altairz80: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/altairz80 - from package: simh

You may install the required package with command apt-get install {package}

Error in other languages:
altairz80: bevel nie gevind nie
altairz80: comandă negăsită
altairz80: comando não encontrado
altairz80: commande introuvable
altairz80: command not found
altairz80: käsku ei ole
altairz80: không tìm thấy lệnh
altairz80: komanda nerasta
altairz80: Kommando nicht gefunden.
altairz80: kommandot finns inte
altairz80: komut yok
altairz80: nie znaleziono polecenia
altairz80: níor aimsíodh an t-ordú
altairz80: no se encontró la orden
altairz80: no s'ha trobat l'ordre
altairz80: opdracht niet gevonden
altairz80: parancs nem található
altairz80: perintah tidak ditemukan
altairz80: príkaz nenájdený
altairz80: příkaz nenalezen
altairz80: команда не найдена
altairz80: командата не е открита
altairz80: 命令找不到
altairz80: コマンドが見つかりません