Chapter 2, Views

Disk Configuration View

 Select View, Configuration, Disks

or View, Disk, Configuration.

Disk Configuration Table


Function:

Description:

Data Fields:

Name - The name of the raw disk drive device file.

Blocks - The number of 1K blocks on the disk drive.

Access_min - The minimum access time required to locate and read 1K of data.

Access_avg - The average access time required to locate and read 1K of data.

Access_max - The maximum access time required to locate and read 1K of data.

Transfer - The maximum transfer rate for the disk drive in bytes per second.


The minimum access time is the time taken to move the disk head one disk track and read 1K of data. The maximum access time is the time taken to move the disk head the full width of the disk and then read 1K of data. The average access time is representative of an average I/O operation in the system and consists of the time taken to move the disk head 1/3 of the width of the disk and read 1K of data.

NOTE: The access and transfer statistics measure the real access and transfer times as experienced by a typical user program. It is expected that these statistics will be worse than the minimum seek and maximum transfer values provided by the disk manufacturer due to the operating system overhead.

If the transfer values are dramatically worse, yet the access values are reasonably close to the manufacturers specifications, the interleave factor on the disk could be too low, causing complete revolutions of the disk drive between reading successive blocks. If this is the case, the disk drive should be reformatted with a higher disk interleave and the operating system reinstalled.