JPS6156582B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coaxial disk pack drive, and more particularly to a disk pack drive having a servo surface on each of the upper and lower disk packs.

The disk pack drive device uses a rotating body to directly access information at any location, and can be used as a random access file, as well as multiple disk rotating bodies can be replaced and used as a unit. It can have infinite capacity.

A conventional disk pack drive device equipped with a single disk drive has a disk pack drive as shown in FIG.
A disk drive mechanism (drive motor 7, etc.) that drives and stops the pack 1, an access mechanism (linear motor 3, movable arm assembly 4, etc.) that moves the recording/reproducing head 2 to position it on a desired track, and a disk surface. 11 has a write/read mechanism for writing information to or reading information from the memory.

Usually, a plurality of disk pack drive devices are connected and controlled from a channel device via a disk pack control device, string switch, etc. The user uses the plurality of disk pack drives as random access files for the user's data file, user's program file, work file, system (OS) residence, and the like. In this case, two devices are often used as a set, with one dedicated for user data files and the other for system (OS) files. In this way, when two units are used in pairs, providing separate power supplies and control systems is disadvantageous in terms of materials, space, cost, etc.

In addition, in consideration of space factors, a group disk pack device is used in which two disk pack devices are combined into one device, device decks are placed in two tiers (upper and lower), and common parts such as power supplies are grouped together. ing.

The present applicant has previously proposed a coaxial disk pack drive device in which two disk packs are stacked coaxially in two stages, each pack having a servo surface, and the head is accessed using the information from the servo surface. As shown in FIG. 2, an upper pack 1 and a lower pack 1' are attached to the main shaft 8, and servo disks 5, 5' are provided for each, and a common power supply and
Both packs 1, 1' are rotated by a drive motor 7, and the recording/reproducing heads 2, 2' of both packs are moved by a common access mechanism (linear motor 3, movable arm assembly 4). Users typically use upper pack 1 for their data files and lower pack 1' for system (OS) files.

In this case, the servo disks 5, 5' may be provided on only one side in common on both packs 1, 1', but if there is a slight inclination at the top and bottom of the main shaft 8 due to manufacturing errors, High-precision positioning is possible if each servo disk is provided separately.

Positioning of the recording/reproducing head 2 to the target track is performed by a closed loop servo system comprising an access mechanism such as a linear motor 3 and a positioning circuit shown in FIG. In order to perform high-speed and highly accurate positioning, speed control is performed in velocity mode (VM) until approaching the target track, and position control is performed in position mode (PM) after approaching the target track.

In the speed mode (VM), the reference speed generation circuit 10 is controlled by a speed loop consisting of a tachometer 9, an error amplifier 13, and a power amplifier 14.
Acceleration, constant speed, and deceleration are performed in the shortest possible time according to the reference speed curve generated by

In addition, in position mode (PM), the speed and position at the time of mode switching are set as initial values, and the speed mode (VM) is changed to
The position signal obtained from the position detector 12 or 12' is transferred to the error amplifier 1.
3, the analog quantity is negatively fed back to the linear motor 3 via the power amplifier 14. Therefore, the linear motor 3 stably stops at the point where the position signal becomes OV. In addition, in FIG. 2, the position detector 12 is connected to the servo of the upper pack.
Generate a position signal from disk 5,
Since the position detector 12' generates a position signal from the servo disk 5' of the lower pack,
These are switched and sent.

Recording and reproducing heads 2, 2' are controlled by program commands.
When moving the head to the desired track position, the time required for positioning the heads 2 and 2', that is, the seek time, varies depending on the distance traveled; it is about 10 mS between adjacent track positions, and from the O track to the innermost track. Number at maximum distance to location
It takes 10mS to several 100mS' and occupies the largest proportion of the access time.

In the position detectors 12, 12', the position signal (cylinder signal) 1 shown in FIG.
5 and a position pulse (cylinder pulse) 16 shown in FIG. 3b are generated.

A logic level signal (not shown) is generated between ±15 μm before and after the position signal 15 cuts OV, that is, between lines 17 and 18.
A pulse 16 is generated.

The position pulse 16 is applied to the position transducer 12 in velocity mode (VM) as shown in FIG.
12' to the reference speed generation circuit 10, and the reference speed curves 19, 20, 2 shown in FIG.
1 is created. Figure 3 d shows the position
It shows the distance that decreases sequentially with each pulse. Curves 19, 20, and 21 show the head speeds from track position O to P, M, and N (P<M<N), respectively, and each shows the lowest speed at the starting position and stop position, and the highest speed near the center. ing.

By the way, if a failure occurs in the speed detector (electronic) tachometer 9, power amplifier 14, etc. of the head positioning control system, an abnormal current will flow through the moving coil of the linear motor 3, causing the recording/reproducing head 2, The carriage carrying the 2' may run out of control, collide with it, and be damaged.

To prevent this, conventionally, when a certain period of time has elapsed after the recording/reproducing head starts moving, the output of the speed detector (tachometer) 9 is considered normal when it exceeds a certain level, and abnormal when it is below a certain level. A method of judgment is used.

However, with this method, if the speed detector fails,
In addition, it only detects abnormalities due to failures within a certain period of time, and cannot detect other cases, such as abnormalities in servo information.

Furthermore, when it is determined that there is an abnormality, conventionally there is no best control method, and the only methods are to return the head at low speed or to disconnect the control system and leave it in a free state.

The purpose of the present invention is to quickly detect abnormalities in servo information and to solve these conventional problems.
An object of the present invention is to provide a coaxial disk pack drive device that can prevent a carriage carrying a head from running out of control by performing appropriate control.

The coaxial disk pack drive device of the present invention determines whether the head position signal of the currently selected upper or lower pack is normal or not, generates a determination signal, and in the case of abnormality, moves the head position of the other pack. It is characterized in that the head is positioned by inputting a position signal to an access control system circuit.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 is a block diagram of a head position signal discrimination section and a switching control section of a coaxial diskback drive device showing an embodiment of the present invention.

In FIG. 4, the upper half is a position signal discrimination section, and the lower half is a servo information switching control section.

Position signals 41 and 42 generated from the upper and lower servo disks 5 and 5' are input to analog switches 48 and 48', and in normal operation, the flip-flop 47 is used for the reset state. Back select signal 38
(High level “H” or low level “L”)
Open the EOR gate and select signal 40 goes “L”
When , the upper analog switch 48,
When it is “H”, the lower analog switch 4
Close each contact 8'.

As a result, position signal 41 or 42 corresponding to upper pack 1 or lower pack 1'
is transmitted through one of the contacts of the analog switches 48, 48' and through the operational amplifier 49 to the heads 2, 48'.
2' is input to the control system 50 for access.

Either the upper or lower position signal 43 is
It is fed back to the position signal discriminator, and the comparator 45,
45' with the upper slice level 32 or lower slice level 33, respectively. At this time, if the position signal 43 exceeds at least one of the upper and lower slice levels 32 and 33, the OR gate is opened and the upper threshold signal (hereinafter referred to as UTH) 34 is set to "H".

When a seek start signal 31 is input from a host device (CPU) or servo control logic, a monostable multivibrator 44 generates a pulse output 35 with a preset time width. If the UTH 34 becomes "H" within the time of the pulse output 35 of the monostable multivibrator 44, the position signal 43 is determined to be normal, so the up/down switching signal 40 does not change, but the pulse output 35 If the UTH34 maintains the "L" state within the time, the position signal 43 is determined to be abnormal, so the up/down switching signal 40
changes, and the analog switches 48, 48' switch to select the opposite position signal 41 or 42.

FIG. 5 is an operation time chart of FIG. 4.

Fig. 5a shows the seek start signal 31, Fig. 5b shows the (±) slice levels 32, 33 and position signal 43, Fig. 5c shows the UTH 34, Fig. 5d shows the monostable multivibrator output 35, FIG. 5e shows the set output of flip-flop 46;
FIG. 5f shows the set output 39 of flip-flop 47, respectively.

First, in the case of normal operation, the position signal 43 shown in FIG. 5b exceeds the upper and lower slice levels 32 and 33, so as shown in FIG. Only then, UTH34 becomes “1”. The monostable multivibrator 44 is started by the seek start signal 31, and when the UTH 34 rises to "H" during the period when the output 35 shown in FIG. 5d is "H",
Flip-flop 46 is set. next
When the UTH34 rises, the output 35 of the monostable multivibrator 44 is "L", so it flips.
Since flip 46 is reset, the flip
The set output waveform of flop 46 is as shown in FIG. 5e.

Flip-flop 47 is set if the reset output of flip-flop 46 is "H" at the rising edge of the inverted signal of monostable multivibrator 44.

Under normal conditions, the UTH 34 becomes "H" during the period when the output 35 of the monostable multivibrator 44 is "H", and the flip-flop 46 is set. On the other hand, under normal conditions, when the inverted signal of the output 35 of the monostable multivibrator 44 rises, the D terminal input, that is, the reset output of the flip-flop 46 is "L", so the flip-flop 47 is not set. Therefore, the set output of the flip-flop 47, that is, the position signal activation signal 39 is "L".
, the select signal 40 matches the pack select signal 38.

On the other hand, in the event of an abnormality, the output 35 of the monostable multivibrator 44 is "H" within the time period.
Since UTH34 does not become “H”, the flip
Flop 46 is not set. Therefore, since the reset output of the flip-flop 46 becomes "H", the flip-flop 47 is set at the rising edge of the inverted signal of the output 35 of the monostable multivibrator 44.

As a result, position signal start signal 3
9 becomes "H" when an abnormality occurs, so select signal 4
0 is the inverted value of the pack select signal 38.

For example, position signal 41 or 42
However, when the position signal is shot to the ground, it can be switched to the other position signal and used, so runaway of the carriage can be effectively prevented.

As explained above, according to the present invention, an abnormality in servo information is immediately detected and access control is performed by switching to servo information on the other side, thereby effectively preventing runaway of the carriage in which the head is mounted. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a structural diagram of a conventional single disk pack drive device, Fig. 2 is a diagram showing the structure and head positioning circuit of a coaxial disk pack drive device used in the present invention, and Fig. 3 is a diagram showing the operation time of Fig. 2.・Chart, FIG. 4 is a block diagram of the head position signal discrimination section and switching control section of a coaxial disk pack drive device showing an embodiment of the present invention, and FIG.
The figure is an operation time chart of FIG. 4. 41, 42: Vertical back position signal, 43: Selected position signal, 4
4: Monostable multivibrator, 45,45':
Comparator, 46, 47: Flip-flop, 48, 48': Analog switch, 49:
operational amplifier, 50: access control system, 31: seek start signal, 32, 33: slice level, 34: upper threshold signal, 3
5: Monostable multivibrator output, 38: Pack select signal, 39: Position signal start signal, 40: Select signal.

Claims (1)

[Claims] 1. In a coaxial disk pack drive device in which each of the upper and lower disk packs is provided with a servo surface for controlling head access,
A circuit that determines whether the head position signal of the currently selected upper or lower disk pack is normal or not;
and a coaxial disk pack drive device, further comprising a circuit that switches to a head position signal of the opposite lower or upper disk pack and inputs it to an access control system when the discrimination circuit determines that the head position signal is abnormal.