Historical clue formulations

• 28-pound debut of 1981 — 2020-11-21
• Home tech product discontinued in 1987 — 2014-11-15
• Landmark tech product of 1981 — 2014-05-04
• Tech product introduced in '81 — 2014-03-04
• Machine that was often cloned — 2010-11-02
• 1980s hardware that used Microsoft Basic — 2010-01-11
• Item often cloned — 2007-11-11