1、Standard ECMA-1072nd Edition - June 1995Standardizing Information and Communication SystemsPhone: +41 22 849.60.00 - Fax: +41 22 849.60.01 - URL: http:/www.ecma.ch - Internet: helpdeskecma.chVolume and File Structure ofDisk Cartridges for InformationInterchange.Standard ECMA-1072nd Edition - June 19
2、95Standardizing Information and Communication SystemsPhone: +41 22 849.60.00 - Fax: +41 22 849.60.01 - URL: http:/www.ecma.ch - Internet: helpdeskecma.chMB- ECMA-107.DOC - 08.02.99 16:40Volume and File Structure ofDisk Cartridges for InformationInterchange.Brief HistoryIn 1979 ECMA published its fir
3、st Standard ECMA-58 for file structure and labelling of 200 mm flexible disk cartridges.Further work led to the development and publication in 1984 of Standard ECMA-91 which is applicable to all flexible diskcartridges, in particular to those with FM recording on the Index Cylinder.For many purposes
4、 this Standard ECMA-91 provides a satisfactory data interchange pathway between different types ofinformation-processing systems. However, it imposes some restrictions on the operation of a system as follows:a) Each individual file must be recorded on the disk in a sequential, “batch-processing” mod
5、e. After a set of files has beenrecorded on the disk, a file cannot be extended beyond its pre-determined length.It is common practice in small systems for the user to inter-act continuously with the system to update files. Files having asuitable structure for this purpose are not within the provisi
6、ons of ECMA-91.It is necessary for the interchange cartridge to be created by an “export” copy process from the applications files, after theapplication has terminated. A similar “import” process is required in the receiving system.b) Limitations on the number of file labels permitted on an inter-ch
7、ange FDC prevents the full use of the disk space if theaverage size of files is significantly less than, say 20 Kbytes.For conventional data processing purposes this is mostly satisfactory. However, the file size typically encountered in textprocessing and small single-user systems are very much sma
8、ller and would lead to very inefficient use of the disk space.In view of these requirements it was decided to develop a second standard for volume and file structures of flexible diskcartridges. Work started in 1984 and led to the issue of the present Standard the provisions of which are based on al
9、readyexisting practice in general use world-wide. The new Standard has the following benevicial characteristics, in addition to thoseof ECMA-91.a) Direct updating of the interchange file by an interactive application is possible.b) There will be no limit on the number of individual files on a disk,
10、within the overall limitation of available space for holdingfiles, Any file can be extended whenever required.The characteristics are advantageous for:a) Interchange of sets of text files or of small files, or of multiple-part document files.b) Interchange of any file when sender and recipient wish
11、to carry out frequent update of the file between interchange cycles,for example files of commercial transactionsSince the publication of the first version of this Standard, many types of high capacity Flexible Disk Cartridges (FDCs) andOptical Disk Cartridges (ODCs) have come in use. All the descrip
12、tions (except annex B) of an FDC, throughout this ECMAStandard, can be applied to an ODC as well. It is intended that existing file systems for FDCs, possibly slightly modified, areapplicable to ODCs. ODC specific volume and file structure standards are, e.g., ECMA-167 and ECMA-168. This ECMAStandar
13、d is applicable to the new types of storage media because of revision at the following points:a) Addition of the extended FDC Descriptors (clause 9) to the existing FDC Descriptors.b) Adoption of 16-bit File Allocation Table (FAT) entries (10.2) in addition to the existing 12-bit FAT entriesc) Obsol
14、etion of the Medium Identifier field (table 3 and subclause 9.2.9) because available values are exhausted and the fieldis no more used.ECMA-107 is identical to ISO/IEC 9293.This ECMA Standard has been adopted by the General Assembly of June 1995.- i -Table of contentsSection 1 - General 11 Scope 12
15、Conformance 12.1 Conformance of an FDC 12.2 Conformance of an information processing system 13 References 14 Definitions 24.1 byte 24.2 data field of a sector 24.3 data interchange standard 24.4 defective sector 24.5 descriptor 24.6 FDC 34.7 file 34.8 formatting 34.9 implementation 34.10 initializat
16、ion 34.11 ODC 34.12 originating system 34.13 receiving system 34.14 sector 34.15 physical track 34.16 user 34.17 fixed-length record 34.18 record 34.19 segment 34.20 segmented record 34.21 variable-length record 35 Notations 45.1 Decimal and hexadecimal notations 45.2 Other notations 45.3 Capital le
17、tters 4Section 2 - Volume and file structure/File allocation table and directories 46 Volume structure 46.1 Arrangement of data on an FDC 46.1.1 FDC parameters 46.1.2 Physical Addresses 46.1.3 Logical Sector Number 46.1.4 System Area and Data Area 56.1.5 Parameters of the Volume Structure 56.2 Arran
18、gement of the Data Area 56.2.1 Clusters 56.2.2 Status of clusters 6- ii -6.3 Arrangement of the System Area 66.3.1 FDC Descriptor and space for system use 66.3.2 File Allocation Table (FAT) 66.3.3 Root Directory 76.3.4 Size of the System Area 76.4 Files 76.4.1 File Space 76.4.2 Relation to clusters
19、76.4.3 File length 76.5 Sub-directories 77 Content of a file 88 Recording of descriptor fields 88.1 Numerical values in one-byte fields 88.2 Numerical values in two-byte fields 88.3 Numerical values in four-byte fields 98.4 Pairs of 12-bit integers 98.5 Character set and coding 98.6 Justification of
20、 characters 99 FDC Descriptor 99.1 FDC Descriptor and Extended FDC Descriptor layout 109.2 FDC Descriptor and Extended FDC Descriptor fields 119.2.1 Field reserved for system use (BP 1 to 3) 119.2.2 Creating System Identifier (BP 4 to 11) 119.2.3 Sector Size (BP 12 and 13) 119.2.4 Sectors per Cluste
21、r (BP 14) 119.2.5 Reserved Sector Count (BP 15 and 16) 119.2.6 Number of FATs (BP 17) 129.2.7 Root Directory Entries (BP 18 and 19) 129.2.8 Total Sectors (BP 20 and 21) 129.2.9 Medium Identifier (BP 22) 129.2.10 Sectors per FAT (BP 23 and 24) 129.2.11 Sectors per Track (BP 25 and 26) 129.2.12 Number
22、 of Sides (BP 27 and 28) 129.2.13 Field reserved for future standardization (FDC Descriptor BP 29 and 30) 129.2.14 Field reserved for system use (Extended FDC Descriptor BP 29 to 32) 129.2.15 Total Sectors (Extended FDC Descriptor; BP 33 to 36) 129.2.16 Field reserved for system use (Extended FDC De
23、scriptor BP 37) 129.2.17 Field reserved for future standardization (Extended FDC Descriptor BP 38) 129.2.18 Extended Boot Record Signature (Extended FDC Descriptor BP 39) 129.2.19 Volume ID Number (Extended FDC Descriptor BP 40 to 43) 139.2.20 Volume Label (Extended FDC Descriptor BP 44 to 54) 139.2
24、.21 File System Type (Extended FDC Descriptor BP 55 to 62) 139.2.22 Field reserved for system use (FDC Descriptor BP 31 to 512; Extended FDC Descriptor BP 63 to 512) 1310 File Allocation Table 1310.1 Format Identifier 1310.2 FAT entries 1310.2.1 FAT entry size 1310.2.2 Number of FAT entries 1310.2.3
25、 FAT entry values 1310.2.4 Maximum Cluster Number (MAX) 14- iii -10.3 Number of sectors in each FAT 1410.4 Recorded form of the FAT 1511 File directories 1511.1 Characteristics 1511.2 Directory entry types 1511.3 General definition of Directory Entry fields 1511.3.1 Name (BP 1 to 8) 1511.3.2 Name Ex
26、tension (BP 9 to 11) 1511.3.3 Attributes (BP 12) 1611.3.4 Reserved Field (BP 13 to 22) 1611.3.5 Time Recorded (BP 23 and 24) 1611.3.6 Date Recorded (BP 25 and 26) 1611.3.7 Starting Cluster Number (BP 27 and 28) 1611.3.8 File Length (BP 29 to 32) 1611.4 File Entry 1711.4.1 Name (BP 1 to 8) 1711.4.2 N
27、ame Extension (BP 9 to 11) 1711.4.3 Attributes (BP 12) 1711.4.4 Reserved Field (BP 13 to 22) 1711.4.5 Time Recorded (BP 23 and 24) 1711.4.6 Date Recorded (BP 25 and 26) 1711.4.7 Starting Cluster Number (BP 27 and 28) 1711.4.8 File Length (BP 29 to 32) 1711.5 Volume Label Entry 1711.5.1 Name and Name
28、 Extension (BP 1 to 11) 1711.5.2 Attributes (BP 12) 1711.5.3 Reserved Field (BP 13 to 22) 1711.5.4 Time Recorded (BP 23 and 24) 1711.5.5 Date Recorded (BP 25 and 26) 1711.5.6 Starting Cluster Number (BP 27 and 28) 1811.5.7 File Length (BP 29 to 32) 1811.6 Sub-directory Pointer Entry 1811.6.1 Name (B
29、P 1 to 8) 1811.6.2 Name Extension (BP 9 to 11) 1811.6.3 Attributes (BP 12) 1811.6.4 Reserved Field (BP 13 to 22) 1811.6.5 Time Recorded (BP 23 and 24) 1811.6.6 Date Recorded (BP 25 and 26) 1811.6.7 Starting Cluster Number (BP 27 and 28) 1811.6.8 File Length (BP 29 to 32) 1811.7 Sub-directory Identif
30、ier Entry 1811.7.1 Name (BP 1 to 8) 1811.7.2 Name Extension (BP 9 to 11) 1811.7.3 Attributes (BP 12) 1911.7.4 Reserved Field (BP 13 to 22) 1911.7.5 Time Recorded (BP 23 and 24) 1911.7.6 Date Recorded (BP 25 and 26) 1911.7.7 Starting Cluster Number (BP 27 and 28) 1911.7.8 File Length (BP 29 to 32) 19
31、11.8 Sub-directory Parent Pointer Entry 1911.8.1 Name (BP 1 to 8) 1911.8.2 Name Extension (BP 9 to 11) 19- iv -11.8.3 Attributes (BP 12) 1911.8.4 Reserved Field (BP 13 to 22) 1911.8.5 Time Recorded (BP 23 and 24) 1911.8.6 Date Recorded (BP 25 and 26) 1911.8.7 Starting Cluster Number (BP 27 and 28) 1
32、911.8.8 File Length (BP 29 to 32) 2011.9 Not-currently-used Entry 2011.9.1 Name Field (BP 1 to 8) 2011.9.2 Remaining bytes (BP 9 to 32) 2011.10 Never-used Entry 2011.10.1 Name Field (BP 1 to 8) 2011.10.2 Remaining bytes (BP 9 to 32) 20Section 3 - System requirements 2012 Requirements for the descrip
33、tion of systems 2013 Requirements for an originating system 2013.1 General 2013.2 Files 2013.3 Descriptors 2114 Requirements for a receiving system 2114.1 General 2114.2 Files 2114.3 Descriptors 22Section 4 - Record structure 2215 Record structure 2215.1 General 2215.2 Records 2215.2.1 Characteristi
34、cs 2215.2.2 Measured Data Units 2315.2.3 Fixed-length records 2315.2.4 Variable-length records 2315.2.5 Segmented records 2315.3 Attributes of record-structured files 2415.4 Requirements for systems implementing section 4 2415.4.1 Originating systems 2415.4.2 Receiving systems 24Annex A - Parameter
35、values for other FDC formats 25Annex B - Parameter values for FDCs conforming to a Standard for data interchange 27Annex C - ECMA-6: International Reference Version (IRV) 31Annex D - Example of volume structure and file location 33Annex E - Index of acronyms 37- v -Annex F - Extension to Partial ROM
36、 39- vi -.Section 1 - General1ScopeThis ECMA Standard specifies the volume and file structure of disk cartridges for the interchange of informationbetween users of information processing systems. It also specifies an optional record structure.NOTEAll the descriptions (except those in annex B) of Fle
37、xible Disk Cartridges (FDC) can be applied to Optical DiskCartridges (ODC) as well.This ECMA Standard is applicable to various types of disk cartridges including those identified in clause 3, and othertypes which may be the subject of future International Standards.This ECMA Standard specifies the l
38、ocation of files of information on an FDC and also specifies a set of recordeddescriptors which identifies:- the files which may be interchanged;- the locations of the files;- the attributes of the files;- the location of unused space for recording on the FDC;- the location of defective recording sp
39、ace on the FDC;- the attributes of the FDC and of the descriptors recorded on it.This ECMA Standard also specifies requirements for the processes which are provided within information processingsystems to enable information to be interchanged between different systems, utilizing recorded FDCs as the
40、 medium ofinterchange. For this purpose it specifies the functions within systems which are intended to originate or to receiveFDCs which conform to this ECMA Standard.This ECMA Standard provides a method for the allocation of space that is independent of the number of files whichare recorded on the
41、 volume. It also enables the sizes of the recorded files to be expanded or contracted duringprocessing, subject only to the availability of unused recording space when needed.The content and organization of the files are not specified by this ECMA Standard and are subject to agreementbetween the ori
42、ginator and the recipient of the interchanged FDC.2 Conformance2.1 Conformance of an FDCAn FDC shall be in conformance with this ECMA Standard when all information recorded on it conforms to therequirements of section two of this ECMA Standard.A prerequisite to such conformance is the conformance of
43、 the FDC to the appropriate International Standard fordata interchange by means of FDCs.2.2 Conformance of an information processing systemAn information processing system shall be in conformance with this ECMA Standard if it meets the set ofrequirements specified in section three of this ECMA Stand
44、ard either for an originating system, or for a receivingsystem, or for both types of system. A statement of conformance shall identify which of these sets of requirements ismet by the system.Conformance with this ECMA Standard does not require conformance with section 4.3 ReferencesECMA-6:1991 7-Bit
45、 Coded Character Set for Information Interchange.ECMA-70:1986 Data Interchange on 130 mm Flexible Disk Cartridges Using Modified FrequencyModulation Recording at 7 958 ftprad, on 40 Tracks on Each Side.ECMA-78:1986 Data Interchange on 130 mm Flexible Disk Cartridges Using Modified FrequencyModulatio
46、n Recording at 7 958 ftprad, on 80 Tracks on Each Side.- 2 -ECMA-99:1985 Data Interchange on 130 mm Flexible Disk Cartridges Using Modified FrequencyModulation Recording at 13 262 ftprad, ,on Bothe Sides; 3,8 Tracks per mm.ECMA-100:1988 Data Interchange on 90 mm Flexible Disk Cartridges Using Modifi
47、ed Frequency ModulationRecording at 7 958 ftprad on 80 Tracks on Each Side - ISO type 301.ECMA-125:1987 Data interchange on 90 mm Flexible Disk Cartridges Using Modified Frequency ModulationRecording at 15 916 ftprad, on 80 Tracks on Each Side - ISO type 302.ECMA-147:1990 Data Interchange on 90 mm F
48、lexible Disk Cartridges Using Modified Frequency Recordingat 31 831 ftprad on 80 Tracks on Each Side - ISO type 303.ECMA-153:1994 Information Interchange on 130 mm Optical Disk Cartridges, of the Write Once,Read Multiple WORM Type Using the Magneto-Optical Effect.ECMA-154:1994 Data Interchange on -
49、90 mm Optical Disk Cartridges, Read Only and Rewritable, M.O.ECMA-183:1992 Data Interchange on 130 mm Optical Disk Cartridges - Capacity: 1 Gigabyte per Cartridge.ECMA-184:1992 Data Interchange on 130 mm Optical Disk Cartridges - Capacity: 1,3 Gigabytes perCartridge.ECMA-195:1995 Data Interchange on 130 mm Optical Disk Cartridges - Capacity: 2 Gigabytes per Cartridge.ECMA-201:1994 Data Interchange on 90 mm Optical Disk Cartridges - Capacity: 230 Mbytes per Cartridge.ECMA-207:1994 Data Interchange on 90 mm Flexible Disk Cartridges - 326 Tracks on Each Side - Capacity21 Mbytes - ISO type 3
