System for the management of multiple time-critical data streams

• US 5,630,067 A
• Filed: 06/04/1996
• Issued: 05/13/1997
• Est. Priority Date: 07/29/1994
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Milsted, Kenneth L., Waefler, Susan E., Yoder, Brian E., Vogt, Michael P., Kindell, Craig N.
• Primary Examiner(s): Shin, Christopher B.
• Application Number:
  US08/658,167
• Time in Patent Office: 343 Days
• Field of Search: 395/200.01-209.21, 395/153, 395/154, 395/872, 395/873, 395/874, 395/875, 395/876, 395/871, 348/8
• US Class Current: 709/231
• CPC Class Codes: G06F 9/5011 the resources being hardware resources other than CPUs, Servers and Terminals
• CPC Class Codes: G06F 9/5016 the resource being the memory

Abstract

A networked computer system for storing and presenting multimedia data distributes that data among multiple storage devices of the system. The system includes a plurality of computers, each of which supports at least one viewing station. Each viewing station has access to any file on any of the storage devices and can retrieve and display any file on demand. To provide an efficient system and, at the same time, reduce the probability that the viewing of multimedia data may be interrupted, the system allocates resources, prioritizes access to files, and buffers data prior to the data'"'"'s delivery to video adapters.

Claims

1. A multimedia storage and presentation system for storing video clips, each clip comprising a plurality of segments, and for displaying said video clips in response to requests by viewers, said system comprising:

a computer network;

a plurality of computers connected to said computer network, each computer having attached thereto at least one storage device, at least one viewing station, input means for allowing said viewers to request display of a specific video clip on said at least one viewing station and buffer means for temporarily storing segments of said specific video clip prior to display;

client means in each of the plurality of computers for retrieving one of the video clips from the local storage device coupled thereto and for sending a request for one of said video clips over the computer network to other of said plurality of computers;

server means in each of said plurality of computers responsive to said request for retrieving said video clip from a selected storage device coupled to said computer said server means having a predetermined maximum retrieval capacity;

means cooperating with said server means in one of said plurality of computers for monitoring said buffer means in said one of said plurality of computers coupled to said network to determine a number of video clip segments retrieved from said selected storage device; and

stored in said buffer means; and

means responsive to said number of video clip segments stored in said buffer means and to said maximum retrieval capacity for controlling said client means and said server means to refuse said viewer request to display said specific video clip when said maximum retrieval capacity would be exceeded or said number of said video clip segments stored in said buffer means exceeds a predetermined threshold, the controlling means comprising a configuration table for each of said plurality of computers coupled to said computer network, said configuration containing at least one entry comprising said predetermined maximum retrieval capacity.

2. A multimedia storage and presentation system according to claim 1 wherein each of said plurality of computers coupled to said computer network further includes a cache memory and means for configuring said cache memory to operate as a look-ahead buffer.

3. In a multimedia storage and presentation system for storing video clips, each video clip comprising a plurality of segments, and for displaying said video clips in response to a request by viewers interacting with a computer system, the computer system including a network, a plurality of computers connected to said network, each computer having attached thereto at least one local storage device for storing some of said video clips for distribution thereto and to other of the computers connected to said network, at least one viewing station, input means for allowing said viewers to request display of a specific video clip on said at least one viewing station and buffer means for temporarily storing segments of the specific video clip prior to display, a method of accessing video clips comprising the steps of:

A. In response to a viewer request for a specific video clip received by one of the computers coupled to the network, locating the specific video clip in the at least one local storage device attached to the computer;

B. if the specific video clip is not found in the at least one local storage device attached to the one computer, locating another of the plurality of computers having attached thereto a selected storage device containing said video specific clip;

C. temporarily allocating data transfer resources and retrieving the specific video clip from the selected storage device in said another of the plurality of computers coupled to the network over a path having a predetermined maximum retrieval capacity;

D. monitoring the buffer means in the another of said plurality of computers coupled to the network to determine a number of video clip segments retrieved from the selected storage device and stored in the buffer means; and

E. refusing the viewer request to display the specific video clip when the maximum retrieval capacity of the path would be exceeded during step C or the number of video clip segments stored in the buffer means exceeds a predetermined threshold.

4. The method of claim 3 wherein the data transfer resources include data buffers and C further comprises the steps of:

C1. establishing predetermined threshold levels for information in said data buffers; and

C2. assigning a priority to each of said data buffers based on a comparison of number of clip segments stored in said each data buffer to the predetermined threshold levels established in step C1.

5. The method of claim 4 wherein step C1 comprises the steps of:

C1A. determining video clip delivery requirements of the viewing stations;

C1B. determining the rate of data flow into said data buffers; and

C1C. computing a predetermined threshold level from the delivery requirements determined in step C1A and the data flow rate determined in step C1B.

6. The method of claim 5 wherein step C2 comprises the step of:

C2A. comparing said predetermined threshold levels to an amount of data stored in said data buffers; and

C2B. reassigning a priority assigned to each of said buffers based upon the comparison in step C2A.

7. The method of claim 6 further comprising the step of:

F. delaying display of a specific video clip until contents of said data buffers involved in the data transfer of said specific video clip are below said predetermined threshold levels.

8. The method of claim 3 wherein step C further comprises the step of:

C1. identifying data transfer resources involved in the data retrieval of step C;

C2. releasing the data transfer resources allocated in step C when the data retrieval is completed.

9. The method of claim 3 wherein step E comprises the steps of:

E1. identifying data transfer resources involved in the data retrieval of step C;

E2. determining a maximum capacity of each data transfer resource identified in step E1.;

E3. determining an average data capacity of each resource identified in step E1 involved in the data retrieval of step C; and

E4. reducing the maximum capacity determined in step E2 by the average data capacity determined in step E3.

10. The method of claim 9 wherein step E further comprises the steps of:

E5. comparing the average data capacity of each resource identified in step E1 involved in the data retrieval of step C to the reduced maximum capacity determined in step E4; and

E6. releasing data transfer resources allocated in step C when the average data capacity of each resource identified in step E1 involved in the data retrieval of step C exceeds the reduced maximum capacity determined in step E4.

11. A computer program product for use with a computer system for storing and displaying video clips in response to requests by viewers interacting with the computer system, each video clip comprising a plurality of segments, the computer system comprising a network, a plurality of computers connected to the network, each computer having attached thereto at least one local storage device for storing some of the video clips for distribution to the computer to which it is attached or to other computers connected to the network, at least one display station, input means for allowing viewers to request display of a specific video club on the viewing station, and buffer means for temporality storing segments of the specific video clip prior to display, the computer program product comprising:

a computer useable medium having computer program code means embodied in the medium for accessing video clips, the computer program code means further comprising;

A. program code means, responsive to a viewer request for a specific video clip, the request received by one of the computers coupled to the network, for locating the specific video clip in the at least one local storage device attached to the computer;

B. program code means for locating another of the plurality of computers having attached thereto a selected storage device containing the specific video clip, if the specific video clip is not found in the local storage device attached to the computer receiving the user request;

C. program code means for temporarily allocating data transfer resources and for retrieving the specific video clip from the selected storage device in another of the computers coupled to the network over a path having a predetermined maximum retrieval capacity;

D. program code means for monitoring the buffer means in the other of the plurality of computers coupled to the network, to determine a number of video clip segments retrieved from the selected storage device and stored in the buffer means; and

E. program code means for refusing the viewer request to display the specific video clip when the maximum retrieval capacity would be exceeded or the number of video clip segments stored in the buffer means exceeds a predetermined threshold.

12. The computer program product of claim 11 wherein element E, the program code means for refusing the viewer request, further comprises:

E1. program code means, responsive to the program code means for temporarily allocating data transfer resources, for identifying the data transfer resources; and

E2. program code means for determining a maximum capacity of each data transfer resource identified.

13. The computer program product of claim 12 wherein element E, the program code means for refusing the viewer request, further comprises:

E3. program code means for determining an average data capacity of each resource identified; and

E4. program code means, responsive to the program code means for determining a maximum capacity and the program code means for determining an average data capacity, for reducing the maximum data capacity of each data transfer resource by the average data capacity of each data transfer resource.

14. The computer program product of claim 11 wherein element C, the program code means for temporarily allocating data transfer resources and for retrieving the specific video clip, further comprise:

C1. program code means for identifying the allocated data transfer resources; and

C2. program code means for releasing the allocated data transfer resources when the data has been retrieved.

15. The computer program product of claim 11 wherein the identified data transfer resources include data buffers, and wherein element C, the program code means for temporarily allocating data transfer resources, further comprises:

C1. program code means for establishing predetermined threshold levels for information in the data buffers; and

C2. program code means for assigning a priority to each of the data buffers based on a comparison of the number of clipped segments stored in each data buffer to the predetermined threshold levels.

16. The computer program product of claim 15 wherein element C1, the program code means for establishing a predetermined threshold level, further comprises:

C1A. program code means for determining video clip delivery requirements to the viewing station;

C1B. program code means for determining the rate of data flow into the data buffers; and

C1C. program code means, responsive to the program code means for determining the video clip delivery requirements and the program code means for determining the rate of data flow, for computing a predetermined threshold level from the determined delivery requirements and the determined data flow rate.

17. The computer program product of claim 16 wherein element C2, the program code means for assigning a priority to said data buffers, further comprises:

C2A. program code means for comparing the predetermined threshold levels to an amount of data stored in the data buffers; and

C2B. program code means, responsive to the program code means for comparing the predetermined threshold levels, for reassigning a priority assigned to each of the data buffers.

18. The computer program product of claim 17 further comprising:

F. program code means for delaying display of a specific video clip until contents of said data buffers involved in the data transfer of the specific video clip are below the predetermined threshold levels.