APC III
The APC III (Advanced Personal Computer) was released by NEC in 1984. An English-speaking market rebrand of the Japanese NEC PC-9801, the APC III was based upon the Intel 8086 processor, with superior specifications to the IBM PC. The computer was well designed from the ground up, and boasted exceptional reliability. It was advertised to business users.
The unit had an attractive look, and was physically smaller than an IBM-PC. The compact case included two 5 1⁄4" half-height disks (two floppies or one floppy and one hard disk), and ample space for standard options (hard disk controller, additional video memory). Special options (including additional system memory) required using expansion slots, of which four were available.
Comparing the IBM PC to the APC III reveals how the two different architectures were derived. The IBM PC had been fast-tracked in an attempt to crack into the home computer market (reference Project Chess), resulting in a machine that actually looked cobbled together, especially internally. Conversely, the APC was truly engineered and showed NEC's considerable experience in the field of consumer electronics.
Expansion cards (PCBs) could be inserted without removal of the exterior case, as was required for the IBM PC. Even modern (IBM clone) designs still require removal of the case to add expansion cards.
The entire computer could be disassembled to functional blocks (e.g.: expansion card cage, power supply, disk drive cage) with removal of a few easy access screws. Other components didn't even need a screwdriver, except for the outer case, by using robust plastic clips. The disk cage could be easily further disassembled if required. Despite the easy disassembly, all components of the system were arranged and secured to reduce or eliminate mechanical stress on the electronics.
As with the IBM PC, the maximum usable memory was 640 KB (the address range of the Intel 8088 and 8086 is 1 MB). The APC came with 128 KB standard, as did the IBM PC.
RS-232 serial, 'Centronics' parallel and video interfaces were built onto the motherboard, whereas expansion cards were required for almost every function of an IBM PC except for the CPU, BIOS and built-in RAM. One significant reason behind IBM's separation of functions was reliability - faulty cards, particularly those at high risk of physical or electrical user damage (i.e. serial, parallel, and video) could be easily and individually replaced, at much lower cost than replacing or servicing the whole system board. In addition, this meant that existing, off-the-shelf hardware could be used, reducing costs and contributing to the fast-tracking of the project. Many years later, when manufacturers were producing reliable hardware, serial, parallel, then video and other interfaces migrated back to PC clone motherboards.
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