Data General Corporation

Joseph Charles Godbout

Michael Alan Feldstein

Richard Bruce McKinstry

A temperature compensation technique for memory disk pack systems used in data processing apparatus wherein the temperatures at the base plate and at the disk pack are monitored so as to generate a temperature compensation error signal. Such error signal is supplied to the feedback path of the record/read head position servo loop of the disk pack system when the record/read head has moved to within a selected distance of its commanded position. The overall disk system is enabled only when the temperature error has stabilized to a value below a preselected level.

Thermal compensation for disk pack systems

A digital magnetic tape transport incorporates a pair of adjacent vacuum storage columns each with oppositely disposed closed and open ends, a magnetic head assembly defining a generally linear tape threading path along one side of the vacuum storage columns and substantially parallel to the vacuum columns lengthwise direction, a pair of tape storage reels mounted at a second side of the vacuum storage columns positioned along a line substantially parallel with the linear tape threading path, whereby a rear closed end of the vacuum column adjacent to a storage reel is tapered at an angle substantially tangent to the adjacent storage reel, allowing for: elimination of an idler roller; an improved take-up path, and; for easier manual threading of the tape. A similar tapered configuration is provided at the rear end of the second vacuum column also eliminating the necessity of an idler roller. The arrangement decreases the total number of idler rollers necessary for the overall tape path to in turn decrease the frictional contact of the tape encountered. At the same time, because of the V-shaped configurations at the rear walls where there are positioned relatively large apertures for supplying vacuum to the vacuum columns, the positioning of a central narrow common plenum is provided for thereby allowing for positioning adjacent elongated chambers with relatively small apertures for separately sensing vacuum in each vacuum column to determine a varying tape loop position.

Tape transport system

A tape loading system for use with tape transport systems having low inertia tape loops formed in vacuum buffer columns in a tape path between the tape storage reels and the tape driving means comprising, a vacuum source for providing vacuum in the vacuum buffer columns and ascertaining a predetermined value of build-up of vacuum in the columns and upon attaining the predetermined vacuum value supplying a predetermined length of tape from the tape storage reels to each of the buffer columns. A tape unloading arrangement also provides for automatically ensuring rewind, then shutting off the vacuum source, and then applying sufficient bias for slight rotation of the storage reels to unwind the tape.

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Acton, MA, United States of America

Joseph Charles Godbout