Improved apparatus for controlling tape speed in a reel-to-reel magnetic tape transport system. A controllable reel drive motor operates in response to a control signal derived from an accumulated count of reel revolutions so that the driven reel is driven at a varying angular velocity chosen to produce a substantially constant predetermined tape speed as the tape is wound. In order to more accurately maintain a constant tape speed an indication of tape speed error is obtained by measuring and comparing with a reference the elapsed time between the writing and recording of a signal using a magnetic head arranged for read-after-write operation, any resulting tape speed error being employed to change the accumulated count in a direction which reduces the tape speed error.
A data reproducing device for reproducing a positional information track formed in the longitudinal direction of a magnetic tape according to the present invention is capable of easily correcting regenerative positional information on the basis of count information even when the regenerative information is not obtained from the positional information tack by obtaining the count information consisting of the number so updating operations of positional information in accordance with a first clock generated based on the regenerative positional information acquired from the positional information track formed in the longitudinal direction of the magnetic tape and with a second clock generated based on rotation frequencies of tape reels for driving the magnetic tape.
A tape driving apparatus in which even if the radius of a magnetic medium such as a magnetic tape wound on a supply and/or take-up reel is varied, a current flowing in a servo motor coupled directly to a capstan, which is varied in accordance with a load, is utilized to make the speed of the servo-motor constant by controlling a reel motor and hence to make the back tension and take-up tension of the magnetic tape equal.
Use of a programmable source of stepping pulses to control the speed of linear movement of a material from a supply spool to a takeup spool wherein feedback signals provide an indication of the angular velocity of the supply spool and a function table provides information on the rate of stepping pulses to be applied to the takeup spool.
The tape transport mechanism, in a tape drive for retrievable informational data storage, is provided with a cross-coupled tape speed control servomechanism, achieving controlled bidirectional movement and stopping of tape, without switching, and requiring only one polarity of power source for the motive elements.
An open loop, stepper-motor-driven, rigid magnetic disc memory apparatus for use with a data processing system. A rigid magnetic disc with high track density is driven by a stepper motor in an open-loop fashion or without servomechanism control. The memory apparatus includes: band structure including a spring bias for coupling stepper motor drive to apparatus supporting magnetic heads above and/or below the spinning disc and for temperature compensating for disc/apparatus expansion and contraction; manually operable control for zeroing the magnetic heads, moving and locking them in the disc's landing zone as, for example, while in transit, and providing a travel limit to head movement when the memory apparatus is operating; keying apparatus for preventing erroneous insertion and mis-alignment of and damage to an optical transducer relative to an optical mask arranged to spin with the disc structure; shim apparatus for precisely positioning the magnetic heads in the spin axis direction; viscously-coupled inertia apparatus for damping the stepping motor's step-rotarymotion; a device for employing spinning motion associated with the disc for cooling purposes; and other structure.
