Quantum DLT 2000 Handbook page 157

The flexibility provided by firmware enables Quantum to adapt
DLTtape systems to meet almost any operating system or vendor
requirements. In addition, when compared to hardware modifica-
tions, firmware changes usually take less development time and are
less expensive to implement. It's important to note that nearly 99 per-
cent of DLTtape firmware remains the same from system to system.
Different Firmware For Libraries
Most DLTtape drives headed to library vendors include a different
firmware to enable the drive to communicate using SCSI protocol
over the system's RS422 serial port, rather than through the SCSI
interface. In cases where multiple DLTtape drives are used in a
library, the firmware enables the library developer to control mul-
tiple drives from a centralized library controller.
Firmware provides the flexibility library makers need to incorpo-
rate DLTtape drives in their systems. For instance, library versions
of DLTtape firmware allow library makers to adjust tape cartridge
unloading resistance. The motor that determines the rate of speed
at which a DLTtape cartridge will pop out of the drive during the
UNLOAD process is controlled via firmware. The amount of
exposed cartridge required for grasping by library robotics varies
from maker to maker. Library makers can select the firmware that
offers the right unload speed for their tape handling system.
Field Upgrades Offer New Features/Fixes
Because DLTtape system firmware is stored in re-writable EEP-
ROM chips, it can be easily upgraded in the field by an end user or
technician. In fact, the very first DLTtape drive, the Digital TF85
(2.6GB native capacity; introduced in 1989), was one of the first
drives on the market to store its firmware in EEPROM memory
(see Chapter 3 for more on DLTtape history).
15.4 FIRMWARE