IBM PC - Model 5150

IBM PC-5150 is the computer, which caused the death of CP/M computers.

In the early part of 1980, IBM decided to create a microcomputer (up to this date, IBM produced only mini and mainframes). They didn't really know that they wanted and they didn't think for one second that producing microcomputer was a profitable business (who would have thought!)! After hesitation between the Intel 8086 (16 bit) and the Motorola MC68000, they decided to use the Intel 8088 (8 - 16 bit) processor, as the two other ones were considered too powerful! Then they asked to Digital Research (the creators of CP/M) to create an operating system for their new computer. Because DR was not very

interested, they then asked a small company Microsoft (famous for its BASIC Programming Language) to write the operating system. Microsoft wasn't capable of doing it. Bill Gates bought the rights to a small, hacked OS written by a small company called Seattle Computer Products: QDOS (which reportedly stood for "Quick and Dirty Operating System", which itself bears a striking resemblance to CP/M), which became PC-DOS and then later MS-DOS!

The original IBM PC wasn't very powerful (and was certainly less powerful than lot of 8 bit computers at the time). The very first PC's had only 16 KB RAM and no floppy disk units, they used cassettes to load & store programs (notice that the commands to handle the cassette drives were present in the operating system all the way up to MS-DOS 5!).

Because of the name and the fame of IBM, it became a standard and IBM ran the business computer market up to the end of the 80's. Now, we can consider that about 90% of the microcomputers are PC compatibles and run under MS-DOS or Windows (At the beginning, Windows was just a graphic interface for MS-DOS, but that's another story).

Although the IBM PC XT was launched in 1983, IBM continued production of both units, in various configurations, for several years. The model types were followed by a xx version number, i.e. 5150-xx, where the xx represented the included options (amount of RAM, single or dual floppy disk drive, etc.).

When these computers (PC and XT) were initially sold, they were built-to-order computers (sounds like Gateway or Dell, doesn't it?). Retail outlets would carry the factory products, which consisted of a boxed computer with basic components such as the motherboard, power supply, floppies & floppy drives, etc. There were no official base model configurations for the PC and XT, nor was there any data backup and recovery. Customers had a choice of RAM, display, serial ports, etc. that they could have installed on-site before the computer went home. One could not purchase a "new" PC/XT and run it out of the box because it was incomplete without additional configuration.

The PC was available with either CGA or MDA (on an MPA card). The CGA adapter actually has an RCA composite output to hook it up to your TV if you did not want the CGA monitor. The output quality was PERFECT!

Another notable great feature of the PC line was the expansion base: it added additional (I think it was eight) 8-bit slots in an external enclosure.