Specifications

Escala Tower PL & S, E, T System Hardware
Chapter 3: External Storage and SAN Subsystems 38/116
9es3s1c3.doc
Rev 5.9
02/12/2003
3.9. The SCSI Host Connection
The main component of the connection to the ESCALA host is the standard dedicated SCSI-2 SE/DE
adapter excepted for the DAS3500 (Fibre Channel). It is a 20MB/s Fast Wide differential MCA/PCI-
to-SCSI-2 Adapter. The connection uses also a SCSI-2 bus cable and an asynchronous RS232 cable
for the DAS1300, DAS2900 and DAS3200.
The DAS3500 uses a Fibre Channel connection (FC-AL) to connect the SP to the Host.
The DAS3500 provides 2 internal 3-port hubs (one for each Storage Processor) to chain the SP of one
DAS3500 or between two DAS3500.
The Host Connection can use also an external hub to chain or to share SP of DAS3500. This solution
is more secure than the internal hub and it is recommended for HA solutions.
The local connections can use copper cables up to 30 meters. The distant connections (DAS3500 or
host) have to use a mix of copper cables and fiber cables (up to 500 meters) with MIAs modules on the
hubs or on the SPs. For Customers who want to get more than 500 meters between DAS3500 and the
Hosts, the Fibre Link Extender module has to be used with fiber cables (9/125µm).
Limits
: 3 DAS3500 per FC-AL loop.
3.10. Disk Drives Specifications
4.2 GB disks discontinued as of 30 November 1999.
8.8 GB and 17.8 GB disks discontinued as of 31 December 2001.
Nominal Disk Capacity (GB) 4.2 8.8 17.8
Actual Disk Capacity (10*6 B) 4372 8800 17800
Interface SCSI-2 SCSI-2 SCSI-2
Form Factor 3.5" 3.5" 3.5"
Seek Time (Average R/W) (ms) 8.4 /9.9 8.5 /10.5 8.5 /10.5
Spindle speed (RPM) 7202.7 7202.7 7202.7
Latency (ms) 4.17 4.17 4.17
Transfer Rate
buffer to/from media (MB/sec) 9.59 to 12.58 10 to 15 10 to 15
buffer to/from host (MB/sec) up to 20
Buffer Size (kB) 512 1024 1024
Disk drives are common to the DAS 1000, 2000 and 3000 Series.