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#16
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Transferring files to Tablet via USB Cable Looses Original Time & Dates of Files
On Wed, 9 Jan 2019 12:49:25 -0600, VanguardLH wrote:
wrote: SNIP You can try MyPhoneExplorer [1] which is an Android/Windows combo which can use an USB or WiFi connection. Since it's a Samsung tablet, you could also use Samsung's 'Kies 3' software, but all references to that seems to have vanished from the Samsung site, in favour of the Smart Switch software. The Smart Switch page [2] still mentions 'Kies', but the 'LEARN MORE' link [3] redirects back to the Smart Switch page! Sigh! I don't know if any of these preserve timestamps when copying, but it's worth a try. My advice is to start with MyPhoneExplorer. [1] https://play.google.com/store/apps/details?id=com.fjsoft.myphoneexplorer.client and https://www.fjsoft.at/en [2] https://www.samsung.com/us/smart-switch [3] http://www.samsung.com/us/support/owners/app/kies Hi, I ordered a USB gender changer from Amazon. I heard from a ham radio friend of mine that he was able to access a USB flash drive using his tablet with the proper cable. That should solve my problem. John Whether it does or not, come on back to post the result. We're curious. Hi Vanguard, UPDATE: I received the USB gender changer. I connected an 8G (FAT32) USB flash drive, with a few text files on it, to my Samsung Galaxy Tab A model SM-T280 tablet. Unfortunately, it was NOT detected by "File Manager+" or "X-plore". I tried "My Files" (came with tablet) and was unable to "see" the USB flash drive. I checked the USB gender changer on my laptop using a USB cable with male connectors on both ends. There is NOTHING wrong with the gender changer. I need to contact my ham radio friend on the air to find out what AP he was using. Note: I have one solution to preserving the file's time & dates when I transfer files to that "stuck" micro SD card, but it isn't the best solution. If I find out what AP he (ham friend) used, I will download it and report back here with another "update". Again Thanks to everyone, John |
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#18
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Transferring files to Tablet via USB Cable Looses Original Time & Dates of Files
Retroman wrote:
On 8 Jan 2019 18:47:02 GMT, Frank Slootweg You can try MyPhoneExplorer [1] which is an Android/Windows combo which can use an USB or WiFi connection. [snip] My advice is to start with MyPhoneExplorer. https://play.google.com/store/apps/details?id=com.fjsoft.myphoneexplorer.client Many thanks for this tip, Frank. These two apps make synching over Wi-Fi easy and fast. Both a phone client and a Windows desktop client are required, the latter being available from fosshub.com. The interface is a bit fiddly but once the tasks are set up and saved, two clicks are all that is needed to update a folder and its subfolders on the SD card. I spent a lot of time looking for an easy and reliable way to do this and this is it! You're welcome For the kind of tasks you describe, you may also want to have a look at 'SyncMe Wireless'. https://play.google.com/store/apps/details?id=com.bv.wifisync SyncMe Wireless can do one-way or two way 'syncing' between an Android device and a SMB Network Share. Since a Network Share can also be any folder on a Windows system, you can 'sync' between Android and Windows. SyncMe Wireless allows you to set up jobs for repeated operations and such jobs can be executed manually or scheduled. Don't be misled/put_off by the 'sync' term. If the destination folder is empty, then a one-way sync is effectively a copy. For example, I use SyncMe Wireless to make full/incremental backup of (the content of) my Android filesystems to (a HDD connected to) my Windows system. A difference with MyPhoneExplorer is that you initiate the operations on/from the Android device instead of on/from the Windows computer. But by combining the two, you can control SyncMe Wireless from MyPhoneExplorer. |
#19
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Transferring files to Tablet via USB Cable Looses Original Time & Dates of Files
wrote:
On Wed, 9 Jan 2019 12:49:25 -0600, VanguardLH wrote: wrote: SNIP You can try MyPhoneExplorer [1] which is an Android/Windows combo which can use an USB or WiFi connection. Since it's a Samsung tablet, you could also use Samsung's 'Kies 3' software, but all references to that seems to have vanished from the Samsung site, in favour of the Smart Switch software. The Smart Switch page [2] still mentions 'Kies', but the 'LEARN MORE' link [3] redirects back to the Smart Switch page! Sigh! I don't know if any of these preserve timestamps when copying, but it's worth a try. My advice is to start with MyPhoneExplorer. [1] https://play.google.com/store/apps/details?id=com.fjsoft.myphoneexplorer.client and https://www.fjsoft.at/en [2] https://www.samsung.com/us/smart-switch [3] http://www.samsung.com/us/support/owners/app/kies Hi, I ordered a USB gender changer from Amazon. I heard from a ham radio friend of mine that he was able to access a USB flash drive using his tablet with the proper cable. That should solve my problem. John Whether it does or not, come on back to post the result. We're curious. Hi Vanguard, UPDATE: I received the USB gender changer. I connected an 8G (FAT32) USB flash drive, with a few text files on it, to my Samsung Galaxy Tab A model SM-T280 tablet. Unfortunately, it was NOT detected by "File Manager+" or "X-plore". I tried "My Files" (came with tablet) and was unable to "see" the USB flash drive. I checked the USB gender changer on my laptop using a USB cable with male connectors on both ends. There is NOTHING wrong with the gender changer. I need to contact my ham radio friend on the air to find out what AP he was using. Note: I have one solution to preserving the file's time & dates when I transfer files to that "stuck" micro SD card, but it isn't the best solution. If I find out what AP he (ham friend) used, I will download it and report back here with another "update". Again Thanks to everyone, John Back to a question asked in my first reply ... You sure the USB port in the tablet is configured for file transfer? I don't know that having to "allow access to the tablet (on the tablet)" means the USB port is actually configured to allow file transfer. I found online copies of the manual for that tablet at: https://static.bhphotovideo.com/lit_files/153238.pdf http://media.datatail.com/docs/manual/328240_en.pdf When searching on "usb", nowhere did it mention a setting for the mode for the USB port. You sure that tablet allows file transfers via the USB port? The USB port might be just for charging. The 2nd online manual copy has a section for transferring files (page 27) but mentions you have to use Samsung's Smartswitch software. https://www.samsung.com/us/smart-switch/ It is not specified if "content" that can be transferred include any folder on the SD card or from default paths in main storage. You never mentioned which Android version is on the tablet. https://www.dummies.com/consumer-ele...-from-your-pc/ That describes the AutoPlay prompt on the Windows PC when it detects the tablet. Yet you say it doesn't appear which makes it sound like you made a choice awhile ago and also made it the default. That's why I asked if the device was listed under the Control Panel - Autoplay wizard and if set to perform some default action instead of letting you choose at the time. |
#20
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Transferring files to Tablet via USB Cable Looses Original Time & Dates of Files
SNIP
Hi Vanguard, UPDATE: I received the USB gender changer. I connected an 8G (FAT32) USB flash drive, with a few text files on it, to my Samsung Galaxy Tab A model SM-T280 tablet. Unfortunately, it was NOT detected by "File Manager+" or "X-plore". I tried "My Files" (came with tablet) and was unable to "see" the USB flash drive. I checked the USB gender changer on my laptop using a USB cable with male connectors on both ends. There is NOTHING wrong with the gender changer. I need to contact my ham radio friend on the air to find out what AP he was using. Note: I have one solution to preserving the file's time & dates when I transfer files to that "stuck" micro SD card, but it isn't the best solution. If I find out what AP he (ham friend) used, I will download it and report back here with another "update". Again Thanks to everyone, John Back to a question asked in my first reply ... You sure the USB port in the tablet is configured for file transfer? I don't know that having to "allow access to the tablet (on the tablet)" means the USB port is actually configured to allow file transfer. I found online copies of the manual for that tablet at: https://static.bhphotovideo.com/lit_files/153238.pdf http://media.datatail.com/docs/manual/328240_en.pdf When searching on "usb", nowhere did it mention a setting for the mode for the USB port. You sure that tablet allows file transfers via the USB port? The USB port might be just for charging. The 2nd online manual copy has a section for transferring files (page 27) but mentions you have to use Samsung's Smartswitch software. https://www.samsung.com/us/smart-switch/ It is not specified if "content" that can be transferred include any folder on the SD card or from default paths in main storage. You never mentioned which Android version is on the tablet. https://www.dummies.com/consumer-ele...-from-your-pc/ That describes the AutoPlay prompt on the Windows PC when it detects the tablet. Yet you say it doesn't appear which makes it sound like you made a choice awhile ago and also made it the default. That's why I asked if the device was listed under the Control Panel - Autoplay wizard and if set to perform some default action instead of letting you choose at the time. Hi Vanguard, I appreciate your willingness to help me. I can live with the Zip file method to preserve the T&D of files, and use "X-plore" to see those files with their original T&Ds. I can view those files without any difficulty. FYI: If I select a file (within Zip file), and copy it to another folder (using Xplore), the T&D of the file copied changes to current T&D. When I connect the tablet via USB cable to laptop with Windows 7, "AutoPlay" displays, "Galaxy Tab A (2016)". When I click on "Computer", I see, besides the C: drive (HD). "Galaxy Tab A (2016), "Portable Media Player" (no drive letter). This tablet has Android 5.1.1. I forgot to mention that the USB flash drive is a Lexar brand. I am in NO hurry to find a better method. I don't know when I will hear this ham friend on the air (he seldom gets on the air). I also want to ask him what brand flash drive he uses, in addition to what AP. He did mention he uses a "On The Go" (OTG) cable. I saw image of the OTG cable and it looks just like a USB female connector on one end, and a micro USB connector on other. This in effect is whet I made with the gender changer. The first time I plug this or other USB flash drive into my laptop, Windows searches for the driver, but before it does that, it detected a new device. When I first installed the SD card into my tablet, the Android OS detected that. It does NOT detect the USB flash drive. When & if I hear my ham friend, and get that info about the Ap, etc. I will post another "Update" here. Regards, John |
#21
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Transferring files to Tablet via USB Cable Looses Original Time & Dates of Files
On 10 Jan 2019 21:00:58 GMT, Frank Slootweg
For the kind of tasks you describe, you may also want to have a look at 'SyncMe Wireless'. https://play.google.com/store/apps/details?id=com.bv.wifisync Thanks again, Frank. I'll check it out. |
#22
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Transferring files to Tablet via USB Cable Looses Original Time & Dates of Files
SNIP
Hi Vanguard, I appreciate your willingness to help me. I can live with the Zip file method to preserve the T&D of files, and use "X-plore" to see those files with their original T&Ds. I can view those files without any difficulty. FYI: If I select a file (within Zip file), and copy it to another folder (using Xplore), the T&D of the file copied changes to current T&D. When I connect the tablet via USB cable to laptop with Windows 7, "AutoPlay" displays, "Galaxy Tab A (2016)". When I click on "Computer", I see, besides the C: drive (HD). "Galaxy Tab A (2016), "Portable Media Player" (no drive letter). This tablet has Android 5.1.1. I forgot to mention that the USB flash drive is a Lexar brand. I am in NO hurry to find a better method. I don't know when I will hear this ham friend on the air (he seldom gets on the air). I also want to ask him what brand flash drive he uses, in addition to what AP. He did mention he uses a "On The Go" (OTG) cable. I saw image of the OTG cable and it looks just like a USB female connector on one end, and a micro USB connector on other. This in effect is whet I made with the gender changer. The first time I plug this or other USB flash drive into my laptop, Windows searches for the driver, but before it does that, it detected a new device. When I first installed the SD card into my tablet, the Android OS detected that. It does NOT detect the USB flash drive. When & if I hear my ham friend, and get that info about the Ap, etc. I will post another "Update" here. Regards, John Hi Vanguard and others, VERY IMPORTANT: I just REALIZED, even if I am able to copy files from a USB flash drive (connected to my tablet) onto my "stuck" SD card, the original time and dates will be replaced with the current T&Ds. Therefore, I no longer have a desire to use that procedure. Since I am unable to remove the SD card, I will use the Zip file & "E-plore" method. Since my previous post, I did a Copy and Paste test on a file that was NOT within a Zip file using "My Files" (came with tablet) and "File Manager+". The results, the T&D of the copied file changed to the current T&D. I am VERY SORRY for not realizing this sooner. John the file was replaced with the current |
#23
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Transferring files to Tablet via USB Cable Looses Original Time & Dates of Files
wrote:
SNIP Hi Vanguard, I appreciate your willingness to help me. I can live with the Zip file method to preserve the T&D of files, and use "X-plore" to see those files with their original T&Ds. I can view those files without any difficulty. FYI: If I select a file (within Zip file), and copy it to another folder (using Xplore), the T&D of the file copied changes to current T&D. When I connect the tablet via USB cable to laptop with Windows 7, "AutoPlay" displays, "Galaxy Tab A (2016)". When I click on "Computer", I see, besides the C: drive (HD). "Galaxy Tab A (2016), "Portable Media Player" (no drive letter). This tablet has Android 5.1.1. I forgot to mention that the USB flash drive is a Lexar brand. I am in NO hurry to find a better method. I don't know when I will hear this ham friend on the air (he seldom gets on the air). I also want to ask him what brand flash drive he uses, in addition to what AP. He did mention he uses a "On The Go" (OTG) cable. I saw image of the OTG cable and it looks just like a USB female connector on one end, and a micro USB connector on other. This in effect is whet I made with the gender changer. The first time I plug this or other USB flash drive into my laptop, Windows searches for the driver, but before it does that, it detected a new device. When I first installed the SD card into my tablet, the Android OS detected that. It does NOT detect the USB flash drive. When & if I hear my ham friend, and get that info about the Ap, etc. I will post another "Update" here. Regards, John Hi Vanguard and others, VERY IMPORTANT: I just REALIZED, even if I am able to copy files from a USB flash drive (connected to my tablet) onto my "stuck" SD card, the original time and dates will be replaced with the current T&Ds. Therefore, I no longer have a desire to use that procedure. Since I am unable to remove the SD card, I will use the Zip file & "E-plore" method. Since my previous post, I did a Copy and Paste test on a file that was NOT within a Zip file using "My Files" (came with tablet) and "File Manager+". The results, the T&D of the copied file changed to the current T&D. I am VERY SORRY for not realizing this sooner. John the file was replaced with the current In one case, you are creating a NEW file. No matter what is the source of the data stream, you are having the OS create a new file and then writing the data stream into that file. That's why the new file has the current timestamps. In another case, you are mistaking an archive file as a real folder or real file in your OS' file system. Nope, what's inside the archive file (e.g., .zip) is a database of records with attributes or fields containing the data. One of the attributes for a "file" record is the time and date of last modified. There are no files or folders inside an archive file, just records, like a database. That the archive tool presents a folder hierarchy with files is simply presenting those records in a format with which you are familiar. When you read the source file, its contents get written into a data field in a record in the archive file. Also written to the record as attributes or fields are the timestamps for the source file. While it is possible to extract the "file" from the archive file where it the NEW file will have the current timestamps, many archive tools and file managers will 'touch' the timestamps of the new file to match the timestamp attributes recorded in the archive file. The extraction from the archive create a new file (that will have the current timestamps) but the archive tool or file manager will touch the new file's timestamps to make them match the timestamp attributes of the "file's" record inside the archive file. There are probably sync tools that will also touch the target file's timestamps to match the source file's timestamps. A simply copy is creating a new file that happens to have written into it the contents read from another file. Think of using Notepad to create a new file (so it has the current timestamps) and then you reading from a piece of paper to write its contents into Notepad and then saving the changes. That's similar to the copy operation where you see the old timestamps of the source file getting changed to the current timestamps for the new file. A move is nothing but a copy followed by a delete. If you want to preserve timestamps, you need to use a tool that does the copy along with touching the timestamps of the newly created destination file. Some file managers will do that when extracting from archive files (but usually not when creating a new destination file when copying a source file). Some sync tools will preserve the old timestamps by touching the timestamps of the new file. Backup programs will do that, too. Archive (zip) tools should do the same timestamp touch, too, after extracting the data stream from a record into a new file. Looks like the file manager you used (File Manager+) either does a simple copy operation where the new destination file gets the current timestamps (time and date) or perhaps it has a timestamp preservation option that you didn't use. Alas, Google usually discards non-alphanumeric characters in a search, so "File Manager+" results in hits on "file manager", and there are lots of those apps. Don't know which one you are using. Too often a user-configurable option for timestamp preservation is usually omitted from the description of an app, so you find other users that have discovered the buried option. While I have Total Commander installed on my Android smartphone, I rarely use it. I hunted around in it but didn't find a timestamp preserve option but me not finding it doesn't mean it doesn't have it. I did see a user comment that mentioned Total Commander could preserve timestamps; see: https://forum.xda-developers.com/sho...11&postcount=4 If timestamps are needed for sorting order, are you sorting on Created or Modified timestamps? |
#24
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Transferring files to Tablet via USB Cable Looses Original Time & Dates of Files
VanguardLH wrote:
wrote: SNIP Hi Vanguard, I appreciate your willingness to help me. I can live with the Zip file method to preserve the T&D of files, and use "X-plore" to see those files with their original T&Ds. I can view those files without any difficulty. FYI: If I select a file (within Zip file), and copy it to another folder (using Xplore), the T&D of the file copied changes to current T&D. When I connect the tablet via USB cable to laptop with Windows 7, "AutoPlay" displays, "Galaxy Tab A (2016)". When I click on "Computer", I see, besides the C: drive (HD). "Galaxy Tab A (2016), "Portable Media Player" (no drive letter). This tablet has Android 5.1.1. I forgot to mention that the USB flash drive is a Lexar brand. I am in NO hurry to find a better method. I don't know when I will hear this ham friend on the air (he seldom gets on the air). I also want to ask him what brand flash drive he uses, in addition to what AP. He did mention he uses a "On The Go" (OTG) cable. I saw image of the OTG cable and it looks just like a USB female connector on one end, and a micro USB connector on other. This in effect is whet I made with the gender changer. The first time I plug this or other USB flash drive into my laptop, Windows searches for the driver, but before it does that, it detected a new device. When I first installed the SD card into my tablet, the Android OS detected that. It does NOT detect the USB flash drive. When & if I hear my ham friend, and get that info about the Ap, etc. I will post another "Update" here. Regards, John Hi Vanguard and others, VERY IMPORTANT: I just REALIZED, even if I am able to copy files from a USB flash drive (connected to my tablet) onto my "stuck" SD card, the original time and dates will be replaced with the current T&Ds. Therefore, I no longer have a desire to use that procedure. Since I am unable to remove the SD card, I will use the Zip file & "E-plore" method. Since my previous post, I did a Copy and Paste test on a file that was NOT within a Zip file using "My Files" (came with tablet) and "File Manager+". The results, the T&D of the copied file changed to the current T&D. I am VERY SORRY for not realizing this sooner. John the file was replaced with the current In one case, you are creating a NEW file. No matter what is the source of the data stream, you are having the OS create a new file and then writing the data stream into that file. That's why the new file has the current timestamps. In another case, you are mistaking an archive file as a real folder or real file in your OS' file system. Nope, what's inside the archive file (e.g., .zip) is a database of records with attributes or fields containing the data. One of the attributes for a "file" record is the time and date of last modified. There are no files or folders inside an archive file, just records, like a database. That the archive tool presents a folder hierarchy with files is simply presenting those records in a format with which you are familiar. When you read the source file, its contents get written into a data field in a record in the archive file. Also written to the record as attributes or fields are the timestamps for the source file. While it is possible to extract the "file" from the archive file where it the NEW file will have the current timestamps, many archive tools and file managers will 'touch' the timestamps of the new file to match the timestamp attributes recorded in the archive file. The extraction from the archive create a new file (that will have the current timestamps) but the archive tool or file manager will touch the new file's timestamps to make them match the timestamp attributes of the "file's" record inside the archive file. There are probably sync tools that will also touch the target file's timestamps to match the source file's timestamps. A simply copy is creating a new file that happens to have written into it the contents read from another file. Think of using Notepad to create a new file (so it has the current timestamps) and then you reading from a piece of paper to write its contents into Notepad and then saving the changes. That's similar to the copy operation where you see the old timestamps of the source file getting changed to the current timestamps for the new file. A move is nothing but a copy followed by a delete. If you want to preserve timestamps, you need to use a tool that does the copy along with touching the timestamps of the newly created destination file. Some file managers will do that when extracting from archive files (but usually not when creating a new destination file when copying a source file). Some sync tools will preserve the old timestamps by touching the timestamps of the new file. Backup programs will do that, too. Archive (zip) tools should do the same timestamp touch, too, after extracting the data stream from a record into a new file. Looks like the file manager you used (File Manager+) either does a simple copy operation where the new destination file gets the current timestamps (time and date) or perhaps it has a timestamp preservation option that you didn't use. Alas, Google usually discards non-alphanumeric characters in a search, so "File Manager+" results in hits on "file manager", and there are lots of those apps. Don't know which one you are using. Too often a user-configurable option for timestamp preservation is usually omitted from the description of an app, so you find other users that have discovered the buried option. While I have Total Commander installed on my Android smartphone, I rarely use it. I hunted around in it but didn't find a timestamp preserve option but me not finding it doesn't mean it doesn't have it. I did see a user comment that mentioned Total Commander could preserve timestamps; see: https://forum.xda-developers.com/sho...11&postcount=4 If timestamps are needed for sorting order, are you sorting on Created or Modified timestamps? Nice explanation. Just a related question: I don't know why the default operation isn't necessarily to preserve the source date and time stamps for all of these operations, for all of these utilities (like zip, or whatever). I guess some folks figure the date of the copy or extract operation is more imporant or more relevant than preserving the source file date and time attributes. |
#25
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Transferring files to Tablet via USB Cable Looses Original Time & Dates of Files
Bill in Co wrote:
I don't know why the default operation isn't necessarily to preserve the source date and time stamps for all of these operations, for all of these utilities (like zip, or whatever). I guess some folks figure the date of the copy or extract operation is more imporant or more relevant than preserving the source file date and time attributes. Not only in this file transfer (which is a new file create and data stream write, not actually physically moving the file) across file systems but the transfer is also across operating systems. The new OS is requested to create a new file and a data stream comes in to put into the new file. How would one OS know the timestamps of the source file in a different OS unless somehow the timestamps got touched by whatever was controlling the copy operation on the new file? It isn't just timestamps that can get lost. Permissions are OS based: when permissions are assigned to a folder or file, only the OS in which the permissions were defined knows what are those permissions. That's why you can removed a drive from one computer and attach it as a data drive in another computer to read protected files. The permissions were not defined in the other OS, so they are not honored because they are not known. There are lots of attributes that can be lost in a copy operation between different file systems, say from NFTS to FAT32, and especially for a transfer between operating systems. Think of when you watch streaming media content in your web browser that is delivered from a media server. Your end creates a container (e.g., cache or buffer) for the streamed content and you get the streamed content but you have no clue of the timestamps, permissions, or other attributes of the source file that gets streamed to you. The OS to which a file gets streamed (aka transferred) also only knows it need to create a container (file) for the incoming data stream (for the copy operation). Unless something else touches the destination file, the target OS's file system won't get all the other source file's attributes. Some transfer programs will attempt to copy the other source file attributes onto the destination file but that is above the basic copy operation. They may attempt to change (touch) the destination file's timestamps, set the basic file attributes (those you see using the attrib command), and may even attempt to set permissions the same on the target file as for the source file (except that user SIDs won't be the same, so they can only likely set permissions for the global SIDs and for the account under which the copy operation is running on the target OS). The transfer tool has to do more than just a copy operation. One suggestion that I mentioned (that I found others had mentioned) was using an FTP server on the target OS. It will touch the destination file to keep the timestamps of the source file; however, I can't see FTP also maintaining the permissions in an FTP file transfer. It's possible, just like with sync tools, but those operations would be in addition to the standard FTP protocol which doesn't understand permission attributes in the source and target OS scheme, especially since you can FTP from Windows to Linux which don't use the same permissions schemes. A robust FTP server and client might be able to alter permissions on the newly created target file along provided the permission schemes were the same at both ends but just running the ftp.exe command line program that just does simple FTP is only going to have the FTP server create the new file and write the data stream into it (and try to match the timestamps in the destination file). In fact, unless I test, I'm sure sure basic FTP even tries to duplicate the timestamps onto the destination file to match those of the source file. In a command shell, run "ftp /?" and there are no command-line switches regarding timestamps. http://logic.edchen.org/3-steps-to-m...rve-timestamp/ Even Filezilla which is more robust than a command-line ftp.exe program cannot preserve timestamps unless: - You enable the option in Filezilla. - AND (*very important*) the FTP server supports MFMT command (to modify the Last Modified timestamp) and MFCT (to modify the Create timestamp) of the destination file (the new created one into which the data stream gets copied from the source file). The MFMT command was not part of the original FTP specification. The command was added later as an extension to FTP. The extension is still just a draft (back in 2002); however, that draft expired(*) and I couldn't find where it got ratified into an RFC for an extension to FTP. This means many FTP servers don't support those commands. (*) Some references say the draft has expired. Other references note the draft is experimental (which implies it has not expired) and with an update timestamp of 2008. When the OP zipped up the files into an archive file (.zip), that tool added fields to each file record to track the timestamps of the original files. When he looked inside the archive file, yep, those would be the timestamps for those files but only within that "file system" (database). If he ever extracts those files out of that archive, he relies on whatever tool he uses to not only create a new file in the destination file system but to also touch the new file's attributes to make its timestamps the same as recorded in the archive's record for the data block (aka file). Permissions are not recorded in a .zip file (just timestamps), especially since the archive may get transported to dissimilar OSes (Windows to Linux), so extracting the files from the archive will mean those new files get whatever permissions under whatever account the user performed the extraction. https://en.wikipedia.org/wiki/Zip_(f...)#File_headers You hope that whatever tool you use to extract data block from the archive file will also read the Last Modification Time header for that record and use it to touch the newly created destination file into which the data block gets copied. Notice there is no header for the Create timestamp, just the Modified timestamp. That means after extraction that the newly created destination file could have a Modified timestamp that is before its Create timestamp. The source file might've been last modified months ago but the destination file for the extraction was just created today. |
#26
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Transferring files to Tablet via USB Cable Looses Original Time & Dates of Files
VanguardLH wrote:
Bill in Co wrote: I don't know why the default operation isn't necessarily to preserve the source date and time stamps for all of these operations, for all of these utilities (like zip, or whatever). I guess some folks figure the date of the copy or extract operation is more imporant or more relevant than preserving the source file date and time attributes. Not only in this file transfer (which is a new file create and data stream write, not actually physically moving the file) across file systems but the transfer is also across operating systems. The new OS is requested to create a new file and a data stream comes in to put into the new file. How would one OS know the timestamps of the source file in a different OS unless somehow the timestamps got touched by whatever was controlling the copy operation on the new file? It isn't just timestamps that can get lost. Permissions are OS based: when permissions are assigned to a folder or file, only the OS in which the permissions were defined knows what are those permissions. That's why you can removed a drive from one computer and attach it as a data drive in another computer to read protected files. The permissions were not defined in the other OS, so they are not honored because they are not known. There are lots of attributes that can be lost in a copy operation between different file systems, say from NFTS to FAT32, and especially for a transfer between operating systems. Think of when you watch streaming media content in your web browser that is delivered from a media server. Your end creates a container (e.g., cache or buffer) for the streamed content and you get the streamed content but you have no clue of the timestamps, permissions, or other attributes of the source file that gets streamed to you. The OS to which a file gets streamed (aka transferred) also only knows it need to create a container (file) for the incoming data stream (for the copy operation). Unless something else touches the destination file, the target OS's file system won't get all the other source file's attributes. Some transfer programs will attempt to copy the other source file attributes onto the destination file but that is above the basic copy operation. They may attempt to change (touch) the destination file's timestamps, set the basic file attributes (those you see using the attrib command), and may even attempt to set permissions the same on the target file as for the source file (except that user SIDs won't be the same, so they can only likely set permissions for the global SIDs and for the account under which the copy operation is running on the target OS). The transfer tool has to do more than just a copy operation. One suggestion that I mentioned (that I found others had mentioned) was using an FTP server on the target OS. It will touch the destination file to keep the timestamps of the source file; however, I can't see FTP also maintaining the permissions in an FTP file transfer. It's possible, just like with sync tools, but those operations would be in addition to the standard FTP protocol which doesn't understand permission attributes in the source and target OS scheme, especially since you can FTP from Windows to Linux which don't use the same permissions schemes. A robust FTP server and client might be able to alter permissions on the newly created target file along provided the permission schemes were the same at both ends but just running the ftp.exe command line program that just does simple FTP is only going to have the FTP server create the new file and write the data stream into it (and try to match the timestamps in the destination file). In fact, unless I test, I'm sure sure basic FTP even tries to duplicate the timestamps onto the destination file to match those of the source file. In a command shell, run "ftp /?" and there are no command-line switches regarding timestamps. http://logic.edchen.org/3-steps-to-m...rve-timestamp/ Even Filezilla which is more robust than a command-line ftp.exe program cannot preserve timestamps unless: - You enable the option in Filezilla. - AND (*very important*) the FTP server supports MFMT command (to modify the Last Modified timestamp) and MFCT (to modify the Create timestamp) of the destination file (the new created one into which the data stream gets copied from the source file). The MFMT command was not part of the original FTP specification. The command was added later as an extension to FTP. The extension is still just a draft (back in 2002); however, that draft expired(*) and I couldn't find where it got ratified into an RFC for an extension to FTP. This means many FTP servers don't support those commands. (*) Some references say the draft has expired. Other references note the draft is experimental (which implies it has not expired) and with an update timestamp of 2008. When the OP zipped up the files into an archive file (.zip), that tool added fields to each file record to track the timestamps of the original files. When he looked inside the archive file, yep, those would be the timestamps for those files but only within that "file system" (database). If he ever extracts those files out of that archive, he relies on whatever tool he uses to not only create a new file in the destination file system but to also touch the new file's attributes to make its timestamps the same as recorded in the archive's record for the data block (aka file). Permissions are not recorded in a .zip file (just timestamps), especially since the archive may get transported to dissimilar OSes (Windows to Linux), so extracting the files from the archive will mean those new files get whatever permissions under whatever account the user performed the extraction. https://en.wikipedia.org/wiki/Zip_(f...)#File_headers You hope that whatever tool you use to extract data block from the archive file will also read the Last Modification Time header for that record and use it to touch the newly created destination file into which the data block gets copied. Notice there is no header for the Create timestamp, just the Modified timestamp. That means after extraction that the newly created destination file could have a Modified timestamp that is before its Create timestamp. The source file might've been last modified months ago but the destination file for the extraction was just created today. Thanks for that detailed explanation. So now I see that preserving the date and time stamps of the source file is just an added "feature", and one that can only work in certain situations. And that also explains why I have seen files with the modified time stamp before the create time stamp, which was another mystery to me. |
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