Hi Peter; On Sat, 2008-05-24 at 23:34 +0800, Peter Teoh wrote: > On Sat, May 24, 2008 at 11:31 PM, Peter Teoh <[EMAIL PROTECTED]> wrote: > > Sent on behalf of William Case: > > > > From: William Case <[EMAIL PROTECTED]> > > Date: Sat, May 24, 2008 at 11:26 PM > > Subject: fork and exec > > > > Hi; > > > > I have a fundamental question about why Linux/Unix uses the parent and > > child modal to start and run new processes. > > > > [snip]
> > My question is: Why did the original designers of Multics/Unix choose > > to use the forking modal to start a new processes? Do not other OSs use > > other modals? What problem(s) did the fork overcome? Couldn't a system > > have been designed that just (in some way) starts each process raw? > > can u elaborate what is meant by "RAW"?? > I was using the word "raw" simply as a metaphor for a process that is directly placed in memory and accessed without first copying a parent or being overlaid on a space (buffer) created by a child. Two possibilities come to mind: 1) Starting a process the same way that PID 0 (swap ??) is started, or, 2) Starting a process the way that other Operating Systems start a process. In 2) above, I don't know how other OSes might start their processes but everything I have read about Unix related systems *implies* that the parent-child relationship is unique to or central to *nixes. I.e other OSes must be doing it differently. > I like new ideas....please elaborate....things necessarily have to be > different all the time.....that's how Windows can survive in > business.... > > > Intuitively, copying a process then overwriting it seems wasteful or at > > least inelegant, so why is it needed? How does a parent-to-child > > process enhance its (*nix's) design philosophy? > > > > Since forking is at the very core of the kernel, I would like to > > understand intellectually why the fork process is necessary? > > Once again, I am not asking how it is done. I am asking why. Is the parent-child relationship used because there is, in fact, no other way to do it? If so why does the claim seem to be made that parent-child processing is unique to *nixes? > > I am not being argumentative, or trolling, or proposing something > > different or better. Although relatively new to kernel programming and > > 'C' I am not a complete newbie. I would just like to see in my > > minds-eye what is going on and *why*. > > > > -- > > Regards Bill > > As I read various manuals, read books on the Linux Kernel source code, and prepare my machine for a virtual Linux system that I can explore and play with. This fork question, WHY?, keeps niggling at me and in some ways makes it harder for me to concentrate on the longer view of what is happening in the kernel. -- Regards Bill -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to [EMAIL PROTECTED] Please read the FAQ at http://kernelnewbies.org/FAQ
