Method and apparatus for prioritizing video frame retrieval in a shared disk cluster

• US 6,609,149 B1
• Filed: 04/12/1999
• Issued: 08/19/2003
• Est. Priority Date: 04/12/1999
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Craft, David Jones, Bandera, Daniel Quinto, Shaw, Wade David
• Primary Examiner(s): VOELTZ, EMANUEL T
• Application Number:
  US09/289,887
• Time in Patent Office: 1,590 Days
• Field of Search: 709/219, 709/217, 709/218, 710/58, 710/60, 710/61, 725/87, 725/93, 725/96, 714/12
• US Class Current: 709/219
• CPC Class Codes: H04N 21/2182 involving memory arrays, e.g. RAID disk arrays RAID arrays per se G06F3/0689; use of parity to protect data in RAID systems G06F11/1008
• CPC Class Codes: H04N 21/2326 Scheduling disk or memory reading operations
• CPC Class Codes: H04N 21/2393 involving handling client requests scheduling or organising the servicing of application requests H04L67/60

Abstract

A first frame deadline is calculated and attached to an I/O request for prioritizing and retrieving video data frames from a shared disk cluster. Disk adapters queue video data frame requests according to the deadline incorporated in the frame requests. Data frames are transmitted to a requesting end user utilizing the attached deadline time to schedule the frames according to a time priority. Alternatively, a “slack” time is computed and utilized to determine when the first frame and subsequent frames of the requested video data may be retrieved from disk and present in the video server'"'"'s memory in order to avoid a visible delay in sending that frame to the end user.

Claims

1. A method for reducing data transmission errors caused by video frame data delays, comprising the steps of:

computing a slack time for an Input/Output (I/O) request;

computing subsequent slack times for subsequent I/O requests;

modifying said I/O requests by attaching said slack time to said I/O request; and

scheduling said modified I/O request with similarly modified subsequent I/O requests based on said slack time.

2. The method of claim 1, further comprising:

determining real-time clock time.

3. The method of claim 1, further comprising:

queuing said modified I/O requests according to least slack time, wherein said modified I/O requests are video data I/O requests.

4. The method of claim 1, further comprising:

routing said modified I/O requests to a data storage system, wherein said modified I/O requests are handled according to a least slack time.

5. The method of claim 1, further comprising:

sending data, ordered by said I/O request, to a buffer wherein said data is scheduled according to a least slack time.

6. The method of claim 1, further comprising:

transmitting said data ordered by I/O request to a station requesting said data.

7. An apparatus for reducing data transmission errors caused by video frame data delays, comprising:

computing means for computing a slack time for an I/O request;

means for computing subsequent slack times for subsequent I/O requests;

means for modifying said I/O requests by attaching said slack time to said I/O request; and

cataloging means for scheduling said I/O request with said subsequent I/O requests based on said slack time.

8. The apparatus of claim 7, further comprising:

timing means for determining real-time clock time.

9. The apparatus of claim 7, further comprising:

data scheduling means for queuing said modified I/O requests according to a least slack time, wherein said modified I/O requests are video data I/O requests.

10. The apparatus of claim 7, further comprising:

means for routing said modified I/O requests to a data storage system, wherein said modified I/O requests are handled according to a least slack time.

11. The apparatus of claim 7, further comprising:

transmitting means for sending data ordered by said I/O request to a buffer wherein said data is scheduled with other data according to a least slack time.

12. The apparatus of claim 7, further comprising:

means for transmitting said data ordered by I/O request to a station requesting said data.

13. A computer program product, having instructions on a computer readable medium for reducing data transmission errors caused by video frame data delays, comprising:

instructions within said computer readable medium for computing a slack time for an I/O request;

instructions within said computer readable medium for computing subsequent slack times for subsequent I/O requests;

instructions within said computer readable medium for modifying said I/O request and said subsequent I/O requests by attaching said slack time; and

instructions within said computer readable medium for scheduling said I/O request with said subsequent I/O requests based on said slack time attached to each I/O request.

14. The program product of claim 13, further comprising:

instructions within said computer readable medium for determining real-time clock time.

15. The program product of claim 13, further comprising:

instructions within said computer readable medium for queuing said modified I/O requests according to a least slack time, wherein said modified I/O requests are video data I/O requests.

16. The program product of claim 13, further comprising:

instructions within said computer readable medium for routing said modified I/O requests to a data storage system, wherein said modified I/O requests are handled according to a least slack time.

17. The program product of claim 13, further comprising:

instructions within said computer readable medium for sending data ordered by said I/O request to a buffer wherein said data is ordered according to a least slack time.

18. The program product of claim 13, further comprising:

instructions within said computer readable medium for transmitting said data ordered by I/O request to a station requesting said data.