Friday, December 2, 2022

So Many Floppies! - Late DOS/Early Windows Era Installations

The CD-ROM format continually promised to make floppy disks obsolete.  First introduced in a usable form in 1986, the CD-ROM's 650MiB capacity was enormous when 1.2MiB 5.25" floppies were largest available removable media at the time and hard drives maxed out at around 50 MiB.  While CD-ROMs were standard equipment on current PCs by 1995 and the principal method for software installation by that year, the PCs reliance on floppy disks for operating system installation lasted for much longer than anyone anticipated.  How long you ask?  Let's find out.

In the earlier days of DOS, DOS usually came on two floppy disks and installing DOS meant copying the system files, the command line interpreter and the various included DOS utilities to a hard disk.  By 1991, MS-DOS was king of the PC Compatible world and the world of PCs had thrown off the yoke of IBM's dominance in the early years.  In June of that year Microsoft released MS-DOS Version 5.0, which was the true beginning of "modern" DOS.  MS-DOS 5.0 came on 3 x 720KiB disks or 6 x 360KiB disks.  MS-DOS Versions 6.0-6.22 MS-DOS came on 3 x 1.44MiB or 4 x 1.2MiB disks.

Microsoft Windows, up to and including Windows Version 3.11, ran on top of DOS and required an installation of DOS to run.  Windows Version 3.1 and Version 3.11  typically came on 6 x 3.5" HD or 7 x 5.25" HD disks.  It required MS-DOS 3.1 or later but recommended 5.0 or better.  

Windows 95 did not require DOS to run and came with its own DOS (7.0). Windows 95 Retail or Upgrade typically came on 14 x 3.5" floppy disks or, for the Upgrade, 1 CD-ROM. It would upgrade a PC with any version of Windows from 3.0 up or OS/2 from 2.0 and up.  Most of those disks used Microsoft's Distribution Media Format, which permitted 1.68MiB on a 3.5" HD disk instead of the usual 1.44MiB.  

As Windows 95 pre-dated the bootable "El-Torito" CD-ROM specification, the Retail CD-ROM Upgrade version came with a boot floppy disk.  There was a Retail version "for PCs without Windows" but only on floppy, not CD-ROM, and it is pretty uncommon.  The CD-ROM versions came with more non-essential elements, like videos, sound themes and MIDI files, than the the floppy versions.  

Windows 98 Upgrade, whether First Edition or Second Edition, would upgrade a PC with Windows 3.1 or better.  The retail Upgrade Editions did not support bootable CD-ROMs, so they came with a boot floppy disk.  Windows 98 was the first version of Windows to be sold at Retail as a CD-ROM version "for PCs without Windows".  There was a floppy disk version of Windows 98 First Edition which came on 39 x 3.5" Floppy Disks.  

Windows Millenium Edition was bootable on CD-ROM with the retail release and the "Upgrade Versions" are scarce.

So if you wanted to install Windows 3.1 on a newly-formatted hard drive, you were looking 9-11 floppy disks.  A few years later if you had a computer which only shipped with MS-DOS and you needed to upgrade that computer to Windows 95 from a fresh hard drive, you would only need Disk 1 of your Windows 3.x install disk to pass the Upgrade check and the boot disk.  

In retail stores, you would typically see the Upgrade versions for sale, which required a prior version of the OS.  Full versions were reserved for OEMs and system builders, who paid a license fee to Microsoft to include an Operating System with their computer systems.  If you were building a system in the late 80s to early 1990s with discrete components, then you were in a bit of a spot when it came putting an OS on your system.  You might be able to buy a set of DOS disks branded by a company like Compaq or AST, but they may not install in your system if they are programmed only to install on the company's own computers.  (Compaq DOS was a safe choice for this purpose, Compaq DOS 3.31 was especially popular because it offered the ability to use larger than 32MiB hard drive volumes.)

For Windows 95, only OEMs had access to OEM Service Releases 2.0, 2.1 or 2.5.  Users of the Retail or original OEM version could update their installation to the equivalent of OSR 1 by downloading Service Pack 1.  OEM 2.0 and above had access to the newer technologies, FAT32, Ultra DMA, IRQ Steering, USB, AGP, MMX and P6 and OpenGL Support. 

The only important differences between Windows 98 Retail and OEM versions is that the OEM Full Version CD-ROMs are bootable whereas the Retail and Upgrade versions are not.  By the time of Windows 98 all users had access to the same patches and feature improvements via Windows Update.  

So in short, a typical PC floppy disk OS install went from two floppy disks (DOS 2.0-4.01) to three (DOS 5.0-6.22) to nine (DOS + Win 3.1) to fifteen (Win 95 floppy + Upgrade Check) or one to two (Win 95 CD, Win 98 FE & SE Retail + Boot Disk & possibly Upgrade Check).  


  1. Operating systems where even the nicer ones to be distributed on floppy disks. I rember for example office suites like Microsoft Office or Lotus Smartsuite having... ~30 disks.

  2. Yes! As the end of the floppy era approached you'd have 3-8 discs even for games. So different than the current world, where you download gigabytes with barely a though given to the data.

  3. Small correction: Windows 3.x didn't exactly run on top of DOS. Things are quite bit more complex
    Raymond Chen's Old New Things:

  4. I remember playing Simon the Sorcerer on A1200 before I got my hard drive.

    9 game disks and one for saving was too much. I didn't manage to get far until I finally got my hands on a cheap IDE hard disk. Even worse is I got a CD-ROM drive later, meaning if I wanted to enjoy the Chris Barrie(Rimmer from Red Dwarf) voice acting I had to buy it again... which I did.