In this page, I am offering my achievements in terms of software for the ZX81. These are programs that I developed and others that I just modified to incorporate new features such as AY sound or characters redefinition.

Some of these programs require special hardware features, which will be identified by the icons below:

UDG
Requires a character board mapped in RAM at address 3000h.
CHR$128
Requires a character board with CHR$128 scheme, mapped in RAM at address 3000h. This card allows the redefinition of up to 128 characters, as opposed to the traditional scheme that allows only 64 characters.