Abstract: A pager system connectable to the existing telephone wiring for activation through the normal residential DTMF telephone instruments, the system including a plurality of pager devices, each connected to the phone line between the tip and ring wires, and each pager including an identification circuit to allow it be individually addressed by a person using the phone, whether or not connection has been made through the central office. For use of the system, the keypad of the telephone instrument is used to enter a sequence of characters (e.g., symbols as well as numbers), which comprise an activation sequence. The DTMF activation sequence includes three parts: a header, a pager address (pager identification PID) and a signal identification (SID). The header portion is a sequence which is not used by the central office as part of its available services. The header portion is a system enabling signal that distinguishes the pager system from central office sequences.

Abstract: There is described a tape format and a method for formatting a length of magnetic tape with a number of system zones. Each system zone contains an area for mechanical load/unload operations or threading operations and an area containing volume format information for the entire magnetic media.

Abstract: A system for recording and reproducing data including user data on a magnetic tape having a number of partitions in which recording can be performed, the tape having at least one system zone in which user data is not recorded, the system having a table of data located near the beginning of the tape and near each system zone with the table including data identifying the physical location of the system zones and partitions and other sections of the tape.

Abstract: A helical type tape recording and reproducing system records blocks of user data of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape. Each physical block is recorded as a double frame on a set of successive helical tracks, preferably 32 tracks. Each double frame has system format data interleaved with the user data. The present invention is directed to system format data that includes a sequence number for each physical block and enables the system to determine during reproducing if any physical block has been lost. The system also includes a partition access bookkeeping feature that stores information relating to locations at which searching or recording has been performed during a current load of a tape in the system, which is useful in accomplishing efficient searching for user data recorded on the tape.

Abstract: A helical type tape recording and reproducing system records blocks of user data-of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape. The system format includes helical tracks in which user data blocks are recorded and longitudinal tracks for storing address information relating to the physical layout of the tape and to the content of the recording in the helical area. The system includes a partition access bookkeeping feature that stores information relating to locations at which searching or recording has been performed during a current load of a tape in the system, which is useful in accomplishing efficient searching for user data recorded on the tape. The present invention is directed to system search capabilities, including longitudinal searching along the tape and searching in the helical recording area of the tape.

Abstract: A recording and reproducing system which has the capability of recording user data and system format data in physical blocks of predetermined size on a recording area of a tape, with the user data being identified by files and contained in data blocks having a predetermined size. Partial overrecording of data blocks can be performed in that physical blocks are retained which have valid data blocks, and new physical blocks are then recorded beginning with a rewritten data block.

Abstract: Separations between the end of one data file and the beginning of the next data file are recognized, without utilizing an entire data storage block by means of a controlling program for a peripheral recording device monitoring the control information headers of helically stored data on a recording tape. When files are stored on the recording tape, the controlling program increments an increase of a file section number by one and increments to zero a data block number at the beginning of a new data file. When the recording device is reading the recording tape and there is detected an incrementation of the file section number and a zero value for a data block number, a recognition is made that this data indicates the end of one data file and the beginning of another data file.

Abstract: There is described an information area of a system zone and a method for formatting a length of magnetic tape with a plurality of information areas containing volume format information for the entire tape volume. The information area contains an area for storing volume format parameters and an area for storing a volume format table generated from the volume format parameters.

Abstract: A helical type tape recording and reproducing system records blocks of user data of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape. Each physical block is recorded as a double frame on a set of successive helical tracks, preferably 32 tracks. Each double frame has system format data interleaved with the user data. The present invention is directed to system format data that includes a sequence number for each physical block and enables the system to determine during reproducing if any physical block has been lost. The system also includes a partition access bookkeeping feature that stores information relating to locations at which searching or recording has been performed during a current load of a tape in the system, which is useful in accomplishing efficient searching for user data recorded on the tape.

Abstract: A method for formatting a length of magnetic tape into a plurality of partition areas to enable data storage in any of these areas and for formatting on the magnetic tape a plurality of spaced system zones, by means of controlling programs of a recording device prompting a host computer system to input the number and spacing of the system zones and the length and number of the partitions to be formatted onto the magnetic tape. The programs also prompts the host computer system to select one of various options for placing a partitions on the magnetic tape.

Abstract: A helical type tape recording and reproducing system records blocks of user data of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape, with the physical blocks being recorded as double frames. Each double frame is recorded on a set of successive helical tracks, preferably 32 tracks. Each double frame has system format data interleaved with the user data block data which identifies the double frame as being of a particular type. The present invention is directed to the types of double frames that are used to begin a recording, particularly an append recording which involves recording by the system at a previously recorded tape which may have been recorded by a different system, as well as the types of double frame that are used to end a recording.

Abstract: A system for recording and reproducing data including user data on a magnetic tape having a number of partitions in which recording can be performed, the tape having at least one system zone in which user data is not recorded, the system having a table of data located near the beginning of the tape and near each system zone with the table including data identifying the physical location of the system zones and partitions and other sections of the tape.

Abstract: A recording and reproducing system records blocks of user data of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape. Each physical block is recorded as a double frame on a set of successive helical tracks, preferably 32 tracks. The system has the capability of verifying whether a physical block has been accurately recorded, and if not, the system automatically rewrites the physical block downstream without stopping or repositioning the tape. If an accuracy verification confirmation does not occur until a next physical block is being recorded, the system demarks or invalidates that physical block being written, and rewrites both the failed physical block and that following physical block downstream of that physical block being written.

Abstract: A tape data recording and reproducing system is disclosed which has an over-writing capability which can result in previously recorded data continuing to exist on the tape after the over-writing has been completed. The present invention uses cyclical redundancy check data that is normally recorded with the data to determine if the data recovered during reproducing is valid data.

Abstract: A tape recording and reproducing system records blocks of user data of predetermined size by reformatting the user data blocks into physical blocks that are recorded on tape. Each physical block is recorded as a double frame on a set of successive helical tracks, preferably 32 tracks. The system has the capability of verifying whether a physical block has been accurately recorded, and if not, the system rewrites the physical block downstream without stopping or repositioning the tape. If an accuracy verification confirmation does not occur until a next physical block is being recorded, the system demarks or invalidates that physical block being written, and rewrites both the failed physical block and that following physical block downstream of that physical block being written.

Abstract: A method and system are provided for generating a synchronized handshake between communicating parts of a digital system operating from a common clock. A request signal is sent from an initiating station to a responding station. The responding station acknowledges receipt of the request by sending an acknowledge signal back to the initiating station, thereby completing a so-called handshake. In accordance with the invention both the request and acknowledge signal are pulses of a fixed duration greater than one but less than two clock cycles. A new request signal may be transmitted concurrently with the reception of an acknowledge signal, resulting in a maximum handshake rate of one half of the common clock rate.