old-DasOS/prototypes/base/concepts.txt

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# DasOS Concepts
## Memory Layout
| Start | Length | Length -h | Description |
|------------|------------|-----------|--------------------------------------------------------------------------|
| 0x00000000 | 0x40000000 | 1 GB | Kernel Space. This is where the kernel and its functionality is located. |
| 0x00100000 | ??? | ??? | Kernel entry point and load target. Here the kernel will be loaded. |
| 0x20000000 | 0x20000000 | 512 MB | Kernel Heap. This memory is used for dynamic allocations in the kernel. |
| 0x40000000 | 0xC0000000 | 3 GB | User Space. This is where Artifacts are loaded and executed. |
### Kernel Heap
A simple storage allocator.
Storage of:
- Task Descriptions
- Memory Mapping Information
- Location of loaded artifacts
- ...
## Starting a Task
### Requirements
- allocate task structure
- allocate mapping directory
- fill mapping directory with
- Lower End: Copy kernel mappings
- Upper End: Copy artifact data
- allocate task stack
## Executables, Libraries and Stuff
Artifact = Executable + Library + Shared Memory
### Artifact Types
| Type | Entry Point | Description |
|------------|-------------|--------------------------------------------------------------------------------------------------------------------------------------|
| Program | _main | A program targeted at user or system administrator. Can be executed with command line arguments. Uses stdin, stdout, stderr. |
| Library | _libmain | Can be loaded by other artifacts and allows utilization of a shared set of functions. |
| Service | _svcmain | A service is a background worker that won't be terminated when its main function returns. Can be 'woken up' by an external artifact. |
| Driver | _drvinit | A driver is loaded at system start and is allowed to request and dispatch interrupts. Can be used to create a flexible OS. |