APC series

The APC-III (Advanced Personal Computer) was released by NEC in 1983. The APC-III was based upon the 8086 Intel processor, with superior specifications to the IBM-PC.

Feature	APC-III	IBM-PC
Speed	8 MHz	4.77 MHz
Resolution	640x400	640x200
Storage (floppy)	720KB (80 track, DD)	360KB (40 track, DD)

The computer was well designed from the ground up, and boasted exceptional reliability. Its target was business users.

The unit had an attractive look, and was physically smaller than an IBM-PC. The compact case included 2x 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.

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.

As with the IBM-PC, the maximum useable memory was 640KB (the address range of the Intel 8088 and 8086 is 1MB). The APC came with 128MB 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 IBM-PCs. One significant reason behind IBMs separation of functions was reliability - a card could simply be changed if it were faulty. Many years later, when manufacturers were producing reliable hardware, serial, parallel and video interfaces were again returned back 'on-board'. Due to the significant form factor changes this required, this co-incided with the release of the ATX form factor.

Display resolution was exceptional for such a 'low' price computer. The resolution was fixed at 640x400 pixels, but the base one bit-per-pixel could be easily upgraded to 3 bits per pixel (taking the computer from monochrome to either 8 colours, or 8 shades of grey). The computer was capable of running monochrome (or grey) through a TV monitor, although this was not recommended. Monochrome (generally green) or colour screens were usually included in the price. The colour screen was exceptionally clear, and gave the impression the resolution was higher than it actually was. The APC-IIIs 'on-board' video controller meant that upgrades (other than internally mounted video memory) could not be achieved, and the display was stuck at 640x400x3 - not the case for the IBM-PC.

The expansion bus was well designed with 16 bit wide data and 20 bit wide address capability. The original IBM sported an 8 bit data bus with 20 bit address, which was later updated to 16 data bits (when IBM moved to the 80286 processor) by addition of another in-line card edge connector. (See ISA bus).

The motherboard was designed to allow easy addition of a math co-processor (8087).

Most units were shipped with two 720KB floppy disk drives (80 track, double density). This was huge compared to the then 360KB (per disk) offering from IBM. 360KB disks were data compatible, by 'double-steping' the 720KB drives.

Users could also purchase a hard disk expansion option. This was limited to the NEC 10MB ST-506 hard disks. This capacity could be increased to 20MB (but no higher) after upgrading to MS-DOS 3.

Since it was deemed that no user would ever want to operate a computer without at least one floppy disk drive, the hard disk controller was only configured to operate a single internal hard disk. An external hard disk expansion port was available, but compatible external hard disks were never produced.

Shipped standard with MS-DOS 2.11, other operating systems were available, such as PC-UX. Later, MS DOS 3.1 was released for the APC.

The failing of the APC-III was price. Although technically superior to IBM-PCs, and substantially more reliable than clones, it entered the market a little cheaper than a genuine IBM, but substantially more expensive than a PC clone.

The APC-III was not 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). At the time of introduction, NEC stood a high likelyhood of 'winning the war for domination of the Home PC market' against IBM. However, both companies were eventually beaten by the rise of the PC clone. IBM continued manufacturing PCs, relying on other sources of revenue. NEC produced other consumer computing products, but did not re-enter the mass PC market.

External links

• The APC-III at the On-line Computer Museum
• Reproduction of an article written when the APC-III was released