PROJECT: SINGLIX Operating System Issue: 2 Revision: 12 Date: 19/05/2009 OWNER: ERDOĞAN TAN / Istanbul / Turkiye
FILE DESCRIPTION TABLE Format of SINGLIX FS1, FS2 file systems
Offset	Item	DATA	Type	Size	Description of Item
0	FDT Sign	‘FDT’	Char	3 byte	TR-SINGLIX File Description Table
3	FS FDT Version	XXh	Byte	1 byte	Must be 0 for Current/This FDT Version
4	Sector Size	XXXXh	Word	2 byte	Bytes per Sector (FS1=512, FS2=2048)
6	FDT Number	XXXXh	Word	2 byte	FDT (Sequence) Number of This File
8	File Number	XXXXXXXXh	Dword	4 byte	The 1st FDT Address of This File (LBA)
12	Next FDT Number	XXXXXXXXh	Dword	4 byte	FDT address of the next section (LBA)
16	Sector Count	XXXXXXXXh	Dword	4 byte	Number of Sectors in this section
20	Parent Dir Number	XXXXXXXXh	Dword	4 byte	The Parent DDT Addr. of This File (LBA)
24	Parent Dir Serial	XXXXXXXXh	Dword	4 byte	The Parent Dir’s Serial No. (Tick Count)
28	File Size	XXXXXXXXh	Dword	4 byte	The lower 4 bytes of 6 byte file size.
32	File Size High	XXXXh	Word	2 byte	The higher 2 bytes of 6 byte file size.
34	File Type	XXXXh	Word	2 byte	Major, Minor Type Descriptor of This File
36	CheckSum	XXh	Byte	1 byte	FileName CheckSum
37	Attributes	XXh	Byte	1 byte	Permissions for Owner, Group, Others
38*	Owner Code	XXXXXXXXh	Dword	4 byte	Owner Description Table Address (LBA)
42*	Group Code	XXXXXXXXh	Dword	4 byte	Group Description Table Address (LBA)
46	Country	XXh	Byte	1 byte	Language, Date, Text Format (default = 0)
47	Time Zone	XXh	Byte	1 byte	-11 to +12  (GMT = 0, default = 0)
48	Creating Year	XXXXh (CCYY)	Word	2 byte	Year in Binary Coded Decimal (BCD)
50	Creating Month	XXh	Bute	1 byte	Month in Binary Coded Decimal (BCD)
51	Creating Day	XXh	Byte	1 byte	Day in Binary Coded Decimal (BCD)
52	Creating Hour	XXh	Byte	1 byte	Hour in Binary Coded Decimal (BCD)
53	Creating Minute	XXh	Byte	1 byte	Minute in Binary Coded Decimal (BCD)
54	Creating Second	XXh	Byte	1 byte	Second in Binary Coded Decimal (BCD)
55	C. Time Mode	XXh	Byte	1 byte	0 = Standard Time, 1 = Daylight Saving
56	Last Modif. Date	XXXXXXXXh	Dword	4 byte	The Last Modification/Write Date (BCD)
60	Last Modif. Time	XXXXXXh	Byte	3 byte	The Last Modification/Write Time (BCD)
63	L. M. Time Mode	XXh	Byte	1 byte	0 = Standard, 1 = Daylight Saving Time
64	File Name	<FileName>	Char	64 byte	64 byte full or zero terminated File Name
128	File Description	Text	Char	128 byte	File Description Text
256	Reserved	?	Byte	256 byte	256 byte Reserved/Optional Data Field
512**	Reserved	?	Byte	1536 byte	Optional/Reserved Area for FS2 Files
* Used by TR-MULTIX (Multi User, Multi Tasking) Operation System, only! ** 1536 byte extra description for 2048 bytes per sector File System (FS2), only ! Optional ! NOTE: Erased/Deleted File Sign: ‘FDE’, ‘E’ at offset 2 instead of ‘T’. (Parent Dir’s Entry: FFFFFFFFh is erased entry, 0 is.end of directory entries. Other 32 bit dir. entry numbers are the 1st FDT addresses.) Parent Dir. Serial used for that purpose: When a dir or file is deleted, it will be removed from parent dir entries by replacing child directory or file number to FFFFFFFFh = deleted entry sign. And, it will be located in UNDELETE Directory as a new deleted file entry. When user want to undelete this file/dir, if parent dir serial number same with in the parent directory descriptor table (as number) declared in child dir decriptor table, the deleted directory or file will be restored in the parent directory. Directory serial number is just a tick count which always different by the computer’s timer ticks. (as like as volume serial number.) For the First FDT (FDT0) of every file, this 1 sector FDT structure is completely valid and used. If a file has multiple FDTs (has more than one data section on the disk), except FDT 0, next and other FDTs use or carry the first 20 bytes of FDT structure as valid. Remain items are not used or not valid. So, the first FDT (FileNumber, Offset 8) is only reference to full FDT structure for file recovery or reverse/trace procedures. (Offset 8 points the FDT 0 address , Offset 6 has the current FDT seguence number.) By using only FDT0 parameters (except the first 20 bytes of FDTs), all of FDT contents after file create, move, update (file name, path and size changements etc.) procedures are kept true/correct for all FDTs. FDT1 and other FDTs (>0) must have valid 20 bytes on to Offset 20, then, must have ZERO bytes. (If a file is in a single data section, only FDT0 –the 1st FDT- is used and Offset 12 of FDT0 has ZERO.) ATTRIBUTES byte: Bit 0 = Owner’s Write Permission (1= Yes, 0= No) [ 0 => Read only file ] Bit 1 = Owner’s Execute Permission (1= Yes, 0= No) [ 0 => Not an executable file ] Bit 2 = Group User’s Read Permission (1=Yes, 0= No) [ 0 => This file is not visible except the owner ] Bit 3 = Group User’s Write Permission (1=Yes, 0= No) [ Can be YES if Bit 0 is YES ] Bit 4 = Group User’s Execute Permission (1=Yes, 0= No) [ Can be YES if Bit 1 is YES ] Bit 5 = Other User’s Read Permission (1=Yes, 0= No) [ 0 => This file is not visible except the group ] Bit 6 = Other User’s Write Permission (1=Yes, 0= No) [ Can be YES if Bit 0 and Bit 3 are YES ] Bit 7 = Other User’s Execute Permission (1=Yes, 0= No) [ Can be YES if Bit 1 and Bit 4 are YES ]