can an os be wrritten in 6 months time

[Pype.Clicker]

Windows 9x and earlier SUCK. They aren't even real operating systems!

Please dude, take the time to step back. Document yourself on those systems, on what they actually provided, on how they worked, etc. before you claim "they aren't even real operating systems", right ? i won't re-argue that since i did it just above. You sound like just camping for a flag that's no longer there, you know ?

most of us were speaking in terms of a minimalist single-user CLI OS. Which is what DOS is, and also what linux is (although it's becoming more and more bloated, and it's no longer single-user though it used to be).

No. Back in '95, linux was already multi-user, had integrated network stack and routing support, etc.

/*
* The "user cache".
*
* (C) Copyright 1991-2000 Linus Torvalds
*
* We have a per-user structure to keep track of how many
* processes, files etc the user has claimed, in order to be
* able to have per-user limits for system resources.
*/

That definitely sound like multi-user to me ! and it is multi-process from its very beginnings too. Please, once again, document yourself before claiming such non-sense stuff.

You have to admit that it is fairly minimalist

Minimalist !?? Dude, the _kernel_ needs to be gzipped to fit a floppy and you call _that_ minimalist !??

It is a modern DOS-like OS (speaking in terms of interface).

So you saw the command line and thought "oh, that's just like dos". How fun. Do you happen to know both CP/M (which QDOS clones) was meant to clone unix interface on small systems. Go deeper than the immediate stuff, okay ? even the crude text interface of linux has support for cut-and-paste with the mouse (if configured so), support multiple screens, input and output histories you can scroll, command (and more recently arguments) completion, etc.

And all this _is_ part of the OS. The shell, the basic commands like "ls", "cp", etc. are definitely part of the operating system even if they're running as user-level code.

[Candy]

Windows 9x and earlier SUCK. They aren't even real operating systems!

I'd like to see you do better?

/*
* The "user cache".
*
* (C) Copyright 1991-2000 Linus Torvalds
*
* We have a per-user structure to keep track of how many
* processes, files etc the user has claimed, in order to be
* able to have per-user limits for system resources.
*/

That definitely sound like multi-user to me ! and it is multi-process from its very beginnings too. Please, once again, document yourself before claiming such non-sense stuff.

Linux was started as a terminal emulator. That wasn't quite multitasking, -process or -user in any way.

You have to admit that it is fairly minimalist

Minimalist !?? Dude, the _kernel_ needs to be gzipped to fit a floppy and you call _that_ minimalist !??

BZip2'ed last time I checked, and most kernels I compile end up not fitting a floppy.

[Solar]

My Gentoo kernel is 2.2 MB. I admit it's not a modular but a really monolithic one, but it has only support for what my 1999 laptop has to offer, hardware wise - nothing else.

Minimalistic? Nah...

[Kemp]

It is a modern DOS-like OS (speaking in terms of interface).

[...] even the crude text interface of linux has support for cut-and-paste with the mouse (if configured so), support multiple screens, input and output histories you can scroll, command (and more recently arguments) completion, etc.

Not to mention the extensive ability to use regex's which DOS (and even windows in its search functions etc) doesn't support. I've seen them get some serious usage.

[Pype.Clicker]

Linux was started as a terminal emulator. That wasn't quite multitasking, -process or -user in any way.

didn't know that ...

however, http://www.oldlinux.org/Linus/index.html reveals that, even at the time of 1.0.0, you had in the "Things missing/incomplete in LINUX"

As mentioned, no login and init processes. Currently LINUX boots up in single-user mode, with the root as console-user. This is enough for some porting work, but not really practical.

That lets me thing that, from the very beginning of linux, there was an intention of supporting multi-users (e.g. http://oldlinux.org/lxr/http/source/include/sys/types.h already contains "uid_t" and http://oldlinux.org/lxr/http/source/fs/open.c appears to check the UID and may deny access if group/user permission do not apply), even if there was no actual tool for managing/authenticating/etc. those users at the time of early releases.

Comparatively, MS-DOS never had even the option of storing an ownership attribute for a file and it was clearly intended to be here "the very same computer blissfully ignoring who's between chair and keyboard".

[NotTheCHEAT]

I am in NO WAY comparing linux to DOS. I'm not saying linux was ever like DOS, or is like DOS. I'm saying DOS would be like linux if it didn't die.

And Windows 9x are not real OSes, so if you want to argue about how great they are you shouldn't do it in an OS dev forum. Windows 9x runs on top of DOS. It has most of the features of a modern OS, but still uses DOS with config.sys setup such that win.exe is used as the shell instead of command.com.

I'm not saying I can do better than Windows 9x. A critic is someone who criticizes something, even if they can't necessarily do better themselves. I plan to do better than Windows 9x, but I'm so busy with school now I have little time for writing kernels. So right now I am a critic - I criticize Windows 9x even though I can't necessarily do better myself.

As mentioned, no login and init processes. Currently LINUX boots up in single-user mode, with the root as console-user. This is enough for some porting work, but not really practical.

Similar to DOS, right? BTW, you can have "multiple user accounts" (VERY limited, no protection, etc.) if you setup config.sys right. I'm not comparing those to linux, because they are incredibly primitive, but you know what I mean, right?

[Colonel Kernel]

And Windows 9x are not real OSes, so if you want to argue about how great they are you shouldn't do it in an OS dev forum.

Nobody said it was great. We're discussing matters of fact, not judgements of whether previous versions of Windows were any good.

For the record, Win9x were real OSes. They ran in protected mode (using V8086 mode quite liberally), supported threads, processes, you name it. They were certainly hacky (full of 16-bit code, had unprotected shared regions of the address space, etc.), but they were real OSes.

It has most of the features of a modern OS, but still uses DOS with config.sys setup such that win.exe is used as the shell instead of command.com.

As others have already said, Win9x used DOS as a bootloader. Once win.exe loads, it switches to protected mode and encapsulates DOS as part of a V8086 monitor.

If you want the real scoop, read "Inside Windows 95". It's like documenting a train wreck but it's interesting anyway.

[NotTheCHEAT]

OK, I admit I was speaking about something I'm no expert on. Maybe I will read the documentation of the "train wreck"...

[Antwarrior]

Keeping in fashion with raising 5 year old threads from the dead.....


I think in 6 months ,developing with an emulator and some home made tools you can produce a reasonable OS. What would be difficult is keep the OS stable over a wide range of hardware.

also depends on what you mean by complete? what features would you need to have something that even feels complete ?

keep it simple and you'll be surprised by how much you get done ....

[Solar]

Keeping in fashion with raising 5 year old threads from the dead.....

???

If you found out that it is a "fashion", you also have found out how we think about it...

[distantvoices]

rip, sweet thread, rip

btw: win95, win98 & others are operating systems. One should definitely look up some stuff ere claiming they aren't.

as for creating an os in 6 months: not feasible, in my opinion, for the standards nowadays users are expecting from an os.

but as usual, opinions vary, and what some (like me) consider incomplete and unusable might appeal others as the finest and greatest stuff in the world.

besides, clicker is a cool project.

[Pype.Clicker]

@BI: forgive me for having thought you were responsible for popping that thread. Eyes aren't working very properly these last days

@popper: popping threads in general is BadIdea (tm), especially flaming threads such as this one (e.g. it may happen that a "best language for xxx" is still unlocked because people 4 years ago proved capable to drop the flame without needing a lock. Don't jump on the occasion to add your grain of salt to the flamewar, right ?

@all: some of the threads around here are pointed as reference by the wiki. This may lead to wiki reader to post replies to them without checking whether they were "active" threads or not. when that occurs (and when the post is obviously more a "fork" of the original question than on-topic additionnal and constructive comment), the thread is then split into "archive" and "new content" by some moderator. That's not "fashion", that's just newbies mistakes we live with).

[com1]

I could probably create a beta version of my "dream" os in 2 years, but without all the customized bells and whistles.

[mathematician]

hi my name is avinash.

i am in my 4th year cs .

i would like to write a simple os and i have about 6mts time

for development . People here in india claim its not possible to develop a full working os ?

is this true ?

Um, well somebody wrote version 1.00 of MS-DOS in about six months, but I would say that you would have to be a pretty nifty assembly language programmer to emulate him.

[Tyler]

hi my name is avinash.

i am in my 4th year cs .

i would like to write a simple os and i have about 6mts time

for development . People here in india claim its not possible to develop a full working os ?

is this true ?

Um, well somebody wrote version 1.00 of MS-DOS in about six months, but I would say that you would have to be a pretty nifty assembly language programmer to emulate him.

I reckon any of the long term OS Developers here could do that in only a few months. The reason it took him so long was he wasn't an OS Developer, just an intel user who wrote a command line program with interrupts that Microsoft sold to IBM under the idea that software wasn't the future. Point being, DOS isn't exactly full of features, it really depends on whether the meaning of the term "Operating System" has evolved. Does anyone consider the kernel an entire operating system any more?