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Compress files to save space in Windows

Why compress files to save space when hard disk drives of 1Tb (1,000Gb) are so cheap? At first sight it might not seem to make sense because hard disk drives are so big these days that it is becoming increasingly rare to run out of space. However, there are several situations where you might need to compress files and folders.

One is when sending files to someone else as attachments to emails. You don't want to clog up someone's email inbox with a huge great attachment or collection of attachments. There is also a limit on the size of attachments that email services allow, and on the maximum size of your inbox. A few large attachments can break these limits and cause problems like non-delivery of messages.

You might also need to compress files to save space on a USB flash memory drive. These have replaced the old floppy disk as a means of carrying files in your pocket from one computer to another, but large capacity ones are really expensive, so often we make do with a smaller and cheaper one. You'll get more files on it if you compress them.

Finally, you should keep backups of important files such as documents, photos, videos, music and so on. Compressing them means they use less space and you can store more backups. Let's see some different ways of compressing files and folders.

ZipGeniusAll Windows systems these days use the NTFS file system and this has compression built right in. Right click a file or folder and select Properties from the menu. Click the Advanced button on the General tab and tick Compress contents to save disk space. When you click the OK buttons to close the dialogs, you may be asked if you want to apply changes to just this folder or all subfolders. It's up to you, but usually you want to apply it to all subfolders.

This compression isn't all that efficient and there is little to gain by compressing files that are already compressed. JPEG images and photos, for example, are compressed, which is why they occupy less space than the raw files you can get off some digital cameras. Files compressed in this way are treated in exactly the same way as ordinary files and you wouldn't know that they are compressed. It's totally transparent and you can open a compressed document in Word, for example, edit it and save it out and it's still stored in its compressed form.

USB flash memory drives are usually formatted as FAT for compatibility reasons, so if you want to use NTFS compression on it you'll have to format it. Plug in the memory stick and then right click it and choose Format. Select NTFS as the file system. This wipes everything off the memory stick so copy your files off first and put them back afterwards. You can in fact, compress a whole disk. After formatting a memory stick with NTFS, right click the drive in the Computer window and select Properties. Tick the box to compress the disk. Now any file you copy to the memory stick will automatically be saved in compressed form.

Another way to compress files is to use the zip compression built into Windows. You just right click a file or folder and choose Send to, Compressed (zipped) folder. This is stronger compression and the resulting files or folders are smaller than the originals. Actually the originals aren't removed so you would need to delete them afterwards in order to save space. It's good for compressing files for attaching to emails.

The compression used by this method in windows is PKzip. Windows just zips the file or files and it doesn't give you any options. There are actually several options that can be used with PKzip compression and the amount of compression can range from none to ultra. Windows chooses speed over compression and the space savings can be bettered by special utilities.

File compression utilities

7-Zip, ZipGenius and PeaZip offer far superior compression of files and they not only support zip files used by Windows, but lots of other compressed file formats too. If you absolutely must have the smallest possible file, you can try several different compression methods and keep the smallest one.

These compression utilities are free and they offer lots of configuration options when creating compressed archives. They aren't the only programs of this type and there are lots of them, but these are typical examples and they are worth trying.

The only problem with using exotic compression formats is that if you email them to someone, they won't be able to open the attachment unless they have the program (or a similar one). Zips are fine, but Windows doesn't know what to do with arc, tar, 7z and others. Make sure you tell people what utility you used to create the compressed file.

My own preference is for the portable versions of PeaZip and 7-Zip. Portable software is supplied as a zip file and you extract the contents and put them somewhere like C:\Portable on the disk drive. There's no installation, they don't change Windows in any way and to uninstall them you just delete the folder.

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