 Monitoring plural process control stations |
| We claim: 1. A monitoring system for process controllers with error recognition and compensation in ... |
|
| Arbitration circuitry for deciding access requests from a multiplicity of components |
| We claim: 1. In a data-handling system with a multiplicity n=2.sup.m of components of different ... |
|
| Ensuring data integrity by locked-load and conditional-store operations in a multiprocessor system |
| In accordance with one embodiment of the invention, a high-performance processor is provided which ... |
|
| Multiplexing communication card and scanning method for run-in testing |
| i The present invention provides a multiplexing communication card and scanning system for testing ... |
|
| Fixture for motor controller power substrate and motor controller incorporating |
| In accordance with a first aspect of the invention, a fixture is provided for securing conducting ... |
|
| Asynchronous digital time-division multiplexing system with distributed bus |
| What we claim is: 1. An asynchronous digital time-division multiplexing system, comprising (a) ... |
|
| Method for executing overlays in an expanded memory data processing system |
| OF THE INVENTION FIG. 1 shows an Expanded Memory System (EMS). The system includes a one megabyte (... |
|
| Robot program checking method |
| An object of the present invention is to provide a robot program checking method which permits ... |
|
|
Method of reading digital data on magnetic tape
| Details |
Inventors: Saitoh, Shuichi;
Assignee: TEAC Corporation (Tokyo, JP)
Primary Examiner: Dzierzynski; Paul M.
Assistant Examiner: Hanig; Richard
Attorney, Agent or Firm: Woodcock Washburn Kurtz Mackiewicz & Norris
A reading method for a magnetic tape having a series of frames each constituted of a predetermined number of data blocks. For reading any given frame of the tape more quickly than heretofore in the face of a possible read error or errors, there is employed a buffer memory capable of temporarily storing the data from one complete frame preparatory to delivery to a host system. As the succesive blocks of the frame are read by an electromagnetic transducer, the data from each block is checked for an error by a check signal read from that block, and the data from only those blocks where no read error has been found are written on the buffer memory. Then, in event a read error has been found on more than a predetermined number (e.g. one) of blocks, all the blocks of the same frame are reread. During this rereading, the data from only those blocks where a read error has been found during the initial reading are checked for an error and written on the buffer memory if no error has been found. The rereading of the same frame may be repeated up to a predetermined number of times until a read error becomes found on not more than the predetermined number of blocks. |
|
DETAILED DESCRIPTION I have hereby invented how to read digital data written in the standard format on a magnetic tape, more quickly than heretofore in the face of possible errors that will occur in reading each tape frame.
Briefly, my invention may be summarized as a reading method for use with an apparatus having a transducer for reading digital data on a magnetic tape having a series of frames each constituted of a predetermined number of blocks, each block having stored thereon the digital data along with a check signal for checking the data read from that block for a read error.
The reading method of my invention involves the use of a temporary storage device capable of storing at one time the data from at least one complete frame of the tape.
According to the method of my invention, as the successive blocks of any given frame are read by the transducer, the data from each block is checked for an error by the check signal read from that block, and the data from only those blocks where no read error has been found are written on the temporary storage device.
All the blocks of the same frame are reread in event a read error has been found during the initial reading.
During the rereading, however, the data from only those blocks where a read error has been initially found are checked for an error and written on the storage device if a read error has not recurred.
The rereading of the same frame may be repeated as required up to a predetermined number (e.
g.
sixteen) of times.
Thus the average reading time for each frame according to the method of my invention is far less than that according to the prior art method that involved the rereading of each block where a read error has been found.
Usually, with this type of digital magnetic tape, each frame has an error check and correction block in addition to data blocks on which the digital data to be read are stored.
The error check and correction block has stored thereon an error check and correction signal whereby, in event a read error has occurred on only one of the data blocks of the frame, that error can be corrected automatically
|
| Related patents |
|
|
Method and apparatus for synchronizing disk drive requests within a disk array
There is provided, in accordance with the present invention, a method and apparatus for generating a single request signal for a logical storage unit including all or a ...
|
|
|
Method and apparatus for an enhanced computer system interface
It is therefore an object of the present invention to provide an improved interface, based in part on the proposed SCSI-2 standard, by which multiple-byte commands, ...
|
|
|
Data processing device having an expandable address space
In the aforementioned CPU, however, the address register has a length of 16 bits, and the memory to be referred to by the CPU has a capacity of 65,536 bytes (=2.sup.16 ...
|
|
|
Single-chip mircocomputer with clock-signal switching function which can disable a high-speed oscillator to reduce power consumption
It is, therefore, an object of the present invention to overcome the problem existing in the conventional arrangement and to provide an improved single-chip ...
|
|
|
Apparatus and method for reading helically recorded tracks and rereading tracks as necessary
OF THE DRAWINGS A helical-scan drive system 10 for recording on and reading magnetic tape 12 is illustrated in FIGS. 1 and 2. A drum 14 is angularly oriented with ...
|
|
|
Tri-statable bus with apparatus to drive bus line to first level and then second level for predetermined time before turning off
An improved high speed bus with virtual memory capability is disclosed. The bus has particular application in computer systems which employ peripheral devices. The bus ...
|
|
|
Method of compactly storing digital data
This invention provides a method of storing digital data in a compact manner which includes the steps of sequentially entering a plurality of digital data entries into a ...
|
|
|
Method, device and microprocessor for selectively compressing video frames of a motion compensated prediction-based video codec
OF A PREFERRED EMBODIMENT A video sequence consists of individual images, or frames, of video data which are two dimensional representations of a three dimensional ...
|
|
|
Bus control for small computer system interface with transfer indication preceding final word transfer and buffer empty indication preceding receipt acknowledgement
Accordingly, it is an object of the present invention to provide a SCSI bus control which has overcome the above mentioned defect of the conventional one. Another object ...
|
|
|
Universal device for coupling a computer bus to a controller of a group of peripherals
We claim: 1. A universal device for coupling a computer bus of a computer to a controller of a group of peripherals connected to one another by a specific link to which ...
|
|
|
I/O Systems 
