How hardware devices work together

Vignesh Sekar
A free video tutorial from Vignesh Sekar
Software Engineer,Computer Science Instructor
4.5 instructor rating • 14 courses • 12,870 students

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Operating Systems from scratch - Part 1

Learn the concepts of Operating Systems from scratch as Operating System forms the core of Computer Science

08:18:41 of on-demand video • Updated October 2020

  • You will become very familiar with the core concepts of Operating Systems
  • You will be able to challenge the interviewer on questions related to Operating Systems
  • You will view Computer Science in a different dimension
  • You will be able to answer all questions of exams like GATE,PGEE,ISRO (after completing all parts of OS course
  • You will be able to get a top grade in your Operating systems course in your Bachelor's degree
  • Understand how Operating Systems work
  • Understand how a process is created
  • Understand how CPU scheduling is done in Operating Systems
  • Understand the various scheduling algorithms we have in Operating Systems
  • Understand how CPU , Memory and Disk work together
  • Understand Memory managment in Operating Systems
  • Understand how a process is moved from hard disk to RAM
  • understand memory allocation strategies used by operating systems
English [Auto] Finally see this see what are in what these men make on Google system. They find that this is young This is a computer system and it is having CPM RAM and the hard disk now. Any problem you make in the computer it will be definitely be present in say Doggett's. Right. Definitely present in say the hard disk. Look this is you. We have a high level program. Right we have a high level program for the high level program into programs which we like for example a C program or a job program or any software that we use like Photoshop or Google Chrome or whatever. We say the most high level program right. No this high level program cannot be directly placed inside the hard disk. Great we can replace it. The reason being c.. Why do we let the programs relate programs. Because those programs has to be exhibited by the C.P. you at some point in their right or even fix the program or even the executive. That is the rule with a program. Now the problem here is NCB you will not be able to understand how program right. Which means the programs are written using C or job or Python or whatever forget such programs cannot be understood by C.P. or you can at best and one new ones and zeroes. They can then bind any numbers with just ones and zeros. So what we do is we can put our source program into something called Machine call machine code is nothing but ones and zeroes. The other program which you write will be converted into a code and this code will have one neat ones and zeroes. This is what we mean by machine code. We can also say this docking Seek-Seek ordering Z-code double call or even low level program that is under various name names being used for machine code. So any problem you take will be converted into machine code by using a program. Our best compiler compiler is also a program software which will convert a high level program in the machine code. Now once we have converted this working you always place the mission core into the hard disk of the computer. That's all there. Any program you take will be present in say the hardest and most importantly that program will be in by machine code. The program will be in machine code fine. So we have placed the program into the heart. There is not any housekeeping who will actually access a program. It see any program you write. It has to be exhibited by the CPP at some point in time. No hope you will exit the program. The most important point here read notice it is our you cannot access the hard disk directly Ray. However you will never be able to access the hard disk directly. However see Puke can only access the RAM directly. This can always happen but this should never happen. So what we do is let those of you CPM requesting for a program say what rights if you think ghosting but a program you want. No one will do it. They will search for Program B one in inside the third I of the program in be on Instagram. See one more important point. You can even see in the background that size of the RAM is very small compared to say size of the hardest things I've promised very small compared to say so far this year even if you take computer there and which we use or something or on for gigabytes of Max it can be somewhere around 16 gigabytes right. This is the size we use create it for right. But if you dig hard is this something that 500 G-B or even to B-B these days. The size of this is very very large. Come back to say so. The reason being this is very cheap ceramics very very costly. So this is the reason the size of this is very large compared to size of ram into these computers. So one thing is for sure we cannot replace all the programs since they are right we cannot make all the programs white because the size of our business is very large. Only few How the hardest programs. How can you place all the programs in say run. It is not possible to write source inside of the Imust very small. We cannot replace all the programs in say the raw file. Now lets come back to this. So once ECP once things preprogram be one it will start in the RAM in case the program is present in the RAM. It is fine it will fetch the program from there I guess if you want is present in say the CPI will fetch the program be 1 and then execute it. OK which fitted line by line and then it will execute it. It is simply very very less that way because here MCP is one only accessing the router right. In order to fix the program be want whereas in case of throw in case it be one is not present in the CCP searching but program we want right now in case if one is not something better and in that case one thing is for show up you want to be definitely present in the artist. Right now what we're really doing is we will copy the program the one and then we will place it in the right. For example you wouldn't be present in say the lamb in the god is now walking away as if P1 is not present in there and B will create a copy of P1 and then new place being one in say that right. Right. Now once this has been moved into the back seat we will dig the program from there and this is how our program is generally accessed by oversleeps you can get the programs present in the Ramsey periodically accessit. In that case it takes very little time. Bogosity was only random access. Damn right we need to access one leader and we know the program is very very fast. Let us guess that the program is not present in the lab. In that case we need access bar disk as well as our way because we need to copy the program from the heart. So we are accessing the hard disk. And once we placed the program into the I am OCB will read the program from the right. So you effectively are accessing the hard disk as the last Rangan been ordered. This is very very slow. It takes a lot of time in order to access the hardest. So give it a C in the program CVO is asking for is present in that are you just going to dig ridiculous TAM for this s.p you access the program. But as soon as the program is non-present in that app you're just going to take a lot of them for you to access the program because we need to access both the hard disk as well less RAM and we know that this is very very slow. They say See these are important points Lammas led them on this right. This is the reason we have the same stuff from the smaller of them hard. It's also obvious very very fast combating brain Hartness.