63Move the selection bar with the cursor keys from on entry to another (pressing the SPACEbar again undoes your choice).The Choose Type menu offers four different Host Drive Types. For thisexample we select RAID 1 and press ENTER. ICPCON displays awarning that all data will be destroyed after confirmation.ICPCON allows you to limit the hard disk size for this Host Drive. Thisbecomes interesting when you configure disk arrays and you want tomake sure that future drives you want to bring into the disk array forreplacement purposes) fit. It wouldbe bad luck if the new drive only had17508 MB. ICPCON couldn't acceptit. To avoid this occurring, you could limit the capacity of each drive to 17000 MB. Any new18 GB drive must have at least this capacity. The 509 MB in our example would be lost. Forthis example we use the full capacity and press ENTER.The new Host Drive is created. It’s status is still build, since the ICP Controller synchronizesboth drives.Upon successful completion of this process the status of this RAID 1 Disk Array changesinto ready, i.e., the data is fully redundant.The functioning of a RAID-1, or mirroring, disk array, is easy to understand: On the ICP Con-troller, one write-access from the host computer is transformed into two write-accesses (toboth Logical Drives forming the mirroring array). If the two Logical Drives are built of harddisks, which are connected with different SCSI channels of the ICP Controller, both write-accesses are performed simultaneously (this method is often called Disk Duplexing). During aread-access of the host computer the data will be read from the Logical Drive whose harddisk has the fastest access to the data requested.If a hard disk should fail (for instance due to a mechanical defect), all data is still availableon the other Logical Drive. In this event, the controller gives an acoustical alarm.C.5 Example 3 - Installing a RAID 5 Disk ArrayThis example is applicable to ICP Controllers with the RAIDYNE® firmware.Press the key combination when the ICP BIOS message comes up (shortly afterswitching on the computer) and load ICPCON from the Flash-RAM of the ICP Controller. Inthis case no operating system is required.
