The Origins of DOS

Chuck Guzis cclist at
Tue Oct 31 15:20:45 CST 2006

On 31 Oct 2006 at 12:34, Fred Cisin wrote:

> >From the time that it was introduced (August 1981), the IBM PC 5150 was
> also available bare for about $1360 (USD).  If you put in your own Tandon
> TM100 drives at ~$150 each, instead of IBM's at ~$500 each, put in your
> own RAM at ~$75 per 16K v IBM's at $300 per 16K, added a serial card for
> ~$150?, added an FDC board for ~$300, a video board for ~$300, and your
> own monitor for ~$100 v IBM's at ~$600, etc. you ended up with a machine
> at comparable prices to an Apple ][.

But it was IBM's picing and packaging of options that engendered the 
third-party add-on board makers, like Quadram and Everex.  What made 
them really attractive was packing more than a single function on a 
board (remember that the original 5150 had only 5 expansion slots)  
So, for example, a board that gave you RAM, a parallel port two 
serial ports, as well as a clock was very attractive if the 
alternative was purchasing an expansion box ($$$) for the extra 
single-function cards that you'd need from IBM.


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