Introduction to Operating Systems

An operating system is a program that manages the computer hardware. It also provides a basis for application programs and acts as an intermediary between the computer user and the computer hardware. An amazing aspect of operating systems is how varied they are in accomplishing these tasks. Mainframe operating systems are designed primarily to optimize utilization of hardware. Personal computer (PC) operating systems support complex games, business applications, and everything in between. Operating systems for handheld computers are designed to provide an environment in which a user can easily interface with the computer to execute programs. Thus, some operating systems are designed to be convenient, others to be efficient, and others some combination of the two.

Before we can explore the details of computer system operation, we need to know something about system structure. We begin by discussing the basic functions of system startup, I/O, and storage. We also describe the basic computer architecture that makes it possible to write a functional operating system.

Because an operating system is large and complex, it must be created piece by piece. Each of these pieces should be a well-delineated portion of the system, with carefully defined inputs, outputs, and functions. In this chapter, we provide a general overview of the major components of an operating system.

Pengertian Sistem Operasi
Sistem Operasi merupakan program utama (Sekumpulan program kontrol atau alat pengendali) yang secara terpadu bertindak sebagai penghubung Software Aplikasi yang digunakan oleh user dengan hardware komputer.

Tujuan / Manfaat Sistem Operasi
Sistem operasi mempunyai tiga sasaran (menurut Stalling), antara lain :
1. Kenyamanan, membuat user menjadi lebih nyaman
2. Efisien, menjadikan penggunaan sumber daya sistem komputer secara efisien.
3. Mampu Berevolusi, memudahkan pengembang-an, pengujian dan pengajuan fungsi2 baru tanpa menggangu layanan yang dijalankan sistem komputer.

Fungsi Dasar Sistem Operasi
Menjembatani hubungan antara hardware dan program aplikasi yang dijalankan user.
Mengatur dan mengawasi penggunaan perangkat keras oleh user dan berbagai program aplikasi (Resource allocator).
Sebagai program pengendali yang bertujuan untuk menghindari kekeliruan (error) atau sebagai penjaga yang melindungi komputer dari berbagai kemungkinan kerusakan.

LAYANAN SISTEM OPERASI
Sistem operasi seharusnya menyediakan layanan-layanan di bidang berikut :
 Pembuatan Program
 Exsekusi Program
 Pengaksesan Perangkat Masukan/Keluaran
 Pengaksesan Terkendali terhadap Berkas
 Pengaksesan Sistem
 Deteksi dan memberi Tanggapan terhadap Kesalahan
 Akunting

JENIS-JENIS SISTEM OPERASI
Jenis Sistem Operasi dapat dibedakan dari aspek:
 Ukuran (media yang digunakan)
    disket » DOS; CD » Linux Live-CD;
    Mainframe, Server, PC, PDA, mobile phone, dll.
 Tujuan (Commercial & Non-commercial)
    Windows, Mac OS, Unix » Commercial
    Linux, FreeBSD, Sun MicroSystem » Free, open source & GNU/GPL)
 Kegiatan (PC stand alone, PC workstation, server, router)
    Windows XP/Vista, MacOS, Linux, Windows 2000 Server, Unix, Novell Netware, Cisco IOS, dll
 Struktur Sistem Operasi (hirarki SO)