JP2504843B2 - Buffer expansion device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buffer expansion device for holding external data of an electronic device that inputs / outputs data from / to an external storage device.

<Prior Art> Conventionally, an electronic device that takes in data from an external storage device and performs a task such as calculation has a fixed-capacity buffer pool 5 for storing data in the external storage 6 as shown in FIG. ing.

When reading the data from the external storage 6, the CPU (not shown) issues an instruction to the input / output management unit 2 via the interface I / F 1 to the input / output management unit 2. Reads the instructed data from the external storage 6 and stores the data in the buffer pool 5. Then, the CPU uses the data stored in the buffer pool 5 to perform work such as calculation.

<Problems to be Solved by the Invention> However, the conventional method described above has the following problems because the capacity of the buffer is fixed.

If the buffer capacity is small compared to the frequency of reading data, the buffer will be filled up immediately with the read data.When reading further data, first discard any data in the buffer or write it to external storage and then store it in the buffer. You have to make an empty area. Therefore, input and output of data to and from the external storage occurs frequently, and the work processing speed is reduced.

When the capacity of the buffer is increased to solve the above problem, the capacity of the entire memory is fixed, and thus the capacity of the area other than the buffer (for example, the user area of the application program) becomes relatively small, Work ability is reduced.

Therefore, it is an object of the present invention to provide a buffer expansion device that expands a buffer that stores external data without squeezing other areas of the memory.

<Means for Solving the Problems> In order to achieve the above object, the present invention particularly includes a fixed buffer for inputting and outputting data to and from an external storage device and holding data from the external storage device. In an electronic device having a memory having an area other than the fixed buffer as a user area, when there is a request to capture data from the external storage device,
First for determining whether or not there is an empty area in the fixed buffer
And a second determining means that determines whether or not there is an empty area in the user area when the first determining means determines that there is no empty area. When it is determined that there is an empty area, the user area stores the data taken in from the external storage device, and the area is registered as an extension buffer; A buffer expansion device comprising: return means for discarding data in the expansion buffer or outputting the data to the external storage device and returning the area to the user area.

<Operation> When a request for fetching data from the external storage device is made, it is determined whether or not there is an empty area in the fixed buffer. When it is determined that there is no empty area, it is determined whether or not there is an empty area in the user area. to decide. Then, if it is determined that there is an empty area,
The data fetched from the external storage device is stored in the user area, and the area is registered as an extension buffer.

When the capacity of the user area becomes insufficient, the data in the expansion buffer is discarded or output to the external storage device and the area is returned to the user area.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a memory peripheral portion of an electronic device to which the present invention is applied.

1 is an interface I / F interposed between a CPU (not shown) and a memory, 2 is an input / output management unit for managing and controlling data input / output to / from the external storage 6, and 5 is data read from the external storage 6. A memory pool for storing memory other than the buffer pool 5, 4 a user area for application programs,
7 is an extended buffer pool Ebp (Extended buffer) which will be described later.
pool). The user area 4, the buffer pool 5, and the extension buffer 7 exist in the main memory.

Here, the external storage 6 is composed of, for example, a magnetic disk device such as a floppy disk or a hard disk.

Next, a second method for obtaining the extended buffer pool 7 will be described.
This will be described with reference to the flowcharts of FIGS.

FIG. 2 shows the operation of the input / output management unit 2 when acquiring the extended buffer pool.

First, when a data request command for the external storage 6 is issued from the CPU via the interface I / F1, the input / output management unit 2 confirms whether or not the requested data is in the buffer pool 5. If the data does not exist in the buffer pool 5, an area acquisition request for reading the data from the external storage 6 is generated in the buffer pool 5 (step S1).
Then, it is confirmed whether or not there is an empty area in the buffer pool 2 (step 2). If there is an empty area, the process proceeds to step S6, and if not, the process proceeds to step S3. In step S3, the memory management unit 3
Request to get memory area for buffer pool. Then, if acquisition of the memory area is successful, step
The acquired memory area is registered as an extended buffer pool (Ebp) in S4, and the process proceeds to step S6. If the acquisition of the memory area fails, the process proceeds to step S5, and any data held in the existing buffer pool is discarded or output to the external storage 6 to create an empty area. In step S6, the empty area of the buffer pool is returned to the control of the CPU. The CPU reads desired data from the external storage 6 into the empty area of the buffer pool via the interface I / F 1 and the input / output management unit 2.

FIG. 3 shows the operation of the memory management unit 3 when the input / output management unit 2 acquires the extended buffer pool.

When the input / output management unit 2 makes a memory area acquisition request for the buffer pool in step S3 of the flow chart of FIG. 2, it is checked in step S8 whether or not there is an empty area in the user area 4, and there is no empty area. For example, in step S9, it is checked whether or not there is an unused area (not shown) that can be used as a buffer pool other than the user area. If an empty area is found in step S8 or step S9,
The buffer pool memory area can be acquired, and the empty area is placed under the control of the input / output management unit 2. Further, it outputs to the input / output management unit 2 that the buffer pool memory area cannot be acquired if no empty area is found.

By the way, the above-mentioned memory area newly registered as an extended buffer pool is not used permanently as a buffer pool, but if there is a memory area return request from the memory management unit 3, the extended buffer pool is separated from the buffer pool. It can be returned under the control of the memory management unit 3. This method will be described with reference to the memory block diagram of FIG. First, the memory management unit 3 issues a return request for the memory area of the user area (or the memory area of another area) to the input / output management unit 2. The input / output management unit 2 confirms whether or not the data exists in the area of the extended buffer pool 7 for which the return request is made, and if the data exists, the data is abandoned or output to the external storage 6 to Is separated from the buffer pool 5. Then, the memory management unit 3 places the separated memory area under its own control as an empty area, and uses the area for desired processing.

As described above, by expanding the buffer pool for storing external data by using the empty area of the other area of the memory at any time, the number of unnecessary data inputs / outputs can be reduced and the work processing speed can be improved.

Also, when there is insufficient capacity in the memory area other than the buffer pool, the newly acquired extended buffer pool is returned to another memory area.
The expansion of the pool does not occupy other areas of memory and interfere with the processing of work.

<Effects of the Invention> According to the present invention, the buffer holding external data can be expanded at any time depending on the availability of the user area, and the expanded buffer is returned at any time when the user area capacity becomes insufficient. Therefore, it is possible to improve the work processing speed by suppressing the number of unnecessary data inputs / outputs as much as possible without affecting the work processing capacity.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a memory peripheral portion of an electronic device to which the present invention is applied, FIG. 2 is a flow chart showing an operation of an input / output management unit, and FIG. 3 is a flow chart showing an operation of a memory management unit. FIG. 4 is a block diagram showing a configuration of a memory peripheral portion of a conventional electronic device. 1 ... interface (I / F), 2 ... input / output management unit,
3 ... Memory management unit, 4 ... User area, 5 ... Buffer pool, 6 ... External storage, 7 ... Extended buffer pool

Claims (1)

(57) [Claims] 1. An electronic device having a memory including a fixed buffer for inputting / outputting data to / from an external storage device and holding data from the external storage device, and having a region other than the fixed buffer as a user area. , When there is a request to fetch data from the external storage device,
First for determining whether or not there is an empty area in the fixed buffer
And a second determining means that determines whether or not there is an empty area in the user area when the first determining means determines that there is no empty area. When it is determined that there is an empty area, the user area is stored with the data fetched from the external storage device, and the area is registered as an extension buffer; A buffer expansion device comprising: a return means for abandoning data in the expansion buffer or outputting it to the external storage device and returning the area to the user area.