SH vs H8
From MobileRobots Research and Academic Customer Support
What is the difference between "SH" and "H8" robots?
What is the difference between "p3dx" and "p3dx-sh" robot subtypes, or p3dx.p and p3dx-sh.p in ARIA's parameter files?
"SH" and "H8" indicate two different microcontrollers used in different generations of Pioneer 2 and 3, Peoplebot, Amigobot and Powerbot robots. The Renesas SH microcontroller replaced the Hitachi H8s microcontroller (which replaced the Siemens C166 in even older robots). The different microcontrollers require different firmware implementations. (Patrolbot, Seekur and Seekur Jr. also use different microcontrollers and different firmware implementations.)
For more about the different versions and types of robot firmware, see Robot Firmware.