Jim Starkey <jas@...> wrote:

>IDMS (and it's PDP-11 derivative) kept space allocation pages that
>reflected the percentage fill of the data pages. Almost every data
>page update required an update to the space management page. In
>a careful write environment, this would be a disaster.

And this is the big problem with a scheme which depends on ordered writes.
Writes go all over the disk, and must happen in a particular order. With a
log you can get those nice sequential writes. So what happened to the WAL
code in IB?

Jan Mikkelsen
janm@...