Storage device and method of controlling access

Abstract

A storage device is provided. The storage device includes a plurality of ports for a first kind of access, a second kind of access having a band-secured access period longer than that of the first kind of access, and other kinds of access; and an access controller. The access controller is configured to prepare a total schedule by connecting a plurality of slot units for the first kind of access having a time frame within a band-secured access period to obtain the band-secured access period within the access period for the second kind of access on a time axis, and to allocate one time slot to one slot unit regarding the ports for the first kind of access and to allocate one time slot to one period of the total schedule regarding the ports for the second kind of access among the plurality of ports.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram conceptually showing access to a storage device provided with a plurality of ports;

FIG. 2 is a diagram illustrating a method of controlling access of the related art in a storage device provided with a plurality of ports;

FIG. 3 is a diagram showing a change in the amount of buffering according to the method of controlling access illustrated in FIG. 2;

FIG. 4 is a diagram illustrating an example of the method of controlling access improved from the method of controlling access shown in FIG. 2;

FIG. 5 is a diagram showing a change in the amount of buffering according to the improved example illustrated in FIG. 4;

FIG. 6 is a block diagram showing the whole configuration of a flash memory device according to an embodiment of the present invention;

FIG. 7 is a diagram illustrating a method of controlling access according to a slot access controller shown in FIG. 6;

FIG. 8 is a diagram showing a change in the amount of buffering according to the method of controlling access shown in FIG. 7; and

FIG. 9 is a diagram showing an example of a configuration of the slot access controller shown in FIG. 6.

Claims

1. A storage device, comprising: a plurality of ports for a first kind of access, a second kind of access having a band-secured access period longer than that of the first kind of access, and other kinds of access; andaccess control means for preparing a total schedule by connecting on a time axis a plurality of slot units each having a length within the band-secured access period of the first kind of access so that the access period of the second kind of access is within the band-secured access period,allocating one time slot to one slot unit regarding the ports for the first kind of access, andallocating one time slot to one period of the total schedule regarding the ports for the second kind of access among the plurality of ports.

2. A storage device according to claim 1, wherein: the access control means locates a time slot of ports for a kind of access not band-secured among the plurality of ports, at the end of the slot unit, and controls the length of the time slot so that the length of the slot unit is within the band-secured access period for the first kind of access.

3. A storage device according to claim 1, wherein the storage device uses a flash memory as a storage medium;the first kind of access is access to reproduce data; andthe second kind of access is access to store data.

4. A method of controlling access performed by an access controller in a storage device having a plurality of ports, comprising the steps of: accessing the ports with a first kind of access;accessing the ports with a second kind of access having a band-secured access period longer than that of the first kind of access;preparing a total schedule by connecting on a time axis a plurality of slot units each having a length within the band-secured access period of the first kind of access so that the access period of the second kind of access is within the band-secured access period;allocating one time slot to one slot unit regarding the ports for the first kind of access among the plurality of ports; andallocating one time slot to one period of the total schedule regarding the ports for the second kind of access among the plurality of ports.

5. A storage device, comprising: a plurality of ports for a first kind of access, a second kind of access having a band-secured access period longer than that of the first kind of access, and other kinds of access; andan access controller configured to prepare a total schedule by connecting on a time axis a plurality of slot units each having a length within the band-secured access period of the first kind of access so that the access period of the second kind of access is within the band-secured access period,allocate one time slot to one slot unit regarding the ports for the first kind of access, andallocate one time slot to one period of the total schedule regarding the ports for the second kind of access among the plurality of ports.