IBM z13s, Техническое руководство

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Appendix H.
Flash Express
This appendix covers the IBM Flash Express feature introduced on the zEC12 server.
Flash memory is a non-volatile computer storage technology. It was introduced on the market
decades ago. Flash memory is commonly used today in memory cards, USB flash drives,
solid-state drives (SSDs), and similar products for general storage and data transfer. Until
recently, the high cost per gigabyte and limited capacity of SSDs restricted deployment of
these drives to specific applications. Recent advances in SSD technology and economies of
scale have driven down the cost of SSDs, making them a viable storage option for
I/O-intensive enterprise applications.
An SSD, sometimes called a
solid-state disk
or
electronic disk
, is a data storage device that
uses integrated circuit assemblies as memory to store data persistently. SSD technology
uses electronic interfaces compatible with traditional block I/O hard disk drives. SSDs do not
employ any moving mechanical components. This characteristic distinguishes them from
traditional magnetic disks, such as hard disk drives (HDDs), which are electromechanical
devices that contain spinning disks and movable read/write heads. With no seek time or
rotational delays, SSDs can deliver substantially better I/O performance than HDDs. Flash
SSDs demonstrate latencies that are 10 - 50 times lower than the fastest HDDs, often
enabling dramatically improved I/O response times.
This appendix includes the following sections:
򐂰 Flash Express overview
򐂰 Using Flash Express
򐂰 Security on Flash Express
H