01 01 Introduction to Operating Systems — Transcript

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1. 0:08[Music]
2. 0:20hi hello there
3. 0:21welcome to introduction to operating
4. 0:24systems
5. 0:26on this video lecture
6. 0:28we will be talking about
7. 0:30what operating systems do
8. 0:33computer system organization
9. 0:35computer system architecture
10. 0:38the operating system operations
11. 0:41resource management
12. 0:43security and protection
13. 0:45virtualization
14. 0:47distributed systems
15. 0:49kernel data structures
16. 0:51computing environments and
17. 0:54the free or libre and open source
18. 0:57operating systems
19. 1:00at the end of this video lecture you
20. 1:02should be able to describe
21. 1:04the general organization of a computer
22. 1:06system
23. 1:07and the role of interrupts
24. 1:10second describe the components in a
25. 1:13modern multi-processor computer system
26. 1:17third illustrate the transition
27. 1:20from user mode to kernel mode
28. 1:23next would be discuss how operating
29. 1:26systems are used in various computing
30. 1:28environments
31. 1:30and
32. 1:31provide examples of free and open source
33. 1:35operating systems
34. 1:38let's get started
35. 1:40let's start with the definition of an
36. 1:43operating system
37. 1:44so what is an operating systems
38. 1:48so i have here different versions or
39. 1:50different uh
40. 1:53operating systems
41. 1:54vendors like windows from microsoft
42. 1:57you've got linux
43. 1:58all right so red hat mac os
44. 2:01freebsd solaris and so on so we have a
45. 2:05lot of operating systems so what is the
46. 2:07role of an operating systems in the
47. 2:10computer system
48. 2:12so basically an operating system is
49. 2:14defined as a program
50. 2:16that acts as the intermediary between
51. 2:18the user of a computer and the computer
52. 2:21hardware
53. 2:22so basically
54. 2:24the operating system is the translator
55. 2:28okay between the
56. 2:29device
57. 2:30or the hardware
58. 2:32and the user
59. 2:34okay
60. 2:35so these are the operating system goals
61. 2:37so execute programs
62. 2:39and make solving user problems easier
63. 2:43second make the computer systems
64. 2:46convenient to use
65. 2:48third
66. 2:49use the computer hardware in an
67. 2:50efficient manner
68. 2:52now imagine your computer without an
69. 2:54operating systems
70. 2:56how can you run how can you execute and
71. 2:59how can you play
72. 3:00okay applications on your
73. 3:02computer okay so how can you navigate
74. 3:06onto the computer systems
75. 3:08and how would you manage
76. 3:10the resources in the computer systems
77. 3:14so basically
78. 3:16that's what an operating system is
79. 3:18if we are going to look at the
80. 3:21technical side of it operating system is
81. 3:24the one who manages the resources of the
82. 3:26computer
83. 3:28okay so we will go into a deep
84. 3:30discussion of those roles
85. 3:34next would be computer system structure
86. 3:37so basically your computer systems
87. 3:41is divided into four components so
88. 3:44you've got hardware you've got operating
89. 3:46system application programs
90. 3:49and users
91. 3:52now for the hardware hardware is any
92. 3:54tangible components
93. 3:56in a computer system
94. 3:57so it provides basic computing resources
95. 4:01now in operating system you will often
96. 4:04heard the word resources resources is
97. 4:07anything that can be shared to other
98. 4:09applications to other programs on your
99. 4:11system
100. 4:13it includes the cpu time
101. 4:15the memory the i o devices all of those
102. 4:19can be shared
103. 4:21next would be the operating system so
104. 4:23operating system controls and
105. 4:25coordinates use of hardware among
106. 4:27various applications and users
107. 4:30so that's what i'm saying earlier the
108. 4:31operating system is the one who manages
109. 4:34the resources
110. 4:36if we are going to have an analogy with
111. 4:39the traffic okay with the car traffic
112. 4:42on the road
113. 4:43so the operating system is a traffic
114. 4:45controller or traffic enforcer
115. 4:48okay
116. 4:49so next would be application programs
117. 4:52it defines the ways in which the system
118. 4:55resources are used to solve the computer
119. 4:58problems of the users
120. 5:01so word processors compilers web
121. 5:03browsers database systems video games
122. 5:06all of those are application programs
123. 5:09and this application programs needs a
124. 5:11lot of resources
125. 5:13okay for instance games
126. 5:15games are often consuming a lot of
127. 5:18memory resources
128. 5:22so the operating system is the one who
129. 5:23is responsible for the allocation of
130. 5:26those resource to these application
131. 5:27programs
132. 5:29okay so if the application program needs
133. 5:32to run
134. 5:33it defines
135. 5:35or it asks for the amount of memory from
136. 5:38the operating systems
137. 5:41okay
138. 5:42and
139. 5:42the last one would be the users
140. 5:45users pertains to people or the end user
141. 5:48people wear but sometimes it is also a
142. 5:51machine
143. 5:52okay or another computer
144. 5:56now let's talk about the abstract view
145. 5:59of components of the computer systems
146. 6:02okay so basically we have users
147. 6:04application programs operating systems
148. 6:08and computer hardware
149. 6:09so we could say that computer
150. 6:12is a hardware
151. 6:14plus the operating system
152. 6:16plus apps
153. 6:18plus users
154. 6:20so os serves as interface between the
155. 6:23hardware
156. 6:24and the apps and users
157. 6:27so os provides services for apps and
158. 6:30users
159. 6:32os manages resources
160. 6:34so government model it doesn't produce
161. 6:36anything
162. 6:38okay so debates about what is included
163. 6:42in the operating system so just the
164. 6:43kernel
165. 6:44or everything the vendor ships is that
166. 6:47it consider the distinction between
167. 6:49system applications and
168. 6:51third-party or user apps
169. 6:55right so basically the user interacts
170. 6:58with the application program traversing
171. 7:02through the operating systems and to the
172. 7:03hardware
173. 7:05no user can communicate directly with
174. 7:08the computer hardware
175. 7:11okay so it should pass us through
176. 7:13application programs and operating
177. 7:15systems
178. 7:19what operating systems do
179. 7:21so depends on the point of view
180. 7:24so users want convenience
181. 7:26is of use in good performance
182. 7:29especially to those who are a gamer
183. 7:32and those who are rendering videos on
184. 7:34their computer
185. 7:36they don't care about resource
186. 7:37utilization especially if you have a lot
187. 7:39or ample amount of resources to use
188. 7:43so but shared computers such as
189. 7:44mainframe or mini computer must keep all
190. 7:48users happy
191. 7:49operating system is a resource allocator
192. 7:52and control program
193. 7:54making efficient use of hardware and
194. 7:56managing execution of user programs
195. 8:00so users of dedicated systems such as
196. 8:02the workstations have dedicated
197. 8:04resources
198. 8:06but frequently used shared resources are
199. 8:08from the servers
200. 8:10so mobile devices like smartphones and
201. 8:13tablets
202. 8:15are resource poor
203. 8:17optimized for usability and battery life
204. 8:21so mobile user interfaces such as
205. 8:23touchscreen
206. 8:24voice recognitions
207. 8:26those are
208. 8:29under mobile devices
209. 8:30or tablets
210. 8:32so some computers have little or no user
211. 8:34interface such as the embedded computers
212. 8:37in devices and automobiles so it runs
213. 8:40primarily without user intervention
214. 8:47defining an operating system
215. 8:49so the term os covers many roles
216. 8:51because of myriad design and uses of oss
217. 8:56so it might be present in toasters
218. 8:59through ships
219. 9:01spacecrafts
220. 9:02okay gay machines
221. 9:04tvs and industrial control system
222. 9:07so born when fixed used computers for
223. 9:10military became more general purpose
224. 9:13and needed resource management and
225. 9:15program control
226. 9:17okay
227. 9:19now let us define an operating system
228. 9:22based on the perspective of an i.t
229. 9:24people
230. 9:26so no universally accepted definition
231. 9:28for the operating system
232. 9:30okay so everything a vendor ships
233. 9:33when you order an operating system is a
234. 9:35good approximation
235. 9:37but virus wealthy okay
236. 9:40so the one program running at all times
237. 9:42on the computer is what you call kernel
238. 9:45kernel is part of the operating system
239. 9:49so everything else is either
240. 9:52a system program or an application
241. 9:54program
242. 9:55okay so system program
243. 9:58ships with the operating system
244. 10:00but not part of the
245. 10:02kernel application program
246. 10:05all programs not associated with the
247. 10:08operating systems
248. 10:10so
249. 10:11one definition that i would give with
250. 10:13the operating system is that
251. 10:15my operating system is my resource
252. 10:18allocator
253. 10:20when you say resource allocator it
254. 10:22manages
255. 10:23and allocates resources
256. 10:26i would also define an operating system
257. 10:28as the one who controls the program
258. 10:31controlling program controls the
259. 10:33execution of user programs and
260. 10:35operations of i o devices
261. 10:39some define an operating system as
262. 10:41kernel
263. 10:42the one program that is running at all
264. 10:44times
265. 10:45or else being in application programs
266. 10:48okay so today's oss for general purpose
267. 10:52and mobile computing also include
268. 10:54middleware
269. 10:55this is a setup software
270. 10:57or software frameworks that provide
271. 11:00additional services or additional
272. 11:01services to applications
273. 11:03developers such as databases multimedia
274. 11:07graphics etc
275. 11:19[Music]
276. 11:26you