There are the following primary scheduler services:
| Service | Description |
| Adjust_Exec_Priority | Raises or lowers priority. |
| Begin_Critical_Section | Claims a critical section. |
| Call_When_Idle | Installs system-idle callback procedure. |
| Call_When_Not_Critical | Installs a critical-section callback. |
| Call_When_Task_Switched | Installs a task-switched callback. |
| Claim_Critical_Section | Claims a critical section. |
| Close_VM | Closes a virtual machine. |
| Create_Semaphore | Creates a semaphore. |
| Destroy_Semaphore | Destroys a semaphore. |
| End_Crit_And_Suspend | Releases critical section and suspends VM. |
| End_Critical_Section | Releases the critical section. |
| Get_Crit_Section_Status | Gets critical section status. |
| Get_Crit_Status_No_Block | Returns claim count and owner. |
| No_Fail_Resume_VM | Resume execution without failing. |
| Nuke_VM | Closes a virtual machine. |
| Release_Critical_Section | Releases the critical section. |
| Resume_VM | Resumes a virtual machine. |
| Signal_Semaphore | Unblocks a waiting virtual machine. |
| Suspend_VM | Suspends a virtual machine. |
| Wait_Semaphore | Waits until semaphore is signaled. |