Abstract: A single gap transducer simultaneously senses recorded control or servo signals and records data signals. A magnetic medium used with this invention is preferably a single coating magnetic medium. During recording, the recording signal is appropriately subtracted from the readback signal for removing write signal effects on the readback signal. The servo signals are preferably deeply recorded into the magnetic coating whereas the data signals are preferably recorded in an outer surface portion of the magnetic coating.

Abstract: Apparatus and method for interconnecting a controlling unit and a controlled unit include providing a plurality of operational nulls. One of the nulls is a logically disconnected null; another of the nulls is a logically connected null. All operations proceed in a predetermined sequence from either of the two nulls. The two units interchange signals indicating the interconnecting state; that is, both units supply the null signal simultaneously except when there is a desire by one of the units to change to another operational state. Unique status recovery procedures and apparatus are disclosed that enable recovery of status and emergency control of units during error prone or degraded operations. All of the functions are based upon an encoded set of tag signals being exchanged. For reliability purposes, complementary tag signal combinations provide diverse functions.

Abstract: In a mass storage system having a multiplicity of storage volumes containing addressable data, the assignment of newly received data sets to the best storage volume is accomplished by determining the best match of the data set to the available volumes. Such selection enables maximum storage use of each volume. The best volume is one that provides memory space efficiency for the job at hand, and considers the volume life expectancy, the numbers of users, the shareability of the volume, and the status of the volume. First, all eligible volumes are listed. Then these volumes are sorted according to each volume's match and risk factors to the data set to be stored. The best fitting volumes are selected first for the actual data transfer and storage operation.

Abstract: A buffer storage apparatus has two buffers alternating between receiving and supplying data signals. The buffer functions are alternated between the buffers when one of the buffers is empty and another one of the buffers has received a predetermined number of signals even though that data-receiving buffer is not yet full. With data transferred in blocks of data bytes, switching between buffers occurs on the predetermined address boundaries of the data blocks. Alternation of functions between the buffers can occur at any one of a plurality of address boundaries within the data-receiving one of the buffers. By using a plurality of such buffer storage apparatus to connect individual data burst units to a plural-port high-speed common unit, each data burst unit has a high speed buffered access to the high speed common unit.

Abstract: A forward/backward compatible apparatus and record member achieves multiple density by multiple track widths as well as multiple lineal densities. In a rotating head recorder a single head has a wide write gap followed by a plurality of narrow read gaps. In recording, narrower tracks--i.e., higher densities, the record medium is moved less than the width of the write gap for recording narrower tracks. The narrower tracks have the same width as the trailing read gaps. During readback, all read gaps are simultaneously operative. Signals from one of the read gaps are processed immediately, while signals from the remaining read gaps are buffered until a dead time occurs, such signals are then processed. The same principles are applicable to magnetic card and magnetic disk recorders. A record member of the disclosure employs a table of contents area always recorded at the lower density--i.e., widest track.

Abstract: A first signal to be stabilized in a magnetic record member is recorded via a head having a given maximal gap length and pole pieces of high saturation induction. After the first signal is recorded, the magnetic record member is surface erased for stabilizing the just recorded signal. In a preferred form, the surface erasing is performed by AC erasing via a transducer having a gap length less than said maximal gap length. The pole pieces of the erasing head need not have the high saturation induction of the first mentioned head. After such stabilization, signals can be easily recorded and recovered from the magnetic record member by using transducers with gap lengths less than such given maximal gap length and using the normal ferrite heads having a lower saturation induction than the first mentioned heads. The first signal can be advantageously employed as a position indicating signal in a magnetic record member, such as a storage disk or tape.

Abstract: A stepping motor mechanism for a rotary device in which one member is indexed linearly and/or rotationally relative to a second rotating member. The indexing member includes at least one portion with a series of equi-distantly spaced ridges and the rotating member includes at least three ferromagnetic members adapted to rotate with the rotating member and spaced from one another, each of the ferromagnetic portions having defined thereon ridges complementary to the ridges on the indexing member but angularly or linearly displaced from one another. A fixed coil and coil carrier is positioned spaced from but adjacent to the ferromagnetic members such that as current is applied to the coils, a magnetic field is induced in the coil carrier and adjacent rotating ferromagnetic member thereby causing the ridges on the adjacent ferromagnetic member to align with the ridges defined on the rotating member.

Abstract: Programmed controllers execute sequences of control functions for controlling a device. External noise can cause controller malfunctions on critically operated devices. Proper sequencing is verified by assigning access key/check codes to particular sequences. A check key code is generated during execution of a sequence only if the sequence is properly executed by the programmed controller. At completion of the control sequence, the generated code is compared with the access or original code for verifying appropriate programmed controller sequencing. Several sequences can be embedded or nested in each other, each having its own check key with the overall sequence also having an independent check key.

Abstract: Method and apparatus for opening stacked disk memory members arranged in a pack for co-rotation and having substantial freedom of axial movement relative to one another, the opening being accomplished by engaging the disk pack with drive means having axially extending pins of varying length, and of a predetermined pattern with the increments of pin length variation being substantially equal to the desired openings between the disk members, and the disk memory members having openings defined therein with corresponding patterns adjacent disk memory members having progressively fewer openings to receive pins of a predetermined pattern with the result that all pins of a predetermined length bear upon a disk memory member and axially separate it from the adjacent disk memory member, thereby providing an opening at the termini of each set of pins of common length.

Abstract: A record storage apparatus consisting of a stack of co-rotating spaced apart flexible record storage disks are stabilized by circumferentially uniform radially outwardly flowing air under a quiescent operating condition. The record storage disks are normally in a parallel relationship. To form a transducing access opening, the disks are axially partially moved to create an enlarged interstice between two of the record storage disks for enabling a transducer to reach a recording surface on one of the two record storage disks. Disks adjacent to such access openings come closer together but should not touch. To avoid the touching and maintain stability, air flow between such more closely spaced disks is automatically adjusted as the disks approach each other.

Abstract: Copy production machine having a print mode for making copies under automatic control interruptible by a copy mode, of making copies. In the print mode images to be copied are automatically supplied to a copy production portion. In the print mode, images are preferably precollated, whereas in the copy mode, produced copies are collated from plural image sources. The first set of each print job is printed one sheet at a time ad seriatum; in subsequent sets all first sides are printed, then all second sides. The first set printing is interleaved with image signal reception and in all subsequent sets, all image signals for the sets or production portion of a set have been received.

Abstract: A copy production machine selectively interleaves copy separation sheets between successive copy jobs, subjobs or job portions. The copy separation sheets can be from the same copy sheet supply source or from an alternate source. The supplied copy separation sheets need not be operated upon by the copy production machines for receiving an image. Such sheets may have been preimaged under certain situations. Before and after a copy job, the number of separation sheets supplied has a predetermined relationship to the number of copy receiving bins in an output portion receiving the copy separation sheets. The number of separator sheets supplied intermediate successive runs of a copy job equals the number of copies to be produced in the next succeeding copy run. The effective capacity of a collator is extended by such interleaving plus a programmable control that tallies copies made versus copies selected greater than the capacity of a collator such that the collator job is automatically segmented.

Abstract: A stack of co-rotating flexible record storage disks is stabilized by maintaining mass flow of stabilizing air within a predetermined range. In a preferred form, mass flow is maintained by sensing both barometric and thermal changes and adjusting the mass flow of the stabilizing air in accordance with such sensed parameters.

Abstract: A disk, tape, etc. record member is contained in a cartridge or cassette. A cartridge type record player has a movable receptacle for receiving the cartridge. The receptacle has two stable and one momentary positions. A center stable position is a load position wherein the cartridge can be inserted into the receptacle. A second stable position, on one side of the center position, is a play position wherein a transducer is in operative association with the second member. The third and momentary position on a second side of the center stable position causes a spontaneous ejection of the cartridge from the receptacle. Usually, from the eject position, the receptacle returns to the center stable position.

Abstract: In a signal storage apparatus employing a rotating record disk, the resonant frequency of a head carriage assembly is tuned to the rotational speed of the record disk. The head carriage assembly, in following a record track on the record disk, has to accommodate record disk rotational perturbations; i.e., run out, eccentric mounting, etc. Such variations are better accommodated in the head carriage assembly by electrically tuning the head carriage assembly to the rotation of the record disk. In a voice coil head assembly actuator, a pair of opposing coils carry equal current amplitudes. These equal current amplitudes are adjusted to rotational speed of the record disk to thereby continuously tune the head carriage assembly to the record disk rotation.

Abstract: A head mount faithfully follows flexible media perturbations. The head mount consists of a pivoted rigid head support arm controlled by an offset spring having an offset damping and yieldably urging relationship to the rigid arm. The rigid arm acts as a free beam. The arm is pivoted to a record support radially movable with respect to a record disk.

Abstract: Signal peaks are identified by measuring the slopes on each side of a signal peak. Each slope measurement is linearized to ascertain a slope angle. Both linearized portions and slope angles are compared to find an intersection of the linearized portions. Such intersection identifies the location of a single peak. The measurement method is particularly useful for detection of peaks in signals with low signal to noise ratios. A programmed digital computer may be used in the measurement method.

Abstract: A sequentially operated machine employs two positionable members, a movable center selection piston member and a movable transducer member for accessing a record storage member selected by the central piston member. Making the record storage member available to the transducer reuires a predetermined time delay. Accordingly, the servomechanism powering the selecting mechanism has a high response, while a following servomechanism transporting the transducer has a low response such that cost is reduced while not adversely affecting access time to the record member.

Abstract: A record disc cartridge has a single internal shutter for opening and closing a head access port adjacent a spindle access member in one wall. A further aperture allows the shutter to be actuated to an open position as the cartridge is moved into a playing position. A spring in the cartridge yieldably biases the shutter to a closed position. When the shutter is open, the spring in the cartridge is cocked to eject the cartridge from a player. Upon release, the spring acts to eject the cartridge.

Abstract: A polynomial based apparatus, such as an error correcting apparatus, is checked by repeatedly supplying test bits to the apparatus. On even cycles, the modulo two sum of the signal contents should be zero, while on odd cycles it should be equal to the pattern used for test purposes.