Suntiamorntut Computer - System Operating Table of pointers is stored in low memory are need. These locations hold address of the interrupt service routines. (interrupt vector) The process when interrupt occur - return address was kept. - other interrupts are disabled.

OS part I, Department of Computer Engineering, PSUWannarat Suntiamorntut I/O Systems

OS part I, Department of Computer Engineering, PSUWannarat Suntiamorntut Different requirements lead to multiple buses Processor bus (on chip) - > 1 GB/sec Memory bus (on processor board) - ~500 Mbytes/sec I/O Bus ~ 100 Mbytes/sec Device Bus (SCSI) (Small Computer System Interface) - ~ 10 Mbytes/sec

OS part I, Department of Computer Engineering, PSUWannarat Suntiamorntut Disks

OS part I, Department of Computer Engineering, PSUWannarat Suntiamorntut I/O Interface

OS part I, Department of Computer Engineering, PSUWannarat Suntiamorntut I/O Interrupts

OS part I, Department of Computer Engineering, PSUWannarat Suntiamorntut I/O Operations

OS part I, Department of Computer Engineering, PSUWannarat Suntiamorntut Hardware Protection

OS part I, Department of Computer Engineering, PSUWannarat Suntiamorntut System Calls or Monitor Call