Bitcoin mining is the process of adding transaction records to Bitcoin's public ledger of past transactions or blockchain. This ledger of past transactions is called the block chain as it is a chain of blocks. The block chain serves to confirm transactions to the rest of the network as having taken place.
The bitcoin network deals with this by collecting all of the transactions made during a set period into a list, called a block. It’s the miners’ job to confirm those transactions, and write them into a general ledger.
Miners have been using different types of hardware for mining bitcoin and release a new block since it was created in 2009. The speed for solving an equation, generating a new block and searching for another it all depend on upon the speed of the hardware used in the bitcoin mining. Including GPU CPU FPGA ASIC .