All --
In the blizzard of commentary about the HP-35s, this might have been noted already, but I can't specifically recall.
When a number is being input on the HP-35s while the delimiters ("," or ".") that separate groups of 1000 are active (i.e., DISPLAY 7 set), the delimiters do not appear until the number is finalized by ENTER, setting change, or other operation. The legacy models (including the HP-33s), by contrast, insert the delimiters as the number is input.
I would assume that the HP-35s behavior stems from the "input buffer" logic adopted from the RPL-based HP-50g, in which input is treated as free-form until it is processed upon some concluding action. The awkward base-arithmetic (hexadecimal/octal/binary) format is another RPL idea that was transferred.
Perhaps these changes were made in order to standardize code between the HP-35s and HP-50g. However, I like the old "RPN way" better...
-- KS
Edited: 15 Sept 2007, 3:56 p.m.