Once more, Australia’s Dave Jones has produces an eminently watchable and helpful video where he tears down three PDAs from 1986, 1996, and 2004: A Psion Organiser, a US Robotics Palm Pilot 5000, and an HP iPaq. Over two decades, processor speeds jumped from 3.6864MHz to 16MHz to 400MHz; RAM jumps from 8 Kbytes to 512 Kbytes, to 128 Mbytes (!); and the processors go from the Hitachi (now Renesas) 8-bit 6303 to the Motorola (now Freescale) 16/32-bit 68328 to the ARM-based Intel 32-bit Xscale PXA255. (Yes, Intel once manufactured ARM processors—and not that long ago!) Construction ranges from through-hole to SMT. The Psion PDA is old enough to pre-date the broad use of Flash memory, so its data is stored in battery-backed SRAM while the other two PDAs make heavy use of Flash memory.
This kind of product archaeology gives system designers a good grounding in ideas that worked (in their day) and stocks your personal design toolbox with much-needed ideas—what once worked, what doesn’t work any more, and what might still work. As usual, Jones’ observations ranging from pcb trace density to interboard connector schemes to design for testability, power conversion, and mechanical assembly. All of these topics are educationally invaluable.