-*- text -*- * The tests in tests/ don't apply the grading patches. * We need better example programs. - Need an mmap example program as a replacement for the crappy mmap FAQ question. * Threads: - join-invalid doesn't compile if tid_t is not scalar type. - mlfqs tests suck. They aren't even correct, e.g. the amarv submission from win0405 is graded incorrectly. * Userprog project: - Don't emphasize that stuff needs to be copied from user space to kernel space. Instead, emphasize validation and suggest that copying is a common solution and that it will be necessary in project 3 and in real OSes. Also revise the grading criteria to match. - Move `join' implementation here, from `threads' project, to help normalize the project difficulties. - The semantics of the join system call should change so that it only returns the exit code once. - Mark read-only pages as actually read-only in the page table. Or, since this was consistently rated as the easiest project by the students, require them to do it. - Don't provide per-process pagedir implementation but only single-process implementation and require students to implement the separation? This project was rated as the easiest after all. Alternately we could just remove the synchronization on pid selection and check that students fix it. * VM project: - Discuss the perils of mixing dirty bits between kernel and user virtual memory. - Sample solution. * Filesys project: - Increase maximum disk size from 8 MB to something that actually requires doubly indirect nodes. There is a negative pressure here from the bitmap object--perhaps we need a specialized bitmap that doesn't have to be all in-memory at once. Alternatively, shrink the inode size. - Add mkdir and ls example user programs. - Add option to disable buffer cache. - Get rid of "dump" commands--they're not really useful. - Sample solution. * Documentation: - Finish writing tour. - Add "Digging Deeper" sections that describe the nitty-gritty x86 details for the benefit of those interested. - Add explanations of what "real" OSes do to give students some perspective. * Assignments: - Add extra credit: . Low-level x86 stuff, like paged page tables. . Specifics on how to implement sbrk, malloc. . Other good ideas. - Add src/testcases/vm, src/testcases/filesys and make it clear to use them? * Tests: - Release some of them. - The threads, userprog, vm test source files could use factorization and cleanup along the lines of fslib in the filesys tests. - The p1-4.c testcase needs significant tuning. Currently it takes too long (especially when SHOW_PROGRESS is turned on) and doesn't show significant improvement.