Application Specific Integrated Circuit (ASIC) was designed to perform the SHA-256 operation. These special chips were sold by various manufacturers and offered a very high hashing rate. This worked for some time, but due to the quickly increasing mining difficulty level, single-unit ASICs are no longer profitable.
Currently, mining is out of the reach of individuals as vast amounts of energy and money is needed to be spent in order to build a profitable mining platform. Now professional mining centers using thousands of ASIC units in parallel are offering mining contracts to users to perform mining on their behalf. There is no technical limitation, a single user can run thousands of ASICs in parallel but it will require dedicated data ...
