Short answers, pulled from the story.
The first-generation HTC Vive was released in April 2016, after preorders opened on the 29th of February 2016. HTC and Valve had originally planned a release before the end of 2015, but pushed it back to April 2016 in December 2015.
The HTC Vive uses external base stations, nicknamed lighthouses, that sweep the play area with infrared lasers on rotating spinners alongside an array of LED lights. Photosensors on the headset and controllers detect the LEDs and compare their timing to the laser sweeps to calculate each device's position, enabling room-scale virtual reality.
HTC developed the Vive in partnership with Valve Corporation, which provided its SteamVR software and hardware platform. Prototypes were demonstrated during 2014, and HTC officially unveiled the device at its Mobile World Congress keynote on the 1st of March 2015.
The HTC Vive Pro, unveiled on the 8th of January 2018, raised per-eye resolution to 1440 by 1600 pixels, a 78 percent increase over the original Vive. It also added a second outward-facing camera, a noise-cancellation microphone, and switched from HDMI to DisplayPort.
The HTC Vive lineup includes standalone headsets that need no connected computer, such as the Vive Focus line, the Vive Flow, and the Vive XR Elite. The Vive Focus targets the business market and competes primarily with Meta Quest, while the Vive Flow and Vive XR Elite use a lightweight, glasses-like design.
Since 2021, HTC has targeted the HTC Vive line toward business and enterprise customers rather than consumers. Vive General Manager Dan O'Brien said the consumer market had gravitated toward subsidized pricing that only one company could tolerate, an apparent reference to Facebook Inc., while calling the enterprise market a very healthy and rapidly growing one.