A: 4K â also known as UHD (more on this in the next answer!) â is a picture technology that quadruples the number of pixels found in a full HD picture. These pixels are usually arranged in a 3,840 x 2,160 configuration, compared with the 1920x1080 you get in a full HD TV.
Files with the .7z extension are very similar to Zip files. These files are compressed archive files, usually created by the 7-Zip file archive utility. 7Z files can make it easier to send files and folders over email and the Web.
The main features of 7-Zip: High compression ratio in new 7z format with LZMA compression. Supported formats: Packing / unpacking: 7z, ZIP, GZIP, BZIP2 and TAR; Unpacking only: ARJ, CAB, CHM, CPIO, DEB, DMG, HFS, ISO, LZH, LZMA, MSI, NSIS, RAR, RPM, UDF, WIM, XAR and Z. For ZIP and GZIP formats 7-Zip provides compression ratio that is 2-10 % better than ratio provided by PKZip and WinZip.