Product manual

CDA 7 Hardware
77 A1 69UP Rev00 2-7
2.2.2 Channel Director Display
The channel director display is located on the right side of the operator panel.
There is a separate display for each channel director.
The operator panel displays the current activity and status of each channel director.
The switches control physical channel on-line/off-line activity.
The channel director display components function as follows for the channel
directors:
POWER
Light indicating that the CDA 7 operator panel is powered on.
READY/ACTIVE LED
Light indicating channel interface state. When the Ready/Active LED is lit, that
channel interface is on-line to the host system. When the Ready/Active LED is
flashing, I/O operations are in progress. For remote link directors (SRDF), these
LEDs have no meaning.
ENABLE/DISABLE SWITCHES
Switch for placing a channel interface in the on-line or off-line state.
2.3 Disk Devices and SCSI Disk Emulation
The CDA 7 uses 3.5-inch disk devices, each having an unformatted storage
capacity of 23 GB (18 GB formatted). The CDA 7 can contain up to 32 disk-
devices.
When using a SCSI interface, the CDA 7 system appears as standard SCSI disk
devices with data stored in fixed-block architecture (FBA) format.
The following paragraphs describe:
• the FBA Data and Command Format
• the Logical Volume Structure