System for updating directory information and data on write once media such as an optical memory card

• US 5,437,012 A
• Filed: 04/19/1993
• Issued: 07/25/1995
• Est. Priority Date: 04/19/1993
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Information Systems Incorporated (Canon Inc.)
• Inventors: Mahajan, Rakesh
• Primary Examiner(s): Powell, Mark R.
• Assistant Examiner(s): CHAUHAN, ULKA J
• Application Number:
  US08/047,663
• Time in Patent Office: 827 Days
• Field of Search: 235/454, 369/58, 369/59, 369/100, 395/400, 395/425, 395/500, 395/600, 395/775
• US Class Current: 711/111
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G11B 20/1215 on cards optical aspect of optical cards G11B7/0033
• CPC Class Codes: G11B 27/102 Programmed access in sequence to addressed parts of tracks of operating record carriers access by moving the head G11B3/08, G11B5/54, G11B7/085, G11B21/022; by moving the record carrier G11B15/005, G11B17/005, by driving of both record carrier and head G11B15/1816
• CPC Class Codes: G11B 27/3027 used signal is digitally coded
• CPC Class Codes: G11B 27/3036 Time code signal
• CPC Class Codes: G11B 27/327 Table of contents
• CPC Class Codes: G11B 7/0033 with cards or other card-like flat carriers, e.g. flat sheets of optical film

Abstract

A method and apparatus for updating data stored in a write once/read many memory which comprises creating a virtual image of data stored in the memory, updating data in the virtual image of the memory and designating updated data in the virtual image, and writing designated updated data from the virtual image to the memory. In the virtual image there is a main journal for organizing file information on the memory and file journals for each file stored on the memory. Each file journal contains self-describing information for its corresponding file.

Claims

1. A method for updating data stored in a write once/read many memory, the method comprising the steps of:

creating a complete virtual image of data stored in the write once/read many memory;

updating data in the complete virtual image of the write once/read many memory and designating updated data in the complete virtual image; and

writing designated updated data from the complete virtual image to the write once/read many memory,

wherein said creating step creates a main journal to organize file information on the write once/read many memory, and creates file journals, each containing a self-describing extent header for providing address information to a next extent of the file, in correspondence to files stored on the write once/read many memory, and wherein said updating step adds extent headers to sequentially contiguous blocks of memory and updates file organization information in the main card journal in correspondence to each added extent.

2. A method according to claim 1, wherein the file journals contain self-describing extent headers and a flag for designating updated data, said flag being set in said updating step.

3. A method according to claim 2, wherein the writing step writes designated updated data in accordance with the flag.

4. A method according to claim 3, wherein the writing step updates data and writes file organization data to the write once/read many memory.

5. A method according to claim 1, wherein the creating step creates the complete virtual image on a randomly accessible read/write storage medium.

6. A method according to claim 1, further comprising the steps of inserting the write once/read many memory into read/write device and locking it therein.

7. A method according to claim 6, further comprising the step of ejecting the write once/read many memory from read/write device, wherein said writing step is performed only once in accordance with ejection of the write once/read many memory.

8. A method according to claim 7, wherein in response to an improper ejection, the complete virtual image is saved in an external memory.

9. A method for maintaining a complete virtual image of a write once/read many optical memory card in an external memory device which includes a read/write device, the method comprising the steps of:

storing data from the write once/read many optical memory card to the external memory device;

designating in the external memory device a file to be updated;

updating data within the designated file stored in the external memory;

updating a file on the write once/read many optical memory card corresponding to the designated file in the external memory in accordance with an update to the designated file; and

maintaining a complete virtual image of the write once/read many optical memory card in the external memory device,

wherein, in the updating step of updating a file in the write once/read many optical memory card, an update operation is performed only once in response to an election signal.

10. A method of storing and accessing information on a write once/read many optical memory card, the method comprising the steps of:

formatting a write once/read many optical memory card;

creating a directory containing a start of file extent pointer and a next allocatable sector; and

creating an extent header for each extent of each file, wherein the extent header contains self-describing attributes of its corresponding extent, and contains a number of contiguous bytes of the file and an address of a next extent.

11. A method according to claim 10, wherein the formatting step formats an option of selecting error correction coding for said optical memory card.

12. A method according to claim 10, wherein the directory is updated to reflect next allocatable address and, in the case a file is deleted, start of file pointers are indicated as being deleted from the directory.

13. A method according to claim 12, wherein a last extent for each file is a blank sector which contains no extent header.

14. A method according to claim 13, wherein the next allocated address in the directory is a next sector following the blank sector of a last file.

15. An apparatus for updating data stored in a write once/read many memory, comprising:

creating means for creating a complete virtual image of data stored in the write once/read many memory;

updating means for updating data in the complete virtual image of the write once/read many memory and designating updated data in the complete virtual image; and

writing means for writing designated updated data from the complete virtual image to the write once/read many memory,

wherein the creating means creates a main card journal to organize file information on the write once/read many memory, and creates file journals, each containing a self-describing extent header providing address information to a next extent of the file, in correspondence to files stored on the write once/read many memory, and wherein said updating means adds extent headers to sequentially contiguous blocks and updates file organization information in the main card journal in correspondence to each added extent.

16. An apparatus according to claim 15, wherein the writing means writes designated updated data in accordance with the flag.

17. An apparatus according to claim 15, wherein the creating means creates the complete virtual image on a randomly accessible read/write storage medium.

18. An apparatus according to claim 17, wherein the writing means writes both updated data and file organization data to the write once/read only memory.

19. An apparatus according to claim 18, further comprising ejecting means for ejecting the memory from read/write device, wherein said writing means is performed only once in accordance with ejection of the memory.

20. An apparatus according to claim 19, wherein in response to an improper ejection, the complete virtual image is saved in an external memory.

21. An apparatus according to claim 15, further comprising inserting means for inserting the write once/read many memory into read/write device and locking means for locking it therein.

24. An apparatus according to claim 20, wherein the formatting means formats an option of selecting error correction coding for said optical memory card.

25. An apparatus according to claim 20, wherein the directory is updated to reflect next allocatable address and, in the case a file is deleted, start of file pointers are indicated as being deleted from the directory.

22. An apparatus for maintaining a complete virtual image of a write once/read many optical memory card in an external memory device which includes a read/write device, comprising:

storing means for storing data from the write once/read many optical memory card to the external memory device;

designating means for designating in the external memory device a file to be updated;

updating means for revising data within the designated file stored in the external memory;

updating means for updating a file on the write once/read many optical memory card corresponding to the designated file in the external memory in accordance with an update to the designated file; and

maintaining means for maintaining a complete virtual image of the optical memory card in the external memory device,

wherein the updating means, for updating a file on the write once/read many optical memory card, performs an update operation only once in response to a signal to eject the write once/read many optical card from the read/write device.

23. An apparatus for storing and accessing information on a write once/read many optical memory card having at least one file which includes at least one extent of data, comprising:

formatting means for formatting an optical memory card;

creating means for creating a directory containing a start of file extent pointer and a next allocatable sector; and

creating means for creating a header for each extent of each file, wherein the extent header contains self-describing attributes of the at least one extent, and contains a number of contiguous bytes of the at least one file and an address of a next extent.

26. An apparatus according to claim 23, wherein a last extent for each file is a blank sector which contains no extent header.

27. An apparatus according to claim 26, wherein the next allocatable address in the directory is the next sector following the blank sector of the last file.

28. A system for updating directory information and data on a write once/read many optical memory card, comprising:

a write once/read many optical drive device;

a write once/read many optical memory medium;

a computer interfaced to the write once/read many optical drive device, the computer including means for storing an application program which includes accessing commands to access the write once/read many optical drive device; and

a driver responsive to the accessing commands, the drive including process steps for creating a complete virtual image of data stored in the optical memory medium, updating data in the complete virtual image of the optical memory medium, designating updated data in the complete virtual image, and writing designated updated data from the virtual image to the optical memory medium,

wherein said driver performs the step of writing designated updated data to the write once/read many optical memory medium only once in response to an ejection signal.

29. A method for updating data in a write once/read many memory, the method comprising the steps of:

creating a card directory of a complete virtual image of files stored in the write once/read many memory, the card directory including a fixed directory field and an updatable directory field;

creating a file journal in the virtual image for files stored on the write once/read many memory, the file journal including size of file data, revision number of file, file name, pointer to a file extent, a date of last revision, and user-definable comment area;

updating data in files stored in the write once/read many memory and updating the updatable directory field and the file header in accordance with updates made to the files; and

writing the card directory, and updated files to the write once/read many memory, wherein the step of writing designated updated data to the optical memory medium is performed only once in response to an ejection signal.