A number of companies entered the 2314 and 3330 plug compatible market with big intentions and spending many R&D dollars. Some never shipped a product. The purpose of this entry is to catalog those that tried but failed to bring a product to market or who who did but had a very short life. The list is limited to drive manufacturers, pure financial companies such as Transamerica are not included

• Ampex (Taxon->Clasco->Ampex) (2314, 3330)
• Burroughs (is this true?)
• Century Data Systems / Calcomp (2314)
• ISS, then Itel, then Sperry Univac (2314, 3330)
  
• Marshall Data Systems (2314)
• Potter Instruments (2314)

Some pure financial companies were

• Greyhound
  
• Telex
• Transamerica

IBM's responses to its plug compatible competition was the subject of a number of anti-trust lawsuits, most of which IBM won. The US government's antitrust lawsuit was dropped by the Regan administration.

Contributors: DecVet, Tom Gardner