Samsung MZ-V6E1T0 Uživatelský manuál stáhnout pdf (Strana 5)

Once the hardware limitations

of SATA are overcome, the

next barrier in performance

is software. The first wave

of SATA-based SSDs, again

seeking maximum compatibility

with legacy hard drives,

used the Advanced Host

Controller Interface (AHCI).

This standardized protocols

so that hard drives and SSDs

were interchangeable, but

compromised performance.

First-generation PCIe-based

SSDs often used proprietary

protocols, enabling them to

achieve better performance

than using AHCI, but requiring

device-specific drivers and

potentially new BIOS. The

standards community responded

with a new logical interface

specification, NVM Express

or NVMe, and the definition of

SATA Express allowing AHCI and

NVMe to co-exist in the same

system.

3

NVMe was designed from

the ground up to provide a

consistent, high performance

logical interface for SSDs over

PCIe. It provides features such

as enhanced queueing, interrupt

steering, and multiple threading.

Instead of the single command

queue with 32 commands in

AHCI, NVMe has 64K queues

with 64K commands each. One

interrupt in AHCI is supplanted

by 2048 in NVMe, and the

locking synchronization scheme

has been eliminated.

4

Both SSD vendors and software

firms have rapidly embraced

the NVMe logical interface.

Microsoft Windows 8.1 added

native support for NVMe, carried

forward into Windows 10.

NVMe support is also available

in Mac OS X Yosemite, and

the latest versions of Linux

and Google Chrome OS. With

advanced, multi-threading

operating systems and multicore

processors, NVMe support is

essential to getting the most

out of new SSDs with PCIe

interfacing and V-NAND flash.

NVME BECOMES THE LOGICAL CHOICE

CONTROLLER MANAGEMENT

Admin

Submission

Queue

Admin

Completion

CORE 0

I/O

Submission

Queue

I/O

Completion

Queue

I/O

Submission

Queue

I/O

Completion

Queue

I/O

Submission

Queue

I/O

Completion

Queue

I/O

Completion

Queue

CORE 1 CORE N

NVMe Controller

Adapted from NVM Express, Inc

MORE CORES, MORE QUEUES, MORE COMPLETED REQUESTS

1 2 3 4 5 6

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