WHAT IS SSD?
A solid-state drive is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. It is also sometimes called a solid-state device or a solid-state disk, even though SSDs lack the physical spinning disks and movable read-write heads used in hard disk drives (HDDs) and floppy disks.
MANUFACTURING PROCESS
What Goes into an SSD?
SSDs consist of a few key components - namely NAND Flash and the Flash Storage Processor (or "controller") - but time is the biggest element to factor into an SSD's development.
That time is broken down into several phases, and across the industry, the top-level phases are all fairly templated: Design, Development, Testing, and Production. Each of these layers spiders into differing sub-phases, depending on the company's primary function. Here's a simplified flowchart to help illustrate the time allotment per phase:
Note: Although there is an axiomatic directedness to the flow of development, none of these departments is ever sitting idle -- everyone is always working on something, even if it's updated to previously launched firmware.
MARKET ANALYSIS AND SSD DESIGN
SSDs have grown in their feature sets with each generation, to hopefully create a faster, more accessible platform; these features are first discussed in the design phase.
Responsible for analyzing customer requests, business requirements, company objectives, performance and endurance specifications, and other desirable facets of the impending product launch, the design phase is where a company defines its goals and entertains feature requests; it's the very first step in a solid-state drive's life. In general, the design phase breaks into something like this:
Marketing Requirements Document:
The marketing team will draw up what they think would make a successful and powerful product by assessing the current market environment.
Engineering Response:
Engineers reply with how much of this is feasible within a set amount of time using currently available technology.
Back & Forth:
The company will decide internally which features can be tabled for later, which ones are immediately possible, and which ones must be developed. Those that need to be further developed will then be discussed with third-party, controller-only manufacturers and the SSD manufacturing team, depending on requirements.
Product Requirements Document:
This finalized document outlines the required hardware and firmware specifications for the SSD. Once this document is approved and everything is greenlit, the SSD manufacturer can then move on to the development phase.
DEVELOPMENT
Here's a look at what the development phase breaks down to:
Preliminary Hardware Design:
The engineering team analyzes the documents produced in the Design Phase and focuses on what needs to exist on a hardware level to make those requirement specifications become reality.
Team Analysis & Review:
The team runs through the new hardware design docs, block diagrams, specifications, and all documentation produced so far, then moves on to the deeper stuff.
Detailed Hardware Design:
Next, the team assesses NAND Flash availability and cost structures to determine the right mix of components for the target market. NAND Flash is by far the costliest part of the BOM (bill of materials) on an SSD, so a lot of analysis is done selecting the right memory chips for the device. The team also looks at form-factor requirements as system drive bay configurations continue to shrink. Drive form-factor affects the components that are used and PCB layout requirements.
Firmware Simulation:
To reduce engineering downtime, while the SSD prototypes are being laid-out and developed, firmware programmers get the jump on their work: Using FPGA devices (field-programmable gate arrays), the developers can test logic design and hardware interactions through simulation. They can then transfer their work to the actual hardware once it is available.
Tape-Out:
Once the firmware prototype is ready, it's taped out and sent to the factory for use in the SSD prototype.
FW Programming on Prototype:
Once the prototypes are ready for testing, the firmware engineers will continue iterating their code to accommodate all the features and take care of as many bugs as possible. This phase bleeds into the SSD Testing Phase, covered next.
So then, the development phase is where all the details are hammered out: That's where your SSD comes to fruition, gets programmed, feature-packed, and detailed. A lot of the features you enjoy in an SSD are a result of complex firmware/controller programming; this all goes into informing the hardware how to deal with reading/write requests, garbage collection, overprovisioning, and other solid-state features.
The overall average/predictable cycle for controller development is -- when iterating upon existing controllers (i.e., not making an entirely new product) -- somewhere in the range of 9 months to a year. However, this is, again, highly volatile and based upon several factors in the current market and technology environments.
The only thing standing between development and release is, well, more development -- testing, refinement, and fabrication follow.
TESTING AND VALIDATION
Testing and validation methodologies will vary on a company-by-company basis, but the core principles are the same:
Methodology:
Test Engineers and Product Managers develop use case scenarios -- defining the likely utilization of the device, then ranking them by how likely they are to occur in the field. More common uses (like everyday uses) will be tested most heavily, while obscure ones will often be explored only if a customer requires the feature/use case.
Procedure:
After use-case scenarios are developed, test cases get written to reflect these use cases. Test cases are laid out in a step-by-step manner to guide the technician through what would (theoretically) occur in the field. Many companies have adopted automated testing, the complexity of which will vary based upon the task that must be accomplished. However, some elements require technicians to manually initialize or observe; when testing laptops, for instance, it was impossible to automatically log LCD failures -- we needed human eyes for that.
Quality Control:
Reliability engineering is also a factor when testing products and is often more applicable on the manufacturer's end than on the controller supplier's side.
Many testing facilities will use large shock & vibration machines to do the hard work. Since companies cannot test a product for years before launch, they must do their best to artificially provoke age-related failures in a controlled environment.
What about Firmware?
Firmware is tested the most heavily when dealing with SSDs and controllers since the drive itself is fairly solid and they target "weak links" most heavily and try to focus on things that they suspect will break when abused. This means more stable processes that have been previously refined will get less focus, but won't be ignored; time is valuable, and to get a functional product out the door, the engineers call the shots on what gets prioritized.
Almost there! SSD Phases: Solid-State Drive Production
The robotics, the to-the-nanometer precision, and the multi-billion-dollar factories make it quite easy to be truly captivated by the technology involved.
After the wafers, Flash, and other components are acquired by the factory (as ordered by the manufacturer), and after the wafers have been diced into dies, the factory sends all these parts through what are called SMT lines and reflow machines.
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DISCLAIMER
The information is provided by Tecquisition for general informational and educational purposes only and is not a substitute for professional legal advice. If you have any feedback, comments, requests for technical support or other inquiries, please mail us by tecqusition@gmail.com.
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