Arsitektur dan Organisasi Komputer - Operating System

Software:
-> System: utk membantu, cth OS
-> Application: program yg dibuat utk menyelesaikan masalah

OS: kumpulan program utk membantu pemakai utk menggunakan komputer dengan lbh mudah.

Fungsi OS:
- Convenience -> membantu
  cth: kalo mau bikin chart tinggal ambil

- Security (keamanan)
   -> Aman thd ancaman (thread), cth: org yg ga punya hak gabisa buka
        -> Data Availability, data integrity, lost data
   -> Aman thd serangan

- Efficiency: utk mengatur sumber daya (CPU, Memory, I/O) di komputer utk dipakai se efisien mungkin.

Tipe" OS (Sesuai Algo):
1. Interactive
2. Batch
3. Single Program (uni-programming)
4. Multi Programming (multi-tasking)

Early systems -> No OS, program interact directly with hardware

Simple Batch Systems -> resident monitor program

Multi-programming Systems -> I/O Devices are very slow, so when one program is waiting for I/O, another can use the CPU
-> Time sharing systems: Allow users to interact directly with the computer. Multiprogramming allows a number oof users to interact with the computer
-> Scheduling: key of multiprogramming
     -> Long Term: Determines which programs are submitted for processing. E.g. Program masih di hard disk tapi udah diatur nanti program dari HD mau diambil dan ditaro dimana
     -> Medium Term: Part of the swapping function, usually based on the need to manage multiprogramming. Trjd di memori utama
     -> Short Term: Dispatcher. Fine grained decisions of which job to execute next. Trjd di CPU

Process Control Block
- Identifier
- State
- Priority
- Program Counter
- Memory pointers
- Context data
- I/O Status
- Accounting Information

Diagram:

Key Element of OS:

Memory Management
- Uni Program: memori terbagi menjadi 2, satu utk OS (monitor), 1 utk program yg sdg berjalan
- Multi program: "user" part is sub-divided and shared among active processes

(Sisanya baca sendiri ya, ada juga di materi OS :))