Abstract: A tape winding method and apparatus for facilitating the escape of air from between layers of a tape during a tape winding operation. A tape winding apparatus has a tape reel onto which a tape is adapted to be wound during a tape winding operation. A plurality of generally radial slots are provided in at least one of first and second flanges of the tape reel to create a fan-like action that generates a negative air pressure in the vicinity of the tape as the tape is being wound onto the tape reel to facilitate the escape of air from between layers of the tape during the tape winding operation.

Abstract: A method and apparatus for reducing tape dimensional changes during accessing of a tape. A profile for the tape is identified. A determination is then made as to whether a location is being accessed on the tape. Tension applied to the tape is adjusted using the location and the profile, wherein tape width dimensional changes are minimized.

Abstract: Proper coverage of data tracks of a magnetic tape in a magnetic tape drive is ensured by providing a head assembly having a set of read heads configured such that at least one of the read heads reads a desired data track as the magnetic tape moves across the head assembly. At least one of the read heads reads the desired data track by creating lateral differential motion of the head assembly with respect to the longitudinally extending data tracks of the magnetic tape. The differential motion is either created by tracking irregularities between the head assembly and the magnetic tape or by dithering or wobbling the head assembly with respect to the magnetic tape. In operation, a controller selects one of the read data signals generated by the read heads to generate a read back signal. The read back signal is the read data signal from the at least one of the two read heads reading the desired data track.

Abstract: A plug inserted into the access opening of a tape cartridge to prevent movement of the reel inside the cartridge. Damage to the tape media is thus prevented by contact of the reel with the tape media. The plug may also be used to seal the access opening and eliminate environmental contamination which would otherwise enter therethrough.

Abstract: The robust coding system makes use of a robust bar code on a label to enable a label reading system to automatically reconstruct label indicia information, even though the label has been damaged and is partially obliterated. An error correcting code is incorporated into the bar code sequence imprinted on the label to detect and correct a plurality of errors in the bar code. The error correcting bar code digits can be interleaved with the data imprinted in bar code form on the label or appended thereto. In addition, when the robust coding system is used on labels for data media cartridges, additional information is included in the bar code field to identify the type of media contained in the media cartridge.

Abstract: The data recording system writes data on both sides of a two sided magnetic recording tape, in directions of magnetization that are angular displaced with respect to each other, to reduce the effects caused by contact recording and magnetic print through. The media used for the magnetic tape consists of a standard mylar substrate to which a coating of magnetic recording materials is applied, on both sides thereof. In order to reduce the effect of magnetic print through and contact recording, the particles or films that are applied to both sides of the substrate are oriented in differing magnetic orientations that are angularly displaced with respect to each other and two sets of read/write heads are used. The read/write heads can be oriented to produce magnetic fields on one side of the magnetic tape that are angularly displaced with respect to the magnetic fields created on the other side of the magnetic tape.

Abstract: Apparatus and methods are disclosed for writing data on a track in an optical disk data storage device wherein the track is divided into two parts and binary one bits are written into one part of the data track while binary zero bits are written into the second part of the data track. Detection of data written in this manner is performed using two read coherent radiation beams each positioned over one of the parts of the data track. A binary one is detected if the signal from the beam over the first part of the data track is greater than the signal from the beam over the second part of the data track, and a binary zero is indicated if the signal from the beam over the second part of the data track is greater than the signal of the beam over the first part of the data track. In order to detect the data from the two read beams, they must be aligned accurately over the two halves of the data track. To aid this alignment, a third larger beam is used to measure the total energy from the data track.

Abstract: A saturated flux equivalent to three amplitude level recording is attained by recording two levels by conventional saturation of the medium and the third level by writing a high frequency which erases old data and is read back as a zero level due to limited playback or read frequency response.

Abstract: A digital magnetic recording system is disclosed that utilizes partial response signalling to achieve the Nyquist data pulse rate with minimum bandwidth. A. C. bias is introduced to linearize the magnetic medium which, inter alis, permits reliable multilevel (greater than 2) data storage without impairing data accessibility. Preferably Class IV partial response is utilized with one or more sinusoidal lobes in the data frequency spectrum. The basic binary data to be stored is converted to, for example, ternary and the ternary data is precoded. The precoded ternary data is recorded on the magnetic medium via an interleaved dipulse sequence having a spectral null slightly outside the data frequency band. A pilot tone is inserted at the spectral null for timing recovery and automatic gain control.