The kernel is responsible for preparing the UOS executive for use. Any errors encountered during this process will cause the startup to fail. The following steps are performed by the Startup method of the Kernel class instance:
1. Load file system component from the boot device
This is done by reading the boot block and extracting the file system position and length.
2. Load Memory Management component from boot device
3. Load Heap Management component from boot device
4. Set up Memory Management component
This is done by setting the MMC's kernel.
5. Set up Heap Management component
This is done by calling the HMC's End_Startup method.
6. Mount the boot device's file system
If the file system is dirty, it is rebuilt and then mounted.
7. Get path to installed UOS
This is done by getting the link from the \uos\installed.sys file.
8. Load Interrupt Manager component
9. Load File Processor component
10. Load System Services component
11. Dismount the file system and remount via the File Processor
12. Get startup configuration
If the store is read-only, the configuration is read from a buffer maintained by the HAL. Otherwise, it is read from \uos\startup.dat.
13. Process startup configuration
14. Add any RAM disks from the startup configuration to the File Processor
15. Load User Security component
16. Define sys$system: to point to booted installation
17. Create startup process and attach it to the system console
18. Log the startup process in to user 1
19. Run sys$system:startup.ucl