[net.unix-wizards] CBSIZE in 4.1bsd kernel

gorlick (02/06/83)

     Has anyone running 4.1bsd ever tried to increase the size of
`CBSIZE', the number of characters in a clist block?  I increased
it by 50% from 28 to 42 and got trap 8's and 9's when I rebooted
the new kernel.  Any advice would be much appreciated.

-Michael Gorlick-
{decvax, ucbvax}!trw-unix!gorlick

greg (02/24/83)

We have changed CBSIZE to 60 and 124 successively with now problems.
You MUST ,however, update CROUND to CBSIZE + sizeof int -1 (I think
that is the formula, it is printed on the same line in param.c as the
CROUND definition.

I did try to change CBSIZE to 252 but the system would not come up
multi-user. Any comments about that in net-land????

CBSIZE should be some multiple of 4 (preferably power of 2) minus 4
to allow for the array of CBSIZE chars plus a pointer (4 byte) to
the next CBLOCK.

Greg Hidley
ITTDCD

greg (02/24/83)

Increasing the CSIZE definition should allow the pseudo-dma routines
in the DZ driver transfer more chars at interrupt time (if I understand
it correctly!) and will allow DH's and DH like controllers (CS11's etc.)
to do larger DMA's.
Greg Hidley