[NetData69] ~ Rangkuman materi Meet-7 sebagaimana persyaratan tugas adalah sebagai berikut:
Fungsi sistem pembantu dalam OS adalah untuk convenience dalam mempermudah pemakaian serta efisiensi dalam penggunaan resource komputer yang ada.
Dalam komputer sendiri, terdapat beberapa layer hirarki dalam penggunaan sistemnya
- Tidak ada OS
- Programs ber-interaksi langsung dengan hardware
- Dua permasalahan utama:
- Scheduling
- Setup time
- Resident Monitor program
- Users submit jobs to operator
- Operator batches jobs
- Monitor controls sequence of events to process batch
- When one job is finished, control returns to
- Monitor which reads next job
- Monitor handles scheduling
- I/O Device very slow
- When one program is waiting for I/O, another can use the CPU
Single
programming system
Multi programming system
dengan 2 program
- Allow users to interact directly with the computer (i.e: Interactive)
- Multi-programming allows a number of users to interact with the computer
- Key to multi-programming
- Long term
- Medium term
- Short term
- I/O
- Determines which programs are submitted for processing (i.e. controls the degree of multi-programming)
- Once submitted, a job becomes a process for the short term scheduler (or it becomes a swapped out job for the medium term scheduler
- Part of the swapping function (later…)
- Usually based on the need to manage multi-programming
- If there is no virtual memory, memory management is also an issue
- Dispatcher
- Fine grained decisions of which job to execute next (i.e. which job actually gets to use the processor in the next time slot)