1、 Reference number ECMA-123:2009 Ecma International 2009 ECMA-405 1st Edition / December 2013 Data Interchange on Parallel Write/Read Disk Format for 5 Optical Disks Ecma International 2013 COPYRIGHT PROTECTED DOCUMENT i Ecma International 2013 Contents Page 1 Scope 1 2 Conformance . 1 3 Normative re
2、ferences 1 4 Terms and definitions . 1 5 Conventions and notations 4 6 Recording area for non-parity disk type . 4 6.1 General . 4 6.2 System management area 4 6.2.1 General . 4 6.2.2 Header. 4 6.3 UDF management area 9 7 Recording area for parity disk type . 10 7.1 General . 10 7.2 System managemen
3、t area 11 7.2.1 General . 11 7.2.2 Header. 11 7.2.3 Info area 15 7.3 UDF management area 17 7.4 Parity disk 18 7.5 Temporal parity 18 8 Signal quality of the recorded data . 19 Annex A (informative) How to implement write/read operations . 21 Annex B (informative) Address conversion . 33 ii Ecma Int
4、ernational 2013 Introduction Optical disks have been used widely. And the optical disks have advantage for long-term digital data preservation usage. However, single-optical-disk based system has weaknesses for the data capacity and transfer rate compared to other devices. To meet the emerging deman
5、ds for the long-term preservation of digital data, this proposal solves the issues by introducing multiple-disk based system. The system deals multiple disks as a set and writes/reads the set of disks in parallel. Developing an industry standard is strongly needed for promoting the optical disk in t
6、he enterprise usage. The new project for developing two standards, disk cassette in other words, it determines the start disk and its start logical cluster. The proprietary device driver assigns the multiple divided recording data blocks continuously to the start logical cluster and the start disk i
7、n the recordable area. The hatched part in Figure A.3 shows an example of logical clusters with data already recorded. In Figure A.3, the last recorded logical cluster number is i+1, the last recorded disk is Disk1, and the top disk is Disk2. The recording data D1 are assigned from the logical clust
8、er number i+1 on Disk2 to the logical cluster number i+3 on Disk1. Logical cluster i i+1 i+2 i+3 Disk1 Disk2 Disk3 Disk4 Disk5 Figure A.3 Example of recording allocation on disks 4) Recording to media set The proprietary device driver orders recording of an assigned divided recording data block to e
9、ach drive. According to this operation, each drive records the assigned divided recording data block to each disk. Parallel data recording is done as a result. 5) Recording of Info data The proprietary device driver orders the parallel read/write identifier and VAT logical block address to be record
10、ed in the Info area on each of the multiple disks when the proprietary device driver receives “disk unload” command or the user interruption. A.2.2 Data reproduction When a media set is loaded, the file system requests the remaining data capacity and the last recording address. The proprietary devic
11、e driver calculates the total remaining data capacity and the last recording address using the remaining data capacity of the 5 disks and the last recording address. The proprietary device driver returns to the file system the remaining data capacity and the last recording address. 24 Ecma Internati
12、onal 2013 Calculation of information for objective data When the file system requests data reproduction, the proprietary device driver calculates the following information for the objective data in the media set from the logical block address and its size required by the file system. 1) Start readin
13、g logical cluster set number 2) Start reading disk number 3) Last reading logical cluster set number 4) Last reading disk number Data reproduction Data are reproduced according to the above address information. The data are recorded in units of logical clusters as shown in Figure A.3; therefore the
14、proprietary device driver orders D1-1, D1-2, D1-3, D1-4, D1-5, and D1-6 to be read and connects the data as shown in Figure A.4. The proprietary device driver sends data requested by the file system. D1-1 D1-2 D1-3 D1-4 D1-5 D1-6 Data required by file system Figure A.4 Example of data composition A.
15、3 Parity disk type A.3.1 Flow of data recording operations Figure A.5 shows the flow chart for data recording operations. When the media set is inserted into the system, the file system requests the remaining recordable data capacity and the last recorded logical block address from the proprietary d
16、evice driver. The proprietary device driver acquires remaining recordable data capacity of 4 disks except for the parity disk and the last recorded logical cluster set number, and calculates the total remaining recordable data capacity and the last recorded logical block address. Then, the proprietary device driver returns to the file system the total remaining recordable data capacity and the last recorded logical block address.
