NAS Structure Introduction by HDD SFF-8301

NAS structure introduction: When talking about NAS, there are different models in the market that can connect to a variety of storage.

However, the current mainstream leading data storage still goes to the 3.5-inch hard disk because of price and storage volume.

Since the 3.5-inch hard disk connected to the machine inside has to respond to an unexpected situation of hard disk damage that may occur at any time.

So there is a need to make sure user can replace the hard disk without stopping the machine.

To allow various hard disk manufacturers to have a uniform appearance size, and reduce the product and increase versatility.

The SFF (Small Form Factor) committee has developed a standard 3.5-inch hard disk structure size that allows product developers to follow the specifications.

NAS Structure – SFF Committee Introduction

In 1985, the world’s first notebook with a folding screen: The Toshiba T1100 was born.

In the following years, a large number of notebooks were introduced, and the demand for various sizes of storage devices also increased significantly.

Due to the lack of standard specifications for storage devices. There are multiple sizes and storage structures, and it is quite challenging to do the mass production.

To improve this situation, the SFF (Small Form Factor) Committee, the Miniaturized Exterior Specification Committee (from now on referred to as the SFF Committee), founded in August 1990.

The SFF members were the major manufacturers of the storage industry at that time.

The SFF initially set up to have a platform to define a new type of hard disk for  computers and discuss storage topics. Such as physical size, installation method, connector type, and connector position.


NAS Structure – Set Up HDD Standard

The 2.5-inch hard disk size specifications: SFF-8004 specifications are born at this time.

In the same time, the small size hard disk brothers: 1.8-inch hard disk (SFF-8005 spec) and 1.3-inch hard disk (SFF-8006 spec) are born as well.

However, these two size specifications have not been valued by the market and have been abandoned after.

Since November 1992, the SFF committee also has standardized size specifications for critical components. Such as connectors, connectors, cables, motherboards, etc.

Until mid-2016, the SFF Technology Affiliate Technical Work Group (SFF TA TWG, SFF Technical Alliance Working Group) under the SNIA (Storage Networking Industry Association) integrated the units and business scope of the original SFF committee.

They also united more manufacturers to set up more cross-enterprise standards.


NAS Structure – Evolving HDD

As the capacity of hard disks increases, the disk number in the hard disk that is primarily responsible for storing data continues to increase, too.

To compatible the higher density of disk structures and various innovative technologies. The SFF committee has also developed a new hard disk bottom screw pitch. Which increased from the early 44.45 mm to the 76.2 mm now.

Each manufacturer has even started the capacity level of 10 TB. They also has gradually changed the hard disk appearance of each manufacturer to a more compact and flat appearance.

The screw spacing at the bottom of the hard disk has also gradually shifted from the current narrow pitch to a wide pitch.

Moreover, the WD manufacturer has mentioned in their specification that the future hard disk products will use wider spacing at the bottom. Which is also worth for structural designers to keep eyes on their trend.

NAS Structure Introduction by HDD SFF-8301

NAS Structure Introduction by HDD SFF-8301

Currently, the SFF-8301 specification has been transferred and managed by the SFF Technical Alliance Technical Working Group. The Rev 1.9 document has been released in January 2018.

The file indicates the hard disk’s length, width, and height, as well as the side and bottom screws detailed drawings. Such as the size and number of holes, screw specifications, etc.

This file has a significant influence on the internal design structure. Such as a hard disk tray or hard disk track.

The wrong structural design may not only not stabilize the hard disk, but also may cause hard disk appearance damage.

It is believed that in the future, as the demand for storage devices increases, it is also possible to create a new generation of storage device size specifications.

NAS structural designers should also maintain the agility of the device market and enhance self-knowledge on the storage device. To help them designed the NAS structures well such as hard disk trays or hard disk tracks.

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