↗
IBM
The original IBM PC model.
The 5150 placed its keyboard, display, and system unit in separate enclosures. Expansion cards and external peripherals allowed an installation to be configured for different uses.

| Introduced | August 1981 |
|---|---|
| Processor | Intel 8088 at 4.77 MHz |
| Memory | 16 KB on the earliest boards, to 256 KB; 640 KB with cards |
| Display | MDA or CGA on a card |
| Storage | Cassette; one or two 160 KB 5.25-inch floppies |
| Expansion | Five 8-bit slots |
| Firmware | BIOS in ROM, with BASIC |
The 8088 was the compromise that made the machine cheap: a 16-bit processor with an 8-bit external bus, so it could use the inexpensive support chips already in the supply chain. The decision that mattered more was publishing the technical reference, BIOS listing included. That let others build compatible machines legally by reimplementing the BIOS, and the industry that followed was a consequence of documentation rather than of silicon.
The 5150 placed its keyboard, display, and system unit in separate enclosures. Expansion cards and external peripherals allowed an installation to be configured for different uses.
Reference: ATX-OBJ-066-IMG-5132
Source: collection inventory, photographs, and notes accompanying Serious Machines (Amir Husain, 2024).