On August 12, 1981, IBM announced the release of its Personal Computer, identified as model 5150 (photo ©Boffy b). This expression, as well as microcomputers and home computers, had already been used before, so you could say that actually the first personal computer was the Xerox Alto in 1973 or even the Olivetti Programma 101 about a decade earlier. The success of the IBM PC, however, was such that within a short time the expression personal computers started identifying a model compatible with the IBM one.

In the early ’80s, there were several home computers and microcomputers on the market. IBM took the fundamental decision to make their personal computers using an open architecture, using components normally available on the market. The fact that other manufacturers could produce components compatible with the IBM PC greatly contributed to its emergence as a dominant standard in the market.

As the processor, the Intel 8088 at 4.77 MHz was chosen, while the 8086 was considered too powerful. In the choice of the operating system, IBM asked Digital Research to create one more advanced than CP/M, which the company had already created in the past, but they didn’t reach an agreement. Microsoft, then a small company, acquired from another software house the QDOS operating system, a clone of CP/M for 8088/8086 processors, worked a little on it, and proposed it to IBM. The proposal was accepted, and that operating system became PC-DOS and later MS-DOS.

The standard RAM for model 5150 was 16 Kbytes, but there was a configuration with 64 Kbytes, in all cases expandable to 256 Kbytes. The graphics card was a CGA. As mass storage, there were one or two 5¼ floppy disk drives, at the time with 160 Kbytes capacity, with the possibility of having a tape recorder too.

The IBM PC was successful, and the next year the first PCs from other manufacturers appeared on the market. They were defined as IBM-compatible because they replicated the IBM PC’s hardware and software features.

In 1983, IBM put on the market the PC XT, model 5160, which had a hard disk as a standard feature. In 1984 IBM offered the PC AT, Model 5170, featuring the powerful Intel 80286 processor at 8 MHz. Over the years, many other technological improvements were introduced, and competition from manufacturers of IBM-compatible PCs became stronger and stronger.

IBM tried to maintain its leadership by introducing in 1987 the Micro Channel architecture while keeping it a proprietary technology. The popularity of IBM’s open standards, however, had become such that eventually, IBM became a victim of its own success and its inability to handle it properly. At the end of 2004, IBM decided to abandon the production of PCs.

Today, PCs – the expression IBM-compatible is now meaningless – have amounts of memory, both RAM and mass storage, and computing power unimaginable thirty years ago. The technical and commercial choices made ​​by IBM at the time, however, have strongly influenced PC evolution, bringing computers in homes and offices like no company was able to do before.