>agreed that it's a complicated mix of costs and benefits. there's always
>that kind of risk involved in working with volunteers. but leaving out
>interactive kernel debugging tools raises the bar too high, IMO. one of
We just have interactive and many kind of not interactive debugging tools.
I am also been able to discover hardware bugs (Epox lockup by running
disable_dma, now called PCI_QUIRKS) using one of such debugging tools (I
think it was developed by Ingo).
They all are in the IKD patches I am maintaining for the 2.2.x series.
There's also kdb from SGI. The latter is definitely the right debugging
tool for debug soft-deadlocks (when the irq are enabled on the CPU during
the deadlock) or with process in D state. And the last but not the least:
we always have printk (printk-debugging remeber me my first kernel hack
that happened in the awe32 driver: to debug the problem I remeber well I
written a printk at the start of _each_ function in the file awe-wave.c
(really a time consuming task...), then I was comparing the syslogd output
of a not-lockup session with the log of a lockup session; that was the
only way I had to try to fix the bug since I couldn't understand one line
of the kernel at such time :).
>not having debugging tools also means that some code is not as well
>tested, since the existing testing methodologies are intrusive and
I wouldn't test the code using a debugger. I like far more debugging at
runtime using BUG() for example.
>> Surely quality is more important than quantity in terms of amount of
>> code (or features) added to the kernel. Or do people think that Windows
>> 2000 with its 35-40 million lines of code and bloat is a good thing? :-)
>
>i know the entrance bar has always been high for Unix-like systems; it's
Fun :). I think the plain _opposite_. Before discovering Linux my only
entrance for hacking Windows was to binary-patch the assembler. That was a
far higher entrance bar IMHO.
The reason I like GPL is that it makes sure that there will _never_ be an
entrance bar at all, since _everybody_ can enter (and that's really great
IMO). Be sure that I wouldn't be here now if there would been an entrance
bar also on the linux kernel. And new hackers have this great mailing-list
that it's a great place to learn things, where very often many seasoned
kernel hackers (e.g. Linus, Alan, SCT, etc...) teach us new things every
day and really nicely answer to our questions. There is also some great
book where new hackers can learn (I like very much the "Kernel Hackers
Guide" and "The Linux Kernel", maybe there are even better books
avalilable but I never read the not-free ones so I don't know about the
others).
I don't know what you are talking about when you refer to not-Unix-like
systems as not having an high entrance bar. Hints?
Andrea
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