Make long ddb not suck

[Bruce Evans]

> I have a patch that adds a simple paging facility to ddb at the
> db_printf() level using a one-shot callback mechanism.  It includes
> a simple paging callback that rearms itself based on the users
> input (space does another page, enter another line).  I've used this
> facility to replace the hand-rolled paging in 'ps', 'show pci', and
> 'show ktr'.  The patch is at http://www.FreeBSD.org/~jhb/patches/ddb.patch
>
> Comments?

I like it.  It also needs to have some idea of line lengths, so that
20-line pages with too-long lines don't scroll off 25-line terminals.

> Also, I notice that we have a 'show threads' command commented out from
> the original Mach sources.  I think we should change 'ps' back to just
> showing simple process info (and hopefully back to 80 cols) and only
> print thread info for 'show threads'.  Maybe show threads should take a
> PID as the argument?

I would like almost anything to make it readable again.  It now mostly
fits in 80 columns on i386's but is still unreadable because columns
don't line up.  It will never fit in 80 colums on arches with 64-bit
pointers.

Bruce