▁seven ▁segment ▁display , ▁there ▁was ▁also ▁optional ▁V DU ▁supporting ▁ 3 2 × 1 6 ▁text ▁or ▁ 6 4 × 6 4 ▁graphics . ▁Input ▁and ▁output ▁was ▁a ▁ 2 0 - key ▁keyboard ▁and ▁reset ▁switch . ▁Cass ette - based ▁and ▁P ROM ▁storage ▁were ▁optional ▁ex tras ; ▁a ▁sound ▁card ▁was ▁not ▁included ▁but ▁a ▁design ▁for ▁one ▁was ▁provided . ▁▁▁ ▁The ▁on - board ▁RAM ▁could ▁be ▁increased ▁in ▁two ▁ways ; ▁by ▁the ▁addition ▁of ▁an ▁IN S 8 1 5 4 N ▁RAM / IO ▁chip ▁providing ▁an ▁additional ▁ 1 2 8 ▁bytes ▁of ▁RAM ▁along ▁with ▁ 1 6   I / O ▁lines , ▁and ▁also ▁a ▁further ▁ 2 5 6 ▁bytes ▁by ▁adding ▁two ▁ 2 5 6 ▁× ▁ 4 ▁bit ▁RAM ▁ch ips ▁giving ▁a ▁maximum ▁of ▁ 6 4 0 ▁bytes ▁on ▁board . ▁ ▁These ▁memory ▁spaces ▁were ▁not ▁cont igu ous ▁in ▁the ▁memory ▁map . ▁ ▁It ▁was ▁possible ▁to ▁connect ▁off - board ▁RAM ▁giving ▁a ▁ 2 1 7 0 ▁bytes ▁total . ▁ ▁The ▁M K 1 4 ▁could ▁address ▁up ▁to ▁ 6 4   KB ▁of ▁memory ▁space ▁by ▁adding ▁a ▁few ▁ch ips ▁( the ▁N AD S ▁address ▁stro be ▁indicated ▁when ▁the ▁most ▁significant ▁four ▁bits ▁of ▁address ▁were ▁available ▁to ▁be ▁captured ▁by ▁an ▁external ▁l atch ); ▁many ▁pione ering ▁home bre w ▁computer ▁mag az ines ▁such ▁as ▁Personal