Date: Mon, 14 Jan 2002 11:56:57 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Bela Bartok <eugene_bartok@yahoo.com> Cc: freebsd-hackers@freebsd.org Subject: Re: misc Message-ID: <3C433809.5B3147AD@mindspring.com> References: <20020114161642.37953.qmail@web20402.mail.yahoo.com>
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Bela Bartok wrote: > > hi, i am student of computer science, hooked on 2 oses: solaris > and freebsd. I want to understand why people say: 'binaries are not > loaded on memory they are mapped (man 2 mmap)' ?. Because they are demand paged. The pages in a 1M binary are only loaded as they are referenced. Otherwise your startup time would be incredibly bad for any large application, and you would have to have the free memory necessary to map it all into core. Memory is "overcommitted" -- that is, there are more mappings than there are real memory, and if needed, clean pages are simply thrown away, and brought back in from the executable file, as needed, later. > Also, Can any of you explain me in another way (like > graphical or easy-to-learn) way in which i can understand > the 'kernel' of freebsd?, how it works?, the file /kernel > is just a part of the whole kernel that only care about > devices (serial ports, buses devices, etc) ?. You need to read an OS book. I recommend "The Design and Implementation of the 4.4 BSD Operating System". In short, a "kernel" is like the program that gets run when you boot Windows. It owns everything in the machine, and only lends it out to be used by programs that you write. > by the way, What new projects like 'the freebsd developers > handbook' is around?. There are a number of recently published books. Search for "BSD" at Amazon for more of them. > I think freebsd.org should have a part in the website with > the same style but just for developers? Good idea... when will you have it up? 8-). > for example, i learned freebsd as a home user using just > freebsd.org, mailing list and documentation. Why i cant > learn freebsd internals in the same way? Because things change more quickly than they are documented, for one reason... > i want to look for unix internals in a site centralized!. There are several of these. Do a web search for "unix internals" (use the quotation marks). -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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