Boot screen

A boot screen is often displayed by an operating system or other software to visually indicate its initial loading process. Depending on the software, the screen may include version information, a definite or indefinite progress indicator, or status messages. Many boot screens also feature the branding of the loaded software, its developer and/or distributor.

16-bit Windows
In early versions of Windows, the boot screen is a device-dependent standalone module which handles the logo drawing and animation. The logo module stored in a  file on setup disks gets combined during installation with the device independent   component to form the   launcher, which allowed OEMs to ship their own logo code if desired. The first known build to use a boot screen was Windows 1.0 Beta Release, which features a merging Microsoft logo and version information. This screen remained virtually unchanged for retail releases until Windows 1.04, when the Microsoft logo was updated to the 1987 logo.

In Windows 2.0, the logo bitmap and text was separated to a separate common  file, which still gets combined with the other parts to form. The same system remained in place for Windows 3.0 and later 16-bit versions, although the boot screen itself has been changed to a graphical still image stored in the RLE format.

Windows 9x
Windows 95 introduced a new boot screen, which runs in the VGA 256-color mode and changes reserved entries in the end of the color palette in runtime in order to show an animation. In most builds, the main boot logo is contained in  in a compressed form, although it is possible to use a custom logo by saving it as   in the boot drive root directory. The same method can also be used for the "shutting down" and "safe to shutdown"  screens. In all cases, the logo file must be 320x400 pixels in size and should be saved in the RLE format.

Early builds used an animation reminiscent of the "Flying Windows" screensaver, with Windows logos randomly lighting up in a random color all over the screen. This was accomplished by the logo bitmap including a number of the Windows flags, each using a different color from the reserved area. Normally, the reserved entries would be set to black, with the boot animation code setting them to a color in order to accomplish the effect.

The animation was changed as of build 337 to merely rotate the reserved palette entries, which was used for the scrolling arrows effect in later beta builds as well as the rotating gradient bar in the final builds and the breathing Windows logo animation used for the first boot screen in Windows 95 and early Windows 98 builds.

The boot screen was completely missing from Windows Me until Beta 2, due to the changes made to the real mode MS-DOS subsystem.

Windows NT 3.1-4.0
Windows NT 3.1 build 196 uses a grey background with dark text, which has been changed in the October 1991 build to a blue background with white text. Starting with Windows NT 3.5, it also shows the available system memory as well as the amount of processors.

Windows 2000
By introducing boot-time graphics, build 1796 and above are able to display graphical content while booting. However, text-mode content can still overlay these until build 1906, where the  screen was implemented. While earlier builds showed the boot screen windowed, Professional build 1983 as well as Server build 2068 changed it to go full screen.

Windows XP
A new boot screen was added to replace the Whistler version in use since build 2428. The only differences from the RTM boot screen are the following: There is a breathing "loading..." string instead of the animated blue bar seen in build 2481. A "version 2002" label is present, which was removed in build 2485. The boot screen has been updated to include the final rotating bars animation, replacing the breathing loading... text animation that was used in builds 2474 and 2475. However, the "version 2002" tag is still present; this is the last build to contain it on the boot screen. The bootscreen now removes the "Version 2002" text, but other than that, it's still the same as the last build. There's now a full brand new bootscreen. It's a black background with lines of dots flashing across. It also has a new boot screen exclusive to this build, resembling the one used in build 2428 but with the old Windows flag. It introduces a new boot screen to accommodate the new Windows flag, which was present up to build 2474. A similar boot screen is present in build 2419, but with the older Windows flag. This build changes the boot screen with a stylized Windows flag on a black background. The progress bar is now larger (and loops) and the "Starting up..." text has been removed. A new boot screen and safe to shutdown screen is introduced in this build. However, the only changes from the Windows 2000 boot screen are the "Microsoft Codename Whistler" name replacing "Windows 2000 Professional" and the removal of the "Built on NT Technology" tag.

Windows Vista/Server 2008 (R2)
During pre-reset stage, the boot screen wasn't changed much. The only two times were build 4011 where the Windows flag was colored white and "Windows XP" has been replaced with "Longhorn" and build 4042 where Segoe UI replaced Franklin Gothic and the flag again received color.

After development reset, the XP boot screen has been reused although with a 2004 copyright date. The first bigger change came with build 5048, where the Windows flag got both white and two-dimensional and "Windows XP" has been replaced one more time with "LONGHORN". Build 5308.6 drastically reduced it to only show the bar and copyright date and notice. Build 5310 used "Loading Windows Vista™" instead. The bar altered during Release Candidate 1 stage and the date got removed during Release Candidate 2 stage. It is still used in Windows Server 2008 R2 and as a fallback screen since Windows 7 and Server 2012.

Windows 8-11/Server 2012-2022
The Windows 7 boot screen got replaced in build 7973 (fbl_core1_kernel_npc) with the image of a betta fish, spinning circles and "Welcome". The latter two grew in size in build 7997. Further changes are:
 * The replacement with "Windows Developer Preview" and the removal of the "Welcome" text
 * The readdition of the betta fish as two-dimensional
 * The re-replacement with "Windows®"

The final iteration of the boot screen of Windows 8, 8.1, 10 as well as their server counterparts can be firstly seen in Windows 8 build 8513. It shows the Windows flag from 2012 and has been updated in Windows 11.

A new boot spinner was introduced in Manganese build 19587 but it was disabled by default. It would later be enabled by default starting with Nickel build 22449.

macOS
Mac OS X Server 1.x shows the boot stages of the Mach kernel inside of a window.

Earlier versions show the Apple logo with spinning lines on white background.

Current versions show the Apple logo with a progress bar on either dark or white background.

Linux
x86 versions show: Uncompressing Linux... Ok, booting the kernel.

while amd64 versions show instead: Decompressing Linux... Booting the kernel.

Ubuntu
Earlier versions displayed a progress bar which at first looped then gone full.

Starting with Ubuntu 10.04, the boot screen contains four or five points which at first glow up then gone back. On lower configurations, a fallback boot screen is displayed, where the Ubuntu logo is replaced with "Ubuntu YY.MM" written in kernel-mode font.

Spinning circles were introduced alongside with UEFI support in Ubuntu 20.04, with the Ubuntu logo at the bottom and (optionally) an OEM logo at the top.

Zorin OS
The boot screen is very minimalistic, only featuring the logo. Starting with Zorin OS 16, it can also display an OEM logo at the top.

Fedora
Similar to Ubuntu, with a spinning circle in the middle, (optionally) an OEM logo at the top and the Fedora logo at the bottom of the screen.

ReactOS
The boot screen is similar to Windows XP/Server 2003.

Windows 7 and Windows Server 2008 R2
NOTE: Server 2008 R2 continued to use the boot screen from its predecessor starting with 7000.