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• Models 1 - 3 announced April 7, 1964 and withdrawn July 16, 1979
  
  
• Models 4 - 6 announced August 9, 1965 and withdrawn July 16, 1979
  
  
• Model 8 announced November 5, 1970 and withdrawn July 16, 1979
  
  
• All models and features withdrawn March 9, 1981

Models 1, 2 and 3

Each of these models, specifically designed for use on the IBM System/360, used a nine-track read/write head and had a single density of 800 bytes per inch. Any of these models could be attached to IBM System/360 through the 2803 or 2804 Tape Control.

• Up to eight 2401s, Model 1, 2 or 3, could be attached to a 2803 or 2804 Tape Control.
  
  
• The 2401 could read magnetic tape in a read-backward mode.
  
  
• The 2401 had a nominal inter-record gap of .6 inches.
  
  
• By use of a special feature, the 2401 could read or write seven-track magnetic tape, providing compatibility with 727, 729 and 7330 magnetic tape units with densities of 200/556/800 bpi.
  
  
• For nine-track operations, the 2401 had correction of one or more errors in a single track on a reread operation.
  
  
• By use of IBM 2816 switching units, Model 1 and special features, up to 16 tape drives could be switched on up to four channels.
  
  
• The IBM 2401, Models 1, 2 and 3, had the following performance ranges:
  

Models 4, 5 and 6

Also specifically designed for use on the IBM System/360, these models of the 2401 used a nine-track read/write head and recorded data at 1600 bytes per inch. They could be attached to IBM System/360 through the IBM 2803/2804 Tape Control, Model 2.

• Up to eight 2401, Models 4, 5 or 6, could be attached to the 2803/2804 Tape Control, Model 2.
  
  
• The 2401 could read magnetic tape in a read-backward mode.
  
  
• The 2401 had a nominal inter-record gap (IRG) of .6 inches
  
  
• A dual density special feature gave the 2401 the capability of handling the nine-track tapes of all models in the 2400 series.
  
  
• With 1600 bpi operations, single track defects were corrected in flight without affecting tape performance.
  
  
• Through the use of IBM 2816 Switching Units, Model 1, and special features, up to 16 tape drives can be switched on as many as four channels.
  
  
• The IBM 2401, Models 4, 5 and 6, had the following performance characteristics:
  

Initial shipments of the improved 2401s from IBM's Boulder, Colo., manufacturing facility began in August 1966, one year after they were announced. More than 30,000 of these tape drives were installed within the first four years of their availability.