File access in C (Nspire)
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File access in C (Nspire)
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bwang


Member


Joined: 15 Mar 2009
Posts: 128
Posted: 30 Apr 2010 12:27:11 pm    Post subject:
Does the Nspire have the standard file access functions in C?
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Lionel Debroux


Member


Joined: 01 Aug 2009
Posts: 170
Posted: 08 May 2010 04:58:12 am    Post subject:
Yes, it does Smile
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Armael


Newbie


Joined: 08 Jan 2010
Posts: 3
Posted: 26 May 2010 01:32:02 pm    Post subject:
And, how ?

Then an other question : I am reluctant to use the OS functions. So, does a way exist to read files directly ? Without using the OS ?
It will be great to wrote a driver for the NAND.

I don't have any idea of how it was on the other calcs, so, do you have an idea of the way we can do this ?

Last edited by Guest on 26 May 2010 01:32:20 pm; edited 1 time in total
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calc84maniac


Elite


Joined: 22 Jan 2007
Posts: 770
Posted: 26 May 2010 01:44:20 pm    Post subject:
That actually would be a nice idea, so we can make programs independent of OS version (and possibly not even needing the OS at all)
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ExtendeD


Advanced Newbie


Joined: 30 Aug 2009
Posts: 91
Posted: 27 May 2010 03:46:07 am    Post subject:
To be able to write to the filesystem, you would need to:

- Write to the NAND: Goplat has probably found much of what is needed for this
- Determine the format of the different headers and maps of Datalight FlashFx (which is in charge of wear levelling, bad block management, etc.). There are no source code or documentation on this: this needs quite an important amount of dissassembly work. I suppose http://staff.ustc.edu.cn/~jpq/paper/flash/2006-Intel%20TR-Understanding%20the%20flash%20translation%20layer%20(FTL)%20specification.pdf may give an idea of the concepts, although the format is completely different
- Determine the Datalight Reliance filesystem format. This part is quite simple, I recommend reading http://www.datalight.com/resources/overview-reliance-concepts-meta-data-and-operation-17-may-2005 and trying the Windows driver ( http://www.datalight.com/resources/reliance-windows-driver-v3-2-7-for-windows-xp-and-windows-vista-build-1376gj ). I have already taken down some notes on it.

Being OS version-dependent is not really a problem, if/when Ndless will work on different OS versions, a syscall handler will be able to dispatch the calls to the right address.

To me time shouldn't be lost re-implementing the OS, workforce is needed for more useful features.
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bwang


Member


Joined: 15 Mar 2009
Posts: 128
Posted: 03 Jun 2010 01:09:36 am    Post subject:
What is the directory structure of the Nspire? For example, if I have Examples/test.tns, what is the path of test.tns?
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ExtendeD


Advanced Newbie


Joined: 30 Aug 2009
Posts: 91
Posted: 03 Jun 2010 02:20:00 am    Post subject:
bwang wrote:

What is the directory structure of the Nspire? For example, if I have Examples/test.tns, what is the path of test.tns?

/documents/Examples/test.tns.

http://www.unitedti.org/forum/index.php?showtopic=8191&view=findpost&p=140767 will help you explore the structure.
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bsl


Advanced Newbie


Joined: 09 Jan 2010
Posts: 94
Posted: 06 Jun 2010 11:31:27 am    Post subject:
The file system very closely resembles a UNIX file system.
The Datalight Command Shell shows this.
Using it the first time might give you dissapointing results.
Example 1: some directories are not searchable.

Code:

REL:A:\phoenix\>dir

Contents of A:\phoenix\
1980-01-01 00:00:00     <Dir> .

Files:                      0
Dirs:                       1
Bytes Per Block:          512
Total Blocks:           57088
Free Blocks:            49893

It first appears there is nothing in the directory, but a bit set on that directory prevents you from viewing its contents.
If you know the name of a subdirectory under phoenix you can still change directory to it.
Example:


Code:

REL:A:\phoenix\syst\>dir

Contents of A:\phoenix\syst\
1980-01-01 00:00:06     <Dir> .
1980-01-01 00:00:00     <Dir> ..
1980-01-01 00:00:06       109 localenames
1980-01-01 00:00:06     <Dir> locales
1980-01-01 00:00:06     <Dir> settings
1980-01-01 00:00:00     <Dir> docbrowserdata
1980-01-01 00:00:00     <Dir> poweroff

Files:                      1
Dirs:                       6
Bytes Per Block:          512
Total Blocks:           57088
Free Blocks:            49893

\phoenix\syst is searchable - I can list its files and directories.

You can also look at the Ndless installation:

Code:

REL:A:\phoenix\ndls\>dir

Contents of A:\phoenix\ndls\
1980-01-01 00:00:02     <Dir> .
1980-01-01 00:00:00     <Dir> ..
1980-01-01 00:00:02     <Dir> locales
1980-01-01 00:02:44       828 hook.tns

Files:                      1
Dirs:                       3
Bytes Per Block:          512
Total Blocks:           57088
Free Blocks:            49893

EDIT: The shell does not seem to have a UNIX equivalent of chmod command to change file/directory attributes

Last edited by Guest on 06 Jun 2010 05:25:34 pm; edited 1 time in total
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