This page was last modified 14:29, 1 June 2020 by Mars2000you. Based on work by Gdx.



Creates a RAMDISK that will get the drive letter H: and optionally displays its actual size.

This command works with MSX-DOS 2, as provided by the MSX-DOS 2 cartridge or the MSX Turbo R machines, with a MSX-DOS 2 disk in the current active drive. It is also supported by Nextor.


  • Only one RAMDISK can be created.
  • If you use the BASIC command after creation of the RAMDISK, it will remain available in the MSX-BASIC environment - see the CALL RAMDISK instruction.
  • Delta BASIC is compatible with this RAMDISK, but drive H: needs to be created before installing Delta BASIC and it will not be acesssible with the DFILES, LDFILES and SETDRIVE instructions.



Character slash (/) serves to declare an option. You can put the option after the command or behind the other parameter.


<Size> is a number to specify in kilobytes the size of the RAMDISK you want to create. This number will be rounded up to the nearest multiple of 16kB since the RAMDISK is always a multiple of 16kB.

This number must be between 0 and 4064. 0 (Zero) has as effect to delete the RAMDISK. If you omit to specify the size when there is not yet a RAMDISK, you will get an error message.

If the RAMDISK already exists, you will normally get a 'Destroy all data on RAM disk (Y/N)?' prompt. It's a security to avoid accidental loss of data. If you answer Y, the existing RAMDISK will be deleted before optionally creating the new RAMDISK.

If you don't specify the size when the RAMDISK already exists, the screen will display the actual size of the created RAMDISK. This size can be different from the entered size, as the system needs to use some RAM for FAT or directories and the size of the memory mapper is taken in account to determine the actual size.

Memory mapper MSX2 / MSX2+ MSX Turbo R
128 kB 32 kB Impossible
256 kB 160 kB 96 kB
512 kB 416 kB 352 kB
1024 kB 928 kB 864 kB
2048 kB 1888 kB 1888 kB
4096 kB 4064 kB 4064 kB

/D is a parameter that removes the mentioned security prompt and allows the automatic deletion of an existing RAMDISK with all its data before optionally creating a new RAMDISK.


(with a 512kB memory mapper and COMMAND2.COM 2.30)



MSX-DOS 2 / Nextor with COMMAND2.COM v2.20 and higher