IBM 150 ユーザーズマニュアル

Storage Architectures and Devices 

SCSI defines many different modes of operation, including several different 
data transfer modes. The most common are shown in Table 19.

It is very likely that you will face problems regarding configuration and 
installation of SCSI adapters and devices.

SCSI cabling can be one of the most confusing topics to encounter. Some of 
the questions that may arise are:

  • How many SCSI devices can be attached to a single SCSI adapter? 

  • What are the right cable features to attach more SCSI devices on the 

same SCSI chain? 

  • What is the right SCSI cabling for an HACMP configuration?

In this section, the main SCSI cabling features used with PCI-based RS/6000 
systems are described, answering some of the questions mentioned above.

SCSI-I

8-bit

5 MHz

5 MB/s

6 meters

Fast SCSI

8-bit

10 MHz

10 MB/s

3 meters

Fast/Wide SCSI

16-bit

10 MHz

20 MB/s

3 meters

Ultra SCSI (or
Fast-20 SCSI)

8-bit

20 MHz

20 MB/s

1.5 meters

Wide Ultra (or
FAST-20 Wide
SCSI)

16-bit

20 MHz

40 MB/s

1.5 meters

Ultra2 SCSI

16-bit

40 MHz

80 MB/s

12 meters

 The single-ended length refers to the length of the SCSI cable without 
using devices and their main characteristics.