摘要:
In a helical scan system for recording information on a storage media in a series of helical tracks, servo information written on the tracks is used to control linear velocity of the media during a write operation. Helical scan system includes a rotating drum upon which write heads and read heads circumferentially are mounted. The write heads and the read heads are positioned on the drum so that during a drum revolution a read head reads servo information recorded on a track at least 1.5 track pitches upstream from the most recently recorded track. A servo controller analyzes, during the recording operation, servo information read back by the read head subsequent to recording thereof by write head. Servo controller uses the servo information read by the read head to generate a signal for application to a motor for controlling linear velocity of the media during the write operation.
摘要:
A capstanless helical scan recording system (14) comprises a supply reel (24); a take-up reel (26); and a media transport path (20) extending from the supply reel to the take-up reel. A drum (30) is positioned along the media transport path and has a read head (R1,R2) and a write head (W1,W2) mounted thereon for recording and reading information in helical stripes on the media. The take-up reel comprises a rotor assembly (60), a rotating hub assembly (70), and a gearing system. The rotor assembly includes a sun gear (80) which rotates at a first rotational speed. The rotating hub assembly rotates carries three planetary gears (160) and imparts a velocity to media transported in the media transport path. The gearing system meshes with the rotor assembly and with the hub assembly for causing the hub assembly to have a greater rotational speed than the rotor assembly. The gearing system preferably has a gear ratio on the order of about 8:1. A tension arm (44) protrudes into the media transport path and decouples the supply reel to compensate for reel runnout during high speed operation. The system has no further means other than the take-up reel and the supply reel for imparting impetus to the media along the media transport path.
摘要:
A method and system for detecting tape attachment to a machine reel of an automatically threading magnetic tape system. During the threading process, a file reel is rotated to allow a sufficient length of tape to be unwound therefrom, which length of tape eventually attaches to the machine reel after being automatically threaded through the desired tape path. The rotation of the file reel is maintained during this threading process by delivering current pulses to a file reel motor. These current pulses are counted per unit time. As soon as the tape attaches to the machine reel, the machine reel begins to pull the tape from the file reel, thereby eliminating the need to deliver current pulses to the file reel motor, at the same rate as needed prior to tape attachment. A change in the rate of the current pulses delivered to the file reel motor signals a tape attached condition.
摘要:
In a servo tracking method and apparatus, a servo head (S) of a helical scan recorder (30) endeavors to travel equidistant between two servo signal-bearing stripes recorded on the tape (32). The recorder (30) determines a reference-crossing time at which the servo head (S) begins to cross a horizontal reference line (606) drawn with respect to the beginning of a stripe on the tape (32). The servo head (S) samples the amplitude of a servo signal provided on the tape (32) at a plurality of predetermined times after the reference-crossing time. A servo tracking circuit (175) uses the amplitude of the servo signal at the predetermined sampling times to determine how to adjust the position of said head (S) relative to the pitch of said stripe.
摘要:
A dual channel helical scan recording system (30) includes a rotating dum (36) having sets of heads (W1, W2) (R1, R2) mounted on its peripheral surface (56). A set of write heads (W1, W2) is situated on an opposite side of the drum (36) from a set of read heads (R1, R2). The write heads (W1, W2) simultaneously write two adjaent tracks (T1, T2), which are read for verification 180 detrees later by corresponding read heads (R1, R2). The heads (W1, W2, R1, R2) are strategically mounted on the drum (36) with respect to angular and axial placement, and have selected head widths and azimuthal angles. Should a block of data (317) written to tape (32) be determined, during readback, to be bad block, that bad block is subsequently rewritten on the tape (32) in the course of writing good blocks and amongst other good blocks. The rewritten block is recorded at a row position on the tape which is sufficiently displaced from the row position of a previous writing to avoid media defects occuring on the tape. In addition, a block written by a first write head (W1) and perceived as having been written as a bad block must be written by a second write head (W2) before that block is rewritten a predetermined number of times.
摘要:
Method and apparatus are provided for developing a digital timing signal indicative of when a head of a helical scan recorder (30) is positioned over a recorded stripe on magnetic tape (32). The method involves rotating a drum (36) upon which a head is mounted while the magnetic tape (32) is transported past the drum at a speed greater than the nominal speed at which stripes were recorded on the tape. Given the geometry of the system and format of the tape, the head is eventually able to recognize a pattern of digital data. The timing of the recognition of the pattern of digital data is used to determine the precise time, relative to each rotation of the drum (36), that the head ceases to traverse a stripe and the precise time during each rotation of the drum that the head begins to traverse a stripe. The determination of the edges of the digital timing signal is repeated upon every rotation of the drum (36). A servo timing signal for a servo head (also mounted on the drum) is generated in ninty (90) degree phase relationship to the digital timing signal.
摘要:
According to the invention, a removable rotational disk storage cartridge for storing computer readable data is disclosed. The cartridge may include a chassis, a shock absorption media and a rotational storage disk. The chassis may define an interior space and may be configured to be detachably and mechanically coupled with a cartridge drive. The shock absorption media may be deposited at least partially within the interior space of the chassis and may be a flexible material. The rotational storage disk may be configured to store computer readable data and may be deposited at least partially within the shock absorption media.
摘要:
A wavelength router that selectively directs spectral bands between an input port and a set of output ports. The router includes a free-space optical train disposed between the input ports and said output ports, and a routing mechanism. The free-space optical train can include air-spaced elements or can be of generally monolithic construction. The optical train includes a dispersive element such as a diffraction grating, and is configured so that the light from the input port encounters the dispersive element twice before reaching any of the output ports. The routing mechanism includes one or more routing elements and cooperates with the other elements in the optical train to provide optical paths that couple desired subsets of the spectral bands to desired output ports. The routing elements are disposed to intercept the different spectral bands after they have been spatially separated by their first encounter with the dispersive element.
摘要:
A tape drive emulator (30) is between a host computer (40) and a removable disk drive (22) and appears to the host computer 40 as a sequential storage system, e.g., a tape drive. However, the tape drive emulator (30) processes the data obtained from or applied to host computer 40 so that the data can be communicated to removable disk drive 22 in a manner compatible with a conventional removable disk drive. Yet in so doing, tape drive emulator 30 imposes on the data (1) an data organization, imperceptible to disk drive 22, for rendering the data expressable and locatable in a tape drive format, and (2) an additional degree of error correction that provides enhanced data integrity necessary for data backup/restore operations.
摘要:
According to the invention, an electronic data storage cartridge for removable coupling to a computing system is disclosed. The electronic data storage cartridge includes a cartridge body, a connector, an optical waveguide, a hard disk drive, and a mechanical write-protect switch that prevents modification of information on the hard disk drive when active. The cartridge body includes at least two outer surfaces. The connector can be used for removable coupling to the computing system, where the connector couples information outside the cartridge body. The optical waveguide is configured to couple light between the two outer surfaces. The hard drive is coupled to the connector.