March 29th, 2022
April 22, 2022
The Zip file itself is really just a container and it holds the real files inside it. The purpose behind the Zip file is transportation and storage and it acts like a Ziploc sandwich bag, i.e. it holds contents inside for easy transporting and storage. This makes Zip files (and their counterpart Rar files) very valuable to those users who share and download the files in a regular manner. But before you compress or uncompress a ZIP file, you must understand the structure of the ZIP FIle.
You can see below, what a ZIP file looks like and it will give you a clear picture of the ZIP file structure
A ZIP file is identified by the presence of a central directory which is located at the end of the structure in order to allow the appending of new files. The central directory stores a list of the names of the entries (files or directories) stored in the ZIP file, along with other Metadata about the entry, and an offset into the ZIP file, pointing to the actual entry data. This allows a file listing of the archive to be performed relatively quickly, as the entire archive does not have to be read to see the list of files.
The entries in the ZIP file also include this information for redundancy. The order of the file entries in the directory need not coincide with the order of file entries in the archive. Each entry is introduced by a local header with information about the file such as the comment, file size, and file name, followed by optional “Extra” data fields, and then the possibly compressed, possibly encrypted file data. The “Extra” data fields are the key to the extensibility of the ZIP format. “Extra” fields are exploited to support the ZIP-64 format, WinZip-compatible AES encryption, file attributes, and higher-resolution NTFS or Unix file timestamps. Other extensions are possible via the “Extra” field. ZIP tools are required by the specification to ignore Extra fields they do not recognize.
Tools that correctly read ZIP archives must scan for the signatures of the various fields, in the ZIP central directory. They must NOT scan for entries because only the directory specifies where a file chunk starts. Scanning could lead to false positives, as the format allows for other data to be between chunks.
The ZIP specification also supports spreading archives across multiple system files. Originally intended for storage of large zip files across multiple 1.44 MB floppy disks this feature is now used for sending zip archives in parts over email, or over other transports or removable media.
Compressed files take up less storage space and can be transferred to other computers more quickly than uncompressed files. You can work with compressed files and folders in the same way that you work with uncompressed files and folders. You can also combine several files into a single compressed folder, making it easier to share a group of files, since you only need to attach one folder to an e‑mail message instead of several files.
This creates a compressed zip folder. To rename it, right-click the folder, click Rename, and then type the new name.
Sometimes a zip file gets corrupted and prompts the error message, “The Compressed (zipped) folder is invalid or corrupted” while opening the zip file. In this case, you can try to repair the corrupt zip file manually by using the WinRAR tool. WinRAR has a built-in repair feature that helps users repair corrupt RAR as well as zip files. You can even Fix Invalid and Corrupt Zip Files for Free. On the other hand, if you are unable to fix the ZIP file corruption issue manually, then you can use the Sysinfo ZIP File Repair Tool. Now you know how to compress and uncompress a ZIP file but any type of error during zipping or unzipping denotes that your ZIP file is corrupted. Therefore, the solutions given above will resolve the error related to the ZIP file.