Using SSDs for Video

Over the past few years the movie and video industries have been changing media storage devices from film and tape to Solid State Drives (SSDs) and Flash Cards.

SSDs have their own set of guidelines for use and storage, which differs substantially from many other media storage types.
This studio blog entry will attempt to cover most of the important guidelines for using SSDs on your movie or video shoot.

Electrostatic Discharge

SSDs are static sensitive devices.

As an electronics engineer, I usually wear a proper static control wrist strap and use a proper ESD mat when working with static sensitive devices including all integrated circuits (IC) and IC devices.

SSDs are typically installed inside of a computer where static discharge is unlikely to occur, and where the drive is not constantly being handled.
The interface (the pins on the connector) for an SSD only has minimal Electrostatic Discharge (ESD) protection, typically 4kV or 5kV (kilovolts) of maximum static discharge voltage before damage occurs.
5kV is low enough that you can easily carry a sufficient charge in your body to damage an SSD without even knowing or feeling the shock.

SSDs are typically packaged inside of a translucent static protection bag inside of the shipping package or retail box.
When removing the packaging on a new SSD, be sure to retain the static protection bag for use during all transporting and storing of the SSD.
Simply cut the seal off of one end of the bag so that you can reuse it for storing the drive.

Whenever an SSD is removed from the camera or device or dock, place it into its static protection bag.

When on location, place the SSD into its static protection bag, and then into an equipment case or bag for additional physical protection.

Whenever an SSD is put into storage, place it into its static protection bag.

Before handling an SSD it is prudent to make sure that you are not carrying any electrostatic charge.
This can usually be done by touching any large metal object next to you, such as the back of a computer or a metal desk or stand.

If the camera has a large metal case, you can also hold onto that while inserting or removing the SSD.

The eSATA (external SATA) interface typically has a higher ESD protection level, due to eSATA being an outward-facing interface.
eSATA connectors on motherboards are typically red in color and are located on the rear of the motherboard, facing out of the back of the computer.
The higher ESD protection level of eSATA is not inherent in any SATA drives including SSDs.
The use of an external eSATA drive dock does not alleviate the need for proper ESD handling of SSD devices.

Drive Insertion and Removal

The SATA (Serial ATA) interface used by most SSDs is designed to support hot-plugging or hot-swapping of devices.
Hot-plugging refers to plugging in or removing a SATA device such as an SSD while the computer or camera is powered on.

The hot-plugging capability is accomplished by using a specific design of staggered interface pins on the connectors.
As seen in the image below, some of the pins on the SATA device’s power and interface connectors are longer than the other pins.
The longer pins are connected to the device’s power and ground terminals, and the shorter pins are connected to the device’s data lines.

The theory behind this staggered pin design is that when hot-plugging a SATA device, the power and ground pins will make contact first.
And when removing a SATA device, the power and ground pins will be disconnected last.
This is important because in electronic integrated circuitry, connecting the data lines while there is no power can damage the integrated circuits.

This may work fine all of the time in theory, but in the real world there is still a chance that damage may occur to the SATA device or host during a hot-plugging operation.
The problem is that in the real-world, the SSD drives often fit too loosely in the device, the camera or SSD contacts may have collected fine dust, or just general random circumstances.
In professional computer servers where hot-plugging is typically found, the SATA drives are usually placed into a proper drive carrier or drive tray that has a much tighter design and fit tolerances where the staggered pin system functions better.

I really would discourage anyone from hot-plugging or unplugging an SSD from their camera.
A loosely fitting drive, and dust or oxidation on the contacts are significant causes for the hot-plugging design to fail.
This will often be seen as a drive that was known to work before, all of a sudden no longer working as soon as it is hot-plugged into the camera or dock.
In the case of SSDs, there is no data recovery service for retrieving the data from a damaged drive, and a lost shoot can literally mean tens-of-thousands or hundreds-of-thousands of dollars of loss.

Always turn the camera power off before inserting or removing the SSD drive.
Always turn the dock power off before inserting or removing the SSD drive.

The correct dock removal procedure is to eject the drive in the operating system, power off the dock, pull the SSD, and place it into its static protection bag.

   

SATA Connector Mating Cycles

The physical SATA connector pins are a curved contact surface of copper alloy with typically 0.75 micrometres (µm) of gold plating and nickel underplating.

SATA connectors for signal and power are rated for typically 500 mating cycles.
In other words, the SSD drive is only rated to be plugged or unplugged 500 times.
This rating is based on the number of cycles before the plating starts to wear excessively.
In most cases, so long as the connector is kept very clean from dust and other abrasives, the actual number of mating cycles can be higher, as many as 1000 or more.

There are a couple of high quality commercial/industrial/military contact sprays that can be used on contacts to provide lubrication that reduces friction and reduces resistance, and does not evaporate.
I won’t mention any specific brand of spray since they should only be used in controlled environments.  They should never be used in an environment where dust can accumulate on the contact surface, as the spray lubrication residue will essentially become like a suspension of sandy grit that wears out the contact surface substantially faster.
So I do not recommend using any contact sprays on the SSD SATA connector.

For comparison, these are the typical mating cycle ratings of a few other common interfaces.
Note that the exact number of mating cycles can vary by the quality of the connector used.

CFast = 10,000 mating cycles
HDMI = 5000 mating cycles
SATA = 500 to 1000 mating cycles
eSATA = 2500 mating cycles
eSATAp = 2500 mating cycles
Thunderbolt = 10,000 mating cycles
USB (large) = 1500 to 3500 mating cycles
USB (micro) = 10,000 mating cycles

Short-term and Long-term Storage

Whenever an SSD is put into storage, place it into its static protection bag.

Tracking the Drive Usage

SSD drives, like most SATA storage drives, include S.M.A.R.T. (Self-Monitoring, Analysis and Reporting Technology) reporting technology.
Since SSDs have a specific lifetime limitation determined by the cell write count, the S.M.A.R.T. report information typically includes information regarding how much data has been written to the drive.
The SM.A.R.T. report information also includes other information and error status which may be useful in determining whether a drive may be succeptible to a premature or impending failure.

There are numerous S.M.A.R.T. applications available that will read and display the current report information from the SSD.
The best place to look initially is with the manufacturer of the drive, as they will often have a free application that is designed for the specific report values that their SSDs support.

The S.M.A.R.T. report attribute fields that are most important for SSDs are those related to drive life, total data written, and any error attributes.

Final Notes

When using a camera that records to SSD media on a shoot, it is prudent to always check the result of each shot to make sure that the SSD media successfully captured the data.
Since SSDs can be easily read on most netbooks and laptops, having a computer with a drive dock on the set will also allow for a quick and easy visual shot check and even a fast backup of the data to a secondary backup drive.

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