JP2644541B2 - Method and apparatus for reading a recording medium - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information storage method for a rewritable recording medium such as a disk.

2. Description of the Related Art As shown in FIG. 10, in a rewritable disk device having a movable head H with respect to a disk D, cylinders serving as storage area units for recording information extend in a circumferential direction and are arranged in a radial direction. Numbers 1 to n are assigned.

Conventionally, the number of a cylinder for recording information, that is, a file, is determined only by the conditions at the time of recording information on a disk.

The cylinder number where the once recorded information exists is unchanged, and remains at the same position until the information is erased unless the information is forcibly rearranged.

Therefore, unless the information in the disk is rearranged systematically in consideration of the read frequency and read order of the recorded information, it is not guaranteed that the cylinders that are frequently used are located close to each other. As the distance becomes longer, the average input / output time of the disk increases, and when information is exchanged with the disk of the central processing unit, a state occurs in which the input / output operation of the disk is completed, and a phenomenon occurs in which the performance cannot be exhibited. .

Therefore, in a conventional rewritable disk device having a movable head, a delay in processing time due to a seek is a matter of course and inevitable.

SUMMARY OF THE INVENTION An object of the present invention is to read a recording medium so that the moving amount of a movable head is reduced as much as possible so that writing or reading of the recording medium by the head can be performed in a short time. To provide a method and apparatus for

Means for Solving the Problems The present invention moves a head for writing and reading across a recording medium while rotating a rewritable disk-shaped recording medium, and moves the head inward in a radial direction of the recording medium. The frequent reading area, the management area, and the infrequent reading area extend in the circumferential direction from the outside in the radial direction, and are formed in this order. These frequent reading area, the management area, and the infrequent reading area The area is the concentric or spiral shape of the recording medium,
A plurality of store area units are respectively formed, and the number of read times for each store area unit of the frequent read area and the infrequent read area is counted, and based on the calculated value, in the frequent read area, the order of read frequency is high. The re-arrangement operation of allocating and allocating the storage area units away from the vicinity of the management area is repeated, and the remaining storage area units not allocated to the frequent reading area are already assigned to the infrequent reading area. The parts that are evicted from the frequent read area are allocated and allocated from the vacant read area that is closer to the management area among the vacant store area units in the frequent read area. , A reserved address for issuing a reservation request for each store area unit derived from the central processing unit, and the actual use of the recording medium in the frequent reading area and the frequent reading area. When a management table for associating the address with the address is stored and the read operation of the frequent read area and the infrequent read area is not performed, the head is brought to the control area, and the reserved address from the central processing unit is reserved. A method for reading a recording medium, wherein an actual address corresponding to the above is read out from the management table and read out to the actual address.

The present invention also relates to (a) a rewritable disk-shaped recording medium, which includes a frequent reading area, a management area, and a frequent reading area from a radially inner side to a radially outer side of the recording medium. Are formed in this order by extending in the circumferential direction. The frequent reading area, the management area, and the infrequent reading area include a plurality of storage area units concentrically or spirally on the recording medium. (B) a disk device for rotating the recording medium and moving a head for reading the recording medium across the recording medium; and (c) securing requests for each storage area unit. A central processing unit for deriving a reserved address to be read; and (d) control means for counting the number of reads for each storage area unit in the frequent reading area and the infrequent reading area, and based on the count value, Frequency reading area Then, in the order of read frequency, the rearrangement operation of allocating and arranging the store area units so as to move away from the vicinity of the management area is repeated, and for the remaining store area units that have not been allocated to the frequent read area, The data in the infrequent reading area is not rearranged, and the area removed from the infrequent reading area is allocated from the free storage area unit in the infrequent reading area that is closer to the management area. In the management area, a management table for associating a reserved address derived from the central processing unit for requesting a reservation for each storage area unit with the actual address of the recording medium in the frequent reading area and the infrequent reading area. When the read operation of the frequent read area and the infrequent read area is not performed, the head is brought to the management area, An apparatus for reading a recording medium, wherein an actual address corresponding to a reserved address from a processing device is read out from the management table and read out to the actual address.

According to the present invention, a rewritable recording medium is read using a movable head, and a storage area unit having a large number of read times out of information recorded on the recording medium is stored in a radial direction more than a management area. The rearrangement operation of assigning and arranging adjacent inner frequent read areas in the order of the read frequency in order of increasing read frequency and away from the vicinity of the management area is repeated, thereby reducing the load of the rearrangement processing. The moving distance when the head seeks can be effectively reduced. This makes it possible to reduce the processing time.

According to the present invention, in the low-frequency read area, the rearrangement operation is not performed regardless of the read frequency of the store area unit. In the low-frequency reading area, the reading frequency in the storage area unit is less than that in the above-mentioned high-frequency reading area, so the processing time becomes too long without rearrangement. Is less. Thus, since it is not necessary to perform the rearrangement process in the low-frequency reading area, the burden for that is reduced, and the moving distance when the head seeks as described above can be effectively reduced.

Embodiment FIG. 1 is a simplified plan view of a disk drive 1 according to an embodiment of the present invention, and FIG. 2 is a block diagram showing an electrical configuration connected to the disk drive 1. Referring to these drawings, a disk 2 as a rewritable recording medium is driven to rotate around a rotation axis 3 as indicated by an arrow 4.

A head H for writing and reading data to and from the disk 2 is fixed to a head arm 5. The arm 5 moves the head H across the disk 2 by driving means 6. The head H, as shown in FIG.
May be configured to be displaced in the radial direction of the disk 2, or may be configured to move linearly or along a curved path at an angle with respect to the radial direction of the disk 2. Good.

Store areas are formed concentrically from the inner side in the radial direction to the outer side in the radial direction on the disk 2, and one or more store areas in the store area unit include a buffer area 7, a frequent area 8, A management area 9 and a low frequency area 10 are included.

In this embodiment, the store area unit is called a cylinder,
The cylinder allocation request is defined as virtual cylinder allocation, and the actual disk cylinder allocation is defined as real cylinder allocation.
Accordingly, the cylinder viewed from the disk control device 11 on the central processing unit side is a virtual cylinder, the number of this virtual cylinder is called a virtual cylinder number, the cylinder in the disk is an actual cylinder, and the actual cylinder number is the actual cylinder number. Say

As the buffer area 7, a cylinder number 7 which is a free store area near the management area is secured.

As shown in FIG. 1, the frequent area 8 includes cylinders which are the store area units having the actual cylinder numbers 1 to 5, the management area 9 has the actual cylinder number 6, and the infrequent area 10 has the actual cylinder number. It has a cylinder which is a store area unit of numbers 8 to n.

Although the cylinders having the actual cylinder numbers 1 to n extend in the circumferential direction and are arranged in the radial direction, the cylinders are formed concentrically. However, in another embodiment, the cylinders have a spiral shape. May be formed.

The assignment of the actual cylinder number is for discriminating the physical position of the store area unit, so that the actual cylinder number is assigned in any order from the inside in the radial direction or the outside from the radial direction. Good.

The buffer area 7 may be in any cylinder as long as the space required for the virtual cylinder moving operation and the management area moving operation is secured.

In relation to such a disk device 1 shown in FIG. 1, a disk control device 11 and a processing circuit 12 shown in FIG.
And a main storage device 13 of the central processing unit connected to the disk control device 1. In FIG. 2, the solid line indicates the flow of the command, and the broken line indicates the flow of the information.

The disk control device 11 has a function of exchanging information to be recorded and reproduced on the disk 2 with a main storage device 13 of the central processing unit.
A virtual cylinder / real cylinder conversion means 14 for recording and reproducing information from the disk control device 11 on the disk 2 is connected.

The virtual cylinder management table buffer unit 15 stores the virtual cylinder /
The virtual cylinder number, file name, relative cylinder number in the file, attribute, number of previous reference times, previous freshness ratio, previous reference frequency, previous freshness ratio, and current time for each virtual cylinder shown in Table 1 used by the real cylinder conversion means 14. A virtual cylinder management table having a reference count, a current freshness rate, a priority determination value, a current actual cylinder number, and a new actual cylinder number is stored.

Further, the processing circuit 12 reads the virtual cylinder management table from the management area 9 of the disk 2 of the disk device 1 according to the instruction of the virtual cylinder / real cylinder conversion means 14, and reads the management area contents to be stored in the virtual cylinder management table buffer unit 15. A means 16 for reading a virtual cylinder management table from the virtual cylinder management table buffer unit 15 according to an instruction of the virtual cylinder / real cylinder conversion means 14 and recording the virtual cylinder management table in the management area 9 of the disk 2 of the disk device 1; In the virtual cylinder moving operation and the management area moving operation, the cylinder moving operation buffer unit 18 for temporarily storing the contents of one or more cylinders of the disk 2, and the disk device 1 according to the instructions of the virtual cylinder / real cylinder converting means 14. Virtual cylinder that rearranges and moves the virtual cylinders of disk 2 using the cylinder moving work buffer section 18. And Da rearrangement means 19 comprises a management area moving means 20 for moving the management area of the disk 2 of the disk device 1 with the cylinder moving the working buffer unit 18 by the instruction of the virtual cylinder / actual cylinder conversion unit 14.

FIG. 3 is a flowchart showing a main processing procedure for explaining operations of the disk control device 11 and the processing circuit 12,
FIG. 4 is a flowchart showing a management area moving procedure.
FIG. 5 is a flowchart showing a procedure for rearranging virtual cylinders.

The process proceeds from step n1 to step n2 in FIG. 3, and the contents of the management area 9 are read out and copied to the virtual cylinder management table buffer unit 15 shown in FIG.

At step n3, it is determined whether or not there is an upward position from the disk controller 11. If there is such information, the process proceeds to step n4, where the registration of the virtual cylinder number in the virtual cylinder management table,
Update and delete.

In step n5, it is determined whether there is a write / read command to the disk device 1, and if so,
In step n6, the process of writing / reading information to / from the disk device 1 by the actual cylinder is performed. The real cylinder number at the time of new writing is preferentially assigned to the management area from among the high frequency areas if the high frequency area is free. If the high frequency is not vacant, the allocation is preferentially performed in the low frequency area from the one closer to the management area.

At step n7, information read from the head H of the disk device 1 is returned to the disk control device 11.

In step n8, it is determined whether or not there is a change in the virtual cylinder management table. If there is a change, the contents of the management area 9 are updated. At step n10, it is determined whether or not the operation rates of the disk control device 11 and the disk device 1 are equal to or less than the set value.
It is determined whether the number of cylinders whose usage frequency is equal to or more than a predetermined number of cylinders 0 greatly fluctuates from a certain ratio and it is necessary to move the management area. It is determined whether the number of references exceeds a set value.

If it is determined in Step n11 that the management area needs to be moved, the management area 9 is moved in Step n13, the virtual cylinders are rearranged in Step n14, and the contents of the management area 9 are stored in Step n15. Be updated.

Table 2 shows a virtual cylinder management table. The virtual cylinder management table in Table 2 is an example of a situation where a file is recorded on a disk having 20 cylinders by the method of the present invention.

The virtual cylinder number 1 has a management area where a virtual cylinder management table is stored.

The virtual cylinder number 2 has a buffer area for temporary evacuation when moving the virtual cylinder.

Seven files are stored in virtual cylinder numbers 3 and above.

File A occupies virtual cylinder numbers 3, 4, and 5, and real cylinders are allocated to the previous two cylinders, but real cylinders are allocated to the third cylinder because no information is recorded. Absent.

The file B is an indexed file. An index key is recorded in the virtual cylinder number 6, and its data portion is recorded in the virtual cylinder number 10. The virtual cylinder number 7 has data deleted and the corresponding real cylinder has been released.

 File C is recorded in virtual cylinder number 8.

Since the files D and E are small, they are recorded together with the virtual cylinder number 9.

File F is recorded in virtual cylinder numbers 12 and 13.

The file G is assigned a virtual cylinder number 14 in the primary assignment, and a virtual cylinder number 16 in the secondary assignment.

The virtual cylinder numbers 11 and 15 are free by erasing the file.

The actual cylinder number 12 is free due to the deletion of the file.

The real cylinder numbers 14 to 20 are free real cylinders to which no file has been assigned yet.

Here, the actual cylinder numbers 1 to 6 have the attribute of the high frequency range, and the actual cylinder numbers 9 to 20 have the attribute of the low frequency range.

The virtual cylinder number is a logical cylinder address for the disk 2 used by the disk control device 11 as described above.

The actual cylinder number indicates the actual address of the cylinder of the disk 2.

The freshness rate this time is M1, the number of times of reference this time is N1, the freshness rate of the previous time is M2, the number of times of previous reference is N2, and the freshness rate before the previous time is
When M3 is set and N3 is set as the number of times of reference two times before, the priority determination value S is a calculation result represented by the first equation.

i indicates this time, the last time, and the time before the previous time.

In another embodiment, the range of i may be 4 or more.

Here, when the freshness rate is large this time, it indicates that the information has been updated recently for the cylinder.

For example, a freshness rate of “1” this time means that information was written before the previous four virtual cylinder rearrangements, and a freshness rate of “5” this time means the last, that is, Means that the information has been written after the rearrangement of the virtual cylinder.

Each time a virtual cylinder is rearranged, the current freshness rate and current reference count are moved to the previous freshness rate and previous reference count fields, and the previous freshness rate and previous reference count are set for the previous freshness rate and previous reference count fields. Go to each. At this time, the freshness rate this time is set to a value reduced by “1”. However, the minimum value is “1”. At the same time, the number of times of reference this time is set to “0”.

Table 3 shows the appearance of Table 2 in an actual cylinder arrangement. An actual cylinder having a smaller number than the actual cylinder number in the management area is a high frequency area, and an actual cylinder having a number larger than the actual cylinder number in the management area is a low frequency area.
An actual cylinder close to the management area is allocated to the buffer area.

Here, it is determined that the actual cylinder that is closer to the management area in the frequent area has the higher use frequency.

The information written in the low frequency area stays at the same actual cylinder number until it is erased unless the information moves to the high frequency area.

When the frequently used information overflows from the frequent area due to the reduced use frequency, the information is moved to the empty real cylinder closest to the management area in the frequent area. The number of cylinders in the frequent area may be, for example, about 40% of the number of cylinders for which information has been recorded.

The information contained in the frequent area is dynamically rearranged and rearranged in the order of frequency in units of cylinders according to the change in the use frequency.

Patterns in which information is recorded and reproduced in order from the states in Tables 2 and 3 will be described based on the virtual cylinder management table.

The procedure for moving the management area in step n13 in FIG. 3 is specifically shown in FIG.

Moving from step r1 to step r2, if the number of cylinders whose usage frequency is equal to or more than the predetermined number of times among the information-recorded actual cylinders is different from the number of actual cylinders in the frequent area by a certain number or more, the number of actual cylinders equal to or more than the predetermined number The transfer destination of the management area is determined so that the space of the minute falls within the frequent area.

In step r3, it is determined whether or not there is a recorded real cylinder at the destination of the management area. If so, the process proceeds to step r4, and the contents of the destination real cylinder are moved to the buffer area 7.

In step r5, the contents of the management area are updated, and in step r6, the contents of the old management area are read, moved to the new management area, and stored.

In step r6, only the actual cylinder number of the management area is changed to the actual cylinder number of the new management area.

In step r7, the actual cylinder number in the old management area is released, and in step r8, the process returns to step n14 in FIG.

The virtual cylinder rearrangement procedure in step n14 shown in FIG. 3 is shown in FIG.

The process proceeds from step s1 to step s2, and the priority semi-fixed value is calculated for each virtual cylinder as shown by the above-described first formula.

In step s3, a real cylinder number is assigned to the virtual cylinder. The assignment is performed by associating the real cylinder numbers closer to the management area in the frequent area in ascending order of the priority determination value. After the assignment of the high frequency range is completed, the remaining portions are allocated to the low frequency range. However, for the virtual cylinders existing in the low-frequency range, the same new real cylinder number as the current real cylinder number is assigned. In other words, information that remains in the low-frequency range is recorded in the same real cylinder without moving. Keep it. For other virtual cylinders that currently exist in the high frequency range and move to the low frequency range, include the newly vacant cylinder number by moving from the low frequency range to the high frequency range,
The virtual cylinder numbers having the highest semi-fixed priority are assigned in order from the free real cylinder number in the low frequency area, which is closer to the management area.

In step s4, the virtual cylinders are sequentially moved in descending order of the priority order determination value.

This sequential movement of the virtual cylinder is performed in the following steps a1 to f1.
Are performed in the following order.

a1. Among the virtual cylinders that have not been moved, the virtual cylinder that exists in the real cylinder number to which the largest priority determination value moves is saved in the buffer area.

b1. Release the actual cylinder number vacated in step a1 from the virtual cylinder management table.

c1. Move the virtual cylinder that enters the empty real cylinder,
Updated virtual cylinder management table.

d1. Release the actual cylinder number occupied by the virtual cylinder moved in step c1 from the virtual cylinder management table.

The operations of e1.c1 and d1 are repeated until the virtual cylinder evacuated at a1 settles on the planned new real cylinder.

The operations from f1.a1 to e1 are repeated until all the virtual cylinders have been moved to the new real cylinders.

In step s5, the virtual cylinder management table is updated in the following order a2 to f2.

a2.Number of previous references → number of previous reference b2.Previous freshness rate → previous number of freshness c2.Number of current references → number of previous references d2.Current freshness rate → priority of freshness e2.Reset to 0 times of current reference f2. Decrease by 1 (however, the minimum value is assumed to be 1). Therefore, based on FIGS.
g3 is performed.

a3. At the time of a file allocation request from the disk controller 11, the virtual cylinder is registered in the virtual cylinder management table.

b3. At the time of an information write request from the disk controller 11,
A real cylinder is allocated to a virtual cylinder based on the virtual cylinder management table, information is recorded in the real cylinder of the disk device 1, and the number of times of reference of the corresponding virtual cylinder number in the virtual cylinder management table is counted up by one, This time, the freshness rate is set to the maximum value.

c3. At the time of information reading request from the disk controller 11,
The actual cylinder corresponding to the virtual cylinder is determined, the recorded information of the actual cylinder is reproduced from the disk device 1 and returned to the disk controller 11, and the number of times this virtual cylinder number in the virtual cylinder management table is referred to by one is counted. Up.

d3. When the entire file is erased at the time of the information erasure request from the disk controller 11, the registration of all the virtual cylinders used by the file is deleted from the virtual cylinder management table, and some of the cylinders in the file area are deleted. Is deleted, the real cylinder allocated to the corresponding virtual cylinder in the virtual cylinder management table is released.

e3. When a value other than the value of the current reference count in the virtual cylinder management table is changed, the new contents of the virtual cylinder management table are written to the disk management area.

f3. When the number of cylinders in the frequent area 10 of the disk 2 of the disk device 1 and the number of actual-recorded actual cylinders whose frequency of use is equal to or more than a predetermined number greatly fluctuate from a certain ratio, the management area is changed. The cylinder is moved so that the number of cylinders equal to or more than a predetermined number falls within the frequent area, and the resulting cylinder allocation status is reflected in the virtual cylinder management table.

g3. When the management area is moved or when the number of times this virtual cylinder reference number registered in the virtual cylinder management table exceeds the set value, the priority determination value is calculated for each virtual cylinder. Assign a new actual cylinder number,
The virtual cylinders are rearranged according to the new actual cylinder numbers and reflected in the virtual cylinder management table.

Based on these operations a3 to g3, virtual cylinder management tables shown in Tables 4 to 21 are created sequentially starting from Table 2.

Table 4 shows a state where a new file H is allocated and occupies virtual cylinder numbers 11, 15, and 17.

Table 5 shows a state where the secondary extension area of the file C occupies the virtual cylinder number 18.

At the stages in Tables 4 and 5, no real cylinders have yet been assigned to the new virtual cylinder.

Table 6 shows a state in which the virtual cylinder numbers 12 and 13 and the real cylinder numbers 10 and 11 are released after the file F is erased.

Table 7 shows a state where the information of the first cylinder of the file G has been deleted and the real cylinder number 4 has been released.

Table 8 shows a state in which the file D coexisting in the virtual cylinder number 9 has been deleted and only the file E has been left.

In Table 9, since the information is recorded in the first cylinder of the file H to which the real cylinder has not been allocated yet, among the frequent frequencies, the free real cylinder number 4 closest to the management area is recorded.
Indicates a state in which is assigned.

Table 10 shows a pattern in which information is recorded in virtual cylinder number 4 which is the second cylinder of file A to which a real cylinder has already been assigned.

If there is writing, the freshness rate is set to 5, which is the maximum this time. The reference count this time is also incremented by one each time.

Table 11 shows a pattern in which the virtual cylinder number 18, which is the second cylinder of the file G, is read and the number of times of reference this time is incremented by one.

Table 12 shows that the actual cylinder number in the management area has moved from 7 to 5 because the ratio of the actual cylinders used in the high frequency area to the actual cylinders used in the low frequency area has become unbalanced. Note that the virtual cylinder number 8 is added first to the real cylinder number 5.
At the same time, the virtual cylinder number 8 is moved to the real cylinder number 8 in the buffer area.

In Table 13, virtual cylinder number 9 is changed to real cylinder number 7
To secure a new buffer area at the actual cylinder number 6.

In Table 14, since the virtual cylinders need to be rearranged as the management area is moved, the priority order determination value is calculated based on the number of times of reference and the freshness rate, and a new real cylinder number is determined.

For the virtual cylinder numbers 11 and 16 in which the new real cylinders move from the high frequency area to the low frequency area, empty real cylinder numbers closer to the management area in the low frequency area are sequentially assigned in accordance with the priority determination value. Specifically, since the real cylinder number 6 is the buffer area, the virtual cylinder number 16 is the real cylinder number 7
And the real cylinder number 8 is assigned to the virtual cylinder number 11.

The same new real cylinder number as the current one is assigned to the virtual cylinder whose new real cylinder still remains in the low frequency range. Therefore, the actual cylinder number 13 is assigned to the virtual cylinder number 6, and the actual cylinder number 9 is assigned to the virtual cylinder number 10.
Is assigned as it is.

In Table 15, as the first stage of the virtual cylinder rearrangement, the virtual cylinder 11 in which the actual cylinder number currently occupies 4 closest to the management area in the frequent area is moved to the actual cylinder number 6 in the buffer area. ing.

In Table 16, the virtual cylinder number 4 has been moved to an empty real cylinder number 4.

In Table 17, the virtual cylinder number 8 is moved to the real cylinder number 3 and the virtual cylinder number 11 is moved to the real cylinder number 8 in order, and the virtual cylinder number 2 is secured again at the real cylinder number 6 as a buffer area. .

In Table 18, the virtual cylinder number 16 has been moved to the actual cylinder number 6 in the buffer area.

In Table 19, the virtual cylinder number 9 is moved to the empty real cylinder number 2, and the virtual cylinder number 2 is secured in the real cylinder number 6 as a buffer area again.

In Table 20, the new actual cylinder numbers 1, 13, and 9 of the virtual cylinder numbers 3, 6, and 10 that do not need to be moved are reset.

At this stage, the rearrangement of the virtual cylinders is completed.

In Table 21, the previous reference count is moved to the previous reference count, the previous freshness rate is set to the previous reference rate, the current reference count is set to the previous reference count, the current freshness rate is shifted to the previous freshness rate, and the current reference count is reset. This time, the freshness rate is set to a value obtained by subtracting 1 from the previous freshness rate. However, if the value of the freshness rate this time is already 1, it is not subtracted.

Thus, the virtual cylinder management table is in a new state. As a result, except for the virtual cylinder number 6 in the low frequency area, all the cylinders with a high access frequency are all arranged near the management area.

 Table 22 shows the actual cylinder layout at this time.

Since the number of times of reference varies, it is expected that the head seek almost reciprocates between the actual cylinder numbers 1 to 9.

In summary, in FIG. 1, during operation, the head H first reads the management area 9 and reads the virtual cylinder management table buffer 15
Based on the contents, the virtual cylinder number and the actual cylinder number are subjected to an address conversion, and the cylinder, which is a storage area unit of the disk 2, is read. The stored contents of the cylinders are rearranged in the order of frequency by moving to the cylinder in the close multi-frequency area 8.

When a new cylinder to be written is required, a free real cylinder number closer to the management area 9 is assigned in the order of the high frequency area 8 and the low frequency area 10.

When the ratio of the used actual cylinders in the high frequency range and the low frequency range greatly fluctuates from a fixed value, the management range is moved so as to achieve a balance.

Thus, in the head H, the number of cylinders located radially inward of the management area 9 and the usage frequency of the cylinders located radially outward are balanced, and cylinders close to the management area 9 are frequently used. Therefore, the amount of head movement can be reduced, and the processing speed can be improved.

FIG. 6 is a simplified plan view of a disk device 1 according to another embodiment of the present invention, and FIG. 7 is a block diagram showing an electrical configuration connected to the disk device 1. Referring to these drawings, a disk 2 as a rewritable recording medium is driven to rotate around a rotation axis 3 as indicated by an arrow 4.

A head H for writing and reading data to and from the disk 2 is fixed to a head arm 5. The arm 5 moves the head H across the disk 2 by driving means 6. The head H is mounted on the disk 2 as shown in FIG.
May be configured to be displaced in the radial direction of the disk 2, or may be configured to move linearly or along a curved path at an angle with respect to the radial direction of the disk 2. Good.

In the disk 2, store area units are formed concentrically from the inside in the radial direction to the outside in the radial direction, and one or more store areas of the store area units are a management area 9, a basic area 21, and a copy area. Including 20.

In this embodiment, the store area unit is called a cylinder,
The cylinder allocation request is defined as virtual cylinder allocation, and the actual disk cylinder allocation is defined as real cylinder allocation.
Accordingly, the cylinder viewed from the disk control device 11 on the central processing unit side is a virtual cylinder, the number of this virtual cylinder is called a virtual cylinder number, the cylinder in the disk is an actual cylinder, and the actual cylinder number is the actual cylinder number. Say

The copy 20 is the actual cylinder number 1 as clearly shown in FIG.
The management area 9 has the actual cylinder number 6 and the basic area 10 has the cylinders which are the actual cylinder numbers 7 to n which are the store area units.

Although the cylinders having the actual cylinder numbers 1 to n extend in the circumferential direction and are arranged in the radial direction, the cylinders are formed concentrically. However, in another embodiment, the cylinders have a spiral shape. May be formed.

The assignment of the actual cylinder number is for discriminating the physical position of the store area unit, so that the actual cylinder number is assigned in any order from the inside in the radial direction or the outside from the radial direction. Good. The number of cylinders in the copy area may be, for example, about one quarter of the total number of cylinders.

In relation to the disk device 1 shown in FIG. 6, the disk control device 11 and the processing circuit 12 shown in FIG.
And a main storage device 13 of the central processing unit connected to the disk control device 11. In FIG. 7, the solid line shows the flow of commands, and the broken line shows the flow of information.

The disk control device 11 has a function of exchanging information to be recorded and reproduced on the disk 2 with a main storage device 13 of the central processing unit.
A virtual cylinder / real cylinder conversion means 14 for recording and reproducing information from the disk control device 11 on the disk 2 is connected.

The virtual cylinder management table buffer unit 15 stores the virtual cylinder /
The virtual cylinder number, file name, relative cylinder number in the file, attribute, number of previous reference times, previous freshness rate, previous reference count, previous freshness rate, and current A virtual cylinder management table having a reference count, a freshness rate this time, a priority determination value, a current basic actual cylinder number, a current duplicate actual cylinder number, a new basic actual cylinder number, and a new duplicate actual cylinder number is stored.

Further, the processing circuit 12 reads the virtual cylinder management table from the management area 9 of the disk 2 of the disk device 1 according to the instruction of the virtual cylinder / real cylinder conversion means 14, and reads the management area contents to be stored in the virtual cylinder management table buffer unit 15. A means 16 for reading a virtual cylinder management table from the virtual cylinder management table buffer unit 15 according to an instruction of the virtual cylinder / real cylinder conversion means 14 and recording the virtual cylinder management table in the management area 9 of the disk 2 of the disk device 1; A virtual cylinder copying unit 22 for copying a virtual cylinder of the disk 2 of the disk device 1 to a copy area in accordance with an instruction from the virtual cylinder / real cylinder conversion unit 14; and a cylinder copying work buffer unit connected to the virtual cylinder copying unit 22 23.

This copying operation means that the virtual cylinder / real cylinder converting means 14 determines that copying is advantageous based on the priority order determination value of the virtual cylinder management table buffer unit 15.
The information of one cylinder belonging to 21 is read by the virtual cylinder copying unit 22 and temporarily stored in the cylinder copying work buffer unit 23, and the head H is moved to the actual cylinder of the new actual cylinder number determined by the priority order determination value. After that, the information stored in the cylinder copy work buffer unit 23 is copied and recorded in the copy area 20, and the current real cylinder number of the virtual cylinder previously recorded in the corresponding real cylinder number is stored in the virtual cylinder management table buffer. Is to remove it from the department.

FIG. 8 is a flowchart showing a main processing procedure for explaining operations of the disk control device 11 and the processing circuit 12,
FIG. 9 is a flowchart showing a procedure for copying a virtual cylinder.

The process moves from step n1 to step n2 in FIG. 8, and the contents of the management area 9 are read out and copied to the virtual cylinder management table buffer unit 15 shown in FIG.

In step n3, it is determined whether or not there is information from the disk controller 11. If there is such information, the process proceeds to step n4, where registration, update, and deletion of the virtual cylinder number in the virtual cylinder management table are performed.

In step n5, it is determined whether there is a write / read command to the disk device 1, and if so,
In step n6, the process of writing / reading information to / from the disk device 1 by the actual cylinder is performed. The actual cylinder number at the time of new writing is preferentially assigned and written from the one closer to the management area among the basic ones. If the copy area is free, it is preferentially assigned to the copy area from the one closer to the management area and written.

At step n7, information read from the head H of the disk device 1 is returned to the disk control device 11.

In step n8, it is determined whether or not there is a change in the virtual cylinder management table. If there is a change, the contents of the management area 9 are updated.

In step n10, it is determined whether the operation rates of the disk control device 11 and the disk device 1 are equal to or less than the set value. If the operation ratio is equal to or less than the set value, the process proceeds to step n12 to determine whether the number of times of reference of any of the virtual cylinders exceeds the set value. It is determined whether or not.

If it is determined in step n12 whether the number of times of reference of any of the virtual cylinders this time has exceeded the set value, in step n14, the virtual cylinder is copied, and in step n14,
At 15, the contents of the management area are updated.

Table 24 shows a virtual cylinder management table. The virtual cylinder management table in Table 24 is an example of a situation where a file is recorded on a disk having 20 cylinders by the method of the present invention.

The virtual cylinder number 1 has a management area where a virtual cylinder management table is stored.

Seven files are stored in virtual cylinder numbers 2 and higher.

File A occupies virtual cylinder numbers 3, 4, and 5, and real cylinders are allocated to the previous two cylinders, but real cylinders are allocated to the third cylinder because no information is recorded. Absent.

The file B is an indexed file. An index key is recorded in the virtual cylinder number 6, and its data portion is recorded in the virtual cylinder number 10. The virtual cylinder number 7 has data deleted and the corresponding real cylinder has been released.

 File C is recorded in virtual cylinder number 8.

Since the files D and E are small, they are recorded together with the virtual cylinder number 9.

File F is recorded in virtual cylinder numbers 12 and 13.

The file G is assigned a virtual cylinder number 14 in the primary assignment, and a virtual cylinder number 16 in the secondary assignment.

The virtual cylinder numbers 2, 11, and 15 are free by erasing the file.

The real cylinder numbers 18 to 20 are free real cylinders to which no file has been assigned yet.

Here, the actual cylinder numbers 1 to 6 have the attribute of the high frequency range, and the actual cylinder numbers 8 to 20 have the attribute of the basic range.

The virtual cylinder number is a logical cylinder address for the disk 2 used by the disk control device 11 as described above.

The actual cylinder number indicates the actual address of the cylinder of the disk 2.

The freshness rate this time is M1, the number of times of reference this time is N1, the freshness rate of the previous time is M2, the number of times of previous reference is N2, and the freshness rate before the previous time is
When M3 is set and the number of times of reference is set to N3 two times before, the priority determination value S is a calculation result represented by the second equation.

i indicates this time, the last time, and the time before the previous time.

In another embodiment, the range of i may be 4 or more.

Here, when the freshness rate is large this time, it indicates that the information has been updated recently for the cylinder.

For example, a freshness rate of “1” this time means that information was written before the previous four virtual cylinder rearrangements, and a freshness rate of “5” this time means the last, that is, Means that the information has been written after the virtual cylinder copying process.

Each time the virtual cylinder is copied, the current freshness ratio and the current reference count are moved to the previous freshness ratio and the previous reference count column, and the previous freshness ratio and the previous reference count are respectively set for the previous freshness ratio and the last reference count column. Go to each.

At this time, the freshness rate is set to a value reduced by “1”. However, the minimum value is “1”. At the same time, the number of times of reference this time is set to “0”.

Table 25 shows the appearance of Table 24 in an actual cylinder arrangement. An actual cylinder having a smaller number than the actual cylinder number in the management area is a copy area, and an actual cylinder having a number larger than the actual cylinder number in the management area is a basic area.

Here, it is determined that the actual cylinder that is closer to the management area in the frequent area has the higher use frequency.

Information written in the basic area remains at the same actual cylinder number until it is erased.

If the information in the copy area overflows from the copy area due to less use, the information is recorded only in the actual cylinder in the basic area.

The information contained in the copy area is dynamically rearranged and rearranged in the order of frequency in units of cylinders according to a change in the use frequency.

Patterns in which information is recorded and reproduced in order from the states in Tables 24 and 25 will be described based on the virtual cylinder management table.

The virtual cylinder copying procedure in step n14 shown in FIG. 8 is shown in FIG.

The process proceeds from step s1 to step s2, where the calculation of the priority order determination value is performed for each virtual cylinder as shown by the above-described second formula.

In step s3, a real copy cylinder number is assigned to the virtual cylinder. The assignment is performed by associating real cylinder numbers closer to the management area of the copy area in ascending order of the priority determination value. When the allocation of the copy area is completed, the rest has no room in the copy area, so that the information is recorded only in the basic area.

The same new basic real cylinder number as the current basic real cylinder number is assigned to the virtual cylinder existing in the basic area.

In step s4, the virtual cylinders are sequentially copied from the basic area to the copy area in descending order of the priority order determination value.

In step s5, the virtual cylinder management table is updated in the following order a2 to f2.

a2.Number of previous reference times → number of previous reference times b2.Previous freshness rate → previous time freshness rate c2.Number of current reference times → previous reference number of times d2.Current freshness rate → previous freshness rate e2. Decrease by 1 (However, the minimum value is 1.) Therefore, based on FIGS. 8 and 9, the following operations a4 to a4 are performed.
f4 is performed.

a4. At the time of a file allocation request from the disk controller 11, the virtual cylinder is registered in the virtual cylinder management table.

b4. At the time of an information write request from the disk controller 11,
A real cylinder is allocated to a virtual cylinder based on the virtual cylinder management table, information is recorded in the real cylinder of the disk device 1, and the number of times of reference of the corresponding virtual cylinder number in the virtual cylinder management table is counted up by one, This time, the freshness rate is set to the maximum value.

When allocating real cylinders, free cylinders are preferentially allocated from the base area closer to the management area. If the copy area is vacant, an empty cylinder is preferentially allocated to the copy area from the one closer to the management area.

Therefore, at the time of updating information, the updating process is performed not only on the actual cylinders in the basic area but also on the actual cylinders in the copy area.

c4. At the time of the information reading request from the disk controller 11,
The actual cylinder corresponding to the virtual cylinder is determined, the recorded information of the actual cylinder is reproduced from the disk device 1 and returned to the disk controller 11, and the number of times this virtual cylinder number in the virtual cylinder management table is referred to by one is counted. Up.

The determination of the corresponding real cylinder when the real cylinder is also in the copy area will give the real cylinder closer to the current head position.

d4. If the entire file is erased at the time of the information erasure request from the disk controller 11, the registration of all the virtual cylinders used by the file is deleted from the virtual cylinder management table, and some of the cylinders in the file area are deleted. Is deleted, the real cylinder allocated to the corresponding virtual cylinder in the virtual cylinder management table is released.

The real cylinder is released for both the basic area and the copy area.

e4. When a value other than the value of the current reference count in the virtual cylinder management table is changed, the new contents of the virtual cylinder management table are written to the disk management area.

f4. When the number of times of reference of any of the virtual cylinders registered in the virtual cylinder management table exceeds the set value, a priority determination value is calculated for each virtual cylinder, a new real cylinder number is assigned, and the virtual cylinder is assigned. The cylinders are rearranged according to the new actual cylinder number, copied, and reflected in the virtual cylinder management table.

Based on these operations a4 to f4, starting from Table 24, virtual cylinder management tables shown in Tables 26 to 39 are created.

Table 26 shows a state in which a new file H is allocated and occupies the virtual cylinder numbers 2, 11, and 15.

Table 27 shows a state where the secondary extension area of the file C occupies the virtual cylinder number 17.

At the stages in Tables 26 and 27, no real cylinder has been assigned to the new virtual cylinder yet.

Table 28 shows a state in which file F is erased and virtual cylinder numbers 12 and 13 and real cylinder numbers 10 and 11 are released.

Table 29 shows a state in which the information of the first cylinder of the file G is erased and the real cylinder number 16 and the copied real cylinder number 4 are released.

Table 30 shows a state in which the file D coexisting in the virtual cylinder number 9 is deleted and only the file E is left.

In Table 31, since information was recorded in the first cylinder of the file H to which no real cylinder has been assigned yet, a free real cylinder number 10 and a free copy real cylinder number 4 were allocated.

Table 32 shows a pattern in which information is recorded in virtual cylinder number 4 which is the second cylinder of file A to which a real cylinder has already been assigned.

If there is writing, the freshness rate is set to 5, which is the maximum this time. The reference count this time is also incremented by one each time.

Table 33 shows a pattern in which the virtual cylinder number 16, which is the second cylinder of the file G, is read, and the number of times of reference this time increases by one.

In Table 34, the priority order determination value is calculated based on the number of times of reference and the freshness ratio for performing the virtual cylinder copying process, and a new actual cylinder number is determined.

The virtual cylinder numbers newly accommodated in the copy area are limited to those that fall within the copy area, counting from the larger priority order determination value.

In Table 35, the virtual cylinder copy processing is executed from the virtual cylinder number 4 whose new copy real cylinder number is closest to the management area.

At this time, the current copy actual cylinder number is deleted from the virtual cylinder number 9 whose copy actual cylinder number was 6.

In Table 36, since the current copy real cylinder number of the virtual cylinder number 8 and the new copy real cylinder number are the same 5, the virtual cylinder management table is updated without actually copying the data.

In Table 37, virtual cylinders required for the copy area are copied in the following order.

In Table 38, the new basic real cylinder number of the virtual cylinder number that has not been copied is reset.

 At this stage, the copying operation of the virtual cylinder is completed.

In Table 39, the previous reference count is moved to the previous reference count, the previous freshness rate is set to the previous freshness rate, the current reference count is set to the previous reference count, the current freshness rate is shifted to the previous freshness rate, the current reference count is reset, This time, the freshness rate is set to a value obtained by subtracting 1 from the previous freshness rate. However, if the value of the freshness rate this time is already 1, it is not subtracted.

 The priority determination value is also reset.

Thus, the virtual cylinder management table is in a new state.

As a result, cylinders with a high access frequency are arranged in two places and one of them is arranged near the management area in order of frequency.

 Table 40 shows the actual cylinder layout at this time.

Since there are two cylinders that can be accessed from the reference function, head seeks are expected to concentrate near the management area.

In summary, in FIG. 6, during operation, the head H first reads the management area 9 and reads the virtual cylinder management table buffer section.
15, and based on the contents, the virtual cylinder number and the actual cylinder number are converted into an address, and the cylinder, which is a storage area unit of the disk 2, is read. Copy area close to
Copy to 20 cylinders and sort the store contents of cylinders in order of frequency.

When a new cylinder to be written is required, it is first allocated to a free real cylinder number near the management area of the basic area 21. If there is free space in the copy area 20, a free real cylinder number near the management area of the copy area 20 is also assigned.

Thus, in the head H, the number of cylinders located radially inward of the management area 9 and the usage frequency of the cylinders located radially outward are balanced, and cylinders close to the management area 9 are frequently used. Therefore, the amount of head movement can be reduced, and the processing speed can be improved.

In another embodiment of the present invention, the disk is a track instead of a cylinder if the disk is a track type, a sector instead of a cylinder if the disk is a sector type, or a block instead of a cylinder if the disk is a block type.
An information recording / reproducing method having the same procedure as described above includes the same steps as described above.

According to the present invention, the following modifications are possible. Recording media are magnetic, electrical, optical,
It is only necessary that information can be recorded and reproduced as a digital signal by magneto-optical or other methods, and that information can be recorded and reproduced a plurality of times at the same recording position, that is, rewritable, regardless of the material.

The recording medium stores information in cylinder format, track format,
In either sector or block format,
It is possible to write and read data on and from the disc, cylinder arrangement track in cylinder format, track arrangement track in track format, sector arrangement track in sector format, and block arrangement track in block format. The array trajectory may be concentric or spiral. That is, the shape of each store area does not matter.

The disk may be either a unit that can be attached and detached as a single unit from the rotation drive mechanism of the disk device, or a unit that cannot be attached and detached as a unit.

If any one of the recording head, the reproducing head, and the recording / reproducing head on the disk of the disk device is movable by the head arm, the moving direction of the head may be either linear or curved. Can freely reciprocate on a fixed line connecting the end points of the places, and
The position of the head on this line is combined with the rotational position of the disk to match the cylinder number in the cylinder format, the track number in the track format, the sector number in the sector format, and the block format. In other words, it suffices if it can be determined in association with the block number.

The disk control device 11 on the central processing unit side may be a dedicated microcomputer incorporating a dedicated processing circuit (CPU) or a general CPU used for a word processor, an image processing device or the like.

In the illustrated embodiment described above, the information is recorded on the disk, and the rewritable characteristics of the rewritable disk device are recorded on the disk, paying attention to the fact that the frequency of reading and the additional update frequency for the information recorded on the disk depend on each cylinder. The following configurations (1) and (2) are provided by devising to utilize it later.

(1) In a rewritable disk device having a movable head H, among the information recorded on the disk 2, information having a particularly high frequency of use is dynamically rearranged and arranged in cylinder units in order of frequency. By shortening the average moving distance at the time of seeking, the speed of reading and updating the information recorded on the disk 2 with a small rearrangement processing load is improved.

(2) In a rewritable disk device having a movable head H, information recorded on the disk 2 that has a particularly high frequency of use is dynamically rearranged in order of frequency in a cylinder unit to another area of the same disk. In this case, the reading distance and the updating speed of the information recorded on the disk 2 can be improved with a small rearrangement copy processing load by shortening the moving distance when the head H seeks.

The embodiment having such a configuration has the following advantages.

Regardless of the file, the most frequently used cylinders in the disk can be concentrated in one place or duplicated in two places, so even if the frequency of use is high and the key part and the record body are in different cylinders, it is far from VTOC Even in the case of a file recorded in a different place, the seek distance of the head is reduced.

As a result, it is possible to reduce the average seek time per operation of the disk drive on the order of milliseconds. Since the average execution time per instruction of the processing circuit (CPU) is on the order of microseconds or nanoseconds, the effect of improving the average seek time greatly contributes to shortening the information processing time.

According to the method of storing a rewritable recording medium as described above, the moving amount of the movable head can be reduced as much as possible, and the reading of the recording medium by the head can be performed in a short time. .

In particular, in the present invention, a rearrangement operation of allocating and arranging the storage area units in the frequent reading area adjacent to each other in the descending order of the reading frequency and away from the vicinity of the management area is repeated, whereby the reading is performed in a short time. Will be able to do it.

Moreover, according to the present invention, in the low-frequency reading area, the operation of rearranging the storage area units is not performed regardless of the reading frequency, so that the load of such rearranging processing can be reduced, and Thus, reading can be performed in a short time.

[Brief description of the drawings]

FIG. 1 is a simplified plan view of a disk drive 1 according to one embodiment of the present invention, FIG. 2 is a block diagram showing an electrical configuration connected to the disk drive 1, and FIG. 4 is a flowchart showing a main processing procedure for explaining the operation of the circuit 12, FIG. 4 is a flowchart showing a management area moving procedure, FIG. 5 is a flowchart showing a virtual cylinder rearranging procedure, and FIG. FIG. 7 is a simplified plan view of the disk device 1 of the embodiment, FIG. 7 is a block diagram showing an electrical configuration connected to the disk device 1 of another embodiment,
FIG. 8 shows a disk controller 11 and a processing circuit 12 of another embodiment.
FIG. 9 is a flowchart showing a main processing procedure for explaining the operation of FIG. 9, FIG. 9 is a flowchart showing a virtual cylinder copying procedure of another embodiment, and FIG. 10 is a simplified plan view of the prior art. 1 ... disk device, 2 ... disk, 3 ... rotating shaft,
5 ... arm, 6 ... driving means, 7 ... buffer area, 8
…… High frequency area, 9 …… Management area, 10 …… Low frequency area, 11 ……
Disk control device, 12 processing circuit, 13 memory, 14
... virtual cylinder / real cylinder conversion means, 15 ... virtual cylinder management table buffer unit, 16 ... management area contents reading means, 17 ... management area contents changing means, 18 ... cylinder moving work buffer unit, 19 ... … Virtual cylinder sorting means, 20
…… Management area moving means, 20 …… Copy area, 21 …… Basic area, 22
... virtual cylinder copying means, 23 ... cylinder copy work buffer

Claims (2)

(57) [Claims] 1. A head for writing and reading is moved across a recording medium while rotating a rewritable disk-shaped recording medium, and the head is moved from a radially inner side to a radially outer side of the recording medium. The frequent reading area, the management area, and the infrequent reading area extend in the circumferential direction and are formed in this order, and the frequent reading area, the management area, and the infrequent reading area record Concentric or spiral of the media,
A plurality of store area units are respectively formed, and the number of read times for each store area unit of the frequent read area and the infrequent read area is counted, and based on the calculated value, in the frequent read area, the order of read frequency is high. The reordering operation of allocating and allocating the storage area units so as to be away from the vicinity of the management area is repeated, and the remaining storage area units not allocated to the frequent reading area are already assigned to the infrequent reading area. The parts that are evicted from the frequent read area are allocated and allocated from the vacant read area that is closer to the management area among the vacant store area units in the frequent read area. , A reserved address for issuing a reservation request for each store area derived from the central processing unit, and the actual use of the recording medium in the frequent reading area and the frequent reading area. When a management table for associating the address with the address is stored and the read operation of the frequent read area and the infrequent read area is not performed, the head is brought to the control area, and the reserved address from the central processing unit is reserved. A method for reading a recording medium, wherein an actual address corresponding to the above is read from the management table, and the actual address is read. (A) A rewritable disk-shaped recording medium, comprising a frequent reading area, a management area, and a low-frequency reading area from a radially inner side to a radially outer side of the recording medium. Are formed in this order by extending in the circumferential direction. The frequent reading area, the management area, and the infrequent reading area include a plurality of storage area units concentrically or spirally on the recording medium. (B) a disk device for rotating the recording medium and moving a head for reading the recording medium across the recording medium; and (c) securing requests for each storage area unit. A central processing unit that derives a reserved address that performs the following: (d) control means, which counts the number of reads for each storage area unit in the frequent reading area and the infrequent reading area, and, based on the calculated value,
In the frequent read area, in the order of the read frequency, the reordering operation of allocating and allocating the store area units away from the vicinity of the management area is repeated, and the remaining store area units not allocated to the frequent read area are repeated. For, the area that has already been in the infrequent reading area is not rearranged, and the part that has been evicted from the infrequent reading area is closer to the management area among the many vacant store areas in the infrequent reading area. In the management area, there are reserved addresses for requesting reservation for each store area unit derived from the central processing unit, and the actual addresses of recording media in the frequent reading area and the infrequent reading area. When the read operation of the frequent reading area and the infrequent reading area is not performed, the head is also stored in the management area. Control means for reading an actual address corresponding to a reserved address from the central processing unit from the management table, and reading the actual address. Equipment for.