What is a CSM?

I went to the Lacey Retreat, this past weekend, with my antique circular sock knitting machine. It's a Legare 47 and was built to knit socks for the troops during WWI.

When you click on the picture, look for the two black cones of wool and scroll up.
I mainly knit socks by hand since I love to do a lot of fancy stitches. The CSM is a great one for ribbing and stockinette stitch. Lace patterns and flat work can also be accomplished. Every time I work with my Legare, I learn something new!