Patent ID: 6018788
Filing Date: 2000-01-25
Classification: G06F

Abstract:
A system for controlling data transfer between a disk drive and a host system, comprising:(A) buffer memory means for (Al) storing data read from a disk of the disk drive and (A2) outputting data when the data corresponding to a data access request from the host system is transferred to the host system;(B) counter means for counting an amount of data read from the disk and stored in the buffer memory means;(C) limit register means for holding a limit value which (C1) represents an amount of data stored in the buffer memory means and (C2) determines a timing at which a read operation of data from the disk is stopped;(D) status means for selectively designating permission or inhibition of a read limit function of stopping the read operation on the basis of the limit value set in the limit register means, said status means including a register means in which a flag for designating permission or inhibition of the read limit function is set; and(E) control means for (E1) storing data read from the disk in the buffer memory means in accordance with the data access request from the host system, (E2) storing consecutive data read from the disk in accordance with an amount of data which can be stored in the buffer memory means, and (E3) transferring the data stored in the buffer memory means to the host system,wherein said status means sets the flag for designating inhibition of the read limit function in the register means when the data access request from the host system is neither a repeat access request nor a sequential access request, andwherein said status means sets the flag for designating permission of the read limit function in the register means when the data access request from the host system is the repeat access request, andwherein said control means performs the read limit function in accordance with the repeat access request from the host system, when the limit value is set in the limit register means and a count value of the counter means coincides with the limit value, andwherein said control means disables the read limit function when the flag for designating inhibition of the read limit function is set in the register means by the status means.