JPH0498657A - Recording medium reading device - Google Patents

Abstract

PURPOSE:To fetch an address and a data only at a required part by providing a comparator circuit for investigating matching between an inside data in a time sequential register group and a data in a time sequential data group at all times, and immediately discriminating a data address mark. CONSTITUTION:A byte synchronizing signal is generated by the synchronizing data group of a synchronizing part and the data group with missing lock of a data address mark part following to this synchronizing data group in a data area on a recording medium. The data of MD0-MD7(35) are successively propagated through storage registers 20, 21 and 22 in a time sequential register group 14 at the timing of BSYNC 13. The respective BIT outputs of the storage registers 20, 21 and 22 are immediately compared with the respective bits constituting respective correspondent data 30, 31 and 32 of a time sequential data group 15 by a comparator circuit 16 and outputted as a data address mark detection signal. Thus, the load of a software is considerably reduced and a parallel processing is enabled.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is directed to a recording medium using a magnetic recording medium having a sector group consisting of an ID address area and a data area consisting of data modulated by MFM. The present invention relates to a recording medium reading device that separates and demodulates read data.

[Prior Art] A recording medium reading device disclosed in Japanese Patent Application No. 191865/1987 filed by the applicant is a floppy disk controller rFDc necessary for reading an MFM modulated recording medium, especially 18M format FD data. ) and a variable frequency oscillator (VFO) with a simple circuit at low cost.

To this end, when reading information stored on a recording medium from a drive device that drives the recording medium, such a recording medium reading device amplifies and differentiates the output of the head that reads information from the recording medium, and then converts the output into pulses. a generating means for periodically generating a constant time signal, a current state and a signal from the pulsing means, and a means for making a state transition based on the signal from the generating means, and pulsing the signal. The timing of the data generated by the means, the generating means, and the state transitioning means is adjusted.

By the way, in general, in FD data, a collection of sectors constituted by an ID address area and a data area forms one track, and among these, the data area consists of a data address mark part and an actual data part.

However, in the device disclosed in Japanese Patent Application No. 62-191865, the discrimination of the data address mark in the data address mark section also relies on software control, and the control section side must constantly monitor the data address mark. The load on the central CPU increased, and for the same reason it was difficult to use an inexpensive CPU with low performance. Further, since it is not possible to immediately process the discrimination of data address marks, all sector data must be temporarily stored in the memory, resulting in an increase in memory capacity.

[Problems to be solved by the invention] The present invention solves the problems of the conventional example, and
It is an object of the present invention to provide a means that makes it possible to import only the addresses and data that are actually necessary by immediately processing and determining the data address mark and transmitting it to the control.

Means for Solving 1 Problem] To this end, the present invention provides a method for reading information recorded on a magnetic medium having a sector group consisting of an ID address area and a data area consisting of data modulated by MFM. means for amplifying the output of a head that reads information from a recording medium, differentiating it, and then pulsing it; periodic signal generating means for periodically generating a constant time signal; and a current state and means for pulsing the output. in a recording medium reading device, comprising: a signal from the periodic signal generating means; and means for making a state transition based on the signal from the periodic signal generating means, and adjusting the timing of data produced by the pulsing means, the periodic signal generating means, and the state changing means, A byte synchronization signal generated by the sync data group in the sync part of the data area on the recording medium and the data group with missing clock in the data address mark part that follows it, and the data group with missing clock in the data address mark part and the following data group. A time series register group that stores data address mark data continuously in time series in synchronization with the byte synchronization signal, a preset time series data group, and internal data of the time series register group that is always stored in the time series. The present invention is characterized by comprising a comparison circuit means for checking matching with a data group, and means for detecting and transmitting a data address mark to another control section.

[Function] According to the present invention, with the above-described configuration, it is possible to match each byte synchronization signal with time series data, so that instant data address mark detection is possible.

[Example 1] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Figures fA) and fB) show an example of the external configuration of an electronic typewriter as a device to which the present invention can be applied.

Here, 101 is a keyboard section, and key group 1 includes keys for inputting characters such as letters and numbers, and control keys.
02 are arranged, and when not in use, it can be folded by rotating around a hinge 103 as shown in FIG. 1(B). Reference numeral 104 denotes a paper feed tray for feeding a sheet-like recording medium to a printer section inside the apparatus, and when not in use, it is stored covering the printer section as shown in FIG. fB). 105 is a feed knob for manually setting and ejecting a recording medium, 106 is a display for displaying input text, etc., and 107 is a handle used when transporting the apparatus according to this example.

Further, 109 is a floppy disk device having a mechanically known configuration, and a recording medium reading device described below is applied thereto.

FIG. 2 is an explanatory diagram showing the internal structure of a rotating magnetic disk (hereinafter referred to as rotating magnetic memory) used in the floppy disk device 109.

The rotating magnetic memory 1 has a group of tracks arranged in the circumferential direction of rotation from the center of rotation 5, each track 2 is composed of an index mark 4 and a group of sectors 3, and the remaining space is used for data called gaps. It is filled with The magnetic head 5 (hereinafter referred to as head) is connected to the rotating magnetic memory 1
Any track can be accessed by moving in the direction of the arrow above.

FIG. 3 is an explanatory diagram in which the configuration on the track in FIG. 2 is redrawn linearly in time series, and the first index mark 4a and the second index mark 4b are located in the rotating magnetic memory. Index mark 4 on 1 and all (
Although they are the same, they are different in chronological order. Inside each sector 3 is an address section 8 consisting of a sector address mark (not shown) and a sector address (not shown) following this.
, a data section 9 consisting of a data mark (not shown) and subsequent data (not shown), and a gap l connecting these.
It is composed of O.

In the rotating magnetic memory 1, data reading and writing operations are basically carried out in sector units, but in order to perform data reading and writing operations in sector units, it is necessary to confirm that the head 5 is at the desired sector position immediately before this. be.

In reality, at a certain detection interval timing,
The process of continuously performing a check to see if a desired sector address and sequentially recognized sector addresses match is called a sector address check.

FIG. 4 shows an FD read machine 1 according to an embodiment of the present invention.
2 and a system schematic diagram of a data address mark detection device, and is a floppy disk drive (FDD) 1
1 corresponds to a general 3.5' double-sided double-density track, and it is assumed that addresses and data have already been written on the internal medium in the IBM format modulated by MFM. FD read machine 12 (hereinafter referred to as FDRM)
) receives the input of Read Data (18) as serial pulse bit information from the FDD 11 and the human power of the CLOCK 19, and executes the Write Ga
When to (25) is in READ state, if synchronization is achieved with specific data formatted on the FDD media, it can be confirmed by BSYNS 13, and the data latched in 8-bit units at this timing is MDO~M
It is output to D7 (35). MDO~MD7 (35
] The data output to RDO to RD7 (29
1 can be read out in 8-bit units as parallel data.

The RAM 37 and the ROM 38 are connected to the CPU 36 via a common address bus, data bus, read signal line, write signal line, etc.
PU a6 performs sequential calculation control. The RAM 37 is used as a work and stack pointer area for sequential calculation control, and is also used as a storage location for calculation results. Also WRM 40 and Ilo port 41
Similarly, WRM '40 is connected to the CPt136 by common address bus, data bus, read signal line, write signal line, etc., and WRM '40 is 8b written from CPU36.
Write G by performing MFM modulation on information in units of IT.
A pulse signal train for writing to the medium on the FDD 11 is generated while referring to ato (25). Furthermore, l10port41 has a structure for exchanging input/output signals with FDD 11. 26 and 27 are FDD
It is assumed that all conditions necessary for FDD access are satisfied. M.D.O.
-, MD7 (35) is sequentially propagated through the storage registers (20°21.221) in 8-bit units in the time series register group 14 at the timing of BSYNC (131).

Each BIT output of the storage register (20, 21°22) is
Each corresponding 8-bit data of time series data group (15) (
Each bit configuring 30, 31, 321 and comparison circuit 16
The signals are immediately compared and output as a data address mark detection signal.

The FDRM12 uses the FDRM described in the above-mentioned Japanese Patent Application No. 191865/1986, and its detailed explanation is omitted, but it uses MFt4 modulation and 5sync on IBM format.
Missing data address mark with crotch following Hex"00" 12 Bytes Hex"Al" 3 Bytes
For e, automatic synchronization is performed at the first IByte,
Thereafter, the structure is such that MDO to MD7f35+ are sent out together with the output of BSYNC (131) every 32 μsec.

Figure 5 shows the above patent application filed in 1982-19186, which was the subject of improvement.
In the block diagram of the device disclosed in No. 5, a time series register group 14
, time series data group 15, comparison circuit 16, MDO to MD7
(351 and the data address mark detection signal 17 are not present).

FIG. 6 and FIG. 7 show an example of a sector read processing procedure according to this embodiment and a conventional example, respectively. here,
A process of detecting an index while rotating the rotating magnetic memory once (step Sl).

S3), a process of waiting for movement from the index detection position to the position immediately before the desired sector (step S5)
, BSYNC and then determining whether the data immediately after is an ID address mark FC (Hex) (step S
7. S91: If the determination is affirmative, the DRD signal (28) is used to read RDO~RI]7 for Ill address data (step 5131, In address data CRC
fcyclic Redundancy Checkl
(step 515), determining whether the sector is a desired sector (step 519), step S9. S1
5. The retry process (step Sll, S17.5211) when a negative determination is made in S19, and the error process (step 533) performed when a retry fails or when an index is not detected are the same in this embodiment and the conventional example.

However, in the sector read sequence of this embodiment, the data address mark detection signal (1
7) (steps S23, 5)
251 In contrast, in the sector read sequence in the conventional example shown in Figure 7, BSYNC (13) not only is irregular and requires high-speed polling, but also DRD (281) is issued during polling. It becomes necessary to collate data (steps 5123, 5124, 512).
5).

Subsequent processing, that is, RDO to RD by DRD signal
7 for the data including CRC (step 5)
27), a process of verifying the CRC of the data (step 52);
9) and retry processing (step 531).

Note that the processing in steps 57 to Sll can also be replaced with processing for detecting and retrying the signal if the system is configured to output an ID address mark detection signal.

[Embodiment 2] FIG. 8 is a block diagram of a second embodiment of the present invention,
This embodiment differs from the first embodiment in that the data mark detection signal is directly input to the external interrupt of the CPU 36, and in the configurations of the time series register group 14 and the comparison circuit 16.

The functional description is the same as in the first embodiment, so it will be omitted.

9 and 10 are sector read sequences of the second embodiment.

In this example, steps Sl to S21 similar to the procedure in FIG.
Processing for disabling and enabling interrupts is placed before and after processing (step So, 5511), and a standby process (step 553) is placed after enabling interrupts.If an interrupt occurs during standby, the procedure shown in Figure 1O is activated. and if it is a data mark interrupt (step 561), interrupts are disabled (
Step 5 similar to above after performing step 565)
Processes 27 to S33 are performed and data is imported. On the other hand, if it is another interrupt, the corresponding other interrupt processing (step 56
Execute 3). Note that when these processes are completed, interrupts are permitted in step S69.

In the second embodiment, data mark detection is used as an external interrupt trigger, and actual data reading is performed during interrupt processing, so there is no need to perform polling by software to detect data address marks. Therefore, other processing can be performed until an external interrupt occurs.

Note that the present invention is not limited to the above-described embodiments, and can be modified in various ways. For example, the format of the recording medium is not limited to the one described above, and may be of other formats.

Further, the device to which the present invention is applied may be one that is integrated into a document processing device such as an electronic typewriter, a personal computer, or the like, or one that is provided separately.

[Effects of the Invention] As described above, according to the present invention, when reading a recording medium formatted by MFM modulation, adjacent pulse widths of read data are distributed in a fixed time domain, and the marker portion is divided by the state transition. Patent application for automatic synchronization in 1986-
By using FDI'1M described in No. 191865 and adding a simple circuit to it, data address mark pressure detection can be performed immediately. As for software processing,
When reading data in the data area, it is possible to do it by polling only to detect the data address mark over a relatively long periodic span as described above, or by using an external interrupt, which greatly reduces the software load and allows parallel processing of the software. Obtain the effect that makes it possible.

[Brief explanation of the drawing]

Figure 1 (Al and (Bl) are perspective views showing the state of the device when the floppy disk device to which the present invention is applicable is used and when it is stored, and Figure 2 is the internal structure of a rotating magnetic disk, etc. FIG. 3 is an explanatory diagram of the configuration on the l track, FIGS. 4 and 5 are block diagrams of a recording medium reading device according to an embodiment of the present invention and a conventional example, respectively. FIG. 7 is a flowchart showing a sector read processing procedure according to an embodiment of the present invention and a conventional example, respectively. FIG. 8 is a block diagram of a recording medium reading device according to another embodiment of the present invention. The figure and FIG. 10 are flowcharts showing an example of the sector read processing procedure. 1... Magnetic disk, 2... Track, 3... Sector, 4-... Index mark, 11... FDD 12... FD read machine, 14... Time series register group, 15... Time series data group, 16... Comparison circuit, 17... Data address mark detection signal, 36...
CPU. 109...Floppy disk device. Purification of drawings! (No change in content) (A) Figure 5 ++ Figure procedural amendment (method) % formula % 1. Indication of case Patent Application No. 2-214644 / 2゜Name of invention Recording medium reading device 3゜Amendment 3rd floor, Seiko Building 6, 5-1-31 Akasaka, Minato-ku, Tokyo (Delivery date: November 27, 1990) 6゜7゜Subject of amendment Contents of power of attorney, specification, and drawing amendments

Claims (1)

[Claims] 1) A head that reads information from a recording medium when reading information recorded on a magnetic medium having a sector group consisting of an ID address area and a data area consisting of data modulated by MFM. means for amplifying and differentiating the output of the output and then pulsating the output; periodic signal generating means for periodically generating a constant time signal; a current state and the signal of the pulsing means; and a periodic signal generating means for generating a pulse. A recording medium reading device comprising: means for making a state transition based on a signal from the means, and synchronizing the timing of data generated by the pulsing means, the periodic signal generating means, and the state transition means; A byte synchronization signal generated by the sync data group in the data address mark part and the data group with missing clock in the data address mark part that follows, and the byte synchronization signal generated by the data group with missing clock in the data address mark part and the data address mark data following it. Comparison of a time series register group that stores data continuously in time series in synchronization with signals, a preset time series data group, and a match between the internal data of the time series register group and the time series data group. A recording medium reading device comprising circuit means and data address mark detection and transmission means to another control section.