The install talks about slices and partitions. What are slices and partitions?
Slices are seen by other OSes as a primary partition and are created with fdisk. Slices also are like extended partitions in the fact that they contain partitions within them created with disklabel. OpenBSD needs to have the kernel in the first 8Gb of the drive and many people want to make a smaller slice at the beginning of the drive and then create the rest of the drive for the rest of the filesystem. OpenBSD only supports one slice per drive(OpenBSD native, you can dual/triple boot other OSes). You can make one large slice even if it is a 200+Gb drive and make the / partition near the physical start of the drive. This can be one of the more confusing things for people. A lot of experienced users know how to make it work but still get the terminology wrong. Part of the problem is people’s experience with other OSes tend to make it more confusing. If you use fdisk in DOS or Linux then it is making partitions while BSD has fdisk make slices and disklabel make partitions within the slic
