The Compaq Portable shipped in March 1983 as the first portable that could run IBM PC software, using a BIOS Compaq had reverse-engineered rather than copied.
Why it matters
The Compaq Portable showed that a company could build an IBM PC-compatible machine legally, and sell it for $2,995 in a case you could carry. Compaq sold 53,000 in its first year. It weighed 28 lb and had a 9-inch green screen, but it ran the same software as the IBM PC 5150.
What to check before you buy
- Check the keyboard for dead keys; the foam pads fail with age.
- Test the built-in screen for brightness and ghosting.
- Ask about the floppy drives and the hard drive if fitted.
- Confirm it has the carrying handle and the keyboard lid, which are often missing.
- Check the power supply works before connecting it to mains.

