Method and apparatus for evaluating performance on host data transfer within a tape drive

Abstract

A method for evaluating data transfer performance within a data recording apparatus is disclosed. The data recording apparatus includes a buffer and a recording medium. Initially, a Pause time P when data transfer between the buffer and a host being stopped temporarily is measured. Then, an ideal Pause time Y is determined. Next, a determination is made whether or not the Pause time P exceeds a sum of the ideal Pause time Y and an allowance a. If the Pause time P exceeds a sum of the ideal Pause time Y and the allowance a, a warning signal is sent to the host.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention itself, as well as a preferred mode of use, further objects, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a block diagram of a tape drive;

FIG. 2 shows the data flows between a host and a tape drive;

FIG. 3 shows the Pause time values P in relation to calculated values Y when there is no problem in a tape drive;

FIG. 4 shows the Pause time values P in relation to the calculated values Y when where there are problems in a tape drive;

FIG. 5 shows control means inside of a tape drive for comparing the Pause time P and the calculated value Y;

FIG. 6 is a high-level logic flow diagram of a Host Performance Checker for measuring a host transfer rate H;

FIG. 7 is a high-level logic flow diagram of a Pause Time Checker for measuring a Pause time P during which data transfer from a host is being kept waiting;

FIG. 8 is a high-level logic flow diagram of a Error Counter for collecting information on various recoverable errors in an E drive; and

FIG. 9 is a high-level logic flow diagram of a Performance Checker for comparing an actual measured value P and a calculated value Y.

Claims

1. A method for evaluating performance on data transfer in a data recording apparatus, wherein said data recording apparatus includes a buffer and a recording medium, said method comprising: measuring a Pause time P when data transfer between said buffer and a host is stopped temporarily;determining an ideal Pause time Y;determining whether or not said Pause time P exceeds a sum of said ideal Pause time Y and an allowance a;in response to a determination that said Pause time P exceeds a sum of said ideal Pause time Y and said allowance a, sending a warning signal to said host.

2. The method of claim 1, wherein said Pause time P is measured as a time period when no free space exists in a buffer because preceding data temporarily saved in said buffer have not been written into a recording medium of said data recording apparatus, or as a time period when reading of data into a host is kept waiting because data have not been read out from said recording medium to said buffer.

3. The method of claim 1, wherein said ideal Pause time Y is determined by

4. The method of claim 1, wherein said allowance a is an electromechanical property of said data recording apparatus.

5. A computer usable medium having a computer program product for evaluating performance on data transfer in a data recording apparatus, wherein said data recording apparatus includes a buffer and a recording medium, said computer usable medium comprising: program code means for measuring a Pause time P when data transfer between said buffer and a host is stopped temporarily;program code means for determining an ideal Pause time Y;program code means for determining whether or not said Pause time P exceeds a sum of said ideal Pause time Y and an allowance a;program code means for, in response to a determination that said Pause time P exceeds a sum of said ideal Pause time Y and said allowance a, sending a warning signal to said host.

6. The computer usable medium of claim 5, wherein said Pause time P is measured as a time period when no free space exists in a buffer because preceding data temporarily saved in said buffer have not been written into a recording medium of said data recording apparatus, or as a time period when reading of data into a host is kept waiting because data have not been read out from said recording medium to said buffer.

7. The computer usable medium of claim 5, wherein said ideal Pause time Y is determined by

8. The computer usable medium of claim 5, wherein said allowance a is an electromechanical property of said data recording apparatus.

9. A data recording apparatus capable of evaluating data transfer performance, wherein said data recording apparatus includes a buffer and a recording medium, said data recording apparatus comprising: a pause time checker for measuring a Pause time P when data transfer between said buffer and a host is stopped temporarily;means for determining an ideal Pause time Y;a performance checker for determining whether or not said Pause time P exceeds a sum of said ideal Pause time Y and an allowance a;means for, in response to a determination that said Pause time P exceeds a sum of said ideal Pause time Y and said allowance a, sending a warning signal to said host.

10. The data recording apparatus of claim 9, wherein said Pause time P is measured as a time period when no free space exists in a buffer because preceding data temporarily saved in said buffer have not been written into a recording medium of said data recording apparatus, or as a time period when reading of data into a host is kept waiting because data have not been read out from said recording medium to said buffer.

11. The data recording apparatus of claim 9, wherein said ideal Pause time Y is determined by

12. The data recording apparatus of claim 9, wherein said allowance a is an electromechanical property of said data recording apparatus.