Editing MSX BASIC (section)

== Distribution ==
[[Image:Msxbasic.png|right|thumb|384px|MSX BASIC version 3.0]]
MSX BASIC came bundled in the [[Read-only memory|ROM]] of all MSX computers. At system start-up MSX BASIC is invoked, causing its command prompt to be displayed, unless other software placed in [[Read-only memory|ROM]] takes control (which is the typical case of [[ROM cartridge|game cartridges]] and disk interfaces, the latter causing the [[MSX-DOS]] prompt to be shown if there is a disk present which contains the DOS system files).

When MSX BASIC is invoked, the ROM code for [[BIOS]] and the [[BASIC interpreter]] itself are visible on the lower 32K of the [[Zilog Z80|Z80]] addressing space. The upper 32K are set to [[Random-access memory|RAM]], of which about 23K to 28K are available for BASIC code and data (the exact amount depends on the presence of disk controller and on the MSX-DOS [[Kernel (operating system)|kernel]] version).