YS MegaBasic
Developer(s)Mike Leaman
Initial release1984; 38 years ago (1984)
Stable release
YSMegaBasicV4.0 / 1985; 37 years ago (1985)
Operating systemZX Spectrum
TypeBASIC programming language interpreter

YS MegaBasic is a BASIC programming language interpreter for the 1982 Sinclair Research ZX Spectrum microcomputer, written by Mike Leaman.[1][2] The interpreter was available by mail-order from Your Spectrum magazine, hence the name "YS MegaBasic".

When loaded it left the user 22K of usable memory. YS MegaBasic allowed keywords to be spelled out letter-for-letter, which was quicker if the user had fitted a full-size full-travel keyboard to their machine, a very popular modification for serious users. This also removed the necessity for memorising the sometimes arcane key combinations necessary to enter less-commonly-used Sinclair BASIC keywords. It also featured three different font sizes, user definable keys, copy-and-paste, a Sinclair QL-like windowing system, sprites and sound effects.[1]

New commands added by YS MegaBasic:[1]

AUTO Causes the computer to automatically produce line numbers
BACKUP Copies tape files
CHANGE Manipulates the attributes file
CLW Clears the current window on-screen
CURRENT Changes the window used for screen output
DELETE Erases a block of program lines
DOWN Prints a string down the screen
EDIT Displays a program line for editing
EXAMINE Displays headers of tape files
FADE Produces special effects on-screen
FONT Selects the character set used for printing
FX Handles miscellaneous functions
INVERT Changes INK to PAPER and vice versa
KEY Creates user-defined keys
MODE Changes the current character size
MON Jumps to front panel
PAN Scrolls a window to the left or right, pixel by pixel
PLAY Produces complex sound effects
SPEED Used in conjunction with TRON to reduce the speed of program execution
SWAP Swaps one attribute for another
TROFF Turns 'trace' mechanism off
TRON Turns 'trace' mechanism on
VDU Equivalent to PRINT CHR$
WINDOW Defines the size and location of the current window on-screen



  1. ^ a b c Your Spectrum:YS MegaBasic, Issue 8, October 1984
  2. ^ YS MegaBasic at SpectrumComputing.co.uk
  3. ^ "World of Spectrum - YS MegaBasic".