Editorial Note
In this issue, we are happy to share about the
new technologies and solutions that we have
showcased at CeBIT 2014. Some of these
included a new range of advanced file system
design, hardware controllers, emerging disk
technologies and new programming paradigm
targeted at Non-Volatile Memories (NVM) of the
future that will enhance storage and processing
efficiencies in data centres. Read more in our
cover story.
We would also like to share about our success
story with Trinax. Through a T-UP collaboration,
DSI has helped the company to improve and
commercialise their product, the TRI-M®. The
project was a success and you can find out
more in the article within.
We hope that you will enjoy the articles in this
issue.
• Editorial Note
• Making Waves at
CeBIT 2014
• Mirroring Success
• Memories in the Sky
• Shingled Magnetic
Recording with NonVolatile Memory
• Enriching Young
Minds!
• Our Invited Papers
• Recent Conferences /
Seminars/ Workshops
Participated By Our
Staff
A Research Institute of the Agency for Science, Technology and Research (A*STAR)
Making Waves at CeBIT 2014
This year’s CeBIT was targeted to be a B2B event as compared to previous years’
where it was more of a B2C event. DSI made its presence felt and saw over 150
potential companies and startups, drawing positive feedback. Among the visitors are a
number of solution end-users and system integrators from countries like Spain, Russia
and Brazil.
DSI’s participation in CeBIT was well covered on several online media such at EuroAsia
Industry and Storage Newsletter.
“One of the few truly innovative idea encountered at CeBIT did not come from any of
the big players and wasn’t an end-user front facing product. It came from A*Star, an
R&D storage institute in Singapore.” – Storage Newsletter
DSI showcased innovative next generation Non-Volatile Memory systems and solutions
at the event. The team demonstrated a new range of advanced file system design,
hardware controllers, emerging disk technologies and new programming paradigm
targeted at Non-Volatile Memories (NVM) of the future that will enhance storage and
processing efficiencies in data centres.
DSI booth at CeBIT 2014
Among these innovations is an advanced file system and memory stacks (NVMOS
Stacks) using NVM technologies called the Database booster, which has been tested
against industry benchmarks and demonstrated its ability in improving database
performance by up to nine-fold as compared to traditional approaches. This system
can be deployed in high speed Network Attached Storage (NAS) servers, high
performance database servers, and used for real-time big data analysis, high speed
cloud gateway and large-scale parallel storage systems such as Hadoop.
Other technologies on display include the Enterprise Network Attached Storage, a high
performance storage system built for the Shingled Magnetic Recording (SMR) drives
that are 10 times more efficient than Facebook’s Flashcache system in terms of
latency. This was achieved with the use of DSI’s intelligent file caching technology.
CeBIT 2014, one of the world's largest trade fair that showcases digital IT and
telecommunications solutions, was held in Hannover, Germany from 11 -14 March
2014. The show received positive reviews from exhibitors, the IT sector and the
tradeshow’s own organisers and led to total capital expenditures of up to EUR 25
billion.
A Series of DSI Success Stories:
Mirroring Success!
Trinax has always been in the forefront of marketing technology and their objective
is to supply cutting edge marketing technologies to the advertising and media
industry. One of their stunning innovations is the TRI-M® - Mirror.
TRI-M® combines the practical function of a mirror with real-time, advertising and
information displays, personalised with information that is relevant to them. This is a
great tool for advertisers as the interactive display platform can now reach out to
consumers like never before.
The concept itself was great, however the team needed some help to refine the
working prototype and they approached DSI for assistance. There were many issues
to be addressed with the prototype, primarily the wiring system had to be optimised
and the prototype had to clear the ingress-protection test before it can be certified
for commercial use.
Through a 9-month T-UP collaboration with Trinax, DSI’s secondee, Mr Ng Lung Tat
from the Drive Systems & Technology division, successfully transferred his skills in
the area of product design and fabrication to further improve the prototype. DSI had
assisted the company in the area of design optimisation and product fabrication.
With the optimised fabrication flow, Trinax was able to reduce its manufacturing cost
yet meet the specifications required by the industry.
The collaboration was a success and here is what Trinax’s CTO, Zack Lim has to say:
“Trinax has gained the confidence to design and produce other products sharing
some similar components that are up to rigorous industrial standards. This includes
digital tables that are spill and impact-resistant, as well as standing kiosks that are
weather-proof.”
About T-UP
The Technology for Enterprise Capability Upgrading (T-UP) scheme involves
seconding Research Scientists and Engineers (RSEs) to local enterprises to enable
them to access the pool of R&D talent in the A*STAR Research Institutes (RIs). The
RIs will endeavour to match suitable RSEs with the company based on the R&D
project in mind. Partial funding will be provided to the eligible company for the
salary of the RSEs up to a maximum of two years. After this period, there is an
option for companies to retain the seconded staff on a full-time basis if there is
mutual agreement.
Interested to collaborate with DSI through a T-UP programme?
Click here to find out more.
Non-volatile memories are known for their ability to retain data without the
constant need for power supply. Despite this unique characteristic, their usage can
be limited by their inability to operate under a wide range of temperature. In this
article, we will look at how the DSI team has managed to develop new materials
with better stability and temperature resistance to meet the needs of the industry.
Memories in the Sky
By Ernult Franck Gerard (Non-volatile Memory Division)
Non-volatile memories such as Phase Change Random Access Memory (PCRAM),
Resistive Random Access Memory (RRAM) or Magnetic Random Access Memory
(MRAM) have the ability to retain data without the need for a constant supply of
power. Their write/erase mechanism relies on the injection of a current through
their structure and is predicted to be highly scalable (i.e. a reduction of the size of
the devices would lead to both an increase of their density and a decrease of their
power consumption). As such, these technologies have been identified as potential
replacement of the current DRAM and Flash memories. Some, PCRAM and MRAM,
were recently introduced to the market for use in mobile phones or automobile
applications.
In the case of PCRAM, this electrical current alternatively transforms the crystal
structure of the active layer from crystalline to amorphous and vice-versa as shown
below in Figure 1. The crystalline state corresponds to a low resistance (associated
to a bit 1) and the amorphous state to a high resistance (associated to a bit 0).
Figure 1
The write/erase mechanisms of these new memories are also believed to be
insensitive to radiation, making them ideal candidates for use aboard aircrafts or
satellites. But so far, their usage has been limited by their inability to operate under
a wide range of temperatures and improvements are necessary to ensure that they
can resist the extreme temperatures to which they might be exposed in these
environments. For example, although the temperature in various parts of airplanes
can vary from -50°C to well above 100°C, conventional materials used in the
fabrication of PCRAM can only survive up to 85°C.
It is then necessary to develop new materials that, while still exhibiting phase
change properties, are stable in the widest possible temperature range.
Making use of the co-sputtering abilities of our Physical Vapor Deposition (PVD)
equipment, various alloys were prepared in DSI. Out of the many developed,
several exhibited promising properties and were selected for the fabrication of
devices with a diameter of 100nm in order to test their performance and compare
them to a commercial benchmark.
After several rounds of process optimisation, successful devices were fabricated and
tested. All alloys tested exhibited the expected phase change properties and could
be successfully written and erased from -55°C to 150°C.
A subsequent optimisation of the write/erase electrical pulses showed that the
endurance of the newly developed devices could be as high as 105 cycles (see
graph on the left), i.e. the same level as the Single Bit per Cell Flash devices
currently available in the market and the commercial PCRAM benchmark.
Data retention was shown to be 10 years (a number frequently used by the nonvolatile memory industry to assess the quality of their devices) at temperatures as
high as 130°C and was still several hours or more at 150°C. Radiation tests
conducted by our team in a proton accelerator showed that the devices were also
able to withstand high radiation fluences.
Based on all these experimental data, our Signal Processing team then developed
an error-correction code which is able to further enhance the performance of our
devices, by improving their Bit-Error-Rate (number of errors per reading) by a
factor of 10 or more. This error correction code has a very short latency of about
2ns and therefore allows us to preserve the fast write/erase property demonstrated
by our device development team.
These new devices improved the maximum operating temperature by more than
80% and were comparable to the commercial benchmark in all other metrics. Our
team is now continuing its effort on widening the operating temperature range of
our non-volatile memories in order to match up to the needs of the industry and
target a high penetration rate for the usage of these new technologies.
As traditional magnetic hard drives approach their limits in capacity growth, various
technologies have been developed to increase drives’ data density. In this article,
we will discuss these technologies, their limitations and how the DSI team’s new
hybrid storage solutions, with the use of non-volatile memory, are able to increase
performance standards and provide a solution for future drives.
Shingled Magnetic Recording with Non-Volatile
Memory By Xi Weiya (Data Centre Technologies Division)
Technologies for high density storage
Traditional magnetic hard drives are fast approaching their limits in capacity
growth [1]. Various technologies such as Shingled Magnetic Recording (SMR), HeatAssisted Magnetic Recording (HAMR), Bit-Patterned Media Recording (BPMR), and
Helium-filled drives, are being developed to increase data density. SMR overlaps, or
shingles, adjacent tracks to increase disk areal density. In Gibson’s Shingling
Geometry Model [2], a SMR disk density can be more than two times higher than a
conventional HDD (Hard Disk Drive). Both HAMR and BPMR have their own
innovative methods of packing data bits even more closely together. However, these
technologies face the challenge of fabrication/assembly. SMR is based on
Perpendicular Magnetic Recording (PMR) technology and does not require much
change in their fabrication/assembly. Helium filled drives can reduce air flowinduced mechanical vibrations which is helpful to increase track density from the
mechanical point of view. SMR drives can be used together with either PMR or HAMR
or BPMR. It can also be used in a helium-filled drive.
SMR drives - problem and approaches
A major problem with SMR is that write updates may erase previously written data.
Therefore in a SMR disk, data writing is restricted to sequential writes through
appending [1]. To address this problem, a data management layer has to be
designed and developed to redirect all update-in-place requests to different locations
so that a host can send unrestricted read/write commands, standard commands
sending to a conventional HDD, to a SMR storage device. The data management
layer can be implemented in the disk drive itself, or in the host, or in both locations
as shown in Figure 1.
Figure 1. Data Manager Layer for SMR
File metadata and data
In a storage system, there are normally two types of data stored. One is the file
metadata and the other is the actual file data. File metadata are data that provides
useful information about the actual data stored in the file. File metadata are small in
size but need to be accessed/updated frequently. The actual file data, on the other
hand, are usually larger and do not need to be updated as often as their metadata.
Compared to conventional HDD, much more data movement is required if the data
is stored in the SMR storage device. The data movement can degrade storage
system performances and increase vibrations due to frequent disk head seeks. The
vibration can cause resonant in a disk array in a data centre.
To improve performance and reduce vibrations, the metadata and other frequently
updated data have to be stored in a non-shingled storage area. DSI adopted a
hybrid solution for SMR storage: In essence, this would mean that frequently
updated data including metadata are stored in small sized Non-volatile Memory
(NVM); while the large amount of cold file data are stored in the SMR storage.
The team at DSI has designed two systems adopting two different approaches. One
is the data manager designed for hybrid shingled drive and the other is a file system
for hybrid shingled storage. Hybrid Data Manager shown in (A) of Figure 2 is
designed for a hybrid SMR disk drive consisting of an embedded NVM and shingled
disk media. With Hybrid Data Manager, the hybrid shingled disk drive can be used
for any standard system and provide high sustained performances. The other is the
High-performance SMR file system (HiSMRfs), a file system for SMR hybrid storage
system as shown in (B) of Figure 2. The HiSMRfs is designed for hybrid storage
system consisting of SSD and SMR drives.
Figure 2. Two approaches for SMR disks
HiSMRfs
HiSMRfs is a general purpose file system with standard interface. It is suitable for a
hybrid storage system either with SSD and SMR or SSD and HDD. To achieve high
performance and reduce disk seek movements, HiSMRfs separates data and
metadata storage, and manages them differently. Metadata are stored in a high
performance random write area such as in a SSD, and data are stored in the low
performance zone such as SMR drives. High performance zone can be SSD or
consolidated NVMs from an array of hybrid drives. Low performance zone can be
either SWD or low performance HDDs.
Prototype and Performance Tests
A prototype has been implemented for HiSMRfs and two different systems have
been built on the prototype to test and compare their performances. One is HiSMRfs
and the other is EXT4 with Flashcache (as shown in Figure 3).
Figure 3. Topology of two systems built on Prototype
The performance results of the two systems under file server application workload
generated by Filebench is shown in Figure 4. It can be seen that HiSMRfs performs
better than the Flashcache system on data allocation, IOPS, throughput and latency.
The pre-allocation is about 9 times shorter than the Flashcache system. HiSMRfs’s
performance is about 11% better than Flashcache system in terms of IOPS,
throughput and latency.
Figure 4. Performance comparison between HiSMRfs and
EXT4 with Flashcache
The design of Garbage Collection (GC) strategy for a SMR storage to reclaim back
the space keeping out-of-dated data is important. Inefficient GC will impact system
performances. Our next step is to analyse various GC strategies to design and
develop efficient GC algorithms for HiSMRfs and Hybrid Data Manager to minimise
performance impact to the system.
[1] Y. Shiroishi, K. Fukuda, I. Tagawa, S. Takenoiri, H. Tanaka, and N. Yoshikawa, "Future
options for HDD storage," IEEE Transactions on Magnetics, vol. 45, no. 10, Oct. 2009.
[2] G. Gibson and G. Ganger, “Principles of Operation for Shingled Disk Devices,” Carnegie
Mellon University Parallel Data Lab Technical Report, CMU-PDL-11-107, April 2011.
Enriching Young Minds!
Students visit to DSI's Network Storage Laboratory
In support of the 15th Asian Physics Olympiad (APhO), DSI hosted 26 students at
our research labs at Fusionopolis on 15 May 2014. The group was invited to tour
our state-of-the-art Network Storage Laboratory (NSL) which is an advanced data
systems laboratory that houses a heterogeneous range of vendor storage systems,
servers, switches and other peripherals used for in-house research.
During the visit, the team also presented a short demo on DSI’s A*Drive, the new
generation of hybrid thin drives. Overall, the visit was enjoyable and enriching for
the young ones.
The APhO was held in Singapore at NUS from 11 May- 19 May 2014 and organised
jointly by NUS, NTU, Institute of Physics Singapore and the Materials Research
Society of Singapore.
The event serves to build a network among the leaders for further collaborative
projects in physics education, such as creating physics competitions in their own
countries.
IWH 2013
From Left: DSI research scientist Dr Xu Xuewu with
Prof T. Shimura and Prof. H. Yoshikawa at IWH 2013.
The International Workshop on Holography and related technologies (IWH 2013)
was held in Hokkaido, Japan, from 15 – 17 October 2013.
DSI scientist, Xu Xuewu, presented his paper on “Spatial-Temporal Multiplexing and
Streaming of Hologram Data for Full-Colour Holographic Video Display”. His paper
revealed the process and bandwidth of multiplexing the sub-holograms to stream
the hologram data for a 10-inch diagonal 3D holographic display, as well as its
limitations.
This is the fifth workshop which covers overall aspects on holography and related
technologies, holographic memories, displays, holographic measurement, computer
generated holograms and digital holography, ranging from their fundamental
physics and technologies to practical systems. Since 2011, this workshop has
extended the scope furthermore; IWH now covers the holographic display as well
as holographic memory.
Recent Conferences/Seminars/
Workshops Participated By Our Staff
07 – 10 October 2013
Bonn, Germany
3rd Bonn Humboldt Award Winners' Forum "Frontiers in Quantum Optics:
Taming the World of Atoms and Photons - 100 Years after Niels Bohr"
15 – 17 October 2013
Hokkaido, Japan
International Workshop on Holography and Related Technologies (IWH 2013)
21 – 22 October 2013
Singapore
A*STAR Scientific Conference 2013 – Discover & Impact – Making a
Difference for Society
26 – 29 October 2013
Busan, South Korea
International Conference on Electrical Machines and Systems 2013
27 October – 01 November 2013
CA, USA
AVS 60th International Symposium & Exhibition
31 October 2013
Singapore
IDEMA DISKCON Asia-Pacific 2013
03 – 06 November 2013
Pennsylvania, USA
SOSP’13: The 24th ACM Symposium on Operating Systems Principles
04 – 08 November 2013
Colorado, USA
58th Annual Magnetism and Magnetic Materials (MMM) Conference
12 – 15 November 2013
Beijing, China
Asia Communications and Photonics Conference 2013
16 - 22 November 2013
Colorado, USA
SC 2013 - The International Conference for High Performance Computing,
Networking, Storage and Analysis
06 December 2013
Singapore
Internet of Things
07 – 11 December 2013
Washington DC, USA
IEEE International Electron Devices Meeting
08 – 11 December 2013
Melbourne, Australia
SPIE Micro+Nano Materials, Devices and Applications 2013
09 – 12 December 2013
Dresden, Germany
6th IEEE/ACM International Conference on Utility and Cloud Computing
10 – 13 December 2013
Florence, Italy
52nd IEEE Conference on Decision and Control
11 – 13 December 2013
Singapore
19th IEEE International Conference on Networks (ICON 2013)