[TUHS] PDP-8 (was: 2.11BSD cross compiler)

Greg 'groggy' Lehey grog at lemis.com
Sat Oct 2 13:46:01 AEST 2010

On Thursday, 30 September 2010 at  6:50:29 -0700, Larry McVoy wrote:
>>>>  If you don't get the question you are not an OS person,
>>>> if you are, of course you get it.
>> Hmm.  Am I expected to understand this?  Seriously, I don't know how
>> many people really wrote anything like swtch ().
> You'd be amazed at how many people did their own user level threads.
> Gotta write swtch() for that.

I think you're missing the joke.  But swtch () is a specific kernel
function in UNIX, though in this thread (excuse the pun) people seem
to be using it as a synonym for a scheduler.  And not many people need
to write their threading library by hand any more.

> And it's not swtch() so much as do you understand the stack frames?

That's a different issue.  Any programmer worth his salt needs to
understand the underlying hardware, including stack frames.  For my
personal understanding of them, see
towards the end, or http://www.lemis.com/grog/Papers/Debug-tutorial/
for the kernel context, page 17 on.

> If you could look at the stack frames and give me a stack trace
> that's more or less the same thing.

(gdb) bt

The real question is not to get a stack trace, but to analyse it.

Finger grog at FreeBSD.org for PGP public key.
See complete headers for address and phone numbers.
This message is digitally signed.  See
http://www.lemis.com/grog/email/signed-mail.php for more details.
If your Microsoft MUA reports problems, please read
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 195 bytes
Desc: not available
URL: <http://minnie.tuhs.org/pipermail/tuhs/attachments/20101002/e02ab2c7/attachment.sig>

More information about the TUHS mailing list