JPS61126626A - Floppy disc drive - Google Patents

Abstract

PURPOSE:To improve the throughput of the whole of a system by switching the head position control method to a prescribed optimum method in accordance with classifications of signals of an objective track TRK and TRKS adjacent thereto. CONSTITUTION:When a control signal is supplied to a microcomputer 51from a host device omitted in the figure, a switch circuit 61 is turned off and a switch circuit 62 is connected to a reproducing-side contact P by the output of the microcomputer 51. A drive signal is supplied from the microcomputer 51 to a motor 13, and heads 11 and 12 are moved to a TRK designated by an open loop. When the head 11 is moved near this TRK, the track position is determined by the servo control of a closed loop. That is, the position of the head 11 is controlled when the head 11 comes near the objective TRK. When the head 11 is moved, the reproduced level is varied and is maximum in a prescribed position.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a Fronbie disk drive that records and reproduces a mixture of video signals and digital data.

Prior Art A video floppy for electronic still cameras is being considered as a small floppy disk (Reference: Nihon Keizai Shimbun, morning edition of June 1, 1980).

That is, in FIG. 9, (1) shows the video floppy as a whole, and (2) shows the rotating magnetic disk. This disk (2) has a diameter of 47n and a thickness of 40μ.
The center core (3) is provided with a center core (3) into which the spindle of a drive mechanism (not shown) fits, and the core (3) has a A magnetic piece (4) is provided for providing a reference angular position.

And (5) is the storage jacket, which is 60X
It has a size of 54 x 3.6 mm, and the disk (2) is rotatably housed in it, as well as the core (3).
and the magnetic piece (4) is inserted into the central opening (
5A). Furthermore, jacket (5)
is formed with an opening (5B) through which the magnetic head comes into contact with the disk (2), and when the disk (1) is not in use, this opening (5B) is closed by a sliding dust-proof shutter (6). covered. Further, (7) is a counter dial that displays the number of images taken, and (8) is a claw for preventing erroneous recording, and the claw (8) is removed when recording is prohibited.

Fifty magnetic tracks can be formed concentrically on one side of the disk (2), with the outermost track being the first track and the innermost track being the fiftieth track. The width of the track is 60u+t,
The guard band width is 40μ.

During image capture, the disk (2) rotates at 3600 rp-
(field turbulence number), and one field of video signal is still recorded as one magnetic track. In this case, the signals recorded are as shown in FIG.
It is converted to Hz FM signal Sr, and F is converted by red color difference signal.
M-modulated FM signal Sr (center frequency 1.2M)
A line-sequential signal Sc is formed of the FM signal Sb (center frequency 1, 3 MIIy) which is FM-modulated by the blue color difference signal, and the FM color signal Sc and the FM
A signal Sa added to the luminance signal Sf is recorded.

Thus, the video floppy (1) has a size, function, and characteristics that are suitable for a video signal recording medium.

Furthermore, the video floppy+13 is also considered to be used as a storage medium for digital data.

That is, FIG. 11 shows the physical formant when recording and reproducing digital data on a video floppy (1), and in FIG. 11A, TRK is a magnetic disk/?
(2) shows an arbitrary track on the top, and this track TRK is 90 degrees in the length direction with the magnetic piece (4) as a reference.
It is divided into four equal sections, each of which is called a sector or block BLCK. Further, the block BLCK in the section including the magnetic piece (4) is the 0th block, and the blocks are the 1st, 2nd, and 3rd blocks in that order. Note that when accessing the data of the host device to the floppy disk (1), the access is performed in units of one block BLC.

As shown in Figure B, the block BLCK has a 4° section from its start end as a gap section GAP for obtaining a margin during read/write, and a subsequent section of 1@ as a burst section BR5T. ing.

In this case, in the 0th block, the center of the gap section GAP corresponds to the magnetic piece (4). Also, burst section BR
5τ is 1. Preamble signal ii, a signal indicating the recording density of the signal! ! 1 + This is the section in which the burst signal BR3T, which also serves as a flag signal indicating that the recorded signal is digital data, is recorded and reproduced.

Furthermore, the section following the burst section BRST is a section of a signal ID for each pin Δ, and the identification signal ID includes an 8-pin synchronization signal 5YNC, an 8-bit flag signal FLAG, as shown in FIG. It consists of a 16-bit format identification signal FMIn, a 16-bit undefined signal R5VD, and a 16-bit error correction signal ECC. In this case, the flag signal FLAG is a signal indicating the status or attribute of the track TRK to which the block BLCK belongs, such as whether it is a defective track or whether it has been erased, and the format identification signal FM
The ID is a signal indicating the logical formant of the floppy disk (1), and includes various identification data. Furthermore, the error correction signal ECC is composed of the signals FLAG, FMID, R3
This is parity data generated by the Reed-Solomon encoding method with a minimum distance of 5 using an x-ray correction code for VD.

Further, the remaining section following this section ID is divided into 128 equal parts, each of which is a section in which a signal called a frame FRM is recorded and reproduced.

In other words, as shown in the same figure, one frame FRM is
Starting from the beginning, 8-bit frame synchronization signals 5YNC,
16-bit frame address signal FAI) 117 and 1
8 pinto check signal FCRC and 16 symbols (
1 symbol = 8 bits) data DATA.

It has 4 symbols of redundant data PRTY, another 16 symbols of digital data DATA, and another 4 symbols of redundant data PRTY. In this case, check signal FC
RC is a CRC for the frame address signal FADR.
It is C. Further, the data DATA is original digital data that is accessed by the host device, but this data DATA has been interleaved to be completed within the digital data of one block BLCK, and the redundant data PRTY is This is parity data generated using the Reed-Solomon encoding method with a minimum distance of 5 for one block of digital data (32 symbols x 128 frames).

Therefore, one block BLCK, ) rank TRK
And the capacity of digital data on floppy (1) is as follows: 1 block: 4096 bytes (-16 symbols x 2 x 12B frame) 1 floppy: 16 bytes (-4096 bytes x 4 blocks) 1 floppy: 800 bytes ( When one side) (1
6 bytes (50 tracks).

Note that when digital data is accessed to the floppy disk (13), the access is performed in units of one block BLCK, so that the digital data access to the floppy disk (1) is in units of 4 bytes.

Also, the number of focuses for one frame FRM and block BLCK is: 1 frame: 352 bits (= 8 + 16 + 8 bits + (16 + 4 symbols) x
8 and 7) XZf fixed) 1 block (identification signal section and frame section only)
: 45120 bits (-352 points x 128 frames), but in reality, the digital signal is transferred to a floppy disk (1)
When recording and playing back, a small DSV is required,
In addition, T win / T ll1ax is small and Tw
Since it is necessary that Signal processing is performed.

Therefore, for the above data density, the actual number of bits in the floppy disk (11) is multiplied by 1078, 1 frame: 440 channel focus 1 block (identification signal section and frame section only): 5
6400 channel bits. Also, as a result, the total section of one block is 59
719 channel bits (-; 56400 channel focus x 90°/85°) is slightly shorter than 85°).

Therefore, the bit rate when accessing the digital signal (signal after 8-10 conversion) to floppy diskette (1) is 14.32 Mbit/s (;:59719 bits x 4 blocks x field frequency), which is 1 A bit corresponds to 69.8 ns (: 1/14.32 Mbit).

Note that it is permitted to mix video signals and digital data on one floppy disk (1) in units of tracks.

Thus, according to this formant, it is possible to read and write 800 bytes of digital data on one side of a 2-inch video floppy disk (1), which is greater than the capacity of a conventional 5-inch floppy disk (320 bytes). ), which means it has a large capacity despite its small size.

In addition, since the rotation speed of the disk (2) is the same as that for video signals, it is also possible to record and reproduce a mixture of video signals and digital data. In that case, both signals recorded and reproduced on the disk (2) The wavenumber spectra of the two signals become similar, and recording and playback can be performed under optimal conditions for electromagnetic conversion characteristics and head contact.Furthermore, even when recording and playing back two signals together, the disc ( 2)
Since there is no need to switch the rotation speed of the servo circuit, there is no need to consider the time required to switch the servo circuit, and the two signals can be used immediately. Furthermore, since the number of revolutions is the same and the mechanism such as the electromagnetic conversion system has the same characteristics or functions, it is also advantageous in terms of cost.

In this way, the video floppy (1) has new effects as a medium for recording and reproducing video signals, for storing digital data, and even as a medium that can record and reproduce a mixture of video signals and digital data. .

[Problem that the invention seeks to solve]

Incidentally, in a conventional FDD (floppy disk drive), for example, a 5-inch FDD, head feeding and positioning are performed by open loop control using a step motor in order to achieve high-speed data access. In addition, since head positioning is open-loop control, it is determined only by mechanical accuracy, and off-track may occur in the head position due to other factors such as recording and playback, temperature, humidity, etc. In order to avoid the effects of off-track, When writing data, both sides of the relevant track are erased (side erase) to form a guard band.

Therefore, in the FDD of video floppy (1),
It is possible to do something similar. However, video floppies (1) are allowed to record and play back a mixture of video signals and digital data, so if the same method as that used for conventional FDDs is adopted, the following problems will occur. Put it away.

That is, for example, as shown in FIG. 12, it is assumed that the old tracks TRKI to TRK4 are formed in the correct pattern, and the erasing head ER5E performs erasing in advance of the read/write head (recording/reproduction head) RDWT. It is also assumed that the track width (erase @) is 140μ for side erase.

Now, when a new signal is recorded on the old track TRK2, the head ER5E and RDWT are recorded on the old track TRK2.
The head ER3E and RD14T were off-track by 20μ on the Ka side, and when a new signal was recorded on the track TRK4, the heads ER3E and RD14T were off-track on the track TRK301.
[If only 20μ gardens were off-track to IJ,
Since track TRK3 is erased by 20 μm on each side, the track width becomes 20 μm.

When the signal recorded on this track TRK3 is digital data, even if the track width becomes as narrow as 20 .mu.l, it is still a digital signal and the C/N ratio is only slightly deteriorated, but there is no problem.

However, when the signal recorded on the track TRK3 is a video signal, this is an analog signal, so if the track width becomes narrow, the reproduced image quality will deteriorate.

Therefore, as is done in VTRs, head ER
It is conceivable to provide a closed loop tracking servo circuit in the feeding mechanism of 5E and RDWT. That is, when recording a new signal on track TRK2 (and TRK4), first, the old track TRK2 (T
Apply trunking servo to RK4) and head H
If the track positions of RSE and RDWT are determined and then a new signal is recorded on track TRK2 (TRK4), track TRK2 (TRK4) will be recorded using the new signal.
) is formed at the same position as the old track TRK2 (TRK4).

Therefore, since the track width of the track TRK3 does not become narrow, even if a video signal is recorded on the track TRK3, the reproduced image quality does not deteriorate.

However, if the positions of the heads ER5E and RDST are performed using closed-loop tracking servo control in this way, it takes time for the positions of the heads ER3E and RDWT to stabilize, making it impossible to write digital data at high speed. .

This invention attempts to solve the above problems.

[Means for solving problems]

Now, eight tracks TRK1 to TR are arranged consecutively.
Assume that a video signal and digital data are recorded on K8 as shown in FIG.

``This then includes all combinations of tracks of video signals and tracks of digital data.

Therefore, in the present invention, first, the following cases 1 to 2 are divided according to the signal of the track TRK.

■ Video signal track (adjacent tracks don't matter)
...TRK1. TRK2, etc.■ Digital data track (at least one of the adjacent tracks is a video signal)...TRK4. TRK6 ■ Digital data track (all adjacent tracks are digital data)... TRK7. TRK8 Then, when erasing a track and recording/reproducing a signal, control is performed as shown in Tables 1 to 5 according to cases ① to ②.

□□□" Furthermore, when booting the floppy diskette (11), for example, as shown in FIG. 4, a track identification table TIT indicating whether the track TRK is one of ■ to The above processing is performed with reference to the table TIT.Of course, when the type of signal of the track TRK is changed, the table TIT is updated.

[Effect]

According to the present invention, the head position control method and signal access method are described in Tables 1 to 1 corresponding to [1 of the signals of the target track TRK and the adjacent track
By switching to the optimal method as shown in Table 5, the throughput of the entire system can be improved, and for example, at least for digital data, it is not possible to achieve high-speed access response as with conventional floppy disks. Furthermore, a high-quality playback screen can also be obtained for video signals.

〔Example〕

In Fig. 1, (11) is the read/write head, (
12) indicates an erase head, and these heads (11).

(12) is integrated so that the head (12) is in front and their track centers coincide;
The track position can be arbitrarily changed by a step motor (13), for example, in 5 μm steps. Note that the track width of the head (11) is 60ptx,
The track width of the head (12) is 140μ.

The heads (11) and (12) are brought into contact with a floppy disk (2) of <11, and the disk (2) is rotated at a rate of 60 times per second by a motor (not shown). Further, a pulse generating means (14) is provided corresponding to the magnetic piece (4) of the floppy disk (1), and this generating means (14) generates a pulse indicating the rotational phase of the disk (2) every rotation. taken out.

Furthermore, (20) is a video signal recording and reproducing system, (30)
(41) is a current source for erasing current; (51) is a system control microcomputer that controls the operation of each circuit; this microcomputer (51) includes a generation means (14); ) is being supplied with output pulses. Further, this microcomputer (51) is connected to a host device (not shown), and when accessing signals to the floppy disk (1), control signals (commands and parameters) for that purpose are supplied.

Then, the signal is accessed as follows by referring to the table TIT and based on the reference result.

When a control signal is supplied from the playback host device to the microcomputer (51) in the cases of ■ and ■, the output of the microcomputer (51) causes the switch circuit (6
1) is turned off, and the switch circuit (62) is connected to the reproduction side contact P.

Further, drive signals (drive pulses and direction signals) are supplied from the microcomputer (51) to the motor (13), and the head (11) (and (12)) is moved to the designated track TRK by open loop. and,
When the head (11) moves close to the corresponding track TRK, the track position is determined by closed-loop servo control. That is, when the head (11) comes close to the target track TRK, the head (11) then moves as shown as (i) to (v) in FIG.
The positions of are controlled sequentially.

When the head (If) moves from (12 to (V)), the playback level changes as shown in (i) to (v) in FIG. 7, and reaches a maximum at (iii).

Therefore, the playback signal (video signal Sa) of the head (11)
is connected to the envelope detection circuit (
54), a signal indicating the playback level of the head (11) is extracted, and this signal is sent to the A/D converter (55).
) is converted into a digital signal and then supplied to the microcomputer (51). The microcomputer (51) then determines the head position (i) based on the signal from the converter (55).
) to (v) are determined, and since the reproduction level is maximum at head position (iii), the head position is determined as (v) = (vi) as shown in FIG.
)=(vi), and is fixed at the position (vi), that is, the just tracking position.

In this way, the head (11) moves to the target track TRK.
The position is fixed by closed-loop servo control.

At this time, the reproduction signal of the head (11) is supplied from the amplifier (24) to the reproduction circuit (25) and the original NT
This is an SC video signal, which is supplied to the host device through a terminal (26).

The positioning of the reproduction (read) head (11) in cases (1) and (2) is the same as in the case (2). However, in this case, the digital data is block BL
Since it is accessed at the CKII level, depending on compatibility, other recording/playback, environmental conditions, etc., even if there is an intervening track TRK, for example, as shown in FIG. ) may not be located.

Therefore, using closed-loop servo control, the head (
11) When determining the position of the corresponding block BLCX
The head position is determined by detecting the playback level only for the head.

When the head position is determined, the reproduction signal (digital data) of the head (11) is transmitted from the contact P of the switch circuit (62) to the reproduction amplifier (36) and then to the demodulation circuit (37).
This 10-8 converted signal is supplied to a decoder (38), and only the signal of the corresponding block BLCK is written to a buffer memory (39) having a capacity for one block. . Then, the signal in the memory (39) is dinterleaved by the decoder (38), and error correction is performed using the redundant code (PRTY) to create correct digital data DA.
TA, and this data DATA is the interface (
32) to the terminal (31) and supplied to the host device.

Playback (read) in the case of ■, ■ A drive signal is supplied from the microcomputer (51) to the motor (13), the head (11) is moved to the specified track TRK by open loose, and at the end of the movement, the head The position is fixed.

Then, in the same way as in the case of ■, the corresponding data D
ATA is played.

Erasing and recording in the case of ■, ■ The head position is determined in the same manner as in case (2).

However, in this case, the old track TRK is the servo target position. In addition, restrictions are imposed from a mechanical standpoint.

Next, the switch circuit (
62) is connected to the erase side contact E, and the erase current from the current source (41) is supplied to the head (11), and at the same time, a drive signal is supplied from the microcomputer (51) to the motor (13), so that the head (11) ) is changed, for example, by one step each time the disk (2) rotates, and as shown in the third prisoner, the left and right sides of the initially determined position are erased in a wide range.

When erasing is completed, the position of the head (11) is returned to the initially determined position, and then the microcomputer (51)
), the switch circuit (62) is connected to the recording side contact R, and the switch circuit (63) is connected to the video signal side contact V. The color video signal from the host device is sent to the recording circuit (22) through the terminal (21).
is supplied to the video signal Sa, and 1 of this signal Sa is
The field is transmitted through the recording amplifier (23), and then through the switch circuits (63) and (62) to the head (
11) and recorded as track TRK.

Erasing and recording (writing) in cases (2) and (2) The head position is determined in the same manner as in the case (2).

However, as in case (2), servo control is performed only on the corresponding block BLCK.

Then, once the head position is determined, the corresponding block BLCK is erased by the head (11) in the same manner as in case (2).

When erasing is completed, the position of the head (11) is returned to the initially determined position, and then the microcomputer (51)
The output of the switch circuit (62) is connected to the contact R, and the switch circuit (63) is connected to the digital data side contact.

Next, the digital data from the host device is transferred to terminal (3).
1) and is further supplied to the encoder (33) through the interface (32) and written into the memory (39), and the encoder (33) adds redundant bits PRTY and interleaves them, and then the memo 'J ( 39) is sequentially supplied to the modulation circuit (34) and subjected to 8-10 conversion, and this converted signal is
Through the recording amplifier (35), the switch circuit (
63)', is supplied to the head (11) through (62) and recorded in the corresponding block BLCK.

Erasing and recording (writing) in cases (2) and (2) The position of the head is determined in the same way as in case (2).

When the head position is determined, the switch circuit (61) is turned on by the output of the microcomputer (51), and
Switch circuit (62) is contact R, switch circuit (63)
is connected to the contact point. In this way, the erase current from the current source (41) is supplied to the head (12), and the corresponding block BLCK is erased in advance, and digital data is recorded in the block BLCK.

Signal access to the floppy disk (1) is performed as described in I to (2) above.

And this! The operations of ~■ are performed by referring to the table T[T and based on the reference result, and the table TIT is formed as follows.

That is, when the floppy (1) is booted or rebooted, for example, the switch circuit (62) is connected to the contact P by the output of the microcomputer (51), and a drive signal is supplied to the motor (13) to drive the head (11). ) are sequentially sought for each track TRK from the 1st track to the 50th track.

Therefore, at this time, from the head (11), the track TR
A reproduced signal of K is obtained, and this reproduced signal is supplied to the amplifiers (24) and (36) through the switch circuit (62).

Now, when the reproduced signal is the video signal Sa, a luminance signal Sy is obtained in the reproduction circuit (25), but this signal Sy is supplied to the synchronization separation circuit (52) and the horizontal synchronization pulse is extracted. The presence or absence of a pulse is detected by a detection circuit (53), and this detection output VSIG is supplied to a microcomputer (51).

Further, when the reproduced signal of the head (11) is digital data, a digital signal converted by 10-8 is obtained from the demodulation circuit (37), but this signal is not transmitted to the burst detection circuit (37).
56), the absence of the burst signal BR3τ is detected, and its detection output DGDT is supplied to the microcomputer (51).

In the microcomputer (51), a signal identification table SIT as shown in FIG. 5, for example, is formed according to these detection outputs VSIG and DGDT.

That is, this table SIT is formed on the RAM of the microcomputer (51), and the addresses 1 to 1 of the RAM are
Address 50 corresponds to the 1st to 50th racks.

However, the address here is a relative address with respect to a certain predetermined absolute address 5ADR, and for example, 1 corresponding to the first track.
The address is an absolute address (SADR+1).

At each address, the first bit b1 and the Oth bit (bo) of the data indicate the type of reproduced signal, and are determined by the detection outputs 05IG and DGDT.The remaining bits b7 to b2 are, for example, All are set to “0゜.”

Then, when this table SIT is formed, the track identification table TI is subsequently created based on this table SIT.
T is formed on the RAM of the microcomputer (51).

In this table TIT as well, the RAM
Addresses (relative addresses) 1 to 50 are the first to
Corresponds to the 50th track. In each address, the seventh bit b7 and the sixth pint b@ of the data indicate the type of the corresponding track TRK.
For example, the remaining 5th bit b5 to Oth bit of each data
Bit BO is used for attribute information of each track.

When accessing a signal to the floppy disk (1), this table TIT is referred to, and the signal is accessed by one of the methods (1) to (2) described above based on the reference result.

Also, when the signal of the track TRK changes from a video signal to digital data as a result of recording a signal on the floppy disk (1), and vice versa, the table SIT
, TIT are updated.

Thus, according to the present invention, the target track TR
Since the head position control method and signal access method are switched to the optimal method as shown in Tables 1 to ff15, depending on the type of signal from track TRK and the adjacent track TRK, the overall system It is possible to improve throughput, and for example, for digital data at least, it is possible to achieve high-speed access response similar to that of conventional floppy disks, and it is also possible to obtain high-quality playback screens for video signals. .

Note that, in the above description, the tables TIT and SIT can also be in other formats, and for example, both can be integrated. Also, create table 5IT (and TIT) on the floppy disk (1) as part of the directory, and read it out when booting to create table TI.
It is also possible to form a T.

〔Effect of the invention〕

According to the present invention, the head position control method and the signal access method are described in Tables 1 to 3 in accordance with the types of signals between the target track TRK and the adjacent track TRK.
By switching to the optimal method as shown in Table 5, the throughput of the entire system can be improved, and for example, at least for digital data, it is possible to achieve a high-speed access response like that of a conventional floppy disk.
Furthermore, a high-quality playback screen can be obtained for video signals as well.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an example of the present invention, and FIGS. 2 to 12 are diagrams for explaining the same. (1) is a video floppy, (20), (30)
is a recording/reproducing system. Figure 7 [μm1 Figure 10

Claims (1)

[Claims] A floppy disk drive in which video signals and digital data are recorded and played back in a mixed manner on a track-by-track basis has a table that shows the signal combinations of a certain track and a track adjacent to this track. When accessing a signal, the table is referred to, and when the predetermined track is a track of the video signal, and the predetermined track is a track of the digital data, and at least one of the adjacent tracks is a track of the video signal, When it is a video signal track,
The head position is determined by closed-loop servo control, and when the predetermined track and all adjacent tracks are digital data tracks, the head position is determined by open-loop control, and the head position is determined by open-loop control. After determining the above, the floppy disk drive was made to access the signal to the predetermined track.