1、SMPTE RECOMMENDED PRACTICE RP 132-1994 Revision of RP 132-1 985 Storage of Edit Decision Lists on 8-in Flexible Diskette Media Page 1 of 6 pages 1 Scope 4 Definitions This practice specifies the file and directory structure of an 8-in flexible diskette used for the interchange of edit decision lists
2、 (EDL). 4.1 BPR: Bits per radian. 4.2 block: Four sectors (512 bytes). 9 2 Normative references 4.3 byte: Eight bits. The following standards contain provisions which, through reference in this text, constitute provisions of this practice. At the time of publication, the editions indicated were vali
3、d. All standards are subject to revision, and parties to agreements based on this practice are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. ANSI X3.73-1980 (R1992), Single-Sided Unformatted Flexible Disk Cartridge (for 6631 BPR Bits
4、Per Radian Use) IBM GA21-9388-0, IBM Diskettes 1, 2, and 2D, Original Equipment Manufacturers Information IBM GA21 -9182, IBM Diskette General Information Manual 4.4 data entry: Information entered in data form for computer processing. 4.5 directory entry: Directory information for a specified file.
5、 4.6 directory segment: Two blocks (1 024 bytes, commonly referred to as 1 k bytes) dedicated to directory information. 4.7 file: One or more blocks of user data. 4.8 interleaving: Relationship of physical to logical sector numbers within a track. 4.9 logical sector address: Software assigned number
6、 to organize physical sectors to read and write data. 4.10 minimal directory: One directory segment. 3 Format 4.11 octal values: Numbers having base 8. 4.12 physical sector number: Sector address recorded in byte 4 of the ID record. 4.13 sector: 128 bytes of information. 4.14 skew: Relationship of p
7、hysical to logical The diskette is a random-access device which allows forthe processing of blocksof dataindependent ofthe datas physical or relativelocation. Each EDLisstored in a group of one or more blocks referred to as a file and identified by a unique filename. Adirectory of files is written a
8、t a particular location on the diskette and contains file name, length, and optional user-defined information. sector numbers between tracks. Copyright O 1994 by the SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Hartsdale Ave., White Plains, NY 10607 (914) 761-1100 Approved February 28,1
9、994 SMPTE RP*132 94 = 635740L 0003554 145 = RP 132-1994 4.15 track: Any of the concentric paths for the recording of data on the surface of a direct-ac- cess storage device, such as a diskette available to one read/write. 4.16 word: Two bytes (16 bits). 5 Media - Physical and magnetic char- acterist
10、ics Edit decision lists shall be recorded on an 8-in single- sided diskette, as defined by ANSI X3.73. 6 Recording method and track format The recording method, track, and sector formatting for EDL shall be such as described for single-density diskettes in IBM GA21 -9388-0 and GA21 -91 82. 7 Logical
11、 sector numbering (see table 1) Logical sector numbers are assigned to physical sectors by the following method: 1) First logical sector: The first logical sector (sector O) is physical sector 1 on track 1. 2) Interleaving: Use all odd-numbered physical sectors, add 3, and use all even-numbered phys
12、ical sectors. 3) Skew: Logical numbering on each track begins with the physical sector 6 greater than the previous track as specified in the formula: First physical sector used = (6 * track number) -5) modulo 26 8 Data organization Data is organized in consecutive blocks of four logical sectors each
13、, in ascending order of logical sector number. 9.2 Files The files referred to by a particular directory segment O shall be contained in continuous logical blocks. 10 Directory 10.1 Directory structure A linked list of 1 to 31 directory segments. Each segment begins with a header of five 16-bit word
14、s. Certain header information is valid only in the first directory segment. There can be 72 directory entries per segment. The last directory entry must have an end-of-segment status word. 10.2 Directory segment header: Number of segments available for entries - 1 word Segment number of next logical
15、 segment - 1 word Segment number of last segment opened - 1 word Number of extra user bytes per entry - 1 word O Logical block number for start of data entries - 1 word 10.2.1 Number of directory segments The first word of the directory header contains the number of directory segments available. Thi
16、s value is only valid in the first directory segment. Allowable values are 1 to 31. 10.2.2 Next logical segment The second word of the directory header contains the segment number of the next logical directory segment. Allowable values are 2 to 31, and O, which indicates no additional segments. 10.2
17、.3 Last segment number The third word of the directory header contains the number of the last directory segment opened. Each time a new directory segment is opened, this number must be updated. This value is only valid in the first directory segment. Allowable values are 1 to 31. 9 Diskette organiza
18、tion 9.1 Directory location and size The directory begins at logical block 6 and consists of a linked list of directory segments. Page 2 of 6 pages SUPTE RP*332 99 m 8357401 0003555 O81 ll- Y o L I- _ (0 Cu In Cu d Cu m Cu Cu Cu T Cu O Cu o) Y Co 7 b T (D T In l- d 7 m l- Cu T T T O T- o) Co b (0 In
19、 d m Cu T L 9 -n o $& .- 85 %!= a In Cu Cu l- d Cu 7 l- m Cu O l- Cu Cu o) l- Cu m O Cu r- o) l- (D m 7 ln r- l- d (D 7 m In T Cu d T l- m l- O mn -E gai .- + o O -I (D m o Cu In Cu v) Cu In Cu In F d T d T d T d O m O m O m O Y o 28 na -E .- 82 o O -I Cu Y o L I- (D Cu In Cu d tu m Cu Cu Cu 7 Cu O
20、N o) T m T b 7 (D l- In l- d T m l- N 7 l- l- O l- o) Co b (D In d m Cu - Cu Cu o) l- Cu Co O Cu r- o) T Co m T v) b T d (D l- 0 In 7 Cu d l- F 2 O In Cu Cu l- d Cu l- T m Cu O T mn -E 3 gj .- 82 o Cu T- Co T 7 Ca T 7 Co 7 7 Co T T b O T b O l- r- O v- r- O 7 (D o) CD Cu T o) Cu Y CY Cu l- o) Y 0 08
21、 -E aa .- $2 o 3 - m Y o I- L RP 132-1994 (D N In Cu d Cu m Cu Cu Cu T Cu O Cu o) T Co T b 7 (D l- In 7 d T m T Cu 7 T l- O T o) m b Co In d m Cu 7 o) T (D m l- In b T d (0 T m Lo 7 Cu d l- T m T O ln N Cu l- d Cu 7 T m Cu O 7 Cu N o) l- Cu m O Cu b mn -E 3 g8 .- zz w b T- d l- b T d l- r- 7 d l- b
22、T m l- (D T 0 7 (D l- 2 (o l- m l- o) Y (D l- 3) r In l- m l- In T Co l- In Y Co T In - Co l- d l- Y o o8 na -E .- 22 w O J Page 3 of 6 pages SMPTE RP*332 94 8357403 0003556 T18 RP 132-1994 10.2.4 Extra user bytes Provision is made for the inclusion of optional user- 2000 Permanent file. The name of
23、 the per- manent file must be unique. O defined words in addition to the seven specified below in each directory entry. The fourth word in the header specifies how many extra bytes are included in each of this segments directory entries. This must be an even number and be the same value in all segme
24、nts of the directory. 10.2.5 Starting block number The fifth and last word of the directory segment header contains the logical block number of the start of the entries in this segment. 10.3 Directory entry format The remainder of the directory segment is filled with directory entries. An entry cons
25、ists of words contain- ing the following information: Status File name (char 1-3) File name (char 4-6) File name extension (1 -3 characters) Total file length Reserved Reserved Optional user bytes 4000 End-of-segment marker. The last entry in a segment must have such a status word, and its remaining
26、 6 words are not required. 12000 Permanent file with the “protect” bit set. This may be used to inhibit deletion of afile. 10.3.2 File name This two-word value contains the symbolic name of the file. An encoding scheme referred to as RADIX-50 is used to pack three ASCII characters into one word. A l
27、imited character set (A-2 and 0-9) is allowed in this name. The file name may be 1 to 6 characters in length. Names of less than 6 characters must be padded with trailing spaces. 10.3.3 File extension This word value contains the packed representation of the file extension “EDL” (O1 7754). 10.3.4 Le
28、ngth The number of logical blocks used by the file. 10.3.1 Status All values given below are octal numbers. Valid types of status words are as follows: 400 Tentative file. 10.3.5 Reserved words The directory entry contains two reserved words allowing for compatibility. 10.3.6 User bytes Any even num
29、ber of extra bytes as specified in the directory segment header. 1000 Empty file. The name and file extension fields are not used. The length of the empty file must be included. Page 4 of 6 pages I SMPTE RP*332 94 m 8357403 O003557 954 m RP 132-1994 Annex A (informative) Additional data O A.l Minima
30、l directory Systems without file-management capabilities may produce single edit decision list diskettes using the following minimal directory: Header: 1 One directory segment O No next segment 1 O Highest open segment is 1 No extra bytes per entry 10 Starting block number Entry 1: 2000 74330 76710
31、17754 746 I Permanent entry PADIX-50 for “SMP” RADIX-50 for “TE(space)” RAD I X- 50 for “ED L” Total file length (logical blocks) i Reserved Reserved All preceding numbers are shown as octal values. This is a suggested single-file directory allocating the entire diskette to the edit decision list fi
32、le. The file name “SMPTE” is shown for example only, and may be any valid 6-character file name as described in 10.3.2. A.2 ASCII to RADIX-50 conversion Each ASCII character is translated into its RADIX-50 equiv- alent as follows: Character (space) A-Z $ (undefined) 0-9 ASCII octal equivalent 40 101
33、 -1 32 44 56 35 60-71 RADIX-50 octal ea uiva1 en t The RADIX-50 equivalent of three characters, C1, C2, and C3, are combined as follows: RADIX-50 value = (Cl * 50) + C2) * 50) + C3 Example: RADIX-50 value of “EDL” = (5 * 50) + 4) * 50) + 14 = o17754 Table A.l provides an alternate method of translat
34、ing from the ASCII character to its RADIX-50 equivalents. RADIX-50 value = The sum of the first character entry + the second character entry + the third character entry. Example: RADIX-50 value of “EDL = 017500 + 000240 + 000014 = 017754 A.3 RADIX-50 to ASCII conversion To convert from the packed RA
35、DIX-50 value to the RADIX- 50 octal equivalents of the three characters, C1, C2, and C3, the following rules are followed: C1 = RAD-50 value / 3100 C2 = RAD-50 value - (RAD-50 value 13100) * 3100) 150 C3 = RAD-50 value - (RAD-50 value / 50) * 50) Example: RADIX-50 value = 74330 (SMP) O 1-32 33 34 35
36、 36-47 C1 = 74330 I3100 = 23 = “S” C2 = 74330 - (74330 13100) * 3100) 1 50 = 15 = “M” C3 = 74330 - (74330 / 50) * 50) = 20 = “P” All preceding numbers of A.2 and A.3 are octal values (see table A.l). Page 5 of 6 pages SMPTE RP8332 94 8357403 0003558 890 W UP 132-1994 Table A.l - Alternate conversion
37、 of ASCII to RADIX-50 Single character or Second Third first character character character Space A B C D E F G H I J K L M N O P Q R S T U v W X Y Z $ Unused O 1 2 3 4 5 6 7 8 9 000000 0031 O0 006200 O1 1300 O1 4400 O1 7500 022600 025700 03 1 O00 0341 O0 037200 042300 045400 050500 053600 056700 062
38、000 0651 O0 070200 073300 076400 101500 104600 107700 1 13000 116100 121200 124300 127400 132500 135600 140700 144000 1471 O0 152200 155300 160400 163500 166600 171700 Space A B C D E F G H I J K L M N O P Q R S T U v W X Y Z $ Unused O 1 2 3 4 5 6 7 8 9 o 000000 000050 O00 1 20 O001 70 000240 00031
39、 O 000360 000430 000500 000550 000620 000670 000740 001010 O0 1 060 O01 130 O0 1 200 O0 1 250 001320 001370 O01 440 001510 O0 1 560 O0 1 630 O0 1 700 O0 1 750 002020 002070 002 1 40 00221 o 002260 002330 002400 002450 002520 002570 002640 00271 O 002760 003030 Space A B C D E F G H I J K L M N O P Q
40、 R S T U v W X Y Z $ Unused O 1 2 3 4 5 6 7 8 9 o 000000 000001 000002 000003 000004 000005 000006 000007 00001 o 00001 1 00001 2 00001 3 00001 4 00001 5 O0001 6 00001 7 000020 000021 000022 000023 000024 000025 000026 000027 000030 000031 000032 000033 000034 000035 000036 000037 000040 000041 000042 000043 000044 000045 000046 000047 Page 6 of 6 pages
