JPH0498658A - 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 an ID 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 an ID address mark part following to this synchronizing part 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 an ID address mark detection signal 17. Thus, the load of a software is considerably reduced and the parallel processing of the software 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] The recording medium reading device disclosed in Japanese Patent Application No. 191865/1983 filed by the applicant is a floppy disk controller ( It provided an FDCI and a variable frequency oscillator (VFO) with a simple circuit at a low cost.

To this end, such a recording medium reading device amplifies and differentiates the output of the head that reads information from the recording medium when reading the information stored on the recording medium from a driving device that drives the recording medium, and then pulses the output. 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 pulsing means; The timing of the data generated by the means for generating the data, the means for generating the state, and the means for performing the state transition 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 ID address mark part also relies on software control, and the control part must constantly monitor it. As the load on the central CPU increased, the same rationale made it difficult to use an inexpensive CPU with low performance. Furthermore, since it is not possible to immediately process the discrimination of data address marks, all sector data must be stored in the -H memory, resulting in an increase in memory capacity.

[Problem 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 ID address mark and transmitting it to the control.

[Means for Solving the Problems] 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 following data group with missing clock in the ID address mark part, and the data group with missing clock in the ID address mark part and the following data group. A time series register group that stores ID 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 are 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 ID address mark to other control sections.

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

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

FIGS. 1A and 1B show an example of the external configuration of an electronic typewriter as a device to which the present invention is applicable.

Here, ID1 is a keyboard section, and key group I includes keys for inputting characters such as letters and numbers, and control keys.
D2 are arranged, and when not in use, they can be folded by rotating around hinge ID3 as shown in Figure 1 (Bl). ID4 feeds the sheet-like recording medium to the printer section inside the device. When not in use, it is stored covering the printer unit as shown in the same figure (Bl). ID5 is a feed knob for manually setting and ejecting recording media, and ID6 is a feed knob for manually setting and ejecting recording media. A display device ID7 for displaying input text, etc. is a handle used when transporting the device according to this example.

Further, ID9 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 ID9.

The rotating magnetic memory l has a group of tracks arranged in the circumferential direction of rotation from the center of rotation 5, each track 2 is made up 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 l 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 I connecting these.
It is composed of D.

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)
) is the input of Read Data (18) as serial pulse bit information from the FDD 11, the input of CLOCK19 (7), and the input of Write.
When Gatof25) is in the READ state, if synchronization is achieved with specific data in a specific format on the FDD media, it can be confirmed by BSYNS 13, and the data latched in 8-bit units at this timing is transferred to the MD.
O~MD7 (Output to 351. MDO~MD7
The data output to f351 is periodically DRD (2
Yotte RDO-RD7 on CPU 36 that powers 81
F291 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.
The PU 36 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 is similarly connected to the CPU 36 through a common address bus, data bus, read signal line, write signal line, etc., and the WRM 40 performs MFM modulation on the information written in 8-bit units from the CPU 36 and writes it.
A pulse signal train for writing to the medium on the FDD 11 is generated while referring to Gato (251).

Furthermore, the lIDport 41 has a structure for exchanging input/output signals with the FDD 11. 26 and 27 are F
This is a group of input and output control signals necessary for the DD, and it is assumed that all conditions necessary for FDD access are satisfied. M
The data of DO-Mn2 (35) is BSYNC (131
The storage registers (20°21.22) in 8-bit units in the time series register group 14 are propagated in order at the timing of Each bit constituting the corresponding 8-bit data +30, 31, 321 and the comparison circuit 1
6, the signals are immediately compared and outputted as an ID address mark detection signal 17.

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 MFM modulation and 5sync on the IBM format.
ID address mark with missing clock following Hex"00" 12 Bytes Hex"A1°' 3 Bytes
, automatic synchronization is performed at the first IByte with the BSYNC (131 output and MDO~A4D7i35) output, and thereafter, RDO~RD7 (2
9) is transmitted.

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-Mn2
(35) and the structure differs from the present example in that there is no ID address mark detection signal 17.

FIG. 6 and FIG. 7 show an example of a sector read processing procedure according to this embodiment and a conventional example, respectively. here,
The process of detecting the index while rotating the rotating magnetic memory once (steps S1 and S3), the process of waiting for the index to move from the index detection position to the position immediately before the desired sector (step S5), and the DRD signal (28) Process of reading RDO to RD7 for In address data (
Step 5131, CRCfCy of ID address data
clic Redundancy Checkl (step 515), processing to determine whether it is a desired sector (step 519), processing to wait for BSYNC and determine whether the data immediately after is a data mark FB (Hexl) (steps S23, 524). ), in the case of an affirmative determination, the process of reading RDO to RD7 by the amount of Data including the CRC using the DRD signal 28 (step 527);
RC verification process (step 529), step S1
5,519. S24゜Retry processing in case of negative determination in S29 (step SL?, S21.S25, 531
1, and error processing (step 533) performed when a retry fails or when an index is not detected, according to this embodiment,
This is the same as the conventional example.

However, in the sector read sequence of this embodiment, the ID address mark detection signal (I7
) (steps S7. S9
). On the other hand, in the sector read sequence in the conventional example shown in FIG. It becomes necessary to verify (step 5ID7.5I08゜5ID9)
.

Note that the processing in steps 523 to S25 can also be replaced with processing for detecting and retrying the signal if the system is configured to output a data 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 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.

FIG. 9 and ID diagram show the sector read sequence of the second embodiment.

In this example, step Sl is similar to the procedure in FIG.

Processing to disable and enable interrupts is placed before and after the processing in S5 (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 executed. launched and ID
If it is an address mark interrupt (step 561), the interrupt is disabled (step 565), and then steps S13 to S33 similar to those described above are performed and data is fetched. On the other hand, if it is another interrupt, the corresponding other interrupt processing (step 563) is executed. Note that when these processes are completed, interrupts are permitted in step S69.

In the second embodiment, the detection of the ID address mark is used as a trigger for an external interrupt, and the actual data reading is performed during the interrupt processing.
No need for software polling. Therefore,
Other processing is possible 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.

〔Effect 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 section automatically synchronizes according to the state transition. Gansho 62-
By using the FDRM described in No. 191865 and adding a simple circuit to it, it becomes possible to immediately detect an ID address mark. As for software processing, when reading an address in the ID address area, it can be done by polling only to detect the ID address mark with a relatively long periodic span as described above, or by using an external interrupt, so the software load is significantly reduced. The effect of this reduction is that parallel processing of software is possible.

[Brief explanation of drawings]

FIG. 1 (A+ and (Bl) are perspective views showing the states of a device to which a floppy disk device, to which the present invention is applied, are being used and stored; FIG. FIG. 3 is an explanatory diagram showing the internal configuration. FIG. 3 is an explanatory diagram of the configuration one track above. FIGS. 4 and 5 are blocks of a recording medium reading device according to an embodiment of the present invention and a conventional example, respectively. 6 and 7 are flowcharts showing the 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. 9 and 10 are flowcharts showing an example of the sector read processing procedure.■...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... ID address mark detection signal, 36...・・C
PU, ID9...floppy disk device. Engraving of drawings (no change in content) (A) No. 51! 1 Procedural amendment (method) % formula % Relationship with the person making the amendment case

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 of the section and the following data group with missing clock of the ID address mark section, and a byte synchronization signal generated by the sync data group of the ID address mark section and the following ID address mark data. 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 means for detecting and transmitting an ID address mark to another control section.