Early electronic cash registers (ECR) were controlled with proprietary software and were limited in function and communication capability. In August 1973, IBM released the IBM 3650 and 3660 store systems that were, in essence, a mainframe computer used as a store controller that could control up to 128 IBM 3653/3663 point of sale registers. This system was the first commercial use of client-server technology, peer-to-peer communications, local area network (LAN) simultaneous backup, and remote initialization. By mid-1974, it was installed in Pathmark stores in New Jersey and Dillard’s department stores.
One of the first microprocessor-controlled cash register systems was built by William Brobeck and Associates in 1974, for McDonald’s Restaurants. It used the Intel 8008, a very early microprocessor (and forerunner to the Intel 8088 processor used in the original IBM Personal Computer). Each station in the restaurant had its own device which displayed the entire order for a customer — for example,  Vanilla Shake,  Large Fries,  BigMac — using numeric keys and a button for every menu item. By pressing the [Grill] button, a second or third order could be worked on while the first transaction was in progress. When the customer was ready to pay, the [Total] button would calculate the bill, including sales tax for almost any jurisdiction in the United States. This made it accurate for McDonald’s and very convenient for the servers and provided the restaurant owner with a check on the amount that should be in the cash drawers. Up to eight devices were connected to one of two interconnected computers so that printed reports, prices, and taxes could be handled from any desired device by putting it into Manager Mode. In addition to the error-correcting memory, accuracy was enhanced by having three copies of all important data with many numbers stored only as multiples of 3. Should one computer fail, the other could handle the entire store.
In 1986, Gene Mosher introduced the first graphical point of sale software featuring a touchscreen interface under the ViewTouch trademark on the 16-bit Atari 520ST color computer. It featured a color touchscreen widget-driven interface that allowed configuration of widgets representing menu items without low level programming. The ViewTouch point of sale software was first demonstrated in public at Fall Comdex, 1986, in Las Vegas Nevada to large crowds visiting the Atari Computer booth. This was the first commercially available POS system with a widget-driven color graphic touch screen interface and was installed in several restaurants in the USA and Canada.