| The IBM 5140, also known as the IBM PC Convertible, was introduced in 1986 as IBM’s first laptop computer. It marked a significant step in portable computing by being the first IBM PC to feature a clamshell design with an LCD screen and detachable keyboard—elements that would become standard in laptop design. Weighing around 13 pounds (about 5.8 kg) and designed to be carried like a typewriter in its molded plastic case, the PC Convertible used an Intel 80C88 processor running at 4.77 MHz. It came with 256 KB of RAM (expandable to 640 KB) and included two 3.5-inch 720 KB floppy disk drives, making it one of the first IBM systems to adopt the 3.5-inch format instead of the 5.25-inch floppy. The monochrome LCD screen had a CGA-compatible resolution of 640×200 pixels, though it lacked backlighting, which limited usability in low-light environments. The system had no built-in hard drive and did not support internal expansion cards, but it could be expanded via external modules and a proprietary expansion connector. The PC Convertible introduced a new power management concept for IBM, allowing operation from battery or AC power. Despite some criticisms regarding its performance and screen readability, the 5140 was a pivotal product that influenced the design of future laptops both within IBM and across the industry. |
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