1. STORAGE DEVICES IN VEHICLES; AN SSD APPROACH
BY ASAWARI KHEDKAR
asawaridani@yahoo.com
Storage Devices in Vehicles; an SSD Approach.
By Asawari Khedkar
Table of Contents
Overview.....................................................................................................................................................................2
Need for Storage Devices in Vehicles.........................................................................................................................2
Understanding the Technology behind SSDs .............................................................................................................2
Performance Parameters ...........................................................................................................................................2
Durability, Shock and Vibration .........................................................................................................................2
Data Access Time and Latency.........................................................................................................................3
Input / Output Operations per Second..............................................................................................................4
Power Consumption............................................................................................................................................5
Performance...............................................................................................................................................................6
Summary.....................................................................................................................................................................6
Comparison Chart........................................................................................................Error! Bookmark not defined.
References..................................................................................................................................................................7
Figure 1 Comparison between Read Latency Values of HDD and SSD......................................................................4
Figure 2 IOPS Values of SSD vs HDD ..........................................................................................................................4
Figure 3 Read Throughput of SSD vs HDD .................................................................................................................5
Figure 4 Power Usage of SSDs vs HDDs.....................................................................................................................5
Table 1 Shock and Temperature Comparison ...........................................................................................................3
Table 2 Data Access Time and Speed Comparison...................................................................................................3
Table 3 Benchmark Results Comparison: HDD vs. SSD..............................................................................................6
Table 4 Comparison between SSD and HDD .............................................................................................................6
pg. 1

2. STORAGE DEVICES IN VEHICLES; AN SSD APPROACH
BY ASAWARI KHEDKAR
asawaridani@yahoo.com
Overview
Convergence of automotive, semiconductor and consumer technologies is transforming the automotive industry.
Vehicles manufactured today are in many ways rolling computers with features like navigation and infotainment.
Need for Storage Devices in Vehicles
Vehicles have advanced technological features like 3D mapping, traffic reporting, multimedia, satellite radio, voice
recognition, and interaction with the driver’s phone. These applications are handled via an on-board computer
system. Multiple sensors are placed at strategic locations, which feed data to the onboard computer. As an
example, the sensor placed on vehicle’s wheels, measures tire pressure and feeds the data to the onboard
computer. The on-board computer requires a storage media to store this information. The on-board computer
system requires a boot up process which in turn needs a storage media to deliver data to the computer.
This white paper describes the breakthrough performance advantages of using Solid State Drives (SSDs) as storage,
over traditional Hard Disk Drives (HDDs) used in current automobiles. Potential benefits of using SSDs are
discussed and comparisons are made against HDDs. The data is based on various organization’s published
specifications. The metrics used in this paper are associated with device performance, reliability, and
environmental factors.
Understanding the Technology behind SSDs
The key components of an SSD (Solid State Drives) are NAND flash non-volatile memory and flash controller. The
NAND flash non-volatile memory stores data and flash controller manages the communication of stored data
with a computer system or other electronic device.
When the computer system needs to read data from or write data to the NAND flash memory, it will communicate
with the flash controller. The flash controller maps the memory cells and creates a directory structure. The
directory structure stores the physical location mapping of the memory locations to the logical sectors of the
controller. On a read or write, the controller looks up the data from the directory and sends it to the requesting
computer system.
Performance Parameters
This white paper describes and compares the following parameters related to SSDs and HDDs; Durability, Shock
and Vibration, Data Access Time and Latency, Input / Output Operations per Second, Throughput, and Power
Consumption.
Durability, Shock and Vibration
SSDs (Solid State Drives) have high resistance to shock, vibration and extended temperatures.
The SSDs are more durable in moisture conditions than HDDs (Hard Disk Drives).
When used in music systems the HDDs need to be mounted at a correct axis. An off road driving vehicle may have
up to ±4g of acceleration in random directions which the spinning HDD cannot tolerate. The HDD drive head will
scratch and potentially damage a music disk if the vehicle drives at a non-horizontal axis.
The SSD does not have any axis and can be mounted at any angle. Since it does not have any moving parts, the
SSD can withstand shocks and vibrations.
pg. 2

3. STORAGE DEVICES IN VEHICLES; AN SSD APPROACH
BY ASAWARI KHEDKAR
asawaridani@yahoo.com
Table 1 Shock and Temperature Comparison
Parameters
SSD HDD
Shock 1500 G 300 G
Operating Temperatures 0 deg C - 100 deg C 0 - 60 deg C
In addition to the enhanced vibration resistance, expanded operating temperatures and humidity ranges, the
storage devices have to address the needs of the on-board computer, such as lower access times, lower latencies
and enhanced performance.
Data Access Time and Latency
One of the main reasons SSD (Solid State Drives) outperforms HDD (Hard Disk Drives) is SSD’s incredibly fast data
access time. Data access time is the delay between the request and the completion of a read or write operation.
It has a random data access time of 0.1 millisecond or less, whereas the mainstream 2.5” HDD takes 10~12
milliseconds to complete a read or write operation. As seen in Table 2, SSDs are 100 times faster than HDDs in
accessing data. The SSD controller communicates via fast ‘Flash Transaction Layer’ controller with the physical
memory (NAND flash), which accelerates the data retrieval time. HDDs are affected by fragmentation and must
wait for spindles, motor heads, and arms to physically locate data locations.
Read latency of SSDs is low. Read Latency is the time the storage device takes, to start any IO task. The smaller
the latency time the better. SSDs deliver consistent lower latencies as they have controllers and NAND Flash based
integrated circuits and do not rely on spinning platters like HDDs to access data. Read latency of HDD is not
consistent and may change for every read operation. The read time is different for every read and depends on the
location of the data on the HDD disk.
Table 2 Data Access Time and Speed Comparison
Category SSD
(540 GB)
HDD
(500 GB, 720 rpm)
Difference
Media NAND Flash Magnetic Platters x3~ 8 / 2 ~ 5
Data Access Time (ms) 0.1 10 ~ 12 x100 ~ 120
Sequential R/W Speed
(MB/s)
540 / 330 60 / 160 (*140 / 70) x 3~8 / 2~5
Random R/W Speed (IOPS) 98,000 / 70,000 450/400 217 / 175
Sustained Read 90+ MB/s 70MB/s ~20+ MB/s
pg. 3

4. STORAGE DEVICES IN VEHICLES; AN SSD APPROACH
BY ASAWARI KHEDKAR
asawaridani@yahoo.com
Read Latency Low High
Figure 1 Comparison between Read Latency Values of HDD and SSD
Input / Output Operations per Second
The time taken to perform a task such as accessing a page (large chunk of data) is measured in Input / Output
Operations per Second. The greater the number of IOPS the better the performance.
Large amount of data is stored in a unit called “page”. The page belongs to a group of pages collectively called
“blocks” on an SSD (Solid State Drives) and HDD (Hard Disk Drives). The SSDs have better IOPS than HDDs as the
SSD controller communicates via fast ‘Flash Transaction Layer’ with the physical memory location (NAND flash).
HDDs rely on motor heads, and arms to physically locate data and deliver it to the requesting device.
The storage IOPS (input/output operations per second) from HDDs has not been able to keep up with the
integrated circuits in the SSDs.
The chart below (Figure 2) shows the IOPS values of HDDs and SSDs. Current SSDs achieve 100x - 1,000x higher
IOPS than HDDs. Figure 2 IOPS Values of SSD vs HDD
0
1000
2000
3000
4000
5000
6000
SSD HDD
Typical Read Latency (us)
SSD HDD
0
1000
2000
3000
4000
5000
6000
SSD HDD
Input / Output Operations per
Second (IOPS)
SSD HDD
pg. 4

5. STORAGE DEVICES IN VEHICLES; AN SSD APPROACH
BY ASAWARI KHEDKAR
asawaridani@yahoo.com
Throughput
The speed at which data is transferred out of or into the storage device, is called throughput and is measured in
bytes per second, commonly kilobytes or megabytes per second. The greater the throughput the better the
performance. SSDs (Solid State Drives) have a higher throughput than the HDDs (Hard Disk Drives). Throughput is
measured at steady state by applying the preconditioning methodology and 5 Round Steady State Determination
formula. The chart in figure 3 compares the typical read throughputs of SSDs vs HDDs.
Figure 3 Read Throughput of SSD vs HDD
Power Consumption
SSDs (Solid State Drives) consume less power than HDDs (Hard Disk Drives). With no moving parts the SSDs have
lower heat output. The storage disk cabinet cooling effort is hence, significantly reduced. As shown in the Figure
4, SSDs consume less power, (about 1.8W), than HDDs (about 7 W) at the peak load. Their energy efficiency can
deliver less power strain on the system and thus a cooler environment. Figure 4 below shows the comparison of
power consumption values at peak loads and at idle times.
Figure 4 Power Usage of SSDs vs HDDs
0
200
400
600
SSD HDD
Typical Read Throughput (MB /
Sec)
SSD HDD
0
2
4
6
8
SSD Load SSD Idle HDD Load HDD Idle
Power Usage in Watts (W)
SSD Load SSD Idle HDD Load HDD Idle
pg. 5

6. STORAGE DEVICES IN VEHICLES; AN SSD APPROACH
BY ASAWARI KHEDKAR
asawaridani@yahoo.com
Performance
The four main factors discussed above, data access times, latency, IOPS and throughput truly indicate the
performance of a storage device. High performance is critical in vehicles as a large portion of the storage accesses
are time critical and extremely essential for passenger safety.
The benchmark results based on industry-standard PCMark test measurements are shown below.
Table 3 Benchmark Results Comparison: HDD vs. SSD
Benchmark HDD SSD
PCMARK Seagate 320GB Intel 80GB
4602 31443
PCMARK Western Digital 6G 1TB Micron 6G 256GB
5580 28179
Summary
Next generation automobiles are taking advantage of SSDs (Solid State Drives) to eliminate the shortcomings of
HDDs (Hard Disk Drives). It is extremely beneficial to adopt SSDs to maximize the input output operations per
second while efficiently minimizing the application latency. The next generation PCIe - NAND Controller based
SSDs have added gains to maximize application processing performance. The ability of SSDs to withstand heat,
irregular axis alignment is an added benefit.
The chart shown in Table 4 summarizes the analysis of this white paper, and emphasizes the benefits of a Solid
State Drive (SSD) against a Hard Disk Drive (HDD).
Comparison
Table 4 Comparison between SSD and HDD
Feature SSD HDD
Mechanism Solid NAND Flash Magnetic rotating platters
Speed 80 - 250 MB/s 65 - 85 MB/s
Average Seek Time 0 < 10ms
pg. 6

7. STORAGE DEVICES IN VEHICLES; AN SSD APPROACH
BY ASAWARI KHEDKAR
asawaridani@yahoo.com
Noise None Noisy
Data Access Time 0.1 12
Read Latency Low High
Power Consumption 2W> 10W. Generates more Heat
Weigh Light Heavy
Endurance MTBF > 2,000,000 hours MTBF < 7000,000
Temperature -40 ~ 100 0 ~ 60
Reliability Anti – shock Non-shock resistant
Shock Vibration
Resistance
Excellent Poor
References
1. Alcorn, Paul. "Micron First to Bring Automotive-grade M500IT SSDs into Your Vehicle." www.Tweaktown.com.
November 3, 2014. Accessed July 30, 2015.
2. Kung, Shawn. "Native PCIe SSD Controllers A Next-Generation Enterprise Architecture For Scalable I/O
Performance." www.Marvell.com. 2012. Accessed July 30, 2015.
3. "Benefits of SSD vs. HDD." www.amplicon.com. Accessed July 30, 2015.
4. Chan, Eric Hong. "Samsung Solid State Drive." www.samsung.com. Accessed July 29, 2015.
5. Janukowicz, Jeff, and David Reinsel. "The Total Cost of Ownership for an SSD-Enabled PC."
www.sandisk.com. July 1, 2011. Accessed July 29, 2015.
6. ."SSD Power Savings Render Significant Reduction to TCO." October 25, 2010. Accessed July 29, 2015.
7. Vamsee Kasavajhala. "SSD vs HDD Price and Performance Study, a Dell technical white paper." Dell
PowerVault Technical Marketing. 11 May 2011. Accessed July 29, 2015.
8. Geoff Gasior . "SSD prices in steady, substantial decline: A look at the cost of the current generation". The Tech
Report. June 21, 2012. Accessed July 29, 2015.
pg. 7