Raw data reader

• US 5,375,224 A
• Filed: 09/02/1993
• Issued: 12/20/1994
• Est. Priority Date: 09/28/1990
• Status: Expired due to Term

• Current Assignee: Certance LLC (Chi Ko Investment Co., Ltd.)
• Original Assignee: Archive Corp. (Whitehouse Group Ltd.)
• Inventors: Larsen, Keith J., Hall, Raymond W.
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): MOHAMED, AYNI Y
• Application Number:
  US08/116,047
• Time in Patent Office: 474 Days
• Field of Search: 395/325, 395/400, 395/500
• US Class Current: 710/33
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0673 Single storage device
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 20/12 Formatting, e.g. arrangement of data block or words on the record carriers within interface between computers and data recorders G06F3/06
• CPC Class Codes: H03M 5/145 Conversion to or from block codes or representations thereof

Abstract

A raw data reader for reading a magnetic medium computer storage device wherein data is stored as binary bits, including a data conditioner responsive to the computer storage device for providing serial binary data representative of the binary data read from the magnetic medium and corresponding thereto on a one-to-one basis, a serial to parallel converter for providing parallel data that includes formatting control information contained in the serial binary data, a decoder for decoding the parallel data, and control circuitry responsive to the serial binary data and the formatting control information for transferring selected decoded data to the host computer.

Claims

1. An apparatus for transferring binary bits output by a magnetic storage device pursuant to serial reading of a series of recorded binary bits contained in a magnetic medium of the storage device, wherein the series of recorded binary bits includes user information and formatting information, and wherein the binary bits output by the magnetic storage device correspond on a one-to-one basis with the series of recorded bits read from the magnetic medium, the apparatus comprising:

serial means responsive to the binary bits output by the magnetic storage device for producing a serial bit-stream of binary data representative of each binary bit read from and output by the magnetic storage device;

conversion means for converting the serial bit-stream of binary data to a parallel data signal representative of each recorded binary bit read from and output by the magnetic storage device;

decoding means for decoding said parallel data signal to produce therefrom decoded parallel data that is representative of each binary bit read from and output by the magnetic storage device, the decoding means including distinguishing means for distinguishing unique formatting sequences from other bit sequences found within the parallel data signal and for producing position indicating signals indicating the position within the serial bit-stream of the unique formatting sequences, and for including within the produced decoded parallel data, distinguishing indicia distinguishing formatting information from user information; and

control and transfer means responsive to said position indicating signals for identifying boundaries of predetermined groupings of bits in the serial bit-stream of binary data and for transferring to a host computer corresponding samples of the decoded parallel data corresponding to said predetermined groupings, said transferred samples of the decoded parallel data signal being representative of each binary bit read from and output by the magnetic storage device so as to include and distinguish the user information and the formatting information contained in the series of binary bits read from and output by the magnetic storage device.

2. The apparatus of claim 1 wherein said control and transfer means includes:

boundary detecting means for detecting the occurrences of one or more predetermined sequences of formatting information indicative of a predefined boundary of said predetermined grouping of bits; and

transfer initiating means, operatively coupled to the boundary detecting means, for initiating said transfer of the corresponding samples of the decoded parallel data to the host computer upon detection of one of said predetermined sequences of formatting information.

3. The apparatus of claim 2 wherein said boundary detecting means includes means for detecting a plurality of gap marks followed by a synch mark, said sequence of formatting information being indicative of the start of a block of user data to be transferred to the host computer and wherein said transfer initiating means responsively initiates said transfer of the corresponding samples of the decoded parallel data to the host computer upon detection of the plurality of gap marks followed by a synch mark.

4. An apparatus for transferring a serial bit-stream of binary bits output by a serial storage device pursuant to serial reading of a series of recorded binary bits contained in a storage medium of the serial storage device, wherein the series of recorded binary bits includes formatting information and user information,

the apparatus comprising:

conversion means for converting the serial bit-stream of binary bits output by the storage device to a parallel data signal representative of each recorded binary bit read from and output by the storage device;

decoding means, operatively coupled to the conversion means, for decoding said parallel data signal and producing therefrom a decoded parallel data signal that is representative of each recorded binary bit read from and output by the storage device, the decoded parallel data signal including distinguishing indicia distinguishing formatting information from user information; and

control and transfer means, responsive to unique formatting sequences within said serial bit-stream of binary data, for detecting the boundaries of predetermined groupings of bits in the serial bit-stream of binary data and for transferring to a host system, samples of the decoded parallel data signal corresponding to said predetermined groupings, said samples of the decoded parallel data being representative of each recorded binary bit read from and output by the storage device and thereby including both the user information and the formatting information contained in the series of recorded binary bits read from and output by the storage device.

5. A data transfer apparatus for transferring parallel data to a parallel-data receiving system wherein the transferred parallel data represents both user data and format data contained in a serial bit stream supplied from a serial bit stream source and wherein the format data of the serial bit stream includes unique bit sequences, said data transfer apparatus comprising:

(a) sequence detecting and decoding means, operatively coupled to the serial bit stream source, for detecting the unique bit sequences of said serial bit stream, for producing position indicating signals indicating the position within the serial bit-stream of the unique bit sequences, and for producing a decoded parallel data signal representative of both the user data and format data contained in said serial bit stream, wherein the decoded parallel data signal has distinguishing indicia for distinctly identifying portions of the decoded parallel data signal representing the format data from other portions of the decoded parallel data signal representing the user data information; and

(b) transfer means, operatively coupled to receive the decoded parallel data signal produced by the sequence detecting and decoding means and responsive to the position indicating signals, for sampling the decoded parallel data signal and supplying the samplings of the decoded parallel data signal to the receiving system, wherein said sampling of the decoded parallel data signal is synchronized to the position indicating signals produced by the sequence detecting and decoding means.

6. A data transfer apparatus according to claim 5, further comprising:

(c) transfer control means, responsive to said position indicating signals and operatively coupled to the transfer means, for initiating the sampling of the decoded parallel data signal in synchronism with the position indicating signals.

7. A data transfer apparatus according to claim 6, wherein the transfer control means is responsive to the position indicating signals and the transfer control means includes:

trigger event detection means for detecting the occurrence of a predefined sequences of said position indicating signals and for initiating the sampling of the decoded parallel data signal upon the detection of the predefined sequence of position indicating signals.

8. A data transfer apparatus according to claim 6, wherein said data transfer apparatus is supported on a printed circuit board configured for installation into a bus expansion slot.

9. A data transfer apparatus according to claim 6, wherein the transfer means includes a data-storage buffer, an input end of the data-storage buffer being coupled to sample and collect the decoded parallel data signal produced by the sequence detection and decoding means, and an output end of the data-storage buffer being coupled to transfer said samplings of the decoded parallel data signal to the receiving system.

10. A data transfer apparatus according to claim 9, whererin the data-storage buffer is a first-in, first-out (FIFO) buffer.

11. A data transfer apparatus according to claim 10, wherein the transfer control means includes handshake means for coordinating the transfer of said samplings from the output end of the data-storage buffer to the receiving system in accordance with a predefined handshake protocol.

12. A data transfer apparatus according to claim 9,

wherein the transfer control means is operatively coupled to the output end of the data-storage buffer for detecting the occurrence of a predefined sequence of samplings of the decoded parallel data signal, and

wherein the transfer control means includes flag means for indicating to the receiving system that said predefined sequence of samplings has been detected.

13. A data transfer apparatus according to claim 12, wherein the transfer control means includes command receiving means, operatively coupled to the receiving system, for receiving instructions from the receiving system.

14. A data transfer apparatus according to claim 13, wherein the instructions received from the receiving system include an identification of a predefined sequence of samplings that the transfer control means is to detect and wherein the transfer control means operates in accordance with the received instruction.

15. A data transfer apparatus according to claim 13, wherein the instructions received from the receiving system include an identification of a predefined sequence of position indicating signals that the trigger event detection means is to detect and wherein the trigger event detection means operates in accordance with the received instruction.