The
APC III (Advanced Personal Computer) was released by
NEC in 1984. An update on the NEC APC II, which replaced the original NEC APC, all the NEC APC models utilized the
Intel 8086 processor, unlike the
IBM PC and clones. The unit was physically smaller than an IBM-PC. The compact case included two 5" half-height disks (two floppies or one floppy and one hard disk), and 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. C-bus expansion cards (PCBs) could be inserted without removal of the exterior case, as was required for the IBM PC. 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 further disassembled if required. 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.
Specification Hardware Interfaces 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.
Display Maximum display capabilities were a text mode of characters (with four planes) and/or graphics at pixels (with two planes). Either text, graphics, or graphics with text overlay were software selectable. The base one bit-per-pixel was easily upgradeable to three bits per pixel (taking the graphics mode from monochrome to either eight colours or eight shades of grey). The computer was capable of running monochrome (or grey) through an NTSC TV monitor, although this was not recommended (text reduced to , graphics to ). Monochrome (usually green) or color screens were usually included in the price. The APC III's 'on-board' video controller meant that upgrades (other than internally mounted video memory) could not be achieved, and the display was stuck at with 8 colors. The NEC APC series supported a proprietary
NEC APC character set and user-definable fonts in text mode.
Expansion bus The expansion
bus supported 16-bit-wide data and 20-bit-wide address capability. By comparison, the original IBM supported an 8-bit data bus with 20-bit address, which was later revised to 16 data bits and 24 address bits in the
PC AT. The motherboard was designed to allow easy addition of an
8087 math co-processor.
Disk drives Most Australian units were shipped with 720 KB floppy disk drives (80 track, double density), although specifications imply the drives were only 360 KB (40 track, DD). 360 KB disks were readable and writeable by 'double-stepping' the 720 KB drives. Users could also purchase a hard disk expansion option. This was initially limited to the 10 MB
ST-506 hard disks. This capacity could be increased to 20 MB (but no higher) after upgrading to
MS-DOS 3.1. The hard disk controller was only configured to operate a single internal hard disk. An external hard disk expansion port was available, so you could have two floppies and an external hard drive, or one floppy with an internal hard drive.
Operating systems Shipped standard with
MS-DOS 2.11, other operating systems were available, such as the
Unix derivative,
PC-UX. Later, MS DOS 3.1 was released for the APC.
Compatibility The APC III was not fully compatible with the IBM-PC, either on a hardware level (although some parts were compatible), or a software level (although again, some software was compatible). Later on NEC released the SLE card, or 'Software Library Expander', that was essentially an IBM PC on an expansion board, although graphics was limited to
CGA only, quite a step down from the native graphics. The earlier penetration of the market saw PC clones adopt the IBM PC architecture. In the export markets, NEC fell into line with the 16-bit
IBM-AT architecture and did not pursue the APC-III architecture any further. ==APC IV==