Sugestions: Directory compare and synchronize

Support for Android version of Total Commander

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TEN
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Re:

Post by *TEN »

ghisler(Author) wrote: 2013-08-22, 14:38 UTC The problem is that there is very little space on most Android screens, not enough for these functions.
Shouldn't the inclusion of Sync be revisited, given how resolutions have improved and most vendor-supplied File Managers have remained crappy, unreliable and incomplete on Android (without a full-fledged shell, and where files can hardly be managed well even over mtp, even if at all mounted)?
Cf. viewtopic.php?f=3&t=21264&p=361571#p361571
Wayne.
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Re: Sugestions: Directory compare and synchronize

Post by *Wayne. »

Hi. I have been searching for such software on Android. I'm sorry to bring up this thread, but I have done suggestions. Feature related uggestions not related to timestamp are down the bottom.

I have communicated with Google in the past about various changes, but time stamp is one of the few they don't change. I wonder if the new system is more insecure and somehow reveals more information than the old system of mass storage. I wonder if it might even be related to bad maid attacks.

- My suggestion is to preserve the order of research and legality of downloaded files, is a copy function to just copy them one at a time from the copy space, according to their modified date. This is a little hassle and less streamlined (but what android copy is high speed) but this will put everything in time order, so that downloaded or developed documents made around the same time are in order. A simple version is just to copy the directory enteries in order, without cross ordering the sub directory entries with each other. You could then identify sections of documents related to each other in research, without having to diet through everything.

-. Second suggestion for a time synced clone or backup. Is to maintain a database file in the backup directory telling the original time stamp, and other missing information from copied files. You then can compare to original location. If android uses a file ID, you could possibly tell if the file at the original location was over written with another copy, by the ID change.

- Third you could add a timestamp in the filename itself, at the end before the file type, but that will likely bust the filesystem on deep directories, which even happens with old windows backups. For some reason, also, some android directories are so deep, even though they have only subdirectory in them, the system falls over before you can get to the end, it might go off screen etc. Weird programming.

- Third part b: if Android supports meta data/file information in/attached, to the file, that gets copied accross. Then copy and put the original modified timestamp information in there, preserving a clean directory. Do comparisons on file contents excluding this information, do even though the size no longer matches because of the extra data, it is compensated fur in comparison calculations.

- Fourth, reconstruct the file/timestamp on the other side.

- Fifth, package the files into a virtual directory, as used in zip, and copy over, preserving timestamp, using the virtual directory files for comparisons and restores. Whatever system used, a Reed-Solomon or other error encoding, for resiliance of backup. Don't except their rubbish.

Non copy timestamp related suggestions:

- Seventh, compare (for duplicates or differences on everything, on file contents, for date, and by wildcard search. Quoting back directory path, as some duplicates are placeholders in a database fashion) merge with same sort of options and with unsame duplicates.

- Eighth wifi to Nas/drive options. I'm sorry had a literal galah (extremely obnoxiously loud bird) flying around screaming overhead for a while, and have forgotten the other suggestions. If I remember any, I'll try to get back. But one idea from timestamps re-occured to me, is it possible to get permission to act as or with the filesystem to intercept the files and reapply the previous time stamp in a copy, even to get permissions to do the same with mtp?

Ok, I remembered something important:

The ability to do bit to bit compared such the cache and buffers are flushed before doing the repair, to read files from the actual storage cells. This is a hidden problem which defeats checksums etc. A file that is cache or buffer is only a view, which has perfect checksum, but when written to storage or if already written, may develop corruption which is not reflected in the cache version being compared to. I know of people who think that a back up strategy is to copy hundreds of terabytes of files each year to fresh media. But, each copy, and just time or near location, or flash leveling, in flash, can potentially cause an issue, and eventually ruin a file.

In xxcopy or xxclone, website, there is a page on this issue. What I would say is, if a big copy multiples too big for caching, write everything, and compare from the beginning, that's possible. But in smaller the buffers and cache would need to be flushed. But, if you are comparing two previous file sets, you wouldn't know their state, so flushing is needed. It's possible that the system has had them in cache for a long time, and the original is corrupted. But, I see their point. A lot of pro/business data needs security of transmission and storage, that's why I mentioned Reed-Solomon encoding. I have rigged up here a powered USB hub and portable drive for copying not requiring a PC nearby. Unfortunately, the phones rapid charging mode tends to kick in if not at a very high percentage battery, leaving not enough for the drive, but cheap wifi direct and USB options are needed, and apps that take advantage of that.


Thank you.
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gezgin
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Re:

Post by *gezgin »

ghisler(Author) wrote: 2013-08-29, 12:51 UTC Yes, "Compare directories" would be possible, but "Synchronize dirs" wouldn't.
OK, I'll be the one to ask: How do I compare directories in ToCo for Android? I'm not interested in synchronizing or in comparing content. I just want the files that are not present on either side highlighted so that I can:
1) delete, from the target folder, the files that aren't in the source folder
and
2) copy the files that are in the source folder but not in the target folder from the source folder to the target folder.

Note: Objections about the "screen being too small" don't apply here. I'm using ToCo Android on a Galaxy Tab S7+, whose screen diagonal is about 30 cms, which is about 2/3 the size of my laptop.

TIA for any help on this.
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Re: Sugestions: Directory compare and synchronize

Post by *DrShark »

Just a new internal command which would do the same as desktop Total Commander's "Compare directories (Shift+F2)" would be a great addition.
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gezgin
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Re: Sugestions: Directory compare and synchronize

Post by *gezgin »

DrShark wrote: 2021-09-11, 11:25 UTC Just a new internal command which would do the same as desktop Total Commander's "Compare directories (Shift+F2)" would be a great addition.
Yes! That's exactly what's needed. I take it then that this function currently not available?
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Re: Sugestions: Directory compare and synchronize

Post by *Bvo »

+1.
Compare dirs is really useful, especially after copying big amount of files - sometimes some files are corrupted. Android is very unreliable and unpredictable, you never know what problem it will bring next...
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Re: Sugestions: Directory compare and synchronize

Post by *Bvo »

BTW, it could be 2 modes: fast (name+size) and by content (by CRC?).
As comparition may be made for files on network, it has sense to compare by small chains (not whole file's CRC at once). If comparison is made by TC/plugins on both sides, there's even more space to improve (ex. not send content by network, but do calc on every side).
It could be really cool! :-) There's no such handy tool for Androud, AFAK.
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