6 ms·For me, the TRS-80 Model I (4k). I later "graduated" to the TI-99/4A (16k) and Commodore VIC-20 (5k).by vraylle 4y agoFor me, the TRS-80 Model I (4k). I later "graduated" to the TI-99/4A (16k) and Commodore VIC-20 (5k).