I have two questions about FAT-32 file system.
With the FAT-32 File System introduced in wiki, and from the structure provided as following:
,
each file can have name with length no larger than 8?
What's more, I found that the data of the first file I create is as expected to be at cluster #3. (Since root directory begin at cluster #2)
So, does this mean root directory can only store metadata about 16 files? (each occupies 32 bytes in root directory...)
Or, root directory can also get 'fragmented' and each fragments get linked by through information in FAT?
Sorry for my bad formatting.... And thanks for all help.
In FAT-32 a file can have two filenames. One is always an olde-style 8+3 file name. The other optional file name can have up to 255 characters. A system that supports long file names creates a unique 8+3 file name based on the long name. That allowed even older systems that only supported 8+3 file names to access FAT-32 file systems.
Related
I found something very weird on a project.
I have 2 files :
One is the input file, it's a .bip file which you can open with GIS software like QGIS
here's the input. this file is provided by the CCSDS and accessible here
The other is the output after been compressed and decompressed by a lossless compression algorithm (CCSDS 123 by ESA)
Those 2 files shares the exact same sha256 and sha1 hash, so they are identical.
3226009de97d66589fc58cdc9af377e6315ccc69a7095bec8dc04447bf3cea2e test_ptn_x100y36z17_16u.bip
3226009de97d66589fc58cdc9af377e6315ccc69a7095bec8dc04447bf3cea2e test_ptn_decomp.bip (sha256 shown here).
The thing is, if the entry is showed by QGIS, the second one displays a message and refuses to open it shows this message (translated : the file test_ptn_decomp.bip is not a recognized or valid data source)
Is there something i don't understand with hashes ? i've tried moving files to other directories and renaming but nothing changes QGIS wise.
It is highly unlikely you got a different content with same sha256 hash by chance. So I'll assume the files are identical. Anyway, it is easy to use any diff program to compare.
So there should be some other differences, things that come to mind:
file name might contain some meaningful information needed by QGIS. Try renaming decompressed file e.g. decomp_ptn_x100y36z17_16u.bip, maybe x100.. is essential?
There are some additional files, that must have matching names. Do you have a .hdr file, as explained in QGIS tutorials?
https://www.qgistutorials.com/en/docs/open_bil_bip_bsq_files.html
In the documentation of pythonforandroid, at https://python-for-android.readthedocs.io/en/latest/buildoptions/, there is a build option described called blacklist.
--blacklist: The path to a file containing blacklisted patterns that will be excluded from the final APK. Defaults to ./blacklist.txt
However, not a word can be found anywhere about how to use this file and what exactly the patterns are supposed to represent. For instance, is this used to exclude libraries, files, or directories? Do the patterns match file names or contents? What is the syntax of the patterns, or an example of a valid blacklist.txt file?
This file should contain a list of glob patterns, i.e. as implemented by fnmatch, one per line. These patterns are compared against the full filepath of each file in your source dir, probably using a global filepath but I'm not certain about that (it might be relative to the source dir).
For instance, the file could contain the following lines:
*.txt
*/test.jpg
This would prevent all files ending with .txt from being included in the apk, and all files named test.jpg in any subfolder.
If using buildozer, the android.blacklist_src buildozer.spec option can be used to point to your choice of blacklist file.
I'm a Powershell beginner and this is my first post on stackoverflow. I can understand some simple pipelines, but the following challenge is too complicated for me at this point:
I have a folder with testdata containing *.bmp files and their associated files. I want a powershell script to check which bmp-files are still used. If not used, move bmp-files and associated files to another folder.
Details:
bmp-files and associated files: For example; car01.bmp, car01.log, car01.file, car02.bmp, (...)
The bmp-files are in use if their file name (eg, car01.bmp) is mentioned in any of the (text/csv) files in at least one of 2 locations (incl. subfolders).
If the file name is not found in any of the text files, I want the script to move that file, and any file who's name differs only by file extension to a designated folder.
Looking forward to your solutions!
After the upload the a sapui5 application on the SAP system has a strange structure. The files are not in the same structure as they were on my machine and the filenames are hashed, except MIMEs. So I am not able to find e.g. a specific "controller.js". The application is still fully working.
In this specific case the SAP Program "/UI5/UI5_REPOSITORY_LOAD" was used to upload the application. The upload protocol looks fine, no hint about renaming or similar. So I am not sure if the problem is with the system or the program.
All the hash files name should be normal naming and should be in sub-folders components. Even the "index.html" file has a hash, this cases a problem when click on "test application", because it opens the hash in the URL. The hash, which is the path and the filename cannot be opened, but if I replace the hash with the original path -> it works
http://scn.sap.com/thread/3809662
A work colleague found the issue in the sap system. It seems it is not allowed to have path + filename longer than 70 characters. If it is longer it hashes the path and filename to place it under the project root folder.
The german comment seems very strange, though ... "Name length should not be a
problem. Do we have anyhow a max length?"
It also creates a file containing the mapping from filepath + filename to hash.
You should not use file names longer than 70 characters.
Also you should not use '-' in your file names.
As far as I know the only allowed characters for valid BSP paths are:
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789./_"
I am trying to figure out what hashing algorithm is used for the Microsoft Symbol Local Cache directory.
For example, the local cache can be something like the following
L:\Symbols
\browseui.dll
\44FBC679fe000
browsue.dll
\browseui.pdb
\44F402F62
browseui.pdb
\explorer.exe
\3EBF1F14f7000
explorer.exe
\explorer.pdb
\3EBF1F141
explorer.pdb
\msvcr71.pdb
\60D915C6AB6A4F3586E9096E2F8856482
msvcr71.pdb
There seems to be some sort of correspondence between a file and its debug database. Other than that, I can’t figure out how the names of these (presumably) hexadecimal string folders are being generated.
Some of them are 9 digits, some 13 digits, and others are 33 digits. It looks like an actual, live-file (which for some reason is stored in the symbol cache) has a 13-digit hash while its (nearly similar) debug database gets a 9-digit hash. Some debug databases get a 13-digit hash; can’t figure out what makes these ones special, although they don’t have a corresponding live-file.
I’ve tried hashing the files with every kind of hash algorithm that I know of (39 of them) and none match in any way (straight up, reversed, alternate endian’d, etc.)
Any ideas?
Update
I think I finally found it. From Symbol Storage Format:
SymStore uses the file system itself as a database. It creates a large tree of directories, with directory names based on such things as the symbol file time stamps, signatures, age, and other data.
Edit
Dang, unfortunately it only mentions that the directory name is derived from various aspects (not quite a hash I guess), but does not say exactly how. The search continues… :-(
This page has info on calculating the IDs for the symbol files as well as executables/DLLs.
Basically, for executables and DLLs, you extract the timestamp and filesize from the PE header as listed in the page that Griff linked to. For PDB files however, you will need the DBH command from the Windows Debugging Tools. Simply load the PDB file into DBH and use the INFO command to get the PdbSig/PdbSig70 and PdbAge. Bam! That’s it.
I just created the appropriate folders for the PDB files that I had in my SYSTEM32 folder for some reason, and finally moved them to the local symbol store.
Try looking at this page: Symbol Server Callback Function
EXE/DLL directory name is created by concatenating hex string of the "file modified" time-stamp and "SizeOfImage" from IMAGE_OPTIONAL_HEADER
Finding PE files
The format for the path to a PE file in a symbol server share is:
"%s\%s\%08X%x\%s" % (serverName, peName, timeStamp, imageSize, peName)
Example:
https://msdl.microsoft.com/download/symbols/ntdll.dll/B29ECF521f0000/ntdll.dll
Finding PDB files
The format for the path to a PDB file in a symbol server share is:
"%s\%s\%s%x\%s" % (serverPath, pdbName, guid, age, pdbName)
Example:
https://msdl.microsoft.com/download/symbols/ntdll.pdb/4BC147AE72E8D05022366D6570A8E3461/ntdll.pdb
Source: Symbols the Microsoft Way by Bruce Dawson.
You can find the answer,
SYMBOL RETRIEVER SHELL EXTENSION
; http://www.vitoplantamura.com/index.aspx?page=symretriever
DebugDir.cpp
; http://www.debuginfo.com/examples/src/DebugDir.cpp
PDB File Internals
; http://www.informit.com/articles/article.aspx?p=22685