If you want a really old distribution, you still can get Slackware-1.1.2 on this mirror
. It includes kernel 0.99.15.
For the records, they have Slackware 2.01, 2.1, 2.2.0, 3.0 and 3.1 as well.
More recent versions are available on many servers.
But will these run on recent hardware
EDIT. I just mirrored Slackware-1.1.2 tree. It weighs 79 862 541 bytes. Slackware-12.2 tree is slightly heavier: 4 315 166 580 bytes, that is to say roughly 54 times more