SCSI Description

3.5SCSI BUS PHASES

The SCSI architecture includes eight distinct phases:

BUS FREE phase

ARBITRATION phase

SELECTION phase

RESELECTION phase

COMMAND phase

DATA phases (In/Out)

STATUS phase

MESSAGE phases (In/Out)

The last four phases are called the “information transfer phases”.

The SCSI bus can never be in more than one phase at any given time. In the following descriptions, signals that are not mentioned are not asserted.

3.5.1 BUS FREE Phase

The BUS FREE phase indicates that there is no current I/O process and that the SCSI bus is available for a connection.

SCSI devices detect the BUS FREE phase after the SEL and BSY signals are both false for at least one bus settle delay.

During normal operation, the BUS FREE phase is entered when the drive releases the BSY signal. However, the BUS FREE phase can be entered following the release of the SEL signal after a SELECTION or RESELECTION phase time- out. BUS FREE might be entered unexpectedly. If, for example, an internal hardware or firmware fault makes it unsafe for the tape drive to continue operation without a full reset (similar to a power-up reset), or if ATN is asserted or a bus parity error is detected during non-tape data transfers.

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Quantum DLT 7000 Tape System

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Quantum Instruments DLT 7000 manual Scsi BUS Phases, BUS Free Phase
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DLT 7000 specifications

The Quantum Instruments DLT 7000 is a state-of-the-art battery-powered light that brings advanced photography and videography offerings to professionals and enthusiasts alike. Renowned for its compact design, the DLT 7000 combines lightweight portability with powerful functionality. It is engineered to enhance the creative process by providing optimal lighting solutions in a variety of settings.

One of the standout features of the DLT 7000 is its innovative LED technology. This light source offers consistency in color temperature and output, ensuring high-quality illumination for both photo and video applications. The unit boasts an impressive color accuracy with a CRI (Color Rendering Index) rating that exceeds 90, making it ideal for capturing true-to-life colors in any situation. The DLT 7000 allows users to adjust the color temperature from a warm 3200K to a cool 5600K, catering to different lighting needs and environments.

Moreover, the DLT 7000 features a dimming function that allows for seamless adjustments from 0 to 100% brightness. This level of control not only aids in achieving the perfect exposure but also helps in creating the desired mood or atmosphere for a shot. The robust design of the DLT 7000 includes durable construction material that can withstand the rigors of location shoots, making it a reliable tool for professionals.

In addition to its lighting capabilities, the DLT 7000 incorporates smart technology. It is equipped with a built-in wireless control system that allows users to adjust settings from a distance, promoting flexibility during shoots. This wireless functionality extends to multiple units, enabling synchronized lighting setups for complex scenes.

Another notable characteristic of the DLT 7000 is its versatile power options. The light can operate on lithium-ion batteries, ensuring long-lasting performance during extended shoots without the constraint of power outlets. There is also an option for AC power, providing users flexibility in various shooting locations.

In summary, the Quantum Instruments DLT 7000 stands out with its combination of advanced LED technology, adjustable color temperatures, built-in dimming capabilities, and smart wireless controls. Whether for professional photography or videography, this light is designed to meet the demands of the most discerning artists, making it an essential addition to any lighting kit.
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