User's Manual

Theory of operations Chapter 7
STT20000N Product Manual Page 51
Theory of operations
Overview
The STT20000 SCSI minicartridge drive is a low-cost, high-performance TR-5
minicartridge tape drive that is ideal for standalone users or small network computer
systems. With capabilities of up to 10 to 20 Gbytes, depending upon media and data
compression, the drive offers quick, efficient backup and restore operations. Its
unique FastSense
TM
feature automatically selects the appropriate transfer rate—
1,000, 733, or 489 Kbytes/sec—depending on the speed of the operating system.
The STT20000 SCSI minicartridge drive is based on proven Seagate designs,
Seagate firmware, and the latest component technologies. This drive uses second
generation custom LSI for efficient circuit layout and increased reliability for low
power consumption. The drive also uses flash EEPROM devices for easy firmware
upgrades.
This chapter describes the drive in more detail and explains implementation specific
information.
Drive configurations
The drive may be configured as Standard (STT20000N) or NS (STT20000N-C). The
NS configuration has all the features of the Standard drive with the following
additions:
• Read While Write(RWW) tape head
• Hardware data compression
• Larger (2-Mbyte) DRAM buffer
Block diagrams
The electronics of the SCSI minicartridge drive are laid out on one main printed
circuit board (PCB).
• Figure 7-1a and 7-1b are simplified block diagrams of the standard and NS
drives, respectively.
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