Streaming information appliance with buffer read and write synchronization

• US 20050283547A1
• Filed: 04/01/2005
• Published: 12/22/2005
• Est. Priority Date: 04/06/1999
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Lorton, Christopher W., Smirnov, Serge, Raja, Jayachandran, Parry, William G., Lee, Mingtzong
• Granted Patent: US 7,139,868 B2
• Time in Patent Office: Days
• US Class Current: 710/52
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 2020/10666 Ring buffers, e.g. buffers wherein an iteratively progressing read or write pointer moves back to the beginning of the buffer when reaching the last storage cell
• CPC Class Codes: G11B 27/034 on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: G11B 27/105 of operating discs
• CPC Class Codes: G11B 27/322 used signal is digitally coded
• CPC Class Codes: H04N 21/44004 involving video buffer management, e.g. video decoder buffer or video display buffer

Abstract

An information appliance receives streaming information and includes a buffer, a writer module, a reader module and a synchronizer. The buffer has a plurality of storage locations, a logical head, a logical tail and a valid data area between the logical head and the logical tail. The logical head and the logical tail move sequentially through the plurality of storage locations in a first logical direction. The writer module has a write position at the logical head of the buffer. The writer module receives the streaming information and writes the streaming information to the buffer at the write position. The reader module is coupled to the buffer and has a first read position which is temporally movable with respect to the write position. The synchronizer is coupled to the writer module and the reader module and maintains the first read position within the valid data area.

Claims

1. A method to handle streaming information in an information appliance having a buffer with a fixed number of storage locations, the method comprising the steps of:

defining a logical head and tail in the buffer and a valid data area between the logical head and tail which comprises a portion of the storage locations;

writing streaming information to the logical head of the buffer with a writer module;

moving the logical head and tail through the storage locations in a first logical direction while writing the streaming information;

reading the streaming information from a first read position within the valid data area with a first reader module, wherein the first read position is temporally movable with respect to the logical head and tail; and

synchronizing the steps of writing the streaming information and reading the streaming information.

2. The method of claim 1 wherein:

the step of writing comprises writing a first block of the streaming information to a first sequence of successive ones of the storage locations; and

the step of synchronizing comprises temporarily blocking the step of writing the first block of the streaming information if the first reader module is currently reading from one of the storage locations within the sequence.

3. The method of claim 2 wherein the step of synchronizing further comprises:

unblocking the step of writing a block of the streaming information when the first read position advances past the first sequence relative to the first logical direction.

4. The method of claim 3 wherein the step of synchronizing further comprises:

increasing a rate at which the reader module accesses the buffer until the first read position advances past the first sequence relative to the first logical direction.

5. The method of claim 2 wherein the step of synchronizing further comprises:

advancing the logical tail of the buffer to an end of the first sequence of the successive ones of the storage locations prior to performing the step of writing the first block of the streaming information; and

temporarily blocking the step of writing a block if the first read position is behind the logical tail relative to the first logical direction.

6. The method of claim 5 wherein:

the step of reading comprises reading a second block of the streaming information from a second sequence of successive ones of the storage locations while advancing the first read position through the second sequence; and

the step of synchronizing further comprises unblocking the step of writing the first block of the streaming information after advancing the read position if the first read position is ahead of the logical tail relative to the first logical direction.

7. The method of claim 1 wherein:

the step of reading comprises reading a first block of the streaming information from a first sequence of successive ones of the storage locations; and

the step of synchronizing comprises temporarily blocking the step of reading the first block of the streaming information if an end of the first sequence is ahead of the logical head relative to the first logical direction and therefore outside the valid data area.

8. The method of claim 7 wherein:

the step of writing comprises writing a second block of the streaming information to a second sequence of successive ones of the storage locations; and

the step of synchronizing further comprises;

advancing the logical head of the buffer to an end of the second sequence after writing the second block; and

unblocking the step of reading a first block of the streaming information after the step of advancing if the end of the first sequence is behind the logical head relative to the first logical direction.

9. The method of claim 1 wherein:

the step of reading comprises reading a block of the streaming information from a first sequence of successive ones of the storage locations; and

the step of synchronizing comprises failing the step of reading the block of the streaming information if a beginning of the first sequence is behind the logical tail relative to the first logical direction and therefore outside the valid data area.

10. The method of claim 1 wherein the step of moving the logical head and tail comprises moving the logical head and tail circularly through the storage locations in the first logical direction.

11. The method of claim 1 and further comprising:

reading the streaming information from a second read position within the valid data area with a second reader module, wherein the second read position is temporally movable with respect to the logical head and tail and with respect to the first read position.