Towards the AT age

The Invention of the Notebook

Zenith helped establish the clamshell design of modern laptops with XT clones such as the ZWL-184-97 and the ZWL-1183-92, both pictured above. LCD screens instead of CRT's, 3.5 inch instead of 5.25 inch drives, and rechargeable batteries as standard equipment. These machines usually came with the full 640Kb of RAM. All the standard external ports were still there, but no longer could you plug in regular expansion cards.

[SuperSport 286] To the right is a Zenith SuperSport 286, a typical AT notebook. It has a 20Mb ESDI hard drive, 640K of RAM, a greyscale CGA LCD display, and an internal 2400 baud modem.

Compaq came out with its first laptop, the SLT/286, in 1988. It had a 12-MHz 80286 CPU, 640KB RAM, 20-40MB hard drive, 3.5-inch disk drive, and a 10-inch grayscale LCD VGA screen. The next year, Compaq introduced its first notebook PC, the Compaq LTE. This model weighed under seven pounds.

So, we had moved from full-scale 8088/80C88/8086/80C86 based machines to miniaturized 80286/80C286 portables. As the AT machines came into their own, important issues appeared on the horizon.

How would you add memory, expansion cards, etc. to these machines now that they did not have standard internal expansion ports? Would a new bus standard be needed?
As video resolution improved, could LCD technology keep up? (Remember, it was maddeningly difficult at first to economically produce greyscale VGA LCD screens--imperfections were regularly found on the displays, and they had to be discarded.) How could sufficient luminosity be generated from the low-powered screen?
How could the portable conserve energy when not in use, now that it relied on battery power? Would special CPU's and chipsets be needed?

Adequate solutions would be found with the arrival of the 386/486 portables.