Data bus widths, Providing adequate cooling

Seagate ST150176LW/LC Data bus widths, Providing adequate cooling, SE and LVD bus configurations

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12	Barracuda 50 Installation Guide, Rev. A

Data bus widths

These drives have a wide (16-bit) SCSI data bus. You can use these drives on a non-wide (8-bit) data bus if you provide proper termination to the upper eight data lines. This is often referred to as providing “high-9 termination” (the other bit is for parity).

The following table lists the maximum cable lengths and number of devices using single-ended and LVD I/O circuits.

Table 1.	SE and LVD bus configurations

SCSI		Maximum
SCSI		number of
driver	I/O transfer rate	number of	Maximum cable
driver	I/O transfer rate	devices on	Maximum cable
type	(Mbytes/s)	devices on	length allowed
type	(Mbytes/s)	bus	length allowed
		bus

SE	20	16	6 meters (19.7 ft.)

SE	40	4	3 meters (9.8 ft.)

SE	40	8	1.5 meters (4.9 ft.)

LVD	80	16	12 meters (39.4 ft.)

Providing adequate cooling

The enclosure design must ensure adequate cooling for the drive. The maximum ambient temperature allowed is 50°C.

The drive’s product manual (83329471) describes how to evalu- ate the air-flow design. The evaluation consists of ensuring that the case temperature of certain critical components remains within acceptable limits during drive operation.

Figure 2 shows two design approaches with one or more fans used to generate air flow. The air-flow patterns can be created

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Contents

Seagate ST150176LW/LC Data bus widths, Providing adequate cooling, SE and LVD bus configurations

Barracuda 50 Installation Guide, Rev. A

Data bus widths

SE and LVD bus configurations

SCSI

Providing adequate cooling

Figure 2 shows two design approaches with one or more fans used to generate air flow. The air-flow patterns can be created