Dedication of space in descriptor for minimizing data processing during communications between a peripheral device and a host system

A method for exchanging control data and status data between a peripheral device and a host system, said control data and said status data comprising a descriptor corresponding to a buffer within a shared memory, the method including the steps of:

• A. generating and writing, by said peripheral device, said status data into a status block of said descriptor that corresponds to said buffer in a first location of said shared memory, to provide status information to said host system;
• B. generating and writing, by said peripheral device, predetermined data into a first predetermined location within said status block;
• C. reading, by said host system, said status data and said predetermined data from said status block for processing data in said buffer that corresponds to said descriptor;
• D. generating and writing, by said host system, said control data into a control block of said descriptor to provide control information to said peripheral device, wherein said control block is at a second location of said shared memory, and wherein said first location of said status block and said second location of said control block are separate independent locations in said shared memory;
• E. writing, by said host system, said predetermined data read from said status block into a second predetermined location within said control block;
• and
• F. reading, by said peripheral device, said control data and said predetermined data from said control block for processing data in said buffer that corresponds to said descriptor;
• wherein said predetermined data read from said second predetermined location within said control block by said peripheral device in said step F is substantially same as said predetermined data priorly written into said first predetermined location within said status block by said peripheral device in said step B.

An apparatus for exchanging control data and status data between a peripheral device and a host system, said control data and status data comprising a descriptor corresponding to a buffer within a shared memory, the apparatus comprising:

• a data storage device including:
• a control block of said descriptor that corresponds to said buffer in said shared memory for storing said control data generated by said host system to provide control information to said peripheral device, and said control block having a first predetermined location for storing predetermined data, and said control block being stored in a first location in said data storage device;
• and
• a status block of said descriptor for storing said status data generated by said peripheral device to provide status information to said host system, and said status block having a second predetermined location for storing said predetermined data, and said status block being stored in a second location in said data storage device, and wherein said first location of said control block and said second location of said status block are separate independent locations in said data storage device;
• a data processing unit of said host system, coupled to said data storage device for writing said control data into said control block and for generating and writing said predetermined data into said first predetermined location within said control block;
• and
• a buffer management unit of said peripheral device, coupled to said data storage device, for writing said status data into said status block, and for reading said predetermined data from said control block to write said predetermined data into said second predetermined location within said status block,
• wherein said data processing unit reads said predetermined data from said second predetermined location of said status block for processing data in said buffer that corresponds to said descriptor;
• and wherein said predetermined data read from said second predetermined location within said status block by said data processing unit is substantially same as said predetermined data priorly written into said first predetermined location within said control block by said data processing unit.

An apparatus for exchanging control data and status data between a peripheral device and a host system, said control data and said status data comprising a descriptor corresponding to a buffer within a shared memory, the apparatus comprising:

• a data storage device including:
• a control block of said descriptor that corresponds to said buffer in said shared memory for storing said control data generated by said host system to provide control information to said peripheral device, and said control block having a first predetermined location for storing predetermined data, and said control block being stored in a first location in said data storage device;
• and
• a status block of said descriptor for storing said status data generated by said peripheral device to provide status information to said host system, and said status block having a second predetermined location for storing said predetermined data, and said status block being stored in a second location in said data storage device, and wherein said first location of said control block and said second location of said status block are separate independent locations in said data storage device;
• a buffer management unit of said peripheral device, coupled to said data storage device, for writing said status data into said status block, and for generating and writing said predetermined data into said second predetermined location within said status block;
• and
• a data processing unit of said host system, coupled to said data storage device, for writing said control data into said control block, and for reading said predetermined data from said status block to write said predetermined data into said first predetermined location within said control block,
• wherein said buffer management unit of said peripheral device reads said predetermined data from said first predetermined location of said control block for processing data in said buffer that corresponds to said descriptor;
• and wherein said predetermined data read from said first predetermined location within said control block by said buffer management unit of said peripheral device is substantially same as said predetermined data priorly written into said second predetermined location within said status block by said buffer management unit of said peripheral device.