To KidGuru:
Although you should really want to master C/C++ first before attempting to code an OS, here is a site with some helpful info - www.osdev.org - seriously though, I would try to hold off for a while. Coding an OS isn't overly difficult (well okay it can be frustrating!), but you really need to have a firm grasp on programming theory and operating systems theory before attempting it. Good luck my friend.
Hillbillie according to my processor docs, it appears that when you call an INT from PM, the CPU checks the PE bit to see if you are in PM or not. If you are, it branches to a diff section than if you are in real mode. The pseudocode for the entire INT instruction is 3 pages long in my book. It seems that the CPU takes care of checking the PE so that you do not have to pop in and out of PM yourself. There are also all kinds of pther things that it checks like TSS's for task switches and other various things.
Bubba:
I did not know that. Very interesting indeed. I'll have to take a closer look at this when I get time.
You've got a long way to go, kid. I'm 19 and have just celebrated a victory of getting a Sony Playstation to display "Hello World" without an official dev kit. From there, I'm hittin a Playstation 2.
Kidguru,
You'll have to learn a lot before you're able to write your own OS and get it up and running. But if you take your time it is possible. I read that you didn't mind it would take some time, so I guess you have the spirit and patience to learn and write an OS on your own.
Take your time to learn about C, assembly, computer architecture and operating system concepts. And after some time when you really understand what's going on on that computer, you'll be able to write a little OS.
Good luck!
Kid, so u want to write an OS?
Why?
- If u've doing it to be rich .. well, ur a little late, if u've doing it to learn and to further ur skills go for it!
If I was u, I wouldn't worry about writing an OS for a PC, there really is no point, Bill Gates (19 ish) got rich through being in the right place at the right time with the right business skills,
Steve Jobs (20ish) did it, but didn't get rich - (when something is very good, it doesn't mean everybody will buy it!)
Linus (at 20ish) got there because he was looking for a PC with Unix on it, and it succeded because the software was free. plus he had the help of hundreds of likeminded programmers all over the world.
What i would do is write an OS which works on a PDA or a mobile phone. the hardware is more compact and it would be easier for one individual to write a full OS from scratch for one of those than for a modern PC.
When I was at college, I had to build a PC with a few LED's and a few flip chips and it taught me that to go from binary to one of those super complex 086's was a hell of a task and not somthing I was going to do .. and thats why I am now an IT salesman and not an world famous computer guru!
best of luck.
I don't want to belong to any club that'll accept me as a member!
Would writing an OS for a mobile phone really easier than for a PC? I don't think so, it is possible to write OS-es for a mobile phone that are more complex then for a PC. In other words, it is possible to write small and easy OS-es that will run on a PC.
The size of the hardware is not relevant for OS development. Ofcourse, when adding more features like USB support, Bluetooth support and all other nice stuff it's going to be quite complex. But I would recommend KidGuru to start writing just a little OS to learn the basics of OS development.
By the way, have you ever thought about how much functionality is available within a mobile phone?
When writing a small and easy OS, you don't need to know all the ins and outs of your microprocessor. Ofcourse you'll need to know about interrupts and have some fundamental knowledge of microprocessors. But you don't need to know the advanced features of it.
I think f0ul meant that he should try on a PDA, since there's not a lot out there for PDAs and cells right now (besides WinCE and PalmOS, what other OSes do PDA's use?)
-Govtcheez
[email protected]
>since there's not a lot out there for PDAs and cells right now
I see. But I would recommend a starter to start with well known technology. There is a lot of knowledge and experience in writing OS-es for PC's, they exist a long long time. I assume KidGuru has a PC, so I would suggest it would be better if he wrote a small OS for the PC.
Shiro, you just want him to make it for the PC so that you can make it for the PDA and become Bill jr. JK
I appreciate that PDA and Mobiles can have complex OS - but the point was that there was no reason to repeat somebody elses work.
OK so Kid is only 10 (yeah right!) but learning about how to control something that is useful now will be useless in the future - How many people wasted their teenage years learning how to manipulate the z80 processor - only to find that the only way of using that technology today is to play with smart cards.
How many people learnt to program in BBC basic to find that now u need to use VB to get anywhere - ( I know its a C++ forum, its only an example!)
To get anywhere in the world today, u need to think ahead, Bill gates did his programming on an Altair, a useless flashing box, but it taught him about the next technology. If he had learnt how to program on a mainframe, would he have had the right skills to be in the right place at the right time? No idea, but I hope it helps point Kid in the right direction.
I don't want to belong to any club that'll accept me as a member!
Bill gates couldn't program very well. He just had a lot of dosh.Originally posted by f0ul
To get anywhere in the world today, u need to think ahead, Bill gates did his programming on an Altair, a useless flashing box, but it taught him about the next technology. If he had learnt how to program on a mainframe, would he have had the right skills to be in the right place at the right time? No idea, but I hope it helps point Kid in the right direction.
The fact he couldn't program very well is irelevant..
he was programming a flashing box when everybody else was playing with calculators.
I guess the fact his programming tool was bought for him by his wealthy father helped a bit, but the point was that he was doing something before anybody else, and thats why they listened to him ( I really don't believe Im defending this fella!) - the fact that he also worked out that getting paid for his software on a licence basis is what made him rich .. but the programming skills came from playing with a little known box.
Imagine that if u could write an OS for one of those Sony Dogs - that would be cool, and people would remember ur name, and world domination is one step closer!
I don't want to belong to any club that'll accept me as a member!
A Small OS
Kid, if you really want to start with an OS, you will need to learn what you need step by step. I may not be the perfect guy to learn from but I enjoy explaining things and I like to think I'm good at it.
If you want me to walk you through the first steps of making an OS, I would be happy to do so. Just E-Mail me at [email protected]. By the way, I'm not saying that any of these guys are inferior to me or anything, most of them are better. It's just that sometimes it can get a little confusing with everyone sugesting things at the same time! Anyway, it's entirely up to you.
>but the point was that there was no reason to repeat
>somebody elses work.
Don't forget that KidGuru has recently started learning C and wants to learn about OS programming. Since he is new to this field, I would strongly recommend not to develop something in an almost quite new field. In fact, I think he'd better try to create something that others already made. So that he learns te basics of OS development, learns from the failures of others etc.
Also don't forget that almost all newer operating systems are built upon knowledge and experience gained from creating the older operating systems.
>how to control something that is useful now will be useless in
>the future
That's not the point. The point is that one should learn the fundamentals of some technology before going into something quite advanced. And therefore I think that KidGuru should learn about the fundamentals of OS development before creating a great OS.
By the way, who says that creating OS-es for mobile phones and PDA's is useful knowledge over 10 years when KidGuru is 20?
At university, the first years I've learned programming and designing systems using quite old systems, like the 68000. But the goal was to understand microprocesssor technology and software. If you know the basics, you can go further and understand more advanced technology.
In my opinion, you can't just start learning how a Pentium works without knowing the fundamentals of microprocessors. Ofcourse you can learn the specs by head, but would you understand it? Would you understand it when they are talking about interrupts, busses etc.?
A different example: digital signal processing. Many new, better, smaller and faster technologies were invented to improve digital signal processing. But if you don't know the basics of DSP, you can't understand for example why something advanced like MPEG works.
And that's the same with operating systems. You need to learn the basic concepts of operating systems before you can understand advanced operating systems. Until you don't understand the concepts, you can't write such operating systems.
>How many people learnt to program in BBC basic to find that
>now u need to use VB to get anywhere - ( I know its a C++
>forum, its only an example!)
Well, that depends on where you want to get. I'm working in the field of embedded systems and I don't know anything of VB. It's all C, C++, assembly and Java at this moment.
>No idea, but I hope it helps point Kid in the right direction.
The difficult thing is: what's the right direction? I don't know. All I know is that KidGuru is a 10 year old programmer who likes to start writing an OS. If I knew the right direction, I would tell it. But I can't. I can just give my opinion, it may be right or wrong, but I hope it provides some useful stuff to think about.
