down ▁+ D ▁interface ▁( market ed ▁by ▁M GT ▁themselves ). ▁Both , ▁however , ▁shared ▁certain ▁features : ▁▁ ▁A ▁Sh ug art - compatible ▁port ▁for ▁connecting ▁one ▁or ▁two ▁flo ppy ▁disk ette ▁drives ▁( the ▁de ▁fact o ▁standard ▁created ▁by ▁Sh ug art ▁Associ ates ) ▁ ▁A ▁parallel ▁printer ▁port ▁ ▁A ▁" mag ic ▁button " ▁ ▁The ▁latter ▁generated ▁a ▁non - mask able ▁interrupt , ▁free zing ▁any ▁software ▁running ▁on ▁the ▁Spect rum ▁and ▁allowing ▁it ▁to ▁be ▁saved ▁to ▁disk . ▁This ▁made ▁it ▁simple ▁to ▁store ▁t ape - based ▁games ▁on ▁disk , ▁to ▁take ▁screens h ots ▁and ▁to ▁enter ▁che at ▁codes . ▁A ▁duplicate ▁expansion ▁conne ctor ▁at ▁the ▁back ▁allowed ▁other ▁peri pher als ▁to ▁be ▁da isy ▁ch ained , ▁although ▁the ▁complexity ▁of ▁the ▁DIS C i P LE ▁meant ▁that ▁many ▁would ▁not ▁work ▁correctly . ▁ ▁However , ▁the ▁real ▁innov ation ▁was ▁in ▁the ▁R OM . ▁Un like ▁most ▁of ▁the ▁compet ing ▁systems , ▁this ▁was ▁compatible ▁with ▁the ▁S inc la ir ' s ▁extended ▁R OM , ▁meaning ▁that ▁the ▁same ▁B AS IC ▁commands ▁used ▁to ▁operate ▁Micro d riv es ▁or ▁the ▁Z X ▁Pr inter ▁now ▁could ▁control ▁flo ppy ▁disk ▁drives ▁or ▁a ▁standard ▁parallel ▁printer . ▁As ▁well ▁as ▁being ▁B AS IC - compatible , ▁it ▁also ▁m im icked ▁the ▁machine ▁code ▁entry ▁points ▁in ▁the ▁Z X ▁Interface