These are nonmemory resident parasitic viruses. They search for COM files on disks and infect them. "Palma.247" overwrites the files, other viruses write themselves to the end of the file.
The viruses contain the texts:
"Palma.503": Palma Ver.2
"Palma.591": Palma Ver.4
C:COMMAND.COM
"Palma.642": Palma Ver.3
"Palma.591" depending on the system date deletes the C:COMMAND.COM file. "Palma.642" displays:
____ __ _ __ __ __
_ _ __ _ _ _ _ _ __ _
___ ____ _ _ _ _ ____
_ _ _ ____ _ _ _ _
