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  • How can I evaluate the best choice of archive format for compressing files?

    - by Mehrdad
    In general, I've observed the following: Linux-y files or tools use bzip2 or gzip for distributing archives Windows-y files or tools use ZIP for distributing archives Many people use 7-Zip for creating and distributing their own archives Questions: What are the advantages and disadvantages of these formats, all of which appear to be open formats? When/why should I choose one (say, 7-Zip) over another (say, ZIP)? Why does the trend above appear to hold, even though all of these are portable formats? Are there any particular advantages to using a particular archive format on a particular platform?

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  • How to split file on Windows 2003 using MS supported tool

    - by Rune
    Hi, Is it possible to split a large file into smaller files on Windows 2003 using a tool provided/supported/sanctioned by Microsoft? I see that there are a lot of freeware tools (various zip tools) for this task, but I need to move files off of a production server, thus would like to avoid tools I don't know if I can trust. I would much prefer some tool included in the Windows Server 2003 Resource Kit Tools or something along those lines. Does such a tool exist? Thank you.

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  • Multithreaded TIFF to PNG conversion

    - by mtone
    I'm working with images of scanned books, so hundreds of high resolution pictures. I'm doing conversion work with Photoshop Elements - I can quickly save them to uncompressed TIFF, but converting to compressed PNG using a single thread takes ages. Do you know a software, ideally simple and free, that would batch convert those TIFFs to PNG in a multi-threaded manner (4 to 8 simultaneous files) to take advantage of those cores and cut converting times? I'm not too worried in slight variations in final size.

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  • CRC error when extracting to SSD from 2nd HDD

    - by gbn
    Hello I have a large RAR file (split up) containing an ISO on my 2nd HDD When I extract it: to the same HDD, it's OK to the system/OS SSD, I get CRC errors I've checked memory, run memtests, checked wires etc I have no other issues; only with this one RAR file Any ideas please?

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  • Minimize HTML, CSS and JS files

    - by karmic
    How do you automatically pack/minimize the HTML, CSS and JS files served on a webpage. More specifically, I wish to have this for a wordpress website. Should it be done at the webserver level (lighttpd), at the application level (wordpress), at the PHP level, or somewhere else?

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  • Three formats? Why?

    - by Yar
    I needed to download the Ruby Source recently from here and it says, "available in three formats" which are .tar.bz2, .tar.gz and .zip. Is there any reason that we need all three formats? At least on Linux and OSX I can do any of the three easily. On Windows, only zip is built-in, I think. Is there anything behind these preferences or is this just a religious battle?

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  • gunzip unexpected end of file

    - by Mark J Seger
    I like to write high volume data directly to a zip file via perl. Works like a champ! However, on some rare occasions I've found that gunzip can't uncompress them declaring an unexpected end-of-file. The thing is I can uncompress it with a simple perl script, which probably misses the corrupted record(s) at the end. My question is, does anyone know of a way to use a standard utility to do the same thing? Maybe with a 'compress-as-much-as-you-can' switch? -mark

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  • Looking for Unix tool/script that, given an input path, will compress every batch of uncompressed 100MB text files into a single gzip file

    - by newToFlume
    I have a dump of thousands of small text files (1-5MB) large, each containing lines of text. I need to "batch" them up, so that each batch is of a fixed size - say 100MB, and compress that batch. Now that batch could be: A single file that is just a 'cat' of the contents of the individual text files, or Just the individual text files themselves Caveats: unix split -b will not work here as I need to keep lines of text intact. Using the lines option is a bit complicated as there is a large variance in the number of bytes in each line. The files need not be a fixed size strictly, as long as it's within 5% of the requested size The lines are critical, and should not be lost: I need to confirm that the input made its way to output without loss - what rolling checksum (something like CRC32, BUT better/"stronger" in face of collisions) A script should do nicely, but this seems like a task someone has done before, and it would be nice to see some code (preferably python or ruby) that does atleast something similar.

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  • How could I compress a folder into splitted archives (individual ZIPs)?

    - by Shiki
    I have to compress folders into ZIP packages. But the size is limited, only a ~10-15mb is allowed to used per package. Every major application comes with the "Split archive to..." option, which does what I want... except I can't uncompress them one-by-one. (You need them all, and then use the .7z, .rar, .zip file to uncompress.) Here is an example. FolderX is 35 mb. That makes 4 packages, 4 zip files. The normal split function would give me: folderx.zip, folderx.zip.001, folderx.zip.002, folderx.zip.003 What I would really need is: folderx_1.zip, folderx_2.zip, folderx_3.zip, folderx_4.zip (Individually uncompressable files/packs.) I can code this down into an app, but it's a waste of time if such a utility already exists.

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  • What's faster, cp -R or unpacking tar.gz files?

    - by Buttle Butkus
    I have some tar.gz files that total many gigabytes on a CentOS system. Most of the tar.gz files are actually pretty small, but the ones with images are large. One is 7.7G, another is about 4G, and a couple around 1G. I have unpacked the files once already and now I want a second copy of all those files. I assumed that copying the unpacked files would be faster than re-unpacking them. But I started running cp -R about 10 minutes ago and so far less than 500M is copied. I feel certain that the unpacking process was faster. Am I right? And if so, why? It doesn't seem to make sense that unpacking would be faster than simply duplicating existing structures.

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  • Is there a tool for verifying the contents of a Zip archive against the source directory's contents?

    - by Basil
    Here's the scenario: I create a ZIP archive using some GUI package like WinZip, 7-Zip or whatever by right-clicking on a directory "somename" and selecting "Compress to archive 'somename.zip'" When the archive is completed, I open it and discover that some files don't exist in the archive (for reasons yet unknown). I want to find all files that are missing from the archive without having to extract the archive to another directory, then doing directory diff, etc. So.. Is there a tool (GUI or command-line, standalone or built into a compressor, for Windows or Linux, I don't care) that can walk through an archive and compare its contents against a directory on the filesystem?

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  • Best archive format & tool for large amounts of data (50gb+)

    - by marcusstarnes
    I only realised this afternoon that the ZIP format has a limit of what appears to be around 20gb. I am trying to automate an archive process (using Automate) to zip/rar/whatever a collection of folders/files on one of my disks. It always appeared to bomb out with an incomplete archive at about 20gb. So I tried using WinRAR and doing it manually as a ZIP file, but it told me of the limit. So, I was wondering, what is a recommended zip format (and tool for accomplishing the task) for archiving up a large amount of data (around 50gb)? Thanks

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  • Archive format & tool for large amounts of data (50gb+)

    - by marcusstarnes
    I only realised this afternoon that the ZIP format has a limit of what appears to be around 20gb. I am trying to automate an archive process (using Automate) to zip/rar/whatever a collection of folders/files on one of my disks. It always appeared to bomb out with an incomplete archive at about 20gb. So I tried using WinRAR and doing it manually as a ZIP file, but it told me of the limit. So, I was wondering, what is a recommended zip format (and tool for accomplishing the task) for archiving up a large amount of data (around 50gb)?

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  • Compression for custom mime type works on IIS 7.5, but not IIS 7.0?

    - by Doogal
    I've managed to set up compression for a custom mime type on IIS 7.5 with no problem. Add the mime type to IIS then add it to the httpCompression element in applicationHost.config. But when I do the same thing on IIS 7, the particular mime type is never compressed. This isn't a problem with compression in general since other mime types are compressed correctly. As far as I can tell, IIS 7 and IIS7.5 are configured in exactly the same way. Does IIS7 behave differently and do I need to do something else to get it working? I've setup failed request tracing and get a NO_MATCHING_CONTENT_TYPE error during compression but I can't figure out what else I need to do to tell IIS about my mime type

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  • How can I turn on DynamicCompression feature of IIS programmatically?

    - by LockeVN
    I'm making an installer program for my web application. My web application uses CSS and JS heavily, so I want to enable both Static and Dynamic HttpCompression for IIS7/7.5. It needs 2 steps: I can modified the web.config, put <httpcompression> tag, it's ok. DynamicContentCompression must be turned on in Windows Feature to make httpCompression work. Static HttpCompression is enable by default in IIS7 and IIS7.5, but Dynamic HttpCompression is not enable by default (although it's available). I can do manually by turn on: Start/ControlPanel/ProgramsAndFeatures/TurnWindowsFeatures on or Off/IIS/WWW Service/Performance features/Dynamic Content Compression, but How can I programmatically turn it on that Windows Feature? I can use PowerShell, C# in my installer. Any idea how I might be able to do this? Thanks.

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  • zlib memory usage / performance. With 500kb of data.

    - by unixman83
    Is zLib Worth it? Are there other better suited compressors? I am using an embedded system. Frequently, I have only 3MB of RAM or less available to my application. So I am considering using zlib to compress my buffers. I am concerned about overhead however. The buffer's average size will be 30kb. This probably won't get compressed by zlib. Anyone know of a good compressor for extremely limited memory environments? However, I will experience occasional maximum buffer sizes of 700kb, with 500kb much more common. Is zlib worth it in this case? Or is the overhead too much to justify? My sole considerations for compression are RAM overhead of algorithm and performance at least as good as zlib.

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  • Compressing three individual jpeg pics containing temporal redundancy?

    - by michael
    I am interfacing and embedded device with a camera module that returns a single jpeg compressed frame each time I trigger it. I would like to take three successive shots (approx 1 frame per 1/4 second) and further compress the images into a single file. The assumption here is that there is a lot of temporal redundancy, therefore lots of room for more compression across the three frames (compared to sending three separate jpeg images). I will be implementing the solution on an embedded device in C without any libraries and no OS. The camera will be taking pics in an area with very little movement (no visitors or screens in the background, maybe a tree with swaying branches), so I think my assumption about redundancy is pretty solid. When the file is finally viewed on a pc/mac, I don't mind having to write something to extract the three frames (so it can be a nonstandard cluge) So I guess the actual question is: What is the best way to compress these three images together given the fact that they are already in JPEG format (it is a possibly to convert back to a raw image, but if i dont have too...)

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  • Algorithms to find longest common prefix in a sliding window.

    - by nn
    Hi, I have written a Lempel Ziv compressor and decompressor. I am seeking to improve the time to search the dictionary for a phrase. I have considered K-M-P and Boyer-Moore, but I think an algorithm that adapts to changes in the dictionary would be faster. I've been reading that binary search trees (AVL or with splays) improve the performance of compression time considerably. What I fail to understand is how to bootstrap the binary search tree and insert/remove data. I'm not actually quite sure the significance of each node in the binary search. I am searching for phrases so will each character be considered a node? Also how and what is inserted/removed from the search tree as new data enters the dictionary and old data is removed? The binary search tree sounds like a good payoff since it can adapt to the dictionary, but I'm just not quite sure of how it's used.

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  • Best method to compress JSON string in term of performance and compress radio

    - by Eric Yin
    For a JSON string, contains all kinds of settings, numbers, string etc. Total JSON string fairly fall into 10k~50K range. I want to compress it before save to database. So I wonder which compress method should I choose, I am using c# 4, I know I can choose gzip and deflate but the compression radio is not good (although speed is good). More specific, compress can be a little slow (since only once) but should be small. Decompress should be lighting fast since decompress happens lots. Please give some advice.

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  • Compressing as GZip WCF requests (SOAP and REST)

    - by Joannes Vermorel
    I have a .NET 3.5 web app hosted on Windows Azure that exposes several WCF endpoints (both SOAP and REST). The endpoints typically receive 100x more data than they serve (lot of data is upload, much fewer is downloaded). Hence, I am willing to take advantage from HTTP GZip compression but not from the server viewpoint, but rather from the client viewpoint, sending compressed requests (returning compressed responses would be fine, but won't bring much gain anyway). Here is the little C# snippet used on the client side to activate WCF: var binding = new BasicHttpBinding(); var address = new EndpointAddress(endPoint); _factory = new ChannelFactory<IMyApi>(binding, address); _channel = _factory.CreateChannel(); Any idea how to adjust the behavior so that compressed HTTP requests can be made?

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  • How does git save space and is fast at the same time?

    - by eSKay
    I just saw the first git tutorial at http://blip.tv/play/Aeu2CAI How does git store all the versions of all the files and still be more economical in space than subversion which saves only the latest version of the code? I know this can be done using compression but that would be at the cost of speed, but this also says that git is much faster (though where is gains the max is the fact that most of its operations are offline). So, my guess is that git compresses data extensively it is still faster because uncompression + work is still faster than network_fetch + work Am I correct? even close?

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