File management of one-time-programmable nonvolatile memory devices

• US 6,957,295 B1
• Filed: 01/18/2002
• Issued: 10/18/2005
• Est. Priority Date: 01/18/2002
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Lexar Media Incorporated (Micron Technology, Inc.)
• Inventors: Estakhri, Petro
• Primary Examiner(s): Padmanabhan, Mano
• Assistant Examiner(s): Namazi, Mehdi
• Application Number:
  US10/054,451
• Time in Patent Office: 1,369 Days
• Field of Search: 711/103, 711/161, 365/185.11, 714/710
• US Class Current: 711/103
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G11C 16/102 External programming circuits, e.g. EPROM programmers; In-circuit programming or reprogramming; EPROM emulators

Abstract

An embodiment of the present invention includes a digital equipment system comprising a host for sending commands to read or write files having sectors of information, each sector having and being modifyable on a bit-by-bit, byte-by-byte or word-by-word basis. The host being operative to receive responses to the commands. The digital equipment further including a controller device responsive to the commands and including one-time-programmable nonvolatile memory for storing information organized into sectors, based on commands received from the host, and upon commands from the host to re-write a sector, the controller device for re-writing said sector on a bit-by-byte or word-for-word basis.

Claims

1. A digital equipment system comprising:

a. a host for sending commands to read or write files having sectors of information, each sector having and being modifyable on a bit-by-bit, byte-by-byte or word-by-word basis, said host being operative to receive responses to said commands;

b. a controller device responsive to said commands, and including,

one-time-programmable nonvolatile memory for storing information organized into sectors, based on commands received from the host; and

a comparator coupled to receive sectors to be written and re-written, wherein upon receiving commands from the host to re-write a sector, the comparator comparing a sector to be re-written to a corresponding stored sector allowing the controller device to re-write said sector to be re-written only on a bit-by-bit, byte-by-byte or word-for-word basis and only as to those locations in the sector that have been modified.

2. A digital equipment system as recited in claim 1 wherein said one-time-programmable nonvolatile memory includes a system area and a data area, said system area for storing information pertaining to the organization of the information stored or to be stored in the data area.

3. A digital equipment system as recited in claim 2 wherein said system area includes storage areas for including Original Engineering Manufacturer (OEM) identification/Bidirectional Input/Output System (BIOS), a File Allocation Table (FAT) 1, a FAT 2 and root disk directory information.

4. A digital equipment system as recited in claim 1 wherein said controller device further includes a first buffer for storing a host-provided sector and a second buffer for storing sectors stored or to be stored in the one-time-programmable nonvolatile memory.

5. A digital equipment system as recited in claim 4 further including a comparator coupled between said first and second buffer for comparing a sector to be modified or accessed by the host with those sectors to which information has been previously written.

6. A digital equipment system as recited in claim 1 wherein during power-up, said controller device for identifying the end-of-file, wherein the location following the location in which the end-of-file resides is identified as the location for the start-of-file of a new file to be stored.

7. A digital equipment system as recited in claim 6 wherein said end-of-file is identified by the use of a flag.

8. A digital equipment system as recited in claim 1 wherein said files are digital photographs.

9. A digital equipment system as recited in claim 1 wherein said files are archives.

10. A digital equipment system as recited in claim 1 wherein said controller device maintains a correlation between logical addresses and physical addresses for translating host-provided addresses to addresses recognized by the one-time-programmable nonvolatile memory.

11. A digital equipment system as recited in claim 10 wherein said controller for maintaining track of defective locations within the one-time-programmable nonvolatile memory.