Siju George wrote:
> Hi,
>
> In there an online openbsd version of
>
> http://linuxgazette.net/issue59/nazario.html
>
> by Jose??
>
> I understad that it is there in his book but am unable to place it on
> the web :-(
>
> Please let me know if it exists on the web!!!
Haven't seen such a beast. LONG ago (before nick@), I actually sat down
to start working on such an article for my own (now mostly abandoned)
OpenBSD help pages. That was back when I was mostly writing in Windows
and uploading to OpenBSD web servers, and it was a royal pain in the
butt to write, as almost every line in a dmesg points to a man page
('course, with what I know now, I could automate that part of the task
with a little scripting. :)
All you really need to do is understand just a little bit about how it
is displayed, and start reading. Information-wise, it is one of the
densest bits of writing you will normally see (short, perhaps, of a hex
dump of a binary executable) -- almost everything has meaning. Let's
look at a small snippet:
> pchb0 at pci0 dev 0 function 0 "AMD 761 PCI" rev 0x12
> ppb0 at pci0 dev 1 function 0 "AMD 761 PCI-PCI" rev 0x00
> pci1 at ppb0 bus 1
> vga1 at pci1 dev 5 function 0 "Matrox MGA G400/G450 AGP" rev 0x04
> wsdisplay0 at vga1 mux 1: console (80x25, vt100 emulation)
> wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
> pcib0 at pci0 dev 7 function 0 "VIA VT82C686 ISA" rev 0x40
> pciide0 at pci0 dev 7 function 1 "VIA VT82C571 IDE" rev 0x06: ATA100, channel
> 0 configured to compatibility, channel 1 configured to compatibility
> wd0 at pciide0 channel 0 drive 0: <WDC WD400BB-75AUA1>
> wd0: 16-sector PIO, LBA, 38166MB, 78165360 sectors
> wd0(pciide0:0:0): using PIO mode 4, Ultra-DMA mode 5
The first "word" of most dmesg lines is a device driver, and in this
case, they all are: pchb, ppb, pci, vga, wsdisplay, pcib, pciide, wd.
And (get this!) they each have a man page! Is that cool or what? :)
So, you want to learn about wsdisplay, "man 4 wsdisplay".
In this case, ppb0 is a PCI-PCI bridge, giving you another PCI bus
(pci1) attached to the first one (pci0). That second PCI bus has the
vga(4) driver hanging off it, and the wsdisplay(4) driver hangs off
vga(4). There's an ISA bus which isn't being used in this snippet, but
is used later in the sysetm for the ISA devices like the keyboard, DMA
controller, etc. (take note: that's one reason why you DON'T SNIP YOUR
DMESG when asking for help!). There's an IDE interface hanging off
pci0, and that has a wd(4)-supported disk hanging off it.
Nifty, eh?
yeah, I probably should write up a "how to read a dmesg" article,
probably be a little long for the FAQ (or maybe not, I *do* get to make
those decisions!), but there are other places it could be put. We could
end up with a whole chorus of people on misc@ beating the snot out of
people who don't post dmesgs or snip them down to only the part THEY
think we need. Might be a good thing. :)
Nick.
