KR100613857B1 - Set-top apparatus and method for logically extending memory device using network - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a set-top device that logically expands memory through a network, and a method of expanding logical memory through a network.

2. The technical problem to be solved by the invention

The present invention provides a set-top that logically extends memory through a network to provide network virtual memory to the set-top device by appropriately adjusting data access between the resident memory of the set-top device and the remote memory of the head-end and the central processing unit of the set-top device. To provide a logical memory expansion method through devices and networks.

3. Summary of Solution to Invention

The present invention provides a set-top device in a network, comprising: network interface means for enabling the set-top device to use the network via a data transmission link; Central processing means for controlling the set-top device and executing commands of a program for a service selected by a viewer; A memory for storing a program block recently used by the central processing means and a program block with a high frequency of use; And receiving a program block request from the central processing means and confirming that the program block is stored in the memory, and if it is stored, transmitting it to the central processing means. Memory management means for storing in memory and forwarding to said central processing means.

4. Important uses of the invention

The present invention is used in a set-top device connected to a network.

Network, Set-top Device, Cable TV, Extended Memory, Remote Memory

Description

SET-TOP APPARATUS AND METHOD FOR LOGICALLY EXTENDING MEMORY DEVICE USING NETWORK}             

1 is an exemplary configuration diagram of a cable television (CA-TV) network to which the present invention is applied.

2 is a diagram illustrating an embodiment of a set-top device logically extending a memory through a network according to the present invention.

3 is an exemplary view illustrating a memory address translation process used in the present invention.

4 is an exemplary view of a program block used in the present invention.
5 is a flowchart illustrating a data processing method in a memory management unit according to the present invention.

6 is a program code processing diagram for logically expanding a memory according to another embodiment of the present invention.
7 is a flowchart of a program generation method in executable code in a linker according to another embodiment of the present invention.
8 is an exemplary view of a program block generated according to another embodiment of the present invention.
9 is a flowchart illustrating a data processing method in a memory management unit according to another embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

21: central processing unit 22: memory management unit

23: cache memory 24: network interface module

25: data access pass

The present invention relates to a set-top device that logically expands memory through a network and a logical memory expansion method through a network. Particularly, a set-top device that logically expands a memory capacity of a device by utilizing a memory available remotely through a network. And a technique for logically expanding memory by utilizing remote memory over a network.

The cable television (CA-TV) industry is undergoing revolutionary changes in the type and complexity of services it offers. Customer demand for equipment to support CA-TV services and interactive application services continues to grow, and this trend is likely to continue. Interactive and customer-centric software applications typically require real-time services, which require set-top devices to be equipped with large memory. However, the conventional set-top device has a problem in that various services cannot be provided due to limitations in memory capacity.

In addition, in order to make the CA-TV service available to many users, not only the service fee but also the necessary hardware and software need to be low, and the set-top device becomes an important cost factor for receiving the CA-TV service. Memory is a relatively expensive electronic device and has a large portion of the total price of the set-top device. Therefore, there is a problem in that the memory capacity cannot be increased unconditionally for a high quality CA-TV service.

The present invention has been proposed to solve the above problems, and provides network virtual memory to the set-top device by appropriately adjusting data access between the resident memory of the set-top device and the remote memory of the head-end and the central processing unit of the set-top device. An object of the present invention is to provide a set-top device that logically expands memory through a network and a logical memory expansion method through a network.

An apparatus of the present invention for achieving the above object comprises: a set top apparatus of a network, comprising: network interface means for enabling the set top apparatus to use the network via a data transmission link; Central processing means for controlling the set-top device and executing commands of a program for a service selected by a viewer; A memory for storing a program block recently used by the central processing means and a program block with a high frequency of use; And receiving a program block request from the central processing means and confirming that the program block is stored in the memory, and if it is stored, transmitting it to the central processing means, and if not, receiving it from the remote memory through the network interface means. And memory management means for storing the data in the memory and transmitting the same to the central processing means.

In addition, the method of the present invention, in the logical memory expansion method applied to the set-top device in the network, if the program block is requested from the central processing means of the set-top device to confirm whether it is stored in the memory if the program block Transmitting to the central processing means, and if not, receiving from the remote memory, storing the same in the memory, and transmitting the received data to the central processing means; And a first storing step of receiving the program block from the remote memory and storing the program block in the memory if the program block being processed in the central processing means includes branch instructions and is not stored in the memory. Characterized in that made.

In addition, another method of the present invention is a logical memory expansion method applied to a set-top device in a network, the block patch to be divided into blocks to be serviced through the network to be executed at a time sufficiently ahead of the execution order of the program A first storing step of inserting and storing an instruction in a program block; And confirming that the program block is requested from the central processing unit of the set-top device and stored in the memory. If the program block is stored, the program block is transferred to the central processing unit. It characterized in that it comprises a first transfer step of storing in the memory and the transfer to the central processing means.

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The present invention extends the memory area within a set-top device by utilizing the available memory of headends connected through a network. The memory management unit (memory management unit as the memory management means) in the set-top device monitors the program executed by the central processing unit (the central processing unit as the central processing means) of the set-top device, inserts the program block from the head-end, and sets the program block into the set-top device. Stored in the device's memory.

The memory manager divides and manages a memory, which is a limited resource in the set-top device, into segments of a sufficient size to store one program block. The program block is downloaded from the head-end by the central processing unit of the set-top device if necessary, and the memory segment storing the program block that is not to be used is reused. The memory manager provides sufficient read-ahead capability to ensure that the central processing unit can execute code at any time.

In this case, the network refers to a network connected using a set-top device such as high definition television (HDTV) and satellite broadcasting, as well as a two-way communication CA-TV network.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the embodiment of the present invention, a cable television (CA-TV) network is taken as an example.

1 is an exemplary configuration diagram of a cable television (CA-TV) network to which the present invention is applied.

As shown in FIG. 1, the CA-TV network consists of a television 11, a set top device 12, a CA-TV transmission link 13 and a headend 14.

In the figure, a single set-top device 12 is simply drawn, but the CA-TV network includes a plurality of set-top devices. The set top device 12 is connected to the headend 14 via a CA-TV transmission link 13 providing a large bandwidth.

As in a typical CA-TV network, a CA-TV network operator provides various types of services from the headend 14 to CA-TV viewers. As those skilled in the art are well aware, the head office 14 receives various video and audio programs (signals) from broadcast stations (producers of various services) and transmits the programs to a large number of assigned broadcast channels. Has equipment for transmitting over the link 13. In addition, the head-end 14 may be a starting point for supplying a program through a broadcast channel locally. In addition, system operator messages, such as program schedules and other necessary data, may be sent to viewers via the CA-TV transmission link 13.
To be more effective, this control information is transmitted over a unique data channel called a Control Data Channel.

The head office 14 has a main computer 141 equipped with a memory 142. The main computer 141 becomes a storage device and a program production device in a network environment of the distributed set-top device 12. The main computer 141 has computer programs necessary for various application services to be used or performed by the set-top device 12.

CA-TV transmission link 13 is a hybrid fiber coax (HFC), fiber to the curb (FTTC), an asymmetric digital subscriber line (ADSL), asynchronous transmission mode ( ATM (Asynchronous Transfer Mode) network is used.

2 is a configuration diagram of an embodiment of a set-top device logically expanding a memory through a network according to the present invention.

As shown in FIG. 2, the set-top device 12 logically extending the memory through the network according to the present invention includes a central processing unit 21 as a central processing unit, a memory management unit 22 as a memory managing unit, and a memory. Cache memory 23 as a network interface, a network interface module 24 as a network interface means, and a data access path 25. As shown in FIG.

Here, the network interface module 24 is a communication interface that enables the set-top device to use the CA-TV transmission link 13.

The central processing unit 21 controls the set-top device 12 and executes instructions of a computer program for the application service selected by the viewer. For example, if the viewer performs a home banking transaction using the CA-TV network, the central processing unit 21 processes the instructions of the home banking program.

If an infinite amount of memory is available in the set-top device 12, all instructions of the banking program are downloaded to the cache memory 23, and the central processing unit 21 may quickly obtain the necessary instructions from the cache memory 23. However, since expensive memories cannot be mounted in the set-top device 12 indefinitely, the size of the cache memory mounted in the set-top device 12 is assumed to be about 128 kilobytes (KB).

Most application services for viewers in CA-TV networks are relatively larger than 128 kilobytes. Thus, such application services cannot be performed in most current set-top devices 12.

The central processing unit 21 is engaged with the memory management unit 22 via the data access path 25. The data access path 25 consists of a serial bus which allows the memory management unit 22 to interface directly with the data bus of the central processing unit 21.

In addition, the central processing unit 21, while processing instructions of a specific application, additionally obtains necessary data from the cache memory 23 via the data access path 25 and the memory management unit 22.

The memory manager 22 monitors which program block the CPU 21 gets from the cache memory 23 and performs a memory virtual address mapping function for the CPU 21. Since the central processing unit 21 does not know the physical memory address for the program block loaded in the cache memory 23, the logical memory presented by the memory management unit 22 through the data access path 25 from the central processing unit 21. The address is converted into the physical memory address of the cache memory 23.

The series of program blocks is in cache memory 23. Since the cache memory 23 is limited in size, the memory manager 22 manages program blocks in the cache memory 23 to replace a more urgent program block and a program block that has not been used for the longest time. .

The cache memory 23 stores recently used program blocks and frequently used program blocks, and can provide the program blocks immediately without being downloaded from the head-end 14 for successive program block requests.

The program block that is used most frequently has the highest priority, and the program block that has not been used for the longest has the lowest priority. If a new program block needs to be downloaded to the cache memory 23 and there is no space available, the program block having the lowest priority in the cache memory 23 is deleted or overwritten. It is obvious that direct access to the cache memory 23 takes much less processing time than access to a CA-TV network.

When the CPU 21 and the memory manager 22 are connected through the data access path 25, two channels may exist between the CPU 21 and the memory manager 22. At this time, one is a channel for control data, and the other is a channel for program instructions and data.

3 is an exemplary view illustrating a memory address translation process used in the present invention. The process of converting a logical memory address into a physical memory address, that is, a virtual address mechanism, is a program block desired by the central processing unit 21 as the memory manager 22. It starts by passing its logical memory address.

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As shown in FIG. 3, the logical memory address is temporarily stored in the buffer 31. The memory manager 22 has a memory location information map 32 of the physical memory address 322 with respect to the logical memory address 321.

In this embodiment, the memory address scheme has a 32-bit address space. Those skilled in the art will appreciate that the present invention can be applied to address spaces of 64 bits or more, depending on the requirements of the system.

When a new logical memory address is found in the buffer 31, the memory manager 22 searches the memory location information map 32. The logical memory address 321 has a corresponding physical memory address 322 such that the memory manager 22 transfers it to the central processing unit 21.

For example, in FIG. 3, when the central processing unit 21 requests a program block of a 1006 logical memory address, the memory manager 22 finds the 1006 logical memory address through the memory location information map 32. The corresponding physical memory address in FIG. 3 is 24. Accordingly, the memory manager 22 accesses the cache memory 23 with 24 physical memory addresses and transfers the program block of the 1006 logical memory address to the central processing unit 21.

In the second example, when the central processing unit 21 requests a program block of 1007 logical memory address, the memory manager 22 searches the memory location information map 32 and loads the program block into the cache memory 23. You know that it is not. The memory manager 22 immediately obtains this program block from the head-end 14 using the network interface module 24. The 1007 program block will be stored at any physical memory address in cache memory 23. The memory location information map 32 is updated and the 1007 program block will be transferred to the central processing unit 21.

Once the conversion process is performed, the memory manager 22 searches for the physical memory address corresponding to the program block requested by the CPU 21.

4 and 5 illustrate a logical memory expansion method through a network in a set-top device.

The memory manager 22 in the set-top device 12 logically loads the necessary program blocks into the cache memory 23 in advance through a read-ahead capability to the program blocks executed in the central processing unit 21. Expand memory.

4 is an exemplary view of a program block used in the present invention.

In addition to providing a virtual address management function, the memory manager 22 performs a read ahead function by checking whether a program block currently being executed includes branch instructions.

As shown in FIG. 4, the currently executing program block 2600 includes two branch instructions 41 and 42. The memory manager 22 examines this block and considers that 2700 and 2800 program blocks are required by two branch instructions, so that the 2700 and 2800 blocks are previewed before the CPU 21 executes the branch instruction. It is taken and loaded into the cache memory 23. That is, pre-fetch two blocks.

Therefore, the memory management unit 22 can immediately provide the central processing unit 21 with the block taken from the cache memory 23 without having to wait for the required block to be downloaded from the head-end 14. The more the traffic headend 14 does not go through, the faster the processing speed of the program is.

5 is a flowchart illustrating a data processing method in a memory management unit according to the present invention.

The necessary block in the central processing unit 21 in the set-top device 12 may or may not be loaded in the cache memory 23. Therefore, the memory manager 22 determines whether to bring the program block from the cache memory 23 or the head-end 14.

In addition, the memory manager 22 checks the branch instruction so that the program block being executed can easily proceed to the next operation by using a read-ahead capability, and then the necessary program block is transferred to the head end 14. It is loaded and loaded into the cache memory.

This will be described with the flow shown in the drawings.

As shown in FIG. 5, the memory management unit 22 in the set-top device 12 receives a program block request from the central processing unit 21 (501), and determines whether the block is loaded in the cache memory 23 ( If it is not loaded, the network interface module 24 is instructed to bring the corresponding program block from the head-end 14 (503). The downloaded block is loaded into the cache memory 23 (504), and transferred to the central processing unit 21 (505).

As a result of determining whether the program block is loaded in the cache memory 23, if it is loaded, the program block is transferred to the central processing unit 21 (505).

The memory manager 22 analyzes a program block currently being used (506) and checks whether a branch instruction is included (507). As a result of the check, if the branch instruction is not included, the operation is terminated, and if it is included, it is checked whether the program block required by the branch instruction is loaded in the cache memory (508).

As a result of checking whether the program block is loaded in the cache memory, the program block is terminated if it is loaded in the cache memory, and if it is not loaded, the network interface module 24 is instructed to take the program block from the head-end 14 (509). ). The downloaded block is loaded into the cache memory 23 (510).

6 to 9 illustrate another embodiment of a logical memory expansion method through a network in a set-top device.

In the embodiment of FIG. 5, logical expansion of the memory is processed through a read function of a program block currently being executed by a memory manager in the set-top device.

Another method of logical memory expansion over a network in a set-top device is in a cable television network, in which the cable television service provider or headend 14 analyzes the program that it wants to provide to the television 11, divides it into blocks, and This is done by inserting the patch instruction that loads the block into the program block so that it executes ahead of time in the execution order.

In this case, the memory manager 22 processes the memory relocation function in the same manner as in the above-described embodiment, but does not analyze the program block to be executed by the CPU 300.

6 is a program code processing diagram for logically expanding a memory according to another embodiment of the present invention.

As shown in FIG. 6, the program to be executed by the central processing unit 21 is in source code. When a program of source code is compiled by the compiler 61, a program of position independent object code is generated. The linker 62 inserts a "block patch instruction" into the program of this object code to make a program of executable code.

These block patch instructions are executed by the central processing unit 21 to cause the central processing unit 21 to send the instructions directly to the memory management unit 22 via the control channel. Get the program block.

FIG. 7 is a flowchart illustrating a program generating method of executable code in a linker according to another embodiment of the present invention, and illustrates a procedure of generating a program of executable code by embodying the contents of FIG. 6.
As shown in Fig. 7, the program of the source code is compiled using a compiler 61 which generates a program of the position independent object code.

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Programs in source code are usually written in high-level languages such as 'C'. The program in the 'C' source code is converted into a program in the object code that the central processing unit 21 can understand and execute.

A program of this object code gathers the built-in functions into one by the linker 62 to generate a blocked execution program that can be executed in the central processing unit 21.

The linker does the following:

First, we will analyze cross-references between individually compiled object codes, examine the existence of branch instructions in the executable object code, and find an effective way to break the program into blocks suitable for download from the CA-TV network. Decide

In addition, by inserting a command in the library of the network program block patch command into the program of the executable code, the CPU 21 can issue a block download command to the memory management unit 22 using the control channel at an appropriate time. .

The generation of a program of executable code in the linker is described with the flow shown in the drawing as follows.

Since the linker 62 accepts the result processed by the compiler 61, the linker 62 operates a program in object code in machine language. Accordingly, the program in the object code is analyzed (701) to find out whether it contains machine language corresponding to branch instructions such as "GOTO", "GOSUB", and "CALLS" (702). The linker 62 then adds the appropriate branch routine to the program in object code (703). The program in object code is divided into downloadable blocks (704). This is called segmentation.

Segmentation divides the program into blocks that are large enough to be loaded into the cache memory 23. Although the program is cut to the same size when creating the segments, they do not necessarily have to be the same size.

A block patch instruction is inserted into the blocked program to generate a program of executable code (705).

8 is an exemplary view of a program block generated according to another embodiment of the present invention.

As shown in FIG. 8, the linker 62 modifies the program so that the central processing unit 21 is not interrupted while the program processor downloads the program block from the head-end 14 while executing the code. For example, if the program source code for a given application is block 2600 as shown in Figure 4 above, the linker 62 changes the execution code of the program to the same content as Figure 9 described below. In an example, code to patch blocks 2700 and 2800 is inserted by linker 62. If the linker 62 confirms that 2700 blocks and 2800 blocks are needed to execute the code, the block patch instruction is inserted into the executable code at a time sufficiently ahead of the execution order of the code, so that the central processing unit 21 Before performing the operation, the required block is downloaded and stored in the cache memory 23.

9 is a flowchart illustrating a data processing method in a memory manager according to another exemplary embodiment of the present invention.

As shown in FIG. 9, the memory management unit 22 in the set-top device 12 receives a program block request from the central processing unit 21 (901), and determines whether the block is loaded in the cache memory 23 ( If it is not loaded, the network interface module 24 is instructed to bring the program block from the head-end 14 (903). The block thus downloaded is loaded into the cache memory 23 (904) and transferred to the central processing unit 21 (905).

As a result of determining whether the program block is loaded in the cache memory 23, if it is loaded, the program block is transferred to the central processing unit 21 (905).

In this case, since the block patch command is already inserted in the program block, the read-ahead capability of the memory manager 22 is not performed.
The method of the present invention as described above may be implemented as a program and stored in a computer-readable recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.). Since this process can be easily implemented by those skilled in the art will not be described in more detail.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

The present invention as described above, by logically expanding the memory of the set-top device, when applied to interactive applications where the reaction time is important, such as interactive games, home banking, home shopping in a network that is connected to the set-top device is widely spread There is an effect that can provide a higher quality service to users quickly.

In addition, the present invention logically expands the memory of the set-top device, so that as application services become more complex and require more memory, the set-top device no longer extends existing services and provides new services to network operators. There is no burden on the effect.

Claims (13)

In a set-top device of a network, Network interface means for enabling the set top device to use the network via a data transmission link; Central processing means for controlling the set-top device and executing commands of a program for a service selected by a viewer; A memory for storing a program block recently used by the central processing means and a program block with a high frequency of use; And Receives a program block request from the central processing means and checks whether it is stored in the memory, and if it is stored, transfers it to the central processing means. Memory management means for storing in the memory and transferring the data to the CPU Set-top device logically expanded memory through a network comprising a. The method of claim 1, The central processing means, Interlocked with the memory management means via a data access path, the data access path being logically memoryd via a network, wherein the memory management means is connected by a serial bus so as to interface directly with the data bus of the central processing means. Extended set-top device. The method according to claim 1 or 2, The memory management means, When the CPU requests the program block, the memory virtual address mapping function is performed to check the memory, and the program block being executed by the CPU is monitored to determine whether the program block expected to be used is in the memory. And a function of receiving the data from the remote memory and storing the received data in the remote memory. The method of claim 3, wherein The network, A set-top device logically expanding memory through a network, which is a cable television (CA-TV) network. A logical memory expansion method applied to set-top devices in a network, The program block is transferred from the central processing means of the set-top device to determine if it is stored in the memory. If not, the program block is transferred to the central processing means. A first delivery step of delivering to the processing means; And A first storing step of receiving the program block from the remote memory and storing the program block in the memory if the program block being processed in the central processing means includes branch instructions and is not stored in the memory. Logical memory expansion method comprising a. The method of claim 5, The first delivery step, A first checking step of checking whether the memory management means of the set-top device is requested to transfer a program block from the central processing means and stored in the memory; A second transfer step of receiving the program block from the memory and transferring the program block to the central processing unit if it is stored as a result of the check of the first verification step; And A third delivery step of receiving the program block from the remote memory through a network interface means, storing the program block in the memory and transmitting the result to the central processing means if it is not stored; Logical memory expansion method comprising a. The method according to claim 5 or 6, The first storage step, An investigation step of checking, by the memory management means of the set-top device, whether the program block being processed by the central processing means includes branch instructions; A second checking step of confirming whether a program block being processed in said central processing means and including a branch instruction is stored in said memory; And A second storing step of receiving a program block not stored in the memory from the remote memory through the network interface means and storing the program block in the memory; Logical memory expansion method comprising a. A logical memory expansion method applied to set-top devices in a network, A first storing step of dividing a program to be serviced through the network into blocks and inserting and inserting a block patch instruction into a program block to be executed at a time sufficiently ahead of the execution order of the programs; And It is requested to transfer the program block from the central processing means of the set-top device to check whether it is stored in the memory, and if it is stored, transfer the program block to the central processing means. A first delivery step of storing in a memory and delivering to the central processing means Logical memory expansion method comprising a. The method of claim 8, The first storage step, A program generation step of compiling a program of source code to be serviced through the network to generate a program of position independent object code; And A second storage step of dividing the program of the position independent object code and inserting a block patch instruction to generate and store a program block of execution code; Logical memory expansion method comprising a. The method of claim 9, The second storage step, An analysis step of analyzing a program of the position independent object code in machine language; A branch instruction search step of finding a branch instruction in the program of the position independent object code; A branch routine adding step of adding a branch routine to the program of the position independent object code; A block dividing step of dividing the program of the position independent object code including a branch routine into program blocks suitable for transmission in the network; And An instruction insertion step of inserting a block patch instruction into the program block such that the block patch instruction is executed at a time sufficiently preceding the execution order; Logical memory expansion method comprising a. The method according to any one of claims 8 to 10, The first delivery step, Confirming, by the memory management means of the set-top device, receiving the program block from the central processing means and storing the program block in the memory; A second transfer step of receiving the program block from the memory and transferring the program block to the central processing unit if it is stored; And A third delivery step of receiving the program block from the remote memory via a network interface means, storing the program block in the memory and transmitting the result to the central processing means if it is not stored; Logical memory expansion method comprising a. delete delete

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