Intel SRCMR, User Manual

Page: 29 / 180

Getting Started 29
The adapter supports both Single-ended (SE) and Low Voltage Differential (LVD) hard disk
drives but it is recommended that you use only one type of drive technology (SE or LVD) on any
one channel at a time. Each is explained below. The RAID adapter is designed to optimally utilize
an Ultra 60 SCSI controller implementation on the server board; yet, it is backward compatible with
older SCSI hard disk drive specifications.
✏
NOTE
If both SE and LVD devices are attached to the same channel/bus, the entire bus must operate at
the single ended mode speed of the slower device. See Table 7 for the maximum cable length
distances that apply to each mode.
Table 7. Supported SCSI Hard Disk Drive Standards
Maximum Cable
Length (meters)
1
SCSI Drive
Standard Speed
(MB/Sec) Bus Width
(Bits)
Single-
Ended
LVD
Adapter Maximum
Devices per SCSI
Channel
SCSI-1
(2)
5 8 6 (3) 8
Fast SCSI
(2)
10 8 3 (3) 8
Fast Wide SCSI 20 16 3 (3) 16
Ultra SCSI
(2)
20 8 1.5 (3) 8
Ultra SCSI
(2)
20 8 3 NA 4
Wide Ultra SCSI 40 16 NA (3) 16
Wide Ultra SCSI 40 16 1.5 NA 8
Wide Ultra SCSI 40 16 3 NA 4
Ultra2 SCSI
(2, 4)
40 8 (4) 12 8
Wide Ultra2
(4)
80 16 (4) 12 16
Ultra160 (Ultra3) 160 16 (4) 12 16
NOTES:
1. May be exceeded in Point-to-Point and engineered specific applications.
2. Use of the word “Narrow”, preceding SCSI, Ultra SCSI, or Ultra2 SCSI (for example, Narrow SCSI) is
optional.
3. LVD was not defined in the original SCSI standards for this speed. If all devices on the bus support LVD,
then 12-meters operation is possible at this speed. However, if any device on the bus is single-ended only,
then the entire bus swtiches to single-ended mode and the distances in the single-ended column apply.
4. Single-ended is not defined for speeds beyond Ultra.
5. After Ultra2, all new speeds are wide only.
The preceding information is based on the “STA-Endorced Terms & Terminology for SCSI Parallel
Interface Technology” specification published by the SCSI Trade Association. It can be viewed at:
http//www.scsita.org/terms/scsiterms.html
Support for Non-Hard Disk Drive SCSI Devices (Non-Direct Access Devices)
The Intel RAID Controller SRCMR will pass through to the host operating system direct access to
non-direct access SCSI devices which are connected to a SCSI bus (channel) of the RAID
Controller. The RAID controller passes through all control of these devices to the host operating
system.