1. Sistem Operasi – 13 – Memory 1: Address Translation and Virtual Memory
  2. Sistem Operasi – 14 – Memory 2: Caching
  3. Sistem Operasi – 15 – Memory 3: Demand Paging
  4. Sistem Operasi – 16 – Memory 4: Demand Paging Policy
  5. Sistem Operasi – 17 – Performance, Storage Devices.
  6. Sistem Operasi – 18 – Queueing Theory, Disk Scheduling, and File Systems.

Disc scheduling is an important process in operating systems that determines the order in which disk access requests are serviced. The objective of disc scheduling is to minimize the time it takes to access data on the disk and to minimize the time it takes to complete a disk access request.

Read more: Sistem Operasi – 18 – Queueing Theory, Disk Scheduling, and File Systems.
Time seekNote from CS162 Lecture 18 (4/2/2020): Queueing Theory, Disk Scheduling & File Systems
3:17flash memory
14:00queue: simple deterministic world
21:40reality: a bursty world
28:28background: general use of random distribution
48:19a little queuing theory: some result
55:30why unbounded response time?
57:37a little queuing theory: an example
1:02:14optimize I/O performance
1:04:04I/O scheduling discussion
1:06:00Disk scheduling
1:10:22how do we hide I/O latency
1:11:11from storage to file system
1:13:27I/O & storage layer
1:14:11C (language) low level operations
1:14:36building a file system
1:16:40translating from user to system view
1:18:10disk management policy
1:20:54what does the file system need
1:21:47data structure on disk

Poin-poin Penting

  • on a stable system, arrival rate equal to departure rate (little’s law)
  • if arrival rate greater than departure rate, the system become unstable, since the queue will grow infinitely. however, in reality, the queue capacity is finite, so the response time should be finite. but is has cost: if the queue is full, further arrival will be rejected.
  • file system used to translate from user (file name and path) to system view (block/sector of a disk)

Latar Belakang

I/O transaction is slow, need to hide or optimize.

Queuing theory resources

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