Taking up the old floor was a disgustingly messy job. I took up the linoleum and then spent a couple of days chiseling off a layer of concrete. Then I used a paint stripper to get through a few layers of paint and some well dissolved tar paper to get to the original poured concrete sub floor that was in excellent condition. I used a circular sander to get rid of the stubborn paint and filled in the two holes in the subfloor. For some mysterious reason, it has a top coat of red tinted concrete. It is scored, I think, to assist the tile installer.
The laying of the new tile floor appears to have worked. Everything is level. One minor crisis. As soon as I began to apply the thinset mortar, it became clear to me that we would not have enough to complete the job. Husband ran to the hardware store. They didn't have it, so he dashed across Central Park to the Home Depot and got back just as I was scraping the bottom of the bucket.
The spacers made such an eerie landscape. I didn't want to remove them.