6-32 Installationand Maintenance Volume
Octel 200/300 S.4.1 PB60019−01
Hard Disk Drive Diagnostics (DEX)
The purpose of the DEX command is to “exercise” the disks; hence its name Disk EXerciser. Because
only a small percentage of disk sectors are accessed in the course of normal operation and disk-error
handling cannot be performed for any sectors that are never accessed, DEX provides an orderly and
efficient means to read all disk sectors.
Each disk is divided into five regions, as follows:
Region 1 Critical sectors
Region 2 File system
Region 4 Prompts
Region 8 Message headers
Region 10 Voice data
DEX tests each of the specified regions separately, starting with the lowest-numbered region through the
highest-numbered region. Up to six drives are tested.
When the DEX command finishes testing a region, it displays a status line, as follows:
REGION WW COMPLETE DISK #1: XXXXX DISK #2: XXXXX DISK #3: XXXXX
DISK #4: XXXXX DISK #5: XXXXX DISK #6: XXXXX
Where WW is the Region tested, and XXXXX is the Number of sectors on the disk that had read errors.
All drives are listed on the status line, even if not installed. If not installed, zeros are displayed.
To usethe command, at the @ prompt, enter:
DEX x y Enter
Where xand yare one of the following:
This argument specifies which disk to test:
1 = Test disk #1 (if system drive #1 is installed)
2 = Test disk #2 (if system drive #2 is installed)
3 = Test disk #3 (if voice drive #3 is installed)
4 = Test disk #4 (if voice drive #4 is installed)
5 = Test disk #5 (if voice drive #5 is installed)
6 = Test disk #6 (if voice drive #6 is installed)
FF = Test all disks (or those disks that are actually installed)
Enter = Abort background DEX
If all disks are specified but not all are installed, DEX tests only those disks that are
actually installed. If an invalid option is specified, DEX responds with the following:
INVALID DISK NUMBER or DISK EXERCISE ABORTED
If none of the specified disks are actually installed, DEX responds with the
following:
DRIVE NOT INSTALLED
x= DISK