Code Wrangling at its Best
Chapter 40 closed the loop on shell-visible background jobs by giving them local %N references. That matters here because it gave us a stable chapter boundary:the shell can now be scripted without hardcoding fragile PIDs, so the filesystem work that follows can focus on the namespace itself instead of fighting the test harness. The next
Continue Reading “Chapter 41 — Dynamic /programs from the Program Registry”
We now have enough foundation to start multitasking: This chapter adds the first scheduler. Not a preemptive scheduler yet. A cooperative scheduler. That means each kernel thread keeps running until it voluntarily calls: “` cthread_yield(); textkernel thread objectper-thread kernel stackready queuex86 context switch assemblythread_create()thread_yield()thread_exit()round-robin cooperative schedulingtwo-thread test textcreate two kernel threadsswitch between them cooperativelyprove both
Continue Reading “Chapter 9 — Cooperative Multitasking and Kernel Threads”
In Chapter 6, the kernel heap still depended on low identity-mapped physical pages. That worked as a bootstrap step, but it tied the heap to the first 16 MiB of RAM. In Chapter 7, we added a real VMM and proved that the kernel can map and unmap pages anywhere the page tables allow. That
Continue Reading “Chapter 8 – Moving the Heap onto Virtual Memory”
In Chapter 5 we enabled paging, but only with a fixed identity map: In Chapter 6 we built a heap, but it still had an important weakness: because only the first 16 MiB were identity-mapped. Now we fix the architectural problem. This chapter adds a small virtual memory manager, or VMM: This lets the kernel
Continue Reading “Chapter 7 — A Real Virtual Memory Mapping Layer”
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