The Konami Morning Music plays when you power on a Gradius machine. It is part of a boot sequence that has its origins in the Bubble System board, the original hardware platform for Gradius.
Bubble System boot process
The Bubble System was an arcade board developed in the early 1980s by Konami. It got its name from the magnetic bubble memory games were stored on; this was contained in a removable cartridge along with a controller chip that handled reading and writing.
The Bubble System had a relatively long boot process, lasting a few minutes, for multiple reasons. The first was that bubble memory cannot operate at typical room temperatures of 23 degrees, and needs to be warmed up before it can be used. The second was that bubble memory is too slow to be directly usable by games, and so the game needs to be copied from the bubble memory into faster RAM.
The first stage bootloader deals with the warm-up problem. It is stored in the controller chip's firmware; little is known about this firmware but there likely are severe space constraints on its size. As a result, this bootloader does not include any graphics data. Instead, it regularly plays spoken English messages using the on-board speech synthesizer. Once the bubble memory is warm enough to read, the first stage bootloader copies the second stage bootloader into RAM and starts it.
The very first thing the second stage bootloader does is begin playing the Morning Music, a short looping tune. It then loads the rest of itself into RAM, displaying the counter shown above on the screen. While the counter counts down and the Morning Music plays, it reads the rest of Gradius into RAM and gets it ready to play. When it is done, it transfers control once again to the main Gradius program, which performs hardware tests, and finally stops the Morning Music as it shows the title screen.
The Bubble System proved to be expensive and fragile and was quickly abandoned. Konami subsequently re-released TwinBee and Gradius on extremely similar hardware which replaced the bubble memory interface with a fixed set of on-board ROMs for each game. The first stage bootloader was no longer needed, as ROMs do not need to be warmed up before they can be used. To minimize hardware differences, the second stage bootloader was kept, but it was able to complete its job much faster because of the higher speed of ROMs. The countdown was still displayed, but it ended fast enough that the Morning Music is cut short.
Owners of Bubble System boards could purchase replacement cartridges that used ROMs for data storage to increase reliability. Nowadays, these are very rare and little is known about them.
No emulator supports running Bubble System games as of 2017. As such, the ROM version and its boot sequence are the only ones that can be seen in emulators.