accessories for SparcStation: trackball and hard drive

[david at ics.com]

We are expecting a SparcStation in soon. I know it will be short on disk
space.  Are there any drives particularly suitable to it? Would the CDC
Wren II or Wren III be reasonable choices?

I am also wondering whether anyone knows of a trackball which would work
with this hardware.

Thanks very much in advance.

PS: thanks to those who responded to my earlier queries. The font used for
"sun microsystems" is garamond (sp?). Sun has been using a troff/pic/
macro-set combination for its documentation; some recent stuff has been
produced using FrameMaker.