JP4782739B2 - Disk unit - Google Patents

Description

  The present invention relates to a disk device for recording or reading data, and more particularly to a hard disk device suitable for recording an image.

  Currently used hard disk drives (HDD) record data from the outer periphery of the disk toward the inner periphery. Data is recorded in a recording unit (usually 512 bytes) called a sector. The disk surface is divided into several tens of minutes in the radial direction (zone division), and in one divided zone, the area is effectively used so that the surface recording density of the disk becomes almost constant by performing recording with a constant number of sectors. In this way, large capacity has been realized. However, since the HDD operates at a constant disk rotation speed, the number of sectors differs greatly between the outer peripheral portion and the inner peripheral portion, and the transfer rate changes nearly twice as much between the innermost periphery and the outermost periphery of the disk.

  Hybrid recording hard disks have already been commercialized, but this hybrid recording uses flash memory as a large-capacity cache memory to reduce startup time and save power. It does not increase the transfer rate.

  Patent Document 1 describes a magnetic disk device in which a flash memory is mounted in addition to a magnetic disk, and the flash memory is used as part of an information storage area of the magnetic disk. In this document, when an area that is frequently accessed by the host system, for example, a FAT area is arranged on the flash memory, the flash memory can be accessed at high speed. It is described that the average value of the access time to the disk can be shortened, and the same effect as that of shortening the access time of the hard disk device can be obtained (see paragraph 0015).

JP-A-6-314177

  Since the video stream has a constant bit rate, when the video stream is recorded by the HDD, the maximum video bit rate that can be recorded is limited by the recording rate on the inner circumference side with the slowest transfer rate. Therefore, there is a problem that even if the recording rate on the outer peripheral side is high, the high speed cannot be utilized. A video recording HDD is required to minimize the difference in transfer rate between the inner and outer peripheral portions of the disk.

  An object of the present invention is to provide a disk device in which the difference in transfer rate between the inner circumference side and the outer circumference side of the disk is small.

  Of the inventions disclosed in this specification, the outline of typical ones will be briefly described as follows.

(1) In a disk device for recording or reading data, the disk device has a plurality of tracks arranged concentrically, and assigns a larger number of sectors to the outer track of the plurality of tracks, A disk having a small number of sectors allocated to a track, and a non-volatile memory having a sector allocated to compensate for a sector having a small number of sectors on the inner circumference side of the disk, on the inner circumference side of the disk The disk device is characterized in that the sum of the number of allocated sectors and the number of sectors allocated to the non-volatile memory is the same in the outermost track to the innermost track of the disk.

(2) In a disk device that records or reads data, the disk device has a plurality of tracks arranged concentrically, and assigns a larger number of sectors to the outer track of the plurality of tracks, A disk with a small number of sectors allocated to a track, and a non-volatile memory to which a sector for supplementing a sector with a small number of sectors on the inner circumference side of the disk is allocated, and the number of sectors allocated to the disk And the number of sectors allocated to the non-volatile memory is the same for all tracks from the outermost track and the innermost track except the innermost track to the innermost track .

(3) In the above (1) or (2), the disk is divided into zones in the radial direction, the same number of sectors are assigned to tracks belonging to the same zone, and the disk belongs to the outer peripheral zone. A disk device is characterized in that a sector having a large number of sectors is allocated to a track, and a sector having a small number of sectors is allocated to a track belonging to an inner zone .

(4) In the above (1) to (3), said disk is a disk apparatus characterized by rotating at a constant rotational speed.

( 5 ) In the above (1) to ( 4 ), a cache memory for temporarily storing data, and data temporarily stored in the cache memory are recorded in the disk or the nonvolatile memory, or a disk controller for storing the disc or the non-volatile memory said cache memory to temporarily read out data, a disk device, characterized in that it comprises a.

( 6 ) In the above ( 5 ), in the case of sequential access, the disk controller searches for the next recording or reading track on the disk when recording to or reading from the sector allocated to the nonvolatile memory. Alternatively, during recording or reading, the disk device is characterized in that recording or reading is performed on a sector assigned to the nonvolatile memory.

( 7 ) The disk device according to ( 5 ) or ( 6 ), wherein the disk controller does not control the disk when accessing a sector on the nonvolatile memory in the case of random access. .

  According to the present invention, it is possible to reduce the decrease in the recording rate on the inner circumference as compared with the conventional disk device. Therefore, for example, a video stream can be recorded at a higher recording bit rate. This makes it possible to design a magnetic recording apparatus that performs high-definition video recording, for example, which is very useful industrially.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a magnetic disk and flash memory used in the magnetic disk apparatus according to the embodiment of the present invention. 11 is a magnetic disk, and 12 is a flash memory.

  The magnetic disk device according to the embodiment of the present invention adopts a hybrid recording method of the magnetic disk 11 and the flash memory 12 which is a solid-state memory in the magnetic disk device, and allocates more flash memory on the inner circumference side of the disk. This is to reduce the difference in transfer rate between the inner circumference and inner circumference recording.

  The arbitrary sector on the magnetic disk 11 is designated by a track (cylinder) number counted from the outer periphery, a head number for designating which side of the plurality of disks, and a sector number (CHS parameter) on the track. The sector size is usually 512 kBytes. The disk surface is divided into zones with a fixed number of sectors. A 2.5-inch disk is divided into about 20 zones.

  A track is composed of a plurality of sectors (hundreds to thousands). Recording is sequentially performed on the magnetic disk 11 from the outermost track to the inner periphery. At this time, the rotation speed of the disk is controlled to be constant. In order to ensure the recording capacity by using the entire disk surface efficiently while keeping the recording density the same at the inner and outer peripheral portions, many sectors are arranged at the outer peripheral portion and decreased at the inner peripheral portion.

As shown in FIG. 1, the disk surface of the magnetic disk 11 is divided into zone 1, zone 2, zone 3,..., Zone N _z-2 , zone N _z−1 , and zone N _z . Outermost number of sectors zone 1 (1st) is N ₁ sectors / track, the number of sectors the i-th zone i is N _i sectors / track. The maximum number of sectors is Nmax = N ₁ (the number of sectors in the outermost zone).

  A magnetic disk device according to an embodiment of the present invention includes a magnetic disk 11 and a flash memory 12. The magnetic disk 11 has a plurality of tracks arranged concentrically, and is divided into zones in the radial direction. The same number of sectors are assigned to tracks belonging to the same zone, and the outer zone is assigned to the outer zone. This is a magnetic disk in which a sector with a large number of sectors is allocated to a track to which the track belongs and a sector with a small number of sectors is allocated to a track that belongs to an inner zone. The flash memory 12 is a flash memory to which a sector for recording or reading is assigned as a sector of a track on the inner circumference side of the magnetic disk 11.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a sector layout diagram in the magnetic disk apparatus of the first embodiment (full surface hybrid recording). In the magnetic disk device of the present embodiment, N _fi sectors are secured on the flash memory in addition to N _i sectors on the magnetic disk in the track belonging to zone i, and N _i + N _fi = Nmax. By assigning the flash memory in this way, a fixed number of sectors in each zone is ensured.

FIG. 2 shows the number of sectors on the magnetic disk and the number of sectors to be secured on the flash memory in each zone. When the number of disk sectors on the outermost periphery (zone 1) is N _s , the number of sectors on the entire disk surface is made constant by allocating a recording area (sector) secured on the flash memory to the disk sector on the inner periphery side. The recording bit rates on the inner peripheral side and the outer peripheral side can be made constant.

As shown in FIG. 2, in zone 1, sectors 1 to N _s are mapped on the magnetic disk. In zone 2, sectors 1 to N _s-1 are mapped on the magnetic disk, and sector N _s is mapped on the flash memory. In zone 3, sectors 1 to N _s-2 are mapped on the magnetic disk, and sectors N _{s-1 to} N _s are mapped on the flash memory. Generally, in zone i, if the number of sectors mapped on the magnetic disk is N _i and the number of sectors mapped on the flash memory is N _fi , then N _i + N _fi = Nmax Allocate flash memory.

  Therefore, in this embodiment, the sum of the number of sectors of the magnetic disk and the number of sectors of the flash memory in each zone is constant, and the R / W (read / write) speed is constant over the entire surface of the disk. However, a large-capacity flash memory is required.

  FIG. 3 is a sector layout diagram of the magnetic disk device of Example 2 (hybrid recording only on the inner periphery). The present embodiment is an example in which hybrid recording is applied only to the inner periphery, and the allocated amount of flash memory is reduced as compared with the first embodiment.

  FIG. 3 shows the number of sectors on the magnetic disk and the number of sectors to be secured on the flash memory in each zone. Since the recording capacity of the magnetic disk is very large, an extremely large capacity flash memory is required to make the number of sectors constant over the entire disk surface as shown in FIG. 2 (Example 1). For this reason, it is effective to allocate the flash memory only in the vicinity of the innermost periphery as in this embodiment, and to reduce the difference between the recording rates of the inner periphery and the outer periphery.

In the present embodiment, as shown in FIG. 3, the zones 1 to Nz _-2 are mapped only on the magnetic disk. In zones 1 to N _z-2 , a sector with a smaller number of sectors is arranged on the magnetic disk as it goes inward from the outermost zone 1. Even in the zones N _{z−2 to} N _{z on the} inner periphery, a sector with a smaller number of sectors is arranged on the magnetic disk as it becomes inward. However, in the zones N _{z−2 to} N _z on the inner periphery, sectors are secured on the flash memory so that the sum of the number of sectors on the magnetic disk and the number of sectors on the flash memory is constant. That is, in the zone _Nz-2 , all sectors are allocated on the magnetic disk. In the zone N _z−1 , two sectors are allocated on the flash memory, and the other sectors are allocated on the magnetic disk. In the zone N _z , three sectors are allocated on the flash memory, and the other sectors are allocated on the magnetic disk.

  In this embodiment, the R / W speed is not constant over the entire surface of the disk, but it can be realized with an appropriate flash memory capacity. If the hybrid has an inner circumference of about 1/4, even a large-capacity HDD with a total capacity of about 200 GB can be realized with a flash memory of about 4 GB.

  FIG. 4 shows an example in which the effect of hybrid recording in Example 2 (hybrid recording only on the inner periphery) is calculated. FIG. 4 is an example showing how much high speed can be realized by the hybridization of the inner peripheral part 1/4.

As shown in FIG. 4, in the zone _Nz-2 , the number of sectors on the magnetic disk is _Ns0 , and the number of sectors on the flash memory is zero. In the zone N _z−1 , the number of sectors on the magnetic disk is N _s1 and the number of sectors on the flash memory is N _f1 . In the zone N _z (innermost circumference), the number of sectors on the magnetic disk is N _s2 , and the number of sectors on the flash memory is N _f2 . In this embodiment, N _s0 = N _s1 + N _f1 = N _s2 + N _f2 .

When not hybrid recording (in the case of the prior art), the recording amount of one track in the innermost zone is N _s2 × 512 bytes. On the other hand, in the hybrid recording (Example 2), the recording amount of one track in the innermost zone is (N _s2 + N _f2 ) × 512 bytes = N _s0 × 512 bytes. Assuming that the number of sectors in the zone decreases by 2.6% of the maximum number of sectors toward the inner circumference, the number of sectors in the i-th zone is 1- (i-1) with respect to the number of sectors on the outermost circumference. It is a number multiplied by 0.026. Assuming that the total number of zones is 20, in the case of non-hybrid recording (in the case of the prior art), 1-19 × 0.026 = 0.506 in the 20th zone, that is, 51% of the outermost outermost sector in the innermost zone It becomes. On the other hand, in the hybrid recording (Example 2), if the inner circumference ¼ is hybrid recording, the number of zones decreases up to the 15th zone, that is, 1-14 × 0.026 = 0.636. The minimum number of sectors is 64% of the outermost circumference, and the recording rate can be increased to 0.636 / 0.506≈1.26, that is, 26%. Since writing to the flash memory is performed during the seek time, there is no recording loss during the seek time, and further effective speed improvement can be expected.

  As described above, the inner peripheral portion of this embodiment is preferably a track belonging to about ¼ zone on the inner peripheral side. However, in general, the inner peripheral portion of this embodiment is the outermost portion. A range from an arbitrary track excluding the outer periphery and the innermost track to the innermost track can be set. That is, in this embodiment, the sum of the number of sectors allocated to the magnetic disk and the number of sectors allocated to the flash memory may be constant in tracks from any track to the innermost track except the outermost and innermost tracks.

FIG. 5 shows the required capacity of the flash memories according to the first and second embodiments. The number of sectors the outermost (Zone 1) Lmax, Lmax / 2 the number of sectors of the innermost circumference (zone Nz), the number of tracks over the entire surface of the disc is _{T n.}

In the case of full-hybridization (Embodiment 1), the sum of the number of sectors allocated to the magnetic disk and the number of sectors allocated to the flash memory is made constant for all T _n tracks on the entire disk surface. Will be allocated to the flash memory. Area of the magnetic disc portion, as is apparent from _{FIG, Lmax × T n - (Lmax} / 2) a _{× T n / 2 = 3 ×} Lmax × T n / 4, need area of the flash memory (Lmax / 2) × T _n / 2 = Lmax × T _n / 4. A flash memory having a storage capacity of 1/3 of the storage capacity of the magnetic disk is required, and the storage capacity of the flash memory is about 67 GB with respect to a 200 GB magnetic disk.

In the case of the inner quarter 1/4 hybrid (Embodiment 2), the sum of the number of sectors assigned to the magnetic disk and the number of sectors assigned to the flash memory is made constant for T _n / 4 tracks on the inner circumference side. , 52 is assigned to the flash memory. As is apparent from the figure, the area of the portion 52 is (Lmax / 8) × (T _n / 4) / 2 = Lmax × T _n / 64, so that it is 1/16 of that in the case of full-surface hybridization. About 4 GB is the required capacity of the flash memory for a 200 GB magnetic disk.

  FIG. 6 shows an implementation example of Embodiment 2 of the present invention (hybrid recording only on the inner periphery). In FIG. 6, 61 is a magnetic disk device, 62 is a SAS / SATA interface, 63 is an HDD controller (hard disk drive controller), 64 is a large capacity cache memory, 11 is a magnetic disk, 12 Is a flash memory. Sectors are arranged on the magnetic disk 11 and the flash memory 12 as shown in the sector arrangement diagram shown in the upper part of FIG. 6 (the same sector arrangement diagram as FIG. 4).

Data recording (writing) to the magnetic disk device 61 is performed as follows. When a data stream from a host system (not shown) is input to the magnetic disk device 61 via the SAS / SATA interface 62, the data is temporarily stored in the large-capacity cache memory 64. The HDD controller 63 determines the data temporarily stored in the large-capacity cache memory 64 based on the track number and sector number designated from the host system via the SAS / SATA interface 62, and the magnetic disk 11 or flash Recorded in one of the memories 12. That is, if the track designated by the host system belongs to the zone N _{1 to} N _z-2 (a zone in which a sector is assigned only to the magnetic disk), the HDD controller 63 sets the designated sector on the magnetic disk. Record the data. The HDD controller 63 is designated by the host system when the track designated by the host system belongs to the zone N _{z-1 to} N _z (a zone in which sectors are assigned to both the magnetic disk and the flash memory). The determination is made based on the sector number, and data is recorded in the sector of the magnetic disk 11 or the flash memory 12.

Reading of data from the magnetic disk device 61 is performed as follows. The HDD controller 63 makes a determination based on the track number and sector number designated from the host system via the SAS / SATA interface 62, reads data from either the magnetic disk 11 or the flash memory 12, and stores the data in a large capacity. Data stored temporarily in the cache memory 64 and temporarily stored in the large-capacity cache memory 64 is transmitted to the host system via the SAS / SATA interface 62. That is, the HDD controller 63 determines the designated sector of the magnetic disk 11 when the track designated by the host system belongs to the zone N _{1 to} N _z-2 (a zone in which a sector is assigned only to the magnetic disk). Read data from. The HDD controller 63 is designated by the host system when the track designated by the host system belongs to the zone N _{z-1 to} N _z (a zone in which sectors are assigned to both the magnetic disk and the flash memory). Judgment is made based on the sector number, and data is read from the sector of the magnetic disk 11 or the flash memory 12.

  In the case of sequential access (sequential R / W), the HDD controller 63 performs recording / reading by the following algorithm.

For recording: When recording on a track belonging to zones 1 to N _z-2 (a zone in which a sector is allocated only to the magnetic disk), recording is performed on all sectors of the track on the magnetic disk 11 in one rotation. When recording on a track belonging to zone N _z-1 (zone assigned to both magnetic disk and flash memory), sector 1 to Z _s-2 (sector assigned to magnetic disk) As with the HDD of, writing to the magnetic disk 11 is performed. For tracks belonging to the sectors N _{s-1 to} N _s (sectors allocated to the flash memory), the next recording track on the magnetic disk 11 is simultaneously written into the flash memory 12 during search or writing. A recording rate equivalent to that of the zone N _s-2 is ensured. This is achieved by recording data from the large capacity cache memory 64. The same applies to the zone N _z .

In the case of reading: When reading from a track belonging to zone 1 to N _z-2 (a zone in which a sector is allocated only to the magnetic disk), reading is performed from all sectors of the track on the magnetic disk 11 in one rotation. When reading from a track belonging to zone N _z-1 (zone assigned to both magnetic disk and flash memory), sector 1 to Z _s-2 (sector assigned to magnetic disk) Reading from the magnetic disk 11 is performed in the same manner as the HDD. For tracks belonging to the sectors N _{s-1 to} N _s (sectors allocated to the flash memory), the next read track on the magnetic disk 11 is read from the flash memory 12 simultaneously during search or read, A read rate equivalent to that of the zone N _s-2 is ensured. This is realized by temporarily storing the data read from the flash memory 12 and the data read from the magnetic disk 11 in the large-capacity cache memory 64. The same applies to the zone N _z .

  In the case of random access (random R / W), the HDD controller 63 performs recording / reading by the following algorithm.

  The sectors on the magnetic disk 11 and the sectors on the flash memory 12 are accessed independently. The disk is not controlled when the sector on the flash memory 12 is accessed.

The implementation example and operation of the second embodiment (hybrid recording only on the inner periphery) and the operation thereof have been described with reference to FIG. 6. The implementation example and operation of the first embodiment (full-surface hybrid recording) are described with reference to FIG. The same explanation can be made by replacing the zone N _z-2 with the outermost zone 1 in the description.

  As described above, the magnetic disk device (hard disk device) including the magnetic disk 11 and the flash memory 12 has been described as an embodiment and an example of the present invention. However, the present invention is not limited to this, and the disk device performs data recording or reading. A disc having a plurality of tracks arranged concentrically, with a larger number of sectors allocated to the outer track of the plurality of tracks, and a smaller number of sectors allocated to the inner track; Any disk device provided with a non-volatile memory to which a sector for recording or reading is allocated as a sector of a track on the inner circumference side of the disk may be used.

  As mentioned above, the invention made by the present inventor has been specifically described based on the above-described embodiments and examples. However, the present invention is not limited to the above-described embodiments and examples, and does not depart from the spirit of the invention. Of course, various changes can be made.

It is a figure which shows the magnetic disk and flash memory which are used for the magnetic disk apparatus of embodiment of this invention. 1 is a sector layout diagram of a magnetic disk device according to a first embodiment (full hybrid recording) of the present invention. FIG. FIG. 6 is a sector layout diagram of a magnetic disk device according to a second embodiment (hybrid recording only on the inner periphery) of the present invention. It is a figure for demonstrating the effect of the hybrid recording of Example 2 of this invention. It is a figure which shows the required capacity | capacitance of the flash memory of Example 1 and Example 2 of this invention. It is a figure which shows the example of mounting of the magnetic disc unit of Example 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Magnetic disk, 12 ... Flash memory, 51 ... Required capacity of flash memory in Example 1, 52 ... Required capacity of flash memory in Example 2, 61 ... Magnetic disk apparatus, 62 ... SAS / SATA interface, 63 ... HDD Controller, 64 ... Large capacity cache memory

Claims (7)

In a disk device for recording or reading data,
A disk having a plurality of tracks arranged concentrically, allocating a sector with a large number of sectors to the outer track of the plurality of tracks, and allocating a sector with a smaller number of sectors to the track on the inner periphery;
A non-volatile memory to which sectors for supplementing sectors with a small number of sectors on the inner circumference side of the disk are allocated ,
The sum of the number of sectors allocated to the inner circumference side of the disk and the number of sectors allocated to the nonvolatile memory is the same in the tracks from the outermost circumference to the innermost circumference of the disk
A disk device characterized by the above . In a disk device for recording or reading data,
A disk having a plurality of tracks arranged concentrically, allocating a sector with a large number of sectors to the outer track of the plurality of tracks, and allocating a sector with a smaller number of sectors to the track on the inner periphery;
A non-volatile memory to which sectors for supplementing sectors with a small number of sectors on the inner circumference side of the disk are allocated ,
The sum of the number of sectors allocated to the disk and the number of sectors allocated to the non-volatile memory is the same in the tracks from any track to the innermost track except the outermost and innermost tracks,
A disk device characterized by the above . The disk is divided into zones in the radial direction, and the same number of sectors are assigned to tracks belonging to the same zone, and a larger number of sectors are assigned to tracks belonging to the outer zone. 3. The disk apparatus according to claim 1, wherein a sector having a small number of sectors is allocated to a track belonging to the zone. The disk apparatus according to any one of claims 1 to 3 wherein the disc is characterized in that it rotates at a constant rotational speed. Cache memory for temporarily storing data,
A disk controller that records data temporarily stored in the cache memory in the disk or the non-volatile memory, or reads data from the disk or the non-volatile memory and temporarily stores the data in the cache memory;
Claims 1, characterized in that it comprises a to the disk device according to any one of the four. In the case of sequential access, when performing recording or reading on a sector allocated to the non-volatile memory, the disk controller searches the next recording or reading track on the disk during the search or recording or reading. 6. The disk apparatus according to claim 5 , wherein recording or reading is performed on a sector allocated to the volatile memory. It said disk controller, in the case of random access, the disk apparatus according to claim 5 or 6, characterized in that the disk control is not performed when accessing the sectors on the nonvolatile memory.

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