Specifications

ATAPI For Streaming Tape QIC-157 Rev B

4. Streaming Tape (Task File) Commands

4.1. ATA (Task File) Command Implementation Requirements

This section details the Commands that the Device shall support from the ATA Standard definition

of the commands. All ATAPI commands other than “A0” packet command shall use ATA

command protocol as defined in the ATA Standard.

4.1.1. ATAPI Soft Reset

See 3.2 ATAPI Soft Reset Command and Protocol on page 17.

4.1.2. Check Power Mode

This command checks the power mode.

If the Device is in, going to, or recovering from the Standby Mode, the Device shall set BSY, set

the Sector Count Register to 00h, Clear BSY, and generate an interrupt.

If the Device is in Idle Mode, the Device shall set BSY, set the Sector Count Register to FFh, clear

BSY, and generate an Interrupt.

4.1.3. Execute Drive diagnostics

This command shall perform the internal diagnostic tests implemented by the Device. The DRV bit

is ignored. Both Devices, if present, shall execute this command. See the ATA Standard

(X3T9.2/791D) for more information.

Implementor's Note: ATAPI Device Drivers issuing the Execute Diagnostics command will cause

all ATA and ATAPI Devices to execute a diagnostic command resulting in a Device reset. To

prevent unwanted resets and or Driver compatibility issues, ATAPI Drivers should not issue the

Execute Diagnostics command. The command is implemented by ATAPI Devices for ATA

compatibility only.

4.1.4. Idle Immediate

This command causes the Device to set BSY, enter the Idle Mode, clear BSY, and generate an

interrupt. The interrupt is generated even though the Device may not have fully transitioned to Idle

Mode.

4.1.5. Nop

This command enables a Host that can only perform 16-bit register accesses to check Device status.

The Device shall respond as it does to an unrecognized command by setting Abort in the Error

4.1.6. Packet Command

See section 2.2 PACKET Command on page 5.