For the real IBM PC's, you can 'dump' their BIOS with the MS-DOS 'debug' command, by reading the specific memory range with it.
C:\> DEBUG
-N MYF000.BIN (resulting file will be named MYF000.BIN)
-R BX (set BX=0000H/CX=8000H as count of bytes to write, 00008000H = 32K)
BX 0000
:0000
-R CX
CX 0000
:8000
-M F000:0 8000 0100 (copy 32K bytes from F000:0 to offset 0100 in local segment)
-W 0100 (write from offset 0100 in local segment)
Writing 8000 bytes
-N MYF800.BIN (resulting file will be named MYF800.BIN)
-M F800:0 8000 0100 (copy 32K bytes from F800:0 to offset 0100 in local segment)
-W 0100 (write from offset 0100 in local segment)
Writing 8000 bytes
-Q
C:\>copy /b myf000.bin+myf800.bin final.bin