This is a recording of commodore 64-cassette. Recorded via cassette walkman, from phones output to laptop line input. Please be careful with the volume! sound might get very loud!.
Inserting 3. 5 inch floppy-disk into a floppy disk drive, with the typical sliding sound first and then the spring-activated locking mechanism snapping it shut.
The rather elusive razor waveform, as it is commonly called due to its peculiar shape, from the commodore 64's sid chip, acheivable only by activating the outputs of any two waveforms on the oscillator section.