Our website has many large files available in zipped or compressed format. The result is a smaller file that downloads faster. If you haven't used zipped files before, or are having trouble working with them, this tutorial is to help you.
what is the difference between zipped and unzipped files
Zipped files (known by many names, see the table to the right, but in this document called "zipped files") are one or more files on a computer disk that have been combined into a single file in a space-efficient manner to reduce their total file size. This is very useful when disk space is limited or when people download files. Since multiple files can be stored in a zipped file, a single file can be downloaded then unzipped to easily download many files at once. You can think of a zipped file as a set of books on a shelf:
In order to work with zipped files, they must be unzipped or extracted first. Windows has a built in program called Windows Compressed Folders which can do this for you. If you have installed a zip program, such as WinZip* or 7-Zip*, Windows Compressed Folders may not be easily available on your computer. If you follow the instructions below for Windows Compressed Folders, but a different program opens, you can still follow the instructions listed, and it should generally still work.
Other software programs exist for zipping and unzipping files. Two popular programs are WinZip * and 7-Zip *. Both of these allow you to unzip and zip with two clicks: Here, I have right-clicked on the zipped file and selected "Extract to here." "Extract" is the same thing as "unzip." Windows also sometimes places "Extract files" links in toolbars which may be useful to you. Windows generally opens a wizard to ask where you want the files extracted. The location of the "extract files" tool varies depending on how Windows Explorer is set up and what version of Windows you are using.
As you can see in the screenshot, the files are copied into the zip folder, and not moved or deleted from their original location. Now, you can transfer, backup, or do whatever else you want with your zipped contents.
A new window will open up and you can select where you want the files to be extracted. By default, it will extract the contents to the same directory in which your zip file resides. Just hit extract and a folder will be created that has all of the zipped files in it.
A directory is placed at the end of a ZIP file. This identifies what files are in the ZIP and identifies where in the ZIP that file is located. This allows ZIP readers to load the list of files without reading the entire ZIP archive. ZIP archives can also include extra data that is not related to the ZIP archive. This allows for a ZIP archive to be made into a self-extracting archive (application that decompresses its contained data), by prepending the program code to a ZIP archive and marking the file as executable. Storing the catalog at the end also makes possible hiding a zipped file by appending it to an innocuous file, such as a GIF image file.
diff command compares to see any difference betwenn two files. Can the same be used to compare two zip files, i.e if there is any difference in data ,like counts etc in individual files in the zipped files?
If you mean this, then, according to the wiki page, the .war format is the same as the .jar format. .jar files are just .zip files which contain compiled java code, meant to be used as a library or executable. So the answer would be no, there is no technical difference; but .jar files should only be used for what they're intended for, not as general-purpose archives.
If you mean this, then there is a slight difference: this .war format is a gzipped-tar (.tar.gz) file, again meant to hold specific data (web pages). Gzip and Zip both use the same compression algorithm; however:
Gzip is not to be confused with the ZIP archive format, which also uses [the DEFLATE compression algorithm]. The ZIP format can hold collections of files without an external archiver, but is less compact than compressed tarballs holding the same data, because it compresses files individually and cannot take advantage of redundancy between files.
These are both things that you do to assets on your website (things like .css files and .js files). They are both things that reduce the size of the file, making it more efficient in crossing the network between servers and browsers. As in, good for performance. The network is the speed bottleneck of the web and reducing file size helps.
This might appear senseless in comparison to server-native gzip compression. It becomes interesting in respect to SEO bots: If those bots measure the unzipped payload you might be a few points ahead. On the other hand this method produces runtime overhead at the browser side, eventually producing worse total page load time.
In cases like these, you may find it beneficial to gzip the files ahead of time and configure your web server to serve the gzipped files directly (along with the appropriate content type headers, of course). This will reduce the amount of work that your web server has to do each time someone loads the page (of course, this could be mitigated in other ways, too, like using browser caching).
A KMZ file consists of a main KML file and zero or more supporting files that are packaged using a Zip utility into one unit, called an archive. The KMZ file can then be stored and emailed as a single entity. A NetworkLink can fetch a KMZ file from a web server. When the KMZ file is unzipped, the main .kml file and its supporting files are separated into their original formats and directory structure, with their original filenames and extensions. In addition to being an archive format, the Zip format is also compressed, so an archive can include only a single large KML file. Depending on the content of the KML file, this process typically results in 10:1 compression. Your 10 Kbyte KML file can be served with a 1 Kbyte KMZ file.
The element contains a element that specifies a COLLADA file to load into Google Earth. COLLADA files specify 3D objects and have a .dae file extension. The element also contains an element, that contains a mapping between the (the texture file to be fetched by Google Earth) and the (the path specified for the texture file in the COLLADA .dae file). If the element contains a relative path, Google Earth interprets this path as relative to the .dae file that references it (not relative to the doc.kml file as in all other cases). For example:
It depends. For sending and storing, both .zip and .tar.gz files will allow you to send relatively large packages as a single file. However, there are some pretty major differences when it comes to accessing data within the files and the compression efficiency.
Yes. Since .tar.gz compresses multiple files all at once, it can take advantage of similarities between individual files to save on space. Generally speaking, a collection of files archived and compressed as a .tar.gz will be more space-efficient (i.e., smaller) than the same collection compressed as a .zip.
WinZip applications, which create Zip files (.zip or .zipx), allow you to choose between two different compression methods. The Legacy method creates Zip files that are compatible with almost every other Zip file utility, but the compression used is not likely to create the smallest Zip files possible. The Best method alternative uses compression that will create smaller Zip files (usually) with a .zipx extension, but this method will not be compatible with all Zip file utilities.
The Legacy (Zip 2.0) compression method, which creates .zip files, uses a traditional data compression algorithm, known as deflate. Deflate is supported by all versions of WinZip and virtually all other Zip file utilities. The deflate method is generally considered to be a good, all-purpose compression algorithm for use with most types of files. .Zip: Legacy compression is your best choice if you will be sharing your Zip file, especially if you do not know what Zip file utility the receiver of your shared files will use or if you already know that an older or limited utility will be used. WinZip applications use the highest deflate method setting available, which is maximum deflate. Using WinZip, your .zip files will be easily unzipped and they will be as small as possible for this compression method.
Well open Id-er the simplest answer would be to say that there is no difference. But there is a small difference. Normally you would extract files from a zipped folder. Unlike normal documents that you could just make copies of. But on the flip side you could go into a zipped folder and copy files that you want and then paste them.
Although the differences are sometimes made opaque in casual conversation, there is in fact a complete difference between archiving files and compressing them. Archiving means that you take 10 files and combine them into one file, with no difference in size. If you start with 10 100KB files and archive them, the resulting single file is 1000KB. On the other hand, if you compress those 10 files, you might find that the resulting files range from only a few kilobytes to close to the original size of 100KB, depending upon the original file type.
The bzip2 command is the new kid on the block. Designed to supersede gzip, bzip2 creates smaller files, but at the cost of speed. That said, computers are so fast nowadays that most users won't notice much of a difference between the times it takes gzip or bzip2 to compress a group of files.
Caution - The security offered by the Zip program's password protection isn't that great. In fact, it's pretty easy to find a multitude of tools floating around the Internet that can quickly crack a password-protected Zip archive. Think of password-protecting a Zip file as the difference between writing a message on a postcard and sealing it in an envelope: It's good enough for ordinary folks, but it won't stop a determined attacker. 2ff7e9595c
Opmerkingen