Abstract:
A magnetic tape cartridge includes a non-volatile semiconductor memory storing either a portion of the same data as that to be written to the tape or at least control data sufficient to recover from a delaying tape drive operation or from a mechanical failure in the tape drive thereby permitting signaling to a central processing unit an assurance that the data transferring by the CPU will be correctly written onto the tape. The host data can be directly transferred to the cartridge memory if the cartridge memory is fast enough and large enough to handle the transfer. An intermediate high speed non-volatile memory in the drive is necessary if the cartridge memory is too slow to handle the direct transfer or too small to handle the data transferred by the CPU. The cartridge memory then will contain command data sufficient to control the transfer of the data from the non-volatile drive memory to the tape. Thus the CPU can be assured that the host data sent to the tape drive will be preserved irrespective of any tape drive failure or delaying motion.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to a cassette for containing a magnetic tape. More specifically, the present invention relates to a cassette (i.e., cartridge) which contains a magnetic tape and a non-volatile semiconductor memory with the semiconductor memory storing either the same data as that on the tape or at least data sufficient to recover from a mechanical failure in the drive. 
     FIELD OF THE INVENTION 
     As is well known, magnetic tape cassettes have been extensively used for storing data in a data processing system. The tape cassette is used in association with a data recording/reproducing device which is interconnected with a host computer to store data required by the host computer perhaps in a later processing operation. The data is magnetically written onto the tape in serial fashion on what could be a plurality of such data tracks in one tape cartridge. The serialization of the data onto the tape is generally much slower than the data transfer in the host computer. It is common practice to employ an electronic data buffer between intermediate data units such as the host computer and the recording and reproducing apparatus for enhancing data exchanges between the units. It has been found particularly advantageous to provide an electronic buffer between an electromechanical data processing device and a completely electronic data processing unit. This is an example of, for instance, a magnetic tape drive coupled to a central processing unit including the host computer. The idea is to mask or hide the relatively slow electromechanical device action from the electronic data processing unit. 
     This has led to the practice of first storing all of the data for the magnetic tape device onto a buffer and then transferring the data at a later time or at the leisurely operation of the tape device to the magnetic tape. The electronic data buffer is interposed between the CPU and the magnetic tape drive. The buffer memory could be shared by a plurality of the tape drives such that the number of buffer storage segments of the buffer is less than the number of tape drives. Then there became a problem where the volatility of the data in the buffer caused a loss of data when the power was interrupted in the CPU. Non-volatile read/write memory was then provided as the buffer unit wherein the data was permanently stored in the non-volatile memory until further action could be taken to either write the data from the non-volatile memory onto the tape or to continue action of reading the data from the magnetic tape to the non-volatile memory. However, there are problems that current buffer tape drives cannot handle even with an intervening non-volatile data buffer. It is difficult in any intermediate buffer system to ensure the data is safely on the tape cartridge or that the data has been safely removed from the cartridge and can still be accessed by the CPU. 
     It is, therefore, an object of the present invention to provide a method and apparatus for providing a tape cassette which includes the magnetic tape and a non-volatile read/write memory on the cartridge itself. The non-volatile read/write semiconductor memory accepts the data from the CPU and then either transmits the data from the non-volatile memory to the tape drive or stores sufficient data as a backup to accomplish an eventual transfer of the data by the tape drive system to the tape. 
     DESCRIPTION OF THE PRIOR ART 
     Prior to the present invention, tape cassettes or cartridges having non-volatile memory packages mounted onto the cartridges stored only status data of the tape cartridge for usage by the tape drive to assess the value or the placement of the data. For instance, U.S. Pat. No. 5,606,467, issued on Feb. 25, 1997 to H. Hirata, and entitled, “Apparatus For Continuously Recording and Reproducing of Data From a Magnetic Tape Cassette Comprising A Semiconductor Memory”, discloses a tape drive which includes a semiconductor memory that outputs signals reproduced from the semiconductor memory for providing a continuation of the audio sounds such as music when the magnetic tape is in a reversal mode or is switching between channels. The semiconductor memory stores a particular signal which is generally not the same as the data stored on the magnetic tape. The purpose is not to provide safety in the storage of the data such as is a requirement in a CPU but to provide a continuous operation without a hesitation. 
     It is, therefore, another object of the present invention to provide a method and apparatus for overcoming any data transfer problems in a data processing unit that can be caused by mechanical motion problems in the tape drive itself. 
     U.S. Pat. No. 4,338,644, issued on Jul. 6, 1982 to T. C. J. L. Staar and entitled, “Magnetic Tape Cassettes Provided With Memory Circuits For Storing Information” discloses the use of electronic memories including semiconductor circuits mounted in a cassette housing for storing data relating to the media stored in the housing. The semiconductor memory circuits represent the status of the memory circuits, the information as to the media contained within the cassette, such as text information identifying the cassette, its length, its magnetic bias and equalization value, or the titles of the recordings on the tape in the form of an index or listing. The semiconductor memory can accept rating signals that represent information which changes or which the user may desire to change such as the instantaneous position of the tape, the location of different programs recorded on the media, or the data fields recorded on the media. Thus, in the ‘644’ patent, the semiconductor memory only stores information pertaining to the present status of the media and the cassette or to control the operation of the recording device when the cassette is installed into that device. There is no showing in the ‘644’ patent, and which is required in a data unit, of a semiconductor memory associated with the cassette that ensures that the data is guaranteed to be on the tape. There is no showing in the ‘644’ patent of the use of a semiconductor memory in a media cartridge that can ensure to a host computer that the data is correctly recorded on the media, or will correctly be recorded on the media, or that the data has been transferred from the media to a separate buffer device. 
     U.S. Pat. No. 5,899,576 issued on May 4, 1999 to K. Fukuzawa, and entitled, “Apparatus For Recording And Reproducing Data On And From A Storage Device Having A Plurality Of Kinds Of Storage Media Integrally Provided Therein”, discloses a method of copying data from both a magnetic tape and a non-volatile memory on the tape cassette to the recording apparatus. The data in the non-volatile memory includes information of the content of the recorded data on the tape and does not contain information about the guarantee of having the required data on the tape. 
     U.S. Pat. No. 5,784,227, issued on Jul. 21, 1998 to H. Kitamura, et al, and entitled, “Tape Cassette Mounted With IC Memory Package and IC Connecting System For The Tape Cassette” and a Japanese abstract of application JP07314675, filed on Nov. 8, 1995 by Y. Takayama, et al, and entitled, “Data Recording And Reproducing Device” both disclose methods of interfacing a tape cassette including a non-volatile memory to a drive and do not disclose usages of the data in the non-volatile memory to solve streaming data drive problems. 
     SUMMARY OF THE INVENTION 
     In the preferred embodiments of the present invention, a data processing system having a host central processing unit connected to at least a tape drive storage device which includes a non-volatile semiconductor memory located on the tape cartridge storing either a portion of the same data as that to be written to the tape or at least control data sufficient to recover from a delaying tape drive operation or from a mechanical failure in the tape drive thereby permitting signaling to the host central processing unit an assurance that the data transferring by the host will be correctly written onto the tape or at least correctly stored. The host data can be directly transferred to the cartridge memory if the cartridge memory is fast enough and large enough to handle the transfer. An intermediate high speed non-volatile memory in the drive is necessary if the cartridge memory is too slow to handle the direct transfer or too small to handle the data transferred by the CPU. The cartridge memory then will contain command data sufficient to control the transfer of the data from the non-volatile drive memory to the tape. Thus the CPU can be assured that the host data sent to the tape drive will be preserved irrespective of any tape drive failure or delaying motion. 
     In accordance with the present invention, method and apparatus are provided for hiding mechanical motion in a tape drive which can cause delays in the transfer of data to an attached CPU or from a CPU by storing the control information and data in a non-volatile memory located in the magnetic tape cartridge. The non-volatile memory on the magnetic tape cartridge is used as a buffer to store the control information and the data to avoid backhitch or other mechanical motion problems. The invention specifically is to the data stored in the non-volatile storage device that is physically a part of the media cartridge data that is useful in association with a CPU. The non-volatile storage device can be used to hold information about that specific media cartridge, the media and the cartridge, and the data on the media. 
     Accordingly, one of the principle objects of this invention is to overcome the disadvantage of conventional cassettes containing information for data processing equipment by providing a semiconductor non-volatile memory associated with the cassette that ensures that the data in the cassette is prepared to be safely stored onto the tape cartridge. The control information of data useful to the host processor is stored in a non-volatile memory such as a semiconductor memory attached to the media tape cartridge. The non-volatile memory on the cartridge acts as a buffer to store control information and data, to avoid backhitch tape stoppage or other mechanical motion problems. After the control information is written to the cartridge media, subsequent host data sent from the host is stored in the buffers associated with the cartridge drive units. When the tape drive is resynchronized from the backhitch or a mechanical motion error, the control information is first written to the media from the cartridge memory and the host data is then written from the buffer to the media. Thus, the data transfer from the host processor is not affected by the mechanical motion situations encountered in the drive units. The non-volatile memory is electrically alterable so that the data can be changed to represent the present information of the cartridge, its associated drive unit, the buffer units temporarily storing the data, and the host processing unit. 
     In many tape device applications for use to transfer data to or from a central processing unit, in order to ensure that the data is guaranteed to be on tape, the tape drive buffer must be emptied frequently. This ensures a reliable checkpoint but at a lowering of the data transfer performance. Non-volatile tape buffer memories are now required to be larger requiring longer backhitches (back or reverse drive motions) to ensure the correct data transfer. As a result, performance suffers. 
     This invention is directed to the use of non-volatile semiconductor memory located on the cartridge itself to solve this problem. If there is a high speed interface to the non-volatile cartridge memory, then the data is directly written to the non-volatile cartridge memory when a synchronize buffer command is received from the CPU. Interlocks like a unique key, append point, and time storage could be used to ensure format integrity. As soon as all the data is written to the non-volatile memory on the cartridge, the system application could resume command processing which could typically be more transfer of data to the tape cassette or tape cartridge. 
     The second aspect of the invention is related to the use of a low speed interface to the non-volatile memory on the cassette cartridge. A non-volatile high-speed drive memory is used and must be capable of storing all of the tape cassette data. When a synchronize of the buffer command is requested by the CPU, all of the data is written to the non-volatile drive memory. Interlocks like a unique key, append point, and time stamp might be used to ensure format integrity. Once the data is all written to the drive non-volatile memory, the command processing application is resumed. If a permanent write error or temporary power loss occurs before the data that is located in the non-volatile drive memory could be written successfully to the tape medium in the cassette, the data is directly written to the non-volatile memory in the cassette. In the case of a permanent write error, the data would be written to the cartridge non-volatile memory before reporting the permanent error. In the case of a power loss, the data would be written to the non-volatile cartridge memory before unloading the tape. This alternative aspect of the invention simplifies tape error recovery, since the data would not have to be recovered out of the non-volatile drive buffer. After the control information is written to the cartridge memory, subsequent host data sent from the host CPU is stored in the tape drive buffers. When the tape drive is resynchronzied from the backhitch or other mechanical motion, the control information is first written to the magnetic tape from the cartridge memory. The host data is then written from the tape drive buffer directly to the tape media. Thus, the data transfer from the host CPU is not affected by the mechanical motion problem encountered in the tape drive. 
     The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a magnetic tape cartridge constructed in accordance with a preferred embodiment of the present invention, particularly illustrating the arrangement of respective components in the cartridge; 
     FIG.  2 . is a perspective view of a corner of the cartridge of FIG. 1 including the non-volatile memory of the present invention; 
     FIG.  3 . is a block diagram schematically illustrating the use of the non-volatile cartridge memory in a data processing system; 
     FIG. 4 is a flow chart of one solution for use of the cartridge and its non-volatile memory in association with a data processing system using the data processing system of FIG. 3; 
     FIG. 5 is a flowchart showing the general process of the invention using the data processing system of FIG. 3; 
     FIG. 6 is a block diagram schematically illustrating an alternate embodiment of the invention; 
     FIG. 7 is a flowchart showing the process of the invention using the media drive and control in the data processing system of FIG.  6 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will be described in detail hereinafter with reference to the accompanying drawings, which illustrate preferred embodiments of the present invention. In the drawings, FIG. 1 is a plan view which illustrates a cartridge useful to the present invention. FIG. 1 shows a general view of a tape cartridge housing  10  including the different sides of the cartridge itself. The side of interest is the left side  12  as shown in FIG.  2 . Referring to FIG. 2, the left side  12  of the cartridge  10  is the interface side and includes a leader block  14  held in a receiving well  16  in one corner of the cartridge. The cartridge of FIG. 1 includes a single reel tape cartridge (not shown) for an automatic threading tape drive. The reel includes layers of magnetic tape with the leader block attached to the free end of the tape. The leader block  14  is held in the receiving well  16  in one corner of the cartridge when the cartridge is out of the tape drive. The leader block  14  connects with a threading pin  18  in the threading tape drive (not shown) for threading the tape through the drive to a take-up reel hub. The leader block  14  includes a conforming section that fits the leader block into a channel of the tape drive. Reference is made to U.S. Pat. No. 4,426,047 issued on Jan. 17, 1984, and assigned to the assignee of the present invention to show a more complete outline of a tape cartridge with a leader block and a tape drive that can be useful with interfacing with the tape cartridge. The tape cartridge also includes on its left side  12  as shown in FIG. 2 a non-volatile memory store  20  generally being a semiconductor memory firmly mounted to the left side  12  of the cartridge housing  10 . 
     The magnetic tape cartridge of the present invention is entirely the same as many single reel conventional cartridges in structure with respect to the aforementioned elements. A characterizing feature of the magnetic tape cartridge resides in the semiconductor memory which makes it possible to perform a recording/reproducing operation in response to an electrical signal transmitted from the outside of the magnetic tape cartridge. The semiconductor memory  20  is incorporated in the cartridge  10  on its left side as shown in FIG. 2 in order to be positioned to interface with the tape drive as will be discussed in more detail later. U.S. Pat. No. 5,606,467, previously discussed in the Prior Art section of this document shows the potential interconnection between a semiconductor memory and the tape drive and is useful for an understanding of the possibility of the interconnection, it not being a part of this invention to discuss how the interface occurs. The interface of the cartridge of FIGS. 1 and 2 is further discussed with respect to the present invention as disclosed in FIG.  3 . 
     FIG. 3 illustrates a peripheral subsystem  21 , in simplified form, connected to a host CPU  22  for transferring data signals between such hosts and one of what could be a plurality of tape recording devices  24 . Data signals are exchanged directly with the host  22  over input/output connections. Including in the peripheral subsystem  21  is a data buffer  26 . It is, of course, obvious that other units are required within the peripheral subsystem  21 . Reference is made to U.S. Pat. No. 4,428,064, issued on Jan. 24, 1984 to Hempe, et al and assigned to the assignee of the present invention, for a more thorough discussion of the control of data transfer between the host and the recording devices  24 . Suffice it to say that a control unit  28  under control of the host  22  controls the operations within the peripheral subsystem  21 , specifically the data buffer  26 . The operation of the peripheral subsystem  21  is such that data signals are transferred from the recording device  24  to the data buffer  26 , hence to the host  22  or in the reverse direction from the host  22  through the data buffer  26  to the recording devices  24 . The use of the data buffer  26  provides shorter data access, better input/output channel utilization and, therefore provides more efficient data processing operations. 
     Still referring to FIG. 3 the recording device  24  includes a read/write circuit  32 , a transducer  34  and a take-up reel  36 . The regulation of a length of tape  38  from the cartridge  10  is better described in a U.S. Pat. No. 4,406,425, issued on Sep. 27, 1983 to Bullock, et al, entitled “Method and Apparatus For Regulating Webs Transported In A Reel-to-Reel Web Handler” and assigned to the assignee of the present invention. The semiconductor memory within the cartridge  10  is connected by leads to an interface  12  which is on the outer surface of the tape cartridge  10 . The interface  12 , when the tape cartridge  10  is inserted into the recording device  24 , is placed adjacent to a connector  40  which transfers information into the semiconductor memory  20  and reads information from the semiconductor memory  20 . 
     In FIG. 3, the standard portions of the data processing system without the present invention is the host  22  transferring information to and from a data buffer  26  in the peripheral subsystem  21 . The data buffer  26 , in turn, transmits data to the read/write circuitry  32  in the recording device  24 . The read/write circuits  32 , in turn, transmit the information to and from the transducer  34  for reading and writing the data information onto the tape  38 . For the present invention, the host  22  transmits drive data information into a drive buffer  30  which is connected to a connecting device  40  in the recording device  24  via the control write circuit  32 . The non-volatile semiconductor memory  20  within the cartridge  10  is used as a buffer to store control information and data to avoid the backhitch problems of the tape drive or other mechanical motion operations. After the control information from the host  22  to the drive buffer  30  is written to the semiconductor memory  20 , subsequent host data sent from the host is stored in the magnetic tape drive buffers  30 . When the tape drive is resynchronized after the backhitch or other mechanical motion error, the control information is first written to the magnetic tape from the cartridge memory  20  and host data is then written from the tape drive buffer  30  to the tape  38 . Thus the data transfer from the host processor is not affected by the mechanical motion situations encountered in the tape drive  24 . The data buffer  26  retains all of the required data for storage onto the tape cartridge until the mechanical problems in the recording device  24  are solved and the host  22  has been assured that all the information is stored outside of its control and the information in the semiconductor memory  20  can take over and further control direct the further transfer of the information onto the tape  38  for storage into the tape cartridge  10 . Reference is made to FIG. 4 for a flow chart showing the transfer of data to protect against any mechanical problem into the recording device  24 . Referring to FIG.  3  and to FIG. 4, the host  22  starts to transfer information for writing onto the tape  38 . In the writing of the data besides the data itself, drive information is transmitted to the drive buffer  30  from the host  22  and transmitted to the connecting device  40 . This drive data is stored in the semiconductor memory  20 . 
     In FIG. 4, while using the block diagram of FIG. 3, the writing of the data from the host  22  signals a write operation as shown in block  60  and the data required to continue the operation to completion is stored in the drive buffer  26  as shown in block  64 . As shown in a block  60 , the host signals the start of the write operation. After the drive data is placed into the drive buffer  30  as shown in block  64 , the decision block  66  is triggered to look for a synchronized buffer command completion to signal that all of the data has been transferred. If the synchronized buffer command from the drive buffer  30  has not been received, the data is continued to be buffered into the drive buffer  30  as shown in block  64 . When this buffer command signals that the drive buffer information is emptied and complete, the YES branch is taken from the synchronized buffer command block  66  to a block  70  where the drive buffer  30  information is transferred for storage into the semiconductor memory  20  as shown in block  70 . In a decision block  72 , the information is awaited and the drive buffer continues to transfer the information to the cartridge until the drive buffer  30  is empty. Then the YES decision line is taken from the decision block  72  to a block  74  where the lock and position information is placed into the cartridge semiconductor memory  20 . As shown in block  76 , this completes the transfer of the required information from the host  22  to the semiconductor memory  30  of the data sufficient to ensure to the host that all of the data information that the host  22  transferred to the data buffer  26  will eventually be written onto the tape  33  in the cartridge  10 . The recording device  24  may be in a mechanical position where the tape itself is not being driven or is in a vacuum operation, but the host  22  is assured that the data will eventually be placed on the tape based on the information now stored within the semiconductor memory  20 . The semiconductor memory  20  after this sequence controls the operation of the transfer of the data from the data buffer  26  to the tape  38  by the connecting device reading the information from the semiconductor memory  20  and controlling the continuation of the write operation which, after the problems are complete within the recording device  24 , causes the write operation and the reeling of the tape  38  past the transducer  34  and all of the data information is transferred to the tape  38  irrespective of the problems within the recording device  24 . 
     After the data is written to the tape as shown in a block  76 , the flow continues to a decision block  78  to check whether all of the data has been transferred. After the data has been transferred, the YES line is taken from the decision block  78  to a block  79 . In the block  79 , the lock placed into the cartridge non-volatile memory  20  in block  74  is removed. The cartridge memory  20  is freed to permit another write operation to start from the block  60  to buffer further data into the drive buffer as shown in the block  64 . The lock information is placed into the cartridge memory  20  and is a unique key value for each tape cartridge. The position information is the starting block address and the ending block address of the data to be transferred to the tape. An alternate procedure to the procedure of FIG. 4 is shown in FIG.  5 . 
     In FIG. 5, again, after the host signals a write operation as shown in a block  80 , the drive information is placed into the drive buffer  26  as shown in a block  81  which is similar in operation to the block  64  of FIG.  4 . The synchronized buffer command decision block  66  for the transfer of data is the same as a synchronized buffer command decision block  82  in FIG.  5 . If the drive buffer synchronized command is not received, the data is continued to be placed into the drive buffer  26 . After the synchronized buffer command is received showing the end of the transfer of data, the YES line is taken from the decision block  82  to a block  84  where the block and position information is placed into the cartridge memory in the same manner as shown in the block  74  of FIG.  4 . After the locking position information is transferred into the cartridge memory, the flow in FIG. 5 continues to a block  86  where the drive buffer data is transferred into the semiconductor memory  20  of the cartridge  10 . 
     The decision block  88  continues the emptying of the buffer until the drive buffer is empty and the YES line is taken. After the drive buffer information is emptied into an immediate buffer as shown in the block  88 , the flow continues to a decision block  90  to check whether there has been a power loss or a write failure. If there has not been a power loss or a write failure, the flow continues because it was not necessary to use the information from the semiconductor memory in order to continue the write operation. The data is written to the tape as shown in a block  96 . The flow continues until all of the data is transferred and the flow continues to a block  98  where the lock is removed from the non-volatile cartridge memory  20 . If, however, there was a power failure or a write failure in the decision block  90 , the YES line is taken from the block  92  to transfer the intermediate buffer into the cartridge memory  20  in order to store this information to ensure the host that sufficient information has been stored to ensure to the host that the actual data will be completed. The data information is transferred to the tape under control of the information in the semiconductor cartridge memory  20  as shown in block  94 . The information stored in the cartridge memory  20  contains sufficient drive information to continue the operation of the recording device after the mechanical stoppage. The flow continues to the block  96  to write the data to the tape and then to the block  98  to remove the lock from the cartridge memory  20 . An alternate embodiment of the invention for accomplishing the protection of the data and assuring the host that the correct information will eventually be stored onto the tape is shown in FIG.  6 . 
     In FIG. 6, a host CPU  100  directly transfers all of the data information that is to be written onto the tape into the non-volatile semiconductor memory  20  of the tape cartridge  10  through a connector  106 . The connector  106  interfaces directly to the cartridge memory  20 . After the data is stored in the cartridge memory  20 , the data is retrieved from the cartridge memory  20  through the interface to the connector  106  and is directed to a read and write circuit  108 . The circuit  108  then writes the data onto a magnetic tape  110  through a transducer  112 . The reading and writing onto the tape  110  takes place as the tape  110  is retrieved from the cartridge  10  as stated previously and wound onto a take-up reel  114 . Once all of the data required to be written by the host CPU  100  is stored into the cartridge memory  20 , the host CPU can be signaled that the data has been written onto the tape because any mechanical tape shifting such as backhitching or drive failures can be handled off-line in the tape recording device  102  without any further correspondence with the host  100 . A flow chart showing the process for accomplishing a write operation, responding to the block diagram of this embodiment in FIG. 6, is shown in FIG.  7 . 
     Reference now to FIG. 7, the host requests a write operation as shown at block  120 . The host CPU then sends the data directly to the cartridge memory  20  (see FIG. 6) as shown in block  122 . Essentially, this cartridge memory acts as a buffer data store. Data continues to be sent to the cartridge memory until all the data transmitted by the host is located in the cartridge memory as shown in a decision block  124 . The flow continues to a block  126  where the lock and position information is placed into the cartridge memory. The position information will be used to correctly locate the data onto the tape. At block  128 , the data in the cartridge memory is written onto the tape, immediately if no drive action has occurred that requires a delay or after the backhitch, for instance, is completed. If more data is to be written onto the tape, a decision block  130  signals the host as shown in block  120  to transfer more data. If the writing is completed, the NO line is taken from the decision block  130  to end the write operation. 
     As disclosed in this discussion of the preferred embodiments, a non-volatile semiconductor is placed directly on a tape cartridge to provide a quicker access time for the host CPU to write data onto a non-volatile storage location without causing a delay in the host write operation resulting from a mechanical tape drive hesitation. The tape drive problems could be a required backhitch operation to reposition the tape for a correct positioning of the data onto the tape or the problem could be a drive failure. In one embodiment, only data sufficient to permit the recovery of the tape drive is placed into the cartridge semiconductor memory. The data information to be written on the tape from the host is stored in a separate non-volatile store such as a disk drive. In the second embodiment, the cartridge memory stores all of the data to be written on the tape and the data is directed for writing on the tape when the tape drive is correctly positioned to actually write the data onto the tape. 
     It should be recognized that the cartridge memory for the first embodiment need only store a limited amount of data, that is, data sufficient to control the transfer of the buffered data for writing onto the tape. In the second embodiment, all of the data to be written onto the tape and the write control information must be stored in the non-volatile semiconductor cartridge memory. This understandably would require a large capacity store. One semiconductor memory usable in this invention is a Dallas Semiconductor EE PROM DS2433. This memory is electrically erasable and programmable read only memory. A second semiconductor memory usable in this invention is an INTRL Strata Flash (TRADEMARK) memory. 
     The principles of the present invention have now been made clear in an illustrative embodiment. There will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, the elements, materials and components used in the practice of the invention. For instance, there are other types of cartridges and cassettes that can be used with the invention such as reel-to-reel cartridges. Also the invention should not be limited to magnetic tapes and drives. It should be obvious that other storage media such as optical is equally adaptable to this invention. The appended claims are, therefore, intended to cover and embrace any such modifications, within the true spirit and scope of the invention.