SCSI Commands

Table 5–2 Command Descriptor Block - Field Descriptions

Field

Description

 

 

 

 

 

 

Operation Code

The operation code specifies the command being requested. The list of

 

 

 

supported SCSI commands and their operation codes are contained in Table

 

 

5–1.

 

 

Logical Unit

The Logical Unit Number contains the number of the device being

 

 

Number

addressed. It must be set to 0. The Logical Unit Number is ignored if the

 

 

 

Command Descriptor Block is preceded by an IDENTIFY Message.

 

 

Logical Block

Commands that require additional parameter data specify the length of the

 

Address

Logical Block Address that is needed. See the specific command descriptions

 

 

for more detailed information.

 

 

 

The drive does not support Relative Addressing: it defaults to a value of 0

 

 

 

which specifies that the Logical Block Address specifies the first logical block

 

 

of a range of logical blocks to be operated on by the command. Relative

 

 

 

Addressing indicates a technique used to determine the next Logical Block

 

 

Address to be operated on.

 

 

Transfer Length

The transfer length field normally specifies the number of blocks to be

 

 

 

transferred between the initiator and the drive. For several commands, the

 

 

transfer length indicates the number of bytes (not blocks) to be sent. For

 

 

 

these commands, this field may be identified by a different name.

 

 

Parameter List

The Parameter List Length is used to specify the number of bytes sent during

 

Length

the DATA OUT phase. This field is typically used for parameters that are sent

 

 

to a drive (for example, mode, diagnostic, and log parameters). A parameter

 

 

list length of 0 indicates that no data is to be transferred.

 

 

Allocation Length

The Allocation Length field specifies the number of bytes that the initiator

 

 

 

has allocated for returned data. The Allocation Length is used to limit the

 

 

 

amount of data returned to the initiator.

 

 

 

An Allocation Length of 0 indicates that no data is to be transferred from the

 

 

drive to the initiator. The drive terminates the DATA IN phase when the

 

 

 

specified number of bytes have been transferred to the initiator or when all

 

 

available data has been transferred, whichever is less.

 

 

Control Field

The Control Field is the last byte of every command descriptor block. Its

 

 

 

format is shown in Figure 5–2 and described in Table 5-3, and it contains the

 

 

Flag and Link bits. Use of these bits is initiator-dependent. Setting the Link bit

 

 

= 1 provides an automatic link to the next command, bypassing the usual

 

 

ARBITRATION, SELECTION, and MESSAGE OUT phases that would normally

 

 

occur between commands. Other bits in the Control Field are considered to

 

 

be reserved.

 

 

RelAdr

Relative Address must be 0 (not supported).

 

 

 

 

 

 

 

 

 

 

 

Quantum DLT 7000 Tape System

5-5

 

Page 108 Page 110
Page 109
Image 109
Quantum Instruments DLT 7000 Scsi Commands Command Descriptor Block Field Descriptions, Field Description Operation Code
Page 108 Page 110

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.
Top Page Image Contents