US 6,209,057 B1 · Storage device having data buffer

Abstract

In a storage device in which data is read ahead and stored in a cache memory during reading of data from a medium, a data buffer is managed so that the probability that data to be read is found in the cache memory will improve. The memory area in the cache memory is divided so that a DIR-associated data buffer area used to store a leading address and file name of each file, a FAT-associated data buffer area used to store an address of each file in the next sector, and a data division-associated data buffer area used to store data can all be defined. Addresses referring to the FAT-associated data buffer area and DIR-associated data buffer area are fixed. As a result, as more and more data is read, more and more valid data corresponding to the data residing in the FAT and DIR in a storage medium is found in the cache memory. Consequently, when data reading is requested, data can be transferred without the necessity of reading the storage medium. This results in a shortened reading time.

Claims20

Dependent claims

A storage device having a data buffer in which data to be stored in a storage medium or data read from the storage medium is stored temporarily, and the storage medium including at least a storage unit for first information used to store data items constituting each file that is an information unit, a storage unit for second information which is an index table indicating storage locations of files, and a storage unit for third information which is list information of files, comprising:

a first memory area for said first information which is bounded by a fixed boundary address within the memory area in the data buffer;
a second memory area for said second information which is bounded by a fixed boundary address within the memory area in the data buffer;
a third memory area for said third information which is bounded by a fixed boundary address within the memory area in the data buffer;
and
a data buffer managing means that, when data is read from said storage medium, stores and preserves data read from said first information storage unit in said first memory area, stores and preserves data read from said second information storage unit in said second memory area, and stores and preserves data read from said third information storage unit in said third memory area.

2 more elements

A storage device comprising a storage medium, and a data buffer in which data to be stored in said storage medium or data read from said storage medium is stored temporarily, said storage medium including a storage unit for first information used to store data items constituting each file that is an information unit, a storage unit for second information which is an index table indicating storage location of files, and a storage unit for third information which is list information of files, said storage device for reading or writing desired data on the basis of the information in said storage units, comprising:

memory area with a small storage capacity bounded by a fixed boundary address within the memory area in said data buffer, and used exclusively to store data read from one of said second information storage unit and third information storage unit in said storage medium;
memory area with a large storage capacity bounded by a fixed boundary address within the memory area in said data buffer, and used in common to store data read from the other one of said second information storage unit and third information storage unit in said storage medium, and data read from said first information storage unit;
and
a data buffer managing means that when data is read from said storage medium, stores and preserves data read from one of said second information storage unit and third information storage unit in said storage medium in said memory area with a small storage capacity in said data buffer, and stores and preserves data read from the other one of said second information storage unit and third information storage unit in common in said memory area with a large storage capacity.

1 more element

Dependencies are inferred from the claim text.

Storage device having data buffer

Life of this patent

Storage device having data buffer

Life of this patent

Abstract

Claims20