Table of Contents
Advertisement
O E M FUNCTIONAL SPECIFICATION ULTRASTAR XP (DFHC) SSA MODELS 1.12/2.25 GB - 1.0" H I G H
The Post Command Processing time of .26 ms is defined as the average time required for process
cleanup after the command has completed. If a re-instruct period faster than this time is used, the
difference is added to the Command Execution Overhead of the next operation.
Data Transfer to/from Disk
The average time used to transfer the data between the media and the drive's internal data buffer.
This is calculated from:
(Data Transferred)/(Media Transfer Rate).
There are four interpretations of Media Transfer Rate. How it is to be used helps decide which
interpretation is appropriate to use.
1. Instantaneous Data Transfer Rate
The same for a given notch formatted at any of the supported logical block lengths. It varies
by notch only and does not include any overhead.
2. Track Data Sector Transfer Rate
Varies depending upon the formatted logical block length and varies from notch to notch. It
includes the overhead associated with each individual sector. This is calculated from:
(user bytes/sector)/(individual sector time)
(Contact an IBM Customer Representative for individual sector times of the various for-
matted block lengths.)
3. Theoretical Data Sector Transfer Rate
Also includes time required for track and cylinder skew and overhead associated with each
track. (See 3.3.2.1, "Theoretical Data Sector Transfer Rate" on page 43 for a description on
how to calculate it.)
4. Typical Data Sector Transfer Rates
Also includes the effects of defective sectors and skipped revolutions due to error recovery.
See Appendix B of the Ultrastar XP (DFHC) S S A Models Interface Specification for a
description of error recovery procedures.
Rates for drives formatted at 512 bytes/block are located in Table 7 on page 42.
Source filename=PERFORM
USER RESPONSIBLE F O R VERIFYING VERSION A N D COMPLETENESS
IBM Corporation
Page 41 of 87
Advertisement
Table of Contents
