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V4

pC/TFS

Often, a possibility of the storage of miscellaneous data and information is required in smaller appliances. A small File-System was exactly the correct solution there. Only, professional solutions for appliances with low storage often are to big. MS-DOS compatible systems come fast on 150kB codes already once there. Only the data once simply so any where controls casts off... ?

The here introduced Tiny-File-System is based on hierarchical, lists double-interlinked, through what no limitation is available in number of the files within a table or file size (max 4GB). Each file can produce on that occasion in fragmented or none-fragmented form, administers and is deleted.
This file-system handles all names of directories/files as a STRING, so can used special characters in the names. Not to use are two points in series and the slashes.

reserved names-elements:

.. - one directory back
/  - on the beginning of the Path: for from ROOT
/  - in middle of the Path: as separation for directory/file-names

The whole file-system works case-sensitive !
Parallel battery-buffered sRAM, EEPROM, FRAM, MRAM or 256byte-page NOR-flash as hardware are tested and port's produces. For critical applications, one variation each with Roll-Back-Buffering arrived for a sure letter however, which leads to the duplication of the writing accesses.
The application of other Flash-Memory became on reason of the sector size of >=64kB, the necessary buffering of a such against the update, as well as the long programming time of a whole side intended not. Furthermore, a safeguarding would be to be timewise hardly represented like by an above-mentioned Roll-Back-mechanism.
A use of modern data Flashes with PAGE sizes of 128byte .. 64kbytes can be made possible at any time by means of a "ReadPageToBuffer-UpdateBuffer-ErasePage-WriteBufferToPage" mechanism, however the TinyFileSystem does not examine for optimized (summarized) PageWrite.
When using NOR-Flash, however, it is important to remember that 10.000 .. 100.000 cycles is a very short life with frequent updates in the same page.
In addition, the TinyFileSystem do not respect hot spots (high-update files).


memory consumption of the pC/TFS V2.38b:

ROM: approximately 14 kBytes on a 32bit CPU
         approximately 22 kBytes on a 8bit CPU
RAM: approximately 24 bytes global + 16..24 bytes per user + 9 bytes * TFS_HANDLES
         plus approximately 100 bytes stack

Ports:

sRAM	battery-buffered IS62WV51216, EM7644SU16
FRAM	FM22L16
MRAM	MR4A16
NOR	AT91SAM7SE512 / ATSAM3SD8B
NOR	SAMD21
plus some special processors and their NOR or EEPROM based internal memory

But no mechanisms of the File-sharing are deposited. So a file can be opened simultaneously from many Users to reading but only from one User to writing.
As directory and File-Attribute, Read-Only and Hidden(System) to the disposal, stand. Hidden entries are not declared on that occasion with a TFS_GetFirst.. or TFS_GetNext.., can be grabbed directly, however.
The entire File-System does 4 GBytes on a linear storage area of maximum. The utilization of a MMU is included possible without further.

The optional functions TFS_Defrag to the defragmentation of the drive and TFS_Repair to repairing defect hierarchical concatenations are ready.
Since V2.00 can used links (to files or directories). Since V2.01 are some parameters of functions changed.

download pC/TFS 2.38b (as ZIP)

Releases:

1.00a	first alpa-release
1.20d	some little bug-fixes in TFS_GetFirstEntry() und TFS_GetNextEntry() and two additional fileattributes. Directories havn't attribs. Optimising code.
2.00a	alpha-release with links. Tripple-source for Keil, gcc and Microsoft-C
2.01b	Changed return-parameter of TFS_OpenFile(), TFS_FileRead() and TFS_FileWrite(). Implementation of TFS_GetErrNo(). Implementation of a additional LINUX-Host port's to simulate the TFS in RAM of a PC.
2.10a	handling of users changed - every Task can only be one User, but every User can open TFS_HANDLES files. Adaption of API-Calls. Function of TFS_ExpandFile() changed, new function TFS_ResizeFile() added. For a FileSystem smaller than 64kByte TFSLONG for all length-parameter implemented to minimize the API- and Memory- Overhead. Now a file can opened simultaneously from many Users to reading - but only one User can open a file to writing. If a file opened (more than once) to reading, an other User can't open this file to writing - if a file from one User opened to writing, no other User can open this file for reading or writing.
2.11b	TFS_GetFileSize(), TFS_GetFileAttrib() and TFS_TellFile() added. Little bugfix in internal function TFSChange_Entry().
2.20b	complete code-optimizing.
2.21a	TFS_GetFreeSize() and TFS_MoveFile() added. Bugfix in TFS_RenameFile() and TFS_RenameDir().
2.23b	TFS_WriteFileE() added. SpeedUp in internal function TFSChange_Entry().
2.30d	complete update to U08..U32 types. Typechanges from HANDLE to TFS_HANDLE, TFSLONG to TFS_LONG and ATTR to TFS_ATTR. Small correction in TFS_SeekFile(). Better portability for RTOS-less use implemented. Clean-Up in comments and some code-lines.
2.32a	TFS_GetFirstEntry() and TFS_GetNextEntry() renamed to TFS_GetFirstName() and TFS_GetNextName(). TFS_GetFirst() and TFS_GetNext() added, this functions returns all informations about an entry (DIR/FILE) in the given structure. TFS_GetRev() added.
2.34b	TFS_BecomeUserSubROOT(), TFS_GetCurrentPath(), TFS_ChangeDirTemp() and TFS_BackDirTemp() added.
2.35a	change to task-ID on use of pC/OS for unique identify of running task, TFS_SetEOF() added.
2.36a	correct user-check for GCC & unknown user.
2.37b	TFS_GetEntry added and small correction in internal function TFSChange_Entry.
2.38b	TFS_PATHNAME central for all strings added, internal functions as static as far as possible

Services of the pC/TFS version 2.38b (abbreviation)
This here presented function overview only serves as short overview.
For detailed information, you please look in Reference-Manual about pC/TFS.

TFS-Control:	Description
TFS_Init	Initialization of the File-System
TFS_GetRev	It returns a pointer on TFS revision
TFS_Flush	save the TFS as image into a LINUX-file
TFS_Format	Format the drive

User:	Description
TFS_BecomeUser	As User announce
TFS_BecomeUserSubROOT	As User in a subdirectory as user-ROOT announce
TFS_CloseUser	As User cancel
TFS_GetFreeSize	Return the brutto free-memory of the drive

Directories:	Description
TFS_CreateDir	Create a directory
TFS_RemoveDir	Remove a directory
TFS_RenameDir	Rename a directory
TFS_ChangeDir	Change current path
TFS_ChangeDirTemp	Change current path temorary
TFS_BackDirTemp	returns from temporary path
TFS_GetCurrentDir	Return the name of current directory
TFS_GetCurrentPath	Return the complete current path from (user-)ROOT

Files:	Description
TFS_CreateFile	Create a file
TFS_RemoveFile	Remove a file
TFS_RenameFile	Rename a file
TFS_MoveFile	Move a file
TFS_AttribFile	Change the attributes of a file
TFS_GetFileAttrib	It returns the attributes of a file
TFS_ResizeFile	Resize a file
TFS_GetFileSize	It returns the size of a file
TFS_OpenFile	Open a file in "mode"
TFS_CloseFile	Close the opened file
TFS_SeekFile	Place the pointer in opened file absolutely
TFS_TellFile	It returns the pointer in opened file
TFS_ExpandFile	Expand the size of opened file
TFS_SetEOF	Set EndOfFile in opened file to actual R/W-pointer
TFS_ReadFile	Read data from opened file
TFS_WriteFile	Write data into opened file
TFS_WriteFileE	Write data into opened file, expand this file if its needed
TFS_GetErrNo	read the error-code from Open, Read, Write ...

Links:	Description
TFS_CreateLink	Create a Link to a directory or file
TFS_RemoveLink	Remove a Link
TFS_RenameLink	Rename a Link
TFS_ReadLink	It returns the name of the linked directory or file

Entries:	Description
TFS_GetFirstName	It returns the name of first entry in current directory
TFS_GetNextName	It returns the name of next entry in current directory
TFS_GetFirst	It returns all infos of first entry in current directory into a struct
TFS_GetNext	It returns all infos of next entry in current directory into a struct
TFS_GetEntry	It returns all infos of the given entry (dir/file/link) into a struct

Optional:	Description
TFS_Defrag	Defragment the drive
TFS_Repair	Repair the hierarchical pointer-system

Error-Codes:

Name	Decimal_Value
TFS_NO_ERR	0
TFS_USR_OVF	200
TFS_DBL_USER	201
TFS_NO_USER	202
TFS_SUB_USER	203
TFS_NAME_EXIST	210
TFS_NOT_EXIST	211
TFS_PATH_ERR	212
TFS_TMP_DIR	213
TFS_NO_FILE	214
TFS_FILE_RO	215
TFS_FILE_WO	216
TFS_FILE_EOF	217
TFS_NOT_EMPTY	218
TFS_FILE_OPEN	219
TFS_NO_DATA	220
TFS_WRONG_PTR	221
TFS_LINKED	230
TFS_MAX_LINK	231
TFS_LINK_ERR	232
TFS_NO_LINK	233
TFS_MEM_ERR	250
TFS_MEM_OVF	251
TFS_WR_PTR	252
TFS_WRITE_ERR	253
TFS_INVALID	254