SlackBuildsOrg/system/xAce

xAce is an emulator for the Jupiter Ace that runs under most
flavours of Unix. It was written by Edward Patel and based
on a ZX81 emulator called xz81 written by Russell Marks, which was
in turn based on Ian Collier's xz80, a ZX Spectrum emulator for X.

This xAce Slackware version implements a mod to allow the user
to change between "slow" and "fast" speed emulation speed,
very useful for spooling text sources.

If you prefer to build the vanilla version invoke the
SlackBuild as follows:

SLACKMODS=no ./xAce.SlackBuild