PCSX2 Documentation/MMU mini-series: Difference between revisions
no edit summary
No edit summary |
No edit summary |
||
Line 15: | Line 15: | ||
Let's begin with the root, the Operating System (OS). Hardware can run without any OS but it is often a necessary evil. The OS has 2 major goals: | Let's begin with the root, the Operating System (OS). Hardware can run without any OS but it is often a necessary evil. The OS has 2 major goals: | ||
1 | 1. The first goal of the OS is to control privilege access of processes. | ||
Maybe you want to keep a resource for the hardware or OS internal, for example a hardware watchdog. Maybe you only want to check the validity of a command. It could be as simple as only allowing a stop command after a start command. | Maybe you want to keep a resource for the hardware or OS internal, for example a hardware watchdog. Maybe you only want to check the validity of a command. It could be as simple as only allowing a stop command after a start command. | ||
Line 24: | Line 24: | ||
As you can see, without any OS you could easily kill your system. The OS allows the separation of privileged and standard resources. | As you can see, without any OS you could easily kill your system. The OS allows the separation of privileged and standard resources. | ||
2 | 2. The second goal is to share the resources between processes | ||
You need to understand that processes are independent for coding simplicity and security. | You need to understand that processes are independent for coding simplicity and security. | ||
Let's reuse our hardware counter example | Let's reuse our hardware counter example | ||
Line 66: | Line 66: | ||
* A hardware component needs to access the memory without the CPUs intervention. Do you know which one? Do you know how the addresses are handled? | * A hardware component needs to access the memory without the CPUs intervention. Do you know which one? Do you know how the addresses are handled? | ||
{{PCSX2 | |||
{{PCSX2 Documentation Navbox}} |