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Exos V3
Exos V.3
From the manual:
CTRL + K Display drive error channel
CTRL + O OLD function
CTRL + U Enable saving RAM under Basic ROM
CTRL + S Transfer program into RAM floppy
CTRL + L Transfer program from RAM floppy
CTRL + V Swap program with program in RAM floppy
CTRL + F Increases stepper speed in drive
CTRL + X List Basic program from current position
CTRL + Z List Basic program 50 lines before current position
CBM + F1 and CBM + F3 Transfer screen RAM to RAM drive
CBM + F5 and CBM + F7 Transfer screen RAM from RAM drive
CTRL + A Disable fast loader
F2 / F4 / F6 / F8 SYS 32768 / SYS 4096 * 12 / SAVE" / CLOSE7:OPEN7,8,15"
CTRL + Reset Avoid cartridge start and reset protection (SpeedDOS reset)

Exos was developed by J.Schemmel and released by the german paper magazine 64'er in the December issue of 1986. It was published as a ROM patch which copied the original C64 Kernal to $2000 and patched it there. The reader was supposed to use a monitor to save the new ROM then. The ROM is simply burned to an 8k eprom and added to the C64 using a kernal switching board then. Exos does not require a change on the drive ROM.

REX Datentechnik released Exos v3 as a cartridge (order number 9805).

V-DOS by Völkner Electronic (order number 9716) was created by J.Schemmel as well and is said to be the same as the Rex Datentechnik cartridge release.


  • Fast serial load (can be disabled)
  • LOAD"$",8 redirected to screen output on direct mode
  • Start and end address output
  • OLD function
  • RAM floppy functions
  • some extended LIST support
  • modified reset routine (hold CTRL during reset)


  • Joe as hacker of the V4 Exos version describes the applied changes as:
    • changed colors back to commodore-blue and reset message closer to original C64
    • jsr $fd15 doesn't write vectors to ram at $fd30
    • fixed bug preventing that load"$" prints on screen instead of loading to basic (a correction printed in a 64'er issue)
    • autostart after reset on write-protected floppies (the only new feature)
  • Exos is known to be not the most reliable speeder due to the increased speeding of the stepper motor within the drive


Kernal_ROM_all_rr.c64.org_2021-02.rar contains:

Thanks to Berry de Jager for the V-DOS 3 dump!


Rex V-DOS 3
Völkner V-DOS 3