A backup disc is usually not used for Windows itself or applications, but for personal data. Thus the amount of space needed depends entirely on how much space your files take up.
Because it copies files which you want to backup and creates a special king of archive. So if you want to backup 500 Mb you will get the archive file 500 Mb.
Each disc holds 4.5 gigabytes,so two would hold 9 GB.There must not be much else on the disc.
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The Disc Doctor program is used to clean up and free space on a personal computer's hard disc. It also tells the user how much free space they have on the hard disc.
It will depend upon how much data and programs you have on your system. A Windows 7 installation without any programs on it can be backed up in about 6 Gigabytes, so any modern external hard drive can do a 'system backup' of a modern operating system. It is the programs and documents that are on the system that take up the majority of space in an older computer.
depends on how much space your hard drive or solid state drive can hold.
Installing iWork 09 will take up 658 megabytes of hard disc space.
Windows Exporer
20-40GB depending on version. https://www.microsoft.com/windows/windows-vista/get/system-requirements.aspx
A 20GB hard drive with at least 15GB free space.
Windows 7 required 20 Gigabyte (GB) of space to install a 64-bit version into the system.
During installation, Windows 7 will need about 16GB on a hard drive.