On this day in 1981, 42 years ago IBM introduced the first IBM PC for US$1,565+

OS: IBM BASIC / PC DOS 1.0
CP/M-86
UCSD p-System

CPU: Intel 8088 @ 4.77 MHz
Memory: 16 KB – 256 KB
Graphics: MDA, CGA
Sound: PC speaker 1-channel square-wave/1-bit digital (PWM)