Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Cartridge system
Reexamination Certificate
1999-09-28
2001-08-07
Rivera, William A. (Department: 3653)
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Cartridge system
C242S347000, C242S352300, C360S132000
Reexamination Certificate
active
06270030
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a system for mechanically distinguishing between two tape cartridges of the same form factor that contain magnetic tape having different recording characteristics.
BACKGROUND OF THE INVENTION
Tape cartridges configured to meet certain minimum physical requirements are said to have a particular “form factor.” In the tape cartridge arts, form factor generally defines the peripheral dimensions of the cartridge and the interface characteristics with the tape drive. For a variety of economic and manufacturing reasons, it may be desirable to provide a tape cartridge for a different type of tape drive that has the same form factor as existing tape cartridges. If there are different recording and dimensional characteristics of the magnetic tape for the different tape drive, however, such a tape cartridge must be distinguishable from existing tape cartridges of the same form factor.
Current techniques for distinguishing between different tape cartridges having the same form factor typically rely either on the read/write head assembly to magnetically detect a non-conforming tape format, or on some type of interaction between a physical feature of the tape cartridge and a sensing circuit in the tape drive. European Patent Application 0 389 121, for example, describes a data protection feature for a tape cartridge that enables sensing circuitry within the tape drive to distinguish between two different types of tape cartridges in otherwise identical form factors.
U.S. Pat. No. 5,480,103 (Gerfast et al.) discloses mutually incompatible mechanical cartridge lockout mechanisms incorporated into tape cartridges of the same form factor to mechanically distinguish between tape cartridges containing magnetic tape with different recording characteristics. In operation, the first tape cartridge can not be inserted into the tape drive for reading the second tape cartridge. Conversely, the second tape cartridge can not be inserted into a tape drive for reading the first tape cartridge.
Digital linear tape drives of the type sold under the “DLTtape” trademark are the most popular backup drives on the market today. As the drive and cartridge technology evolves to incorporate magnetic tapes with different recording characteristics, it is desirable for the new drives to be backwardly compatible with the enormous number of existing digital linear tape cartridges in use. In some circumstances, however, a fail-safe mechanical incompatibility is necessary to prevent new tape cartridges with magnetic tape having different recording characteristics for the new tape drive from being inadvertently used in an older style tape drive that might destroy data written on the tape by a newer drive.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to a system for controlling the compatibility of first and second tape cartridges having the same form factor in first and second tape drives. The present system permits backward compatibility of the first tape cartridge in the second tape drive, while prohibiting the second tape cartridge from being used in the first tape drive.
In one embodiment, the first and second tape cartridges each include a housing with an access door extending across a portion of a front face, and a recess along a portion of a side face and a door latch positioned adjacent to the recess and a pivot axis of the door. The first and second tape drives each have a door actuator assembly positioned in a cartridge interface. Each of the door actuator assemblies includes a ramp to unlock the door latch on the first and second tape cartridges and a door actuator surface to open the doors on the first and second tape cartridges as tape cartridges are inserted along an insertion direction, such that the first tape cartridge is compatible with the first and second tape drives. The door actuator assembly on the second tape drive has a gap extending along the insertion direction between the ramp and the door actuator surface. The second tape cartridge comprises a tab projecting distally from the recess. The tab is positioned to contact the door actuator surface on the first tape drive so as to prevent insertion of the second tape cartridge into the first tape drive. The tab defines a cross-sectional area perpendicular to the insertion direction smaller than the gap to permit the second tape cartridge to be inserted into the second tape drive, whereby the second tape cartridge is compatible only with the second tape drive.
In one embodiment, the first and second tape cartridges contain magnetic tape with different recording characteristics. The second tape drive typically distinguishes the first tape cartridge from the second tape cartridge by recording characteristics on magnetic tape contained therein. The tab can be integrally molded into the housing of the second tape cartridge.
The present invention is also direct to a housing for a second tape cartridge having the same form factor as a housing for a first tape cartridge. The first and second housings each include an access door extending across a portion of a front face and a recess along a portion of a side face. A door latch is positioned adjacent to the recess and a pivot axis of the door. The housing for the second tape cartridge comprises a tab projecting distally from the recess. The tab is positioned to contact a door actuator assembly on a first tape drive so as to prevent insertion of the second tape cartridge into the first tape drive along an insertion direction. The tab defines a cross-sectional area perpendicular to the insertion direction smaller than a gap in a door actuator assembly of the second tape drive to permit the second tape cartridge to be inserted into the second tape drive, whereby the first tape cartridge is compatible with the first and second tape drives and the second tape cartridge is compatible only with the second tape drive.
In another embodiment, the system for controlling the compatibility of first and second tape cartridges having the same form factor in first and second tape drives includes a first tape drive having a drive clutch with a first diameter and the second tape drive having a drive clutch with a second diameter smaller than the first diameter. The first and second tape cartridges each include a housing containing a hub with magnetic tape. The housing of the first tape cartridge has an opening larger than the first diameter to permit mechanical coupling of the hub in the first tape cartridge with the drive clutch in the first and second tape drives. The housing of the second tape cartridge comprises an opening larger than the second diameter and smaller than the first diameter to permit mechanical coupling of the hub in the second tape cartridge with the drive clutch in the second tape drive, but not the first tape drive, whereby the second tape cartridge is compatible only with the second tape drive.
In another embodiment, the system for controlling the compatibility of first and second tape cartridges having the same form factor in first and second tape drives includes the first tape drive having a drive clutch with a plurality of teeth and the second tape drive having a drive clutch with a plurality of teeth and at least one flat region at or below a plane defined by valleys of the teeth. The first tape cartridge includes a housing containing a hub with magnetic tape. The hub of the first tape cartridge has a plurality of teeth capable of meshing with the teeth on the drive clutch of the first and second tape drives. The second tape cartridge includes a housing containing a hub with magnetic tape. The hub of the second tape cartridge has a plurality of teeth and at least one flat region located above a plane defined by valleys of the teeth and corresponding to the flat region on the drive clutch of the second tape drive, whereby the second tape cartridge is compatible only with the second tape drive.
REFERENCES:
patent: 3907230 (1975-09-01), Merle et al.
patent: 4159811 (1979-07-01), Grant
patent: 4333618 (1982-06-01), Seaman
pa
Dennis, II Charles L.
Johnson Douglas W.
Johnson Michael W.
Imation Corp.
Levinson Eric D.
Rivera William A.
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