Barracuda 18XL Product Manual, Rev. A 7
3.1 Standard features
The Barracuda 18XL family has the following standard features:
• Integrated SCSI controller
• SCSI multimode single-ended or low voltage differential drivers and receivers
• 8 bit or 16 bit I/O data bus models available
• Asynchronous and synchronous data transfer protocol
• Firmware downloadable via SCSI interface
• Selectable sector sizes from 512 to 4,096 bytes/sector in multiples of 2 bytes/sector
• Programmable drive capacity
• Programmable sector reallocation scheme
• Flawed sector reallocation at format time
• Programmable auto write and read reallocation
• Reallocation of defects on command (post format)
• Enhanced ECC correction capability up to 240 bits
• Sealed head and disc assembly
• No preventative maintenance or adjustment required
• Dedicated laser textured head landing zone
• Embedded servo data rather than a separate servo data surface
• Self diagnostics performed when power is applied to the drive
• 1:1 Interleave
• Zoned bit recording (ZBR)
• Vertical, horizontal, or top down mounting
• Dynamic spindle brake
• 2 MByte data buffer standard (1 Mbyte on some drives, see Table 1) or 4 Mbyte optional
• Hot plug compatibility
• Low audible noise for office environment
• Low power consumption
3.2 Media characteristics
The media used on the drive has a diameter of approximately 3.0 inches (74 mm). The aluminum substrate is
coated with a thin film magnetic material, overcoated with a proprietary protective layer for improved durability
and environmental protection.
3.3 Performance
• Supports industry standard Fast-20, Fast-40, and Fast-80 SCSI interfaces (also called “Ultra SCSI,” “Ultra-2
SCSI,” and “Ultra160 SCSI,” respectively)
• Programmable multi-segmentable cache buffer (see Section 4.4)
• 7200 RPM spindle. Average latency = 4.17 msec
• Command queuing of up to 64 commands
• Background processing of queue
• Supports start and stop commands (spindle stops spinning)
3.4 Reliability
• 1,200,000 hour MTBF (mature)
• LSI circuitry
• Balanced low mass rotary voice coil actuator
• Incorporates industry-standard Self-Monitoring, Analysis and Reporting Technology (S.M.A.R.T.)
• Incorporates Seek To Improve Reliability algorithm (STIR)
• 5-year warranty
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