Evaluation Engineering - 22

AUTOMATED TEST

are fundamentally different and there are aspects of SSDs that
must be actively considered when using them, especially in writeintensive wideband RF RPA applications:
* Endurance: NAND flash SSDs have a finite number of write
cycles. It's usually a high number, but one should be mindful
of this feature when selecting an SSD-based storage solution. SSD manufacturers specify the endurance of an SSD
in terms of terabytes written (TBW) or drive writes per day
(DWPD). For example, a Samsung 970 EVO Plus 2 TB M.2
SSD supports a TBW of 1,200 TB. This means the SSD can be
completely overwritten 1,200/2 = 600 times before suffering
performance degradation for writes. The
TBW scales with the number of SSDs in
a given PXIe SSD RAID module, so a 16
TB SSD RAID module would support a
TBW of 8 x 1,200 or 9,600 TB. DWPD is
related to TBW but considers the warranty period of the SSD. Specifically, TBW
= DWPD x warranty period.
* Clean Up (garbage collection) using SSD TRIM: Because NAND flash
SSDs have limited write cycles, it's
RADX' model LGT1311,
18 GHz RTSA RF RPA

important to treat them differently when deleting data
and files. Operating systems like Microsoft Windows 10
that support NVMe "know" to use SSD "TRIM" as opposed
to HDD "defragmentation" to minimize unnecessary SSD
writes. Note that support for TRIM under MS Windows is
limited to NTFS file systems. Also note that conventional
RAID controllers (as opposed to PCIe switches) can interfere
with TRIM command execution.
* Encryption: Besides being small and fast, M.2 and other
NVMe SSDs are usually smart, too. Most recent M.2 and
U.2 (2.5-inch NVMe format) SSDs support built-in AES-256
encryption using the Opal storage specification
for self-encrypting drives (SED) developed by
the Trusted Computing Group (see https://bit.
ly/307IltF). If one enables Opal encryption, the
data stored on the SSD or SSD module is encrypted with AES-256, which can significantly
decrease the chance of unintended disclosure
of sensitive data.
* Sanitizing SSDs: With frequent use, or for
use in applications where the data is sensitive,
one will eventually need to sanitize
the SSD prior to disposal. NVMe
SSDs support a "user data erase"
RADX

EVALUATION ENGINEERING

EDITORIAL
CALL
SUBMISSION
DEADLINES
October: Abstract due 8/9,
article due 8/28
November: Abstract due
9/9, article due 9/27
December: Abstract due
10/9, article due 10/28

EVALUATION ENGINEERING AUGUST 2019

We at Evaluation Engineering are always looking for
contributed educational content as we can. Here are the
topics we're looking to receive contributed articles for in
upcoming issues:
October: EMC Test, RF/Microwave Test
November: Design-for-Test, Instrumentation
December: Software, 5G, 2020 T&M predictions
These are all broad topics, but we'd let you, the contributor,
pick the specific focus. The format is also up to you, as
it could be a best-practices article, a 'what's trending'
piece, predictions, tips, a Q&A, or you can simply send us
commentary on a specific topic.
OUR GUIDELINES: The key for these articles is to be non-promotional. We'd like such an
article to range from 600 to about 2,200 words, include any accompanying figures or imagery
(hi-resolution), the author's headshot, and up to 50 words of 'about the author' information.
INTERESTED? Reach out to EE Editor-in-Chief Mike Hockett at
mhockett@evaluationengineering.com with an idea or abstract.

https://bit.ly/307IltF https://bit.ly/307IltF

Evaluation Engineering

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