Seagate STT20000A, Product Manual

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Theory of operations Chapter 7
STT20000A Product Manual Page 71
Theory of operations
Overview
The STT20000A is a low-cost, high-performance TR-5 minicartridge tape drive that
is ideal for stand-alone users or small network computer systems. With capacities of
10.0 Gbytes to 20.0 Gbytes dependent upon media and data compression, this
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—based on the speed of the operating system.
The STT20000A is based on proven Seagate designs, Seagate firmware, and the
latest technology. This drive uses second generation, custom LSIs for efficient
circuit layout and increased reliability with 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.
Block diagram
The electronics of the STT20000A are laid out on one main printed circuit board
(PCB). Figure 7-1 shows a simplified block diagram of the drive.
Figure 7-1 Simplified block diagram for STT20000A
IDE
Interface
Digital ASIC
buffer mgr.
ECC
RWW
512KB
DRAM
IDE ONLY
Read Channel
Write Driver
Stepper
Motor
Motor
Control
Head,
Non RWW
Capstan
Motor
Sensors:
-cartridge present
-write protect
-tape hole
-top stop
256KB
EEPROM
(5 volt)
V20 uP
(10 MHz)
40 MHz
Crystal
Control Logic Module
7