MSX-BASIC file formats
This page was last modified 20:40, 1 May 2017 by Tvalenca. Based on work by NYYRIKKI.


MSX-BASIC programs

MSX-BASIC programs can be stored in two formats: Tokenized BASIC program or pure ASCII. In both cases loading can be done with LOAD-command when you work with disks.


Pure ASCII files are usually used in order to use MERGE-command or to transfer files between platforms. These files are stored as ASCII with both CR and LF as linefeed. End of file is marked with EOF (=^Z =#1A) while saving, but is not required while loading. When storing file to cassette you need to use SAVE-command. When storing file to disk you need to use SAVE-command with parameter ",A"

Typical extensions used on disk: .BAS or .TXT

Tokenized BASIC

Saving as Tokenized BASIC is recommended because this way programs fit to smaller space and are faster to load. When using disk you can use SAVE-command. When using cassette, you need to use [CSAVE]-command.

Tokenized BASIC programs are stored as direct memory dump of BASIC program. There is only 1 byte header that is always #FF (255). The memory addresses of lines are stored, but are not required to be correct as they are calculated again during loading time.

Typical extensions used on disk: .BAS or .LDR

MSX-BASIC binary files

These are files that can be loaded with BLOAD-command or saved with BSAVE-command. In MSX1 only normal RAM between #8000 and #FFFF and VRAM can be loaded or saved. In MSX2 and up also all of 128K VRAM can be loaded or saved using ",S" parameter. (See also SET PAGE-command)

Most MSX2 and up graphic softwares uses this format also to store pictures and their palette. (DD-Graphics, Phillips Video designer, Graphsaurus etc. etc.)

These files have 7-byte header:

  • Byte: #FE (Type of file)
  • Word: Begin address of file
  • Word: End address of file
  • Word: Start address of file (Only important when ",R" parameter is defined with BLOAD-command)

Typical extensions used on disk: .BIN, .SC?, .PL?, .GE5, .PIC

Graphic files created with COPY-command

On MSX2 and up you can save or restore part of VRAM to/from disk by using COPY-command.

These files have 4-byte header:

  • Word: Number of X-pixels
  • Word: Number of Y-pixels

Graphics are stored after header in native pixel format from left to right and up to down. This means that number of bits/pixel depends of used graphic mode.

Tables created with COPY-command

These files don't have header. The values are stored one at a time in native BASIC format (2 bytes for integers, 4 bytes for singes and 8 bytes for doubles) after each other starting from 0 to last cell defined by DIM. In multidimensional arrays the dimensions are stored after each other from bottom to up, left to right. The format of array is not stored.