I/O hardware control

A method of information transfer which is used on many newer CPUs designed to accommodate it. The method requires a significant amount of additional hardware, since the input/output device must initiate and control the data transfer directly into or from microcomputer memory. Often the software support is limited to the initiation, termination, and recovery aspects of the transfer. These aspects are often performed automatically without microprocessor intervention. The hardwarecontrol approach is also known as directmemory access or data break. It can be used to transfer blocks of characters directly between a peripheral device——such as tape, cassette, or floppy disk——and main microprocessor memory.; 許多新型的中央處理機采用的一種數據傳輸的方法。這種方法需要大量的附加硬件, 這是由于輸入輸出設備必須啟動和控制數據傳輸直接進出微型計算機內存。軟件支持常常 限于傳輸的起始、結束和恢復等方面,這些方面常常無需微處理機干預即被自動完成了。 硬件控制方法也稱為直接存儲器存取或數據中斷,它可以在微處理機內存和外部設備(如 磁帶、盒式帶或軟盤)之間直接傳輸字符塊。