Thanks jggimi for your help. I tried to get on early to edit my post, but you posted first. Sorry you had to spend time on this.
First, disklabel under OpenBSD, cfdisk under Slackware, and whatever program pclinuxos uses, all showed the same partition size. Those are the systems on this 120 gig hd. Only difference is that linux showed the partition as ext2fs (before formatting it back to fat32) and I had to mount the same partition under OpenBSD with mount -t msdos. I could play all the ogg files (about 2 gig of files) just fine under either linux system, but when booting into OpenBSD to play them, I was shown the old fat32 files, and yes I would run #disklabel -p m wd0 to check the size of the mounted partition
All is well now since I did something last night that I've wanted to do for a while. I backed up my OpenBSD system, deleted that partition, deleted an old fat partition that was beside it (held os/2 files), and then installed current! Now, all 3 systems show the same information for the data partition.
I know it all sounds very confusing, but all that really happened is the data partition went from fat32 to ext2fs and then back to fat32. Formatting (to me) is as fast and safer than "rm -Rf /"
I don't want to get into the habit of typing something like that.
All is well now. Sorry for the noise.