reactos/doc/faq.txt

   1 Kernel Development FAQ (for v0.0.7)
   2
   3 This attempts to answer some of the common questions people developing for
   4 the kernel might want to ask (or at least what I think they should ask).
   5 Obviously I can only detail those parts which I have written so other
   6 developers please fill in the gaps.
   7
   8 Q: What is this, what are you people, what's going on
   9 A: This is the ReactOS, an operating system intended as a clone of windows
  10 NT. See the project website (http://www.sid-dis.com/reactos/) for more details.
  11
  12 Q: Why ReactOS
  13 A: To condemn Bill Gates to penury.
  14
  15 Q: What do I need to compile the kernel
  16 A: DJGPP, get it from http://www.delorie.com/djgpp
  17
  18 Q: How do I compile the kernel
  19 A: Unpack the zip. It is important not to install the kernel in the same
  20 directory as a previous version, this has caused a bit of confusion in the
  21 past. Edit the makefile in the top level directory, in particular select the
  22 correct host to build from. Then run make in the top directory
  23
  24 Q: What files are created when I make the kernel
  25 A: The following files are created in the kernel directory
  26         kimage = the kernel as a coff executable
  27         kimage.bin = the kernel as a raw binary image
  28         kernel.sym = a list of the kernel symbols
  29
  30 Q: How do I load the kernel
  31 A: Run the boot.bat batch file.
  32
  33 Q: Does it boot from disk
  34 A: Not at the moment.
  35
  36 Q: When I run the kernel it crashes
  37 A: The kernel (at the moment) can only be loaded from a clean system. That
  38 is one without EMM386 or any version of windows loaded. A quick way to
  39 ensure this (if you have windows 95) is to set the program to run in msdos
  40 mode and specify an empty config.sys and autoexec.bat. See the windows help
  41 for more information.
  42
  43 If you do that and the problem persists then contact the kernel team
  44 (ros-kernel@sid-dis.com) as it is probably a bug in the kernel
  45
  46 Q6: How do I load a module with the kernel
  47 A: Add the names of any modules to be loaded to the command line of boot.bat.
  48
  49 Q7: I want to add code to the kernel, how do I get it to be compiled
  50 A: You will need to edit the Makefile in kernel directory. There should be
  51 a statement like this
  52
  53     OBJECTS = hal/head.o hal/exp.o kernel/vsprintf.o \
  54               ....
  55               kernel/irqhand.o hal/page.o mm/virtual.o kernel/error.o \
  56               kernel/exports.o kernel/module.o
  57
  58 Add the name of the object file (the file produced when your code is
  59 compiled) to the end of the statement (in this case after kernel/module.o).
  60 If you need to go onto a new line then add a slash to the end of the
  61 previous line. It is also very important to use an editor which preserves
  62 tabs.
  63
  64 Q8: I want to add code to the kernel, how do I make it official
  65 A: Contact the kernel mailing list ros-kernel@sid-dis.com or our coordinator
  66 dwinkley@whitworth.edu. If it is for a specific section then the kernel
  67 website (http://www.geocities.com/SiliconValley/Peaks/1957) has a list of
  68 those working on individual areas, you might what to contact one of them
  69 instead.
  70
  71 Q9: What header files should I use
  72 A: Don't include the usual DJGPP headers like stdio.h unless you are using
  73 something compiler based like stdargs.h. To use the DJGPP headers requires
  74 linking with libc which is useless in kernel mode.
  75
  76 All the header files are in the top-level include directory which is laid
  77 out like this
  78          include  = general win32 api declarations
  79          include/internal = private kernel headers
  80          include/internal/hal = HAL headers
  81          include/ddk = header files with declarations for modules
  82
  83 There should be a file called api.txt which documents all of the functions
  84 (and which header files they need).
  85
  86 Q11: I want to export my function for modules to use, how do I do that
  87 A: Add the function to the list in kernel/exports.lst, then remake the
  88 kernel. Note the function must be declared as extern "C".
  89
  90 Q12: I want to make my functions part of the kernel interface to user mode,
  91 A: That section isn't finished yet, though it will probably mean adding a
  92 pointer to the function and the size of its parameters to a internal table
  93 somewhere.
  94
  95 Q14: I want to write a module, what are the guidelines
  96 A: See modules.txt in this directory
  97
  98 Q15: I want to write an ISR (interrupt service routine)
  99 A: See irq.txt in this directory
 100
 101 Q16: I want to use DMA
 102 A: Firstly this answer covers only DMA via the dma chips *not*
 103 busmaster DMA.
 104
 105 To program the dma chip use the functions in internal/dma.h (look in api.txt
 106 for details). PC DMA can only go to memory with a physical address below
 107 1mb (or 16mb on some systems), use the get_dma_page to allocate this kind
 108 of memory.
 109
 110 Q17: You haven't answered my question
 111 A: Send your questions to ros-kernel@sid-dis.com
 112
 113
 114 - David Welch (welch@mcmail.com)