How do I create a 512 byte filesystem?

[Michael]

According to the manuals, the unix pc supports both the 1K blocksize filesystem
and the 512 byte blocksize filesystems. How do I get mkfs to create a 512 byte
one instead of the 1K one? If not mkfs, does anyone else have a program for 
this? The space lost is non-trivial, and I cannot afford the space.
				Michael
: --- 
: Michael Gersten			 uunet.uu.net!denwa!stb!michael
:				sdcsvax!crash!gryphon!denwa!stb!michael
: What would have happened if we had lost World War 2. Well, the west coast
: would be owned by Japan, we would all be driving foreign cars, hmm...