Abstract: A word processing system with provision for operating a fixed disk via a fixed disk controller. The fixed disk controller is connected to a system floppy disk controller so that the system may be configured with up to four fixed disk drives in addition to or in lieu of floppy disk drives. The system has a display for exhibiting alphanumeric information, a first controller connected to the display for controlling the exhibition of the alphanumeric information, a second controller connected to the first controller for controlling the transfer of data to and from a data storage device, and a fixed disk controller connected to the second controller for controlling the transfer of data to and from a fixed disk. According to another embodiment of the invention, the floppy disk controller includes a DMA controller and a memory for use with both floppy disks and fixed disks.

Abstract: A buffer for use with a word processing fixed disk controller. The buffer is connected to a microprocessor and communications bus used for interfacing a floppy disk processor to a hard or fixed disk controlled. Also connected to the communications bus are a direct memory access (DMA) controller and random access memory. The buffer operates on a first-in/first-out (FIFO), or rotating shift register basis, although it is a stationary four-part buffer. Error checking and correcting can be performed on a disk processor level. A block of data is transferred to the disk via a DMA operation only when the block of data is complete, thus eliminating data early and data late conditions.