SG0-001 · Question #253
What two (2) benefits does SCSI Command Tag Queueing provide? (Choose two.)
The correct answer is A. allows I/O requests to be queued to the device B. determines the most efficient way to order & process commands. SCSI Command Tag Queueing (CTQ) allows multiple I/O requests to be sent to a device, enabling the device to reorder and process these commands for optimal efficiency and improved performance.
Question
What two (2) benefits does SCSI Command Tag Queueing provide? (Choose two.)
Options
- Aallows I/O requests to be queued to the device
- Bdetermines the most efficient way to order & process commands
- Ctags I/O requests so they can be executed first in first out
- Dallows SCSI I/O throughput to equal rates of fibre channel
- Edetermines queue depth position
How the community answered
(30 responses)- A87% (26)
- C7% (2)
- D3% (1)
- E3% (1)
Why each option
SCSI Command Tag Queueing (CTQ) allows multiple I/O requests to be sent to a device, enabling the device to reorder and process these commands for optimal efficiency and improved performance.
Command Tag Queueing allows the host to send multiple I/O commands to a SCSI device without waiting for each command to complete, effectively queuing them at the device level for later processing.
With CTQ, the SCSI device controller can intelligently reorder the queued commands based on its internal logic (e.g., disk head position optimization) to minimize seek times and rotational latency, thereby improving overall I/O performance.
CTQ specifically allows for out-of-order execution for optimization, not strictly first-in-first-out, which would negate its primary benefit of reordering.
While CTQ improves SCSI performance, it does not inherently make SCSI throughput equal to Fibre Channel, which operates at different speeds and is a distinct technology.
CTQ allows for a queue depth (the number of outstanding commands), but it does not determine the specific 'position' within the queue; rather, it manages the overall queue and command ordering.
Concept tested: SCSI Command Tag Queueing benefits
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