User Guide

6-36 Ampex 1308911-02
Model No.
Running Head
dd2_read_perf DD-2 Utilities Manual Pages
sample_rate Integer that specifies the sample rate for displaying read calls. If the
sample rate is 1, every read is displayed. If the sample rate is 10,
every tenth read is displayed.
ENVIRONMENT
The $TAPE environment variable specifies the tape device to use if the
-f <device_special_file> option is omitted.
EXIT STATUS
The dd2 utilities use the following exit status codes, and may also produce output to -stdout
on success:
0 Operation succeeded.
nonzero Operation failed.
A nonzero return value describes the error encountered error during processing (see “Exit
Status” on page 6-5).
EXAMPLES
Run dd2_read_perf with a transfer_size of 1MB, a count of 100, and a sample_rate of 1.
dd2_read_perf -perf :1048576:100:1:
The display might look like this:
Instance Cumulative
Transfer read time Bytes/Sec read time Bytes/Sec
0 11.982909 00838575 11.982909 00838575
1 0.718649 13982592 12.701558 01582258
2 0.662144 15175816 13.363702 02255791
3 0.682304 14727417 14.046006 02861618
4 0.662249 15173410 14.708255 03415964
5 0.663442 15146125 15.371697 03922238
6 0.680675 14762663 16.052372 04381908
7 0.662304 15172150 16.714676 04809462
8 0.662097 15176894 17.376773 05204486
9 0.681994 14734112 18.058767 05564375
Totals:10 18.058954 05564317