HP HP-2117F on ebay

The plot thickens... A more definitive source than user manuals... is the HP1000 M/E/F-series computer engineering and reference documentation (92851-90001). According to the section "HP 1000 E and F-series computer central processing Unit (CPU) Theory of Operation" on page IA 4-33 "Note that in F-series computers a customer may elect to have a 12791A FEM board in lieu of the FAB." Note the use of the word "customer" and "may". This would certainly indicate that a FEM was not necessary in an F. This would suggest that a F was shipped with FAB and not FEM (which was optional) unless the customer wanted/needed more space for microcode. This also suggests that a valid F configuration is FAB only, or FEM only, or FAB & FEM. It also suggests that it would be fairly common for a user to buy the system with just FAB, and later (not from factory) add a FEM board when they needed more space to use in addition to OR in place of, the FAB. So it would appear our experiences both are correct. It seems the systems you have acquired were ordered with the FEM instead of FAB *option*. The systems I have acquired were ordered with the standard part, which got you a FAB and no FEM. But in any case, the determination from the engineering docs is, an F most certainly does not have to have a FEM - and a FEM is not standard/required. I agree that the user manuals seem to be contradictory on this subject. For example, the firmware installation manuals do in fact say that SIS can be installed in a FAB, it says this in the section on the FAB. But in the section on SIS, it mentions just the FEM I believe. Jay West