Start to finish, a modern Linux installation from CD-ROM can be expected to take from ninety minutes to three hours.
Before you can install Linux, you need to decide on one of the ``distributions'' of Linux which are available. There is no single, standard release of the Linux software---there are many such releases. Each release has its own documentation and installation instructions.
Linux distributions are available both via anonymous FTP and via mail order on diskette, tape, and CD-ROM. The Linux Distribution HOWTO, http://www.linuxdoc.org/HOWTO/Distribution-HOWTO.html, includes descriptions of many Linux distributions available via FTP and mail order.
In the dim and ancient past when this HOWTO was first written (1992-93), most people got Linux by tortuous means involving long downloads off the Internet or a BBS onto their DOS machines, followed by an elaborate procedure which transferred the downloads onto multiple floppy disks. One of these disks would then be booted and used to install the other dozen. With luck (and no media failures) you'd finish your installation many hours later with a working Linux. Or maybe not.
While this path is still possible (and you can download any one of several distributions from http://metalab.unc.edu/pub/Linux/distributions/), there are now much less strenuous ways. The easiest is to buy one of the high-quality commercial Linux distributions distributed on CD-ROM, such as Red Hat, Debian, Linux Pro, or WGS. These are typically available for less than $50 at your local bookstore or computer shop, and will save you many hours of aggravation.
You can also buy anthology CD-ROMs such as the InfoMagic Linux Developer's Resource set. These typically include several Linux distributions and a recent dump of major Linux archive sites, such as metalab or tsx-11.
In the remainder of this HOWTO we will focus on the steps needed to install from an anthology CD-ROM, or one of the lower-end commercial Linuxes that doesn't include a printed installation manual. If your Linux includes a paper manual some of this HOWTO may provide useful background, but you should consult the manual for detailed installation instructions.