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Why are there so many flash memory form factors, how did we get here, and where are we going next?

Flash Memory Form Factors

There have been many twists and turns in the development of flash memory, and there is plenty more change to come as new applications are developed and the IoT takes off.

Flash memory comes in many different shapes and sizes, known as form factors. Some are proprietary, though the tendency across the industry is to support universal form factors and differentiate on specifications (storage capacity being just one of many), so that device makers can have the broadest possible choice of capabilities depending on their needs.  

Choice is not the only reason there are so many different sizes of flash memory, and arguably it’s not the most important reason. Flash memory formats keep getting smaller as manufacturing technologies allow, and that means flash can be used in ever-smaller devices or save space inside devices which can be used for other things.  

In the early days, when the leading flash memory formats were SmartMedia and CompactFlash, the divergence of technical standards and form factors caused problems for end users. In the days when we listened to music stored on MP3 players rather than using our phones as a source for streamed or stored music, some companies included a MultiMediaCard (MMC) slot on their devices to allow owners to boost the internal storage. Some of these devices based their specification on a particular card from SanDisk or Infineon – the two primary companies making MMC cards at the time. This meant that purchasers would need to buy a card from the compatible maker.  I had a similar problem with a medical device which would only work with the MMC cards that were sold with the earlier Nokia handsets such as the Nokia 6230 (released in 2004 and my first Cardwave phone). 

There were other examples, and in the end SanDisk, Toshiba and Panasonic got together to try to fix the problem. They came up with the SD form factor, licenced that technology, and created the SD Association to help drive adoption. Standardising like this is not an unusual thing to happen in technology. Think of the Bluetooth SIG or the Wi-Fi Alliance, without which we might have an unthinkable morass of competing wireless standards. 

Still, not every manufacturer or Original Equipment Manufacturer (OEM) wants to play ball, maybe because they don’t want to pay host and card licenses to use the standardised form factors, or because they want to create their own ‘ecosystem’ of customers loyal to their brand. Huawei launched its own proprietary memory form factor called Nano Memory in 2018, and uses this format for its smartphones, and Sony had a format called MemoryStick.  

One of my favourite examples of small storage is the IBM MicroDrive. It’s not flash memory, but when it was launched in 1999 the 1-inch mechanical hard drive in a tiny metal casing was a leader in removable storage. The form factor meant it often needed an adaptor for the widely used PCMCIA slots that featured in laptops. PCMCIA has gone by the wayside as have mechanical hard drives, all but replaced by the continued development of flash memory in the form of SSD.  

MicroDrives also featured in a number of portable technologies. Before I started Cardwave I was involved in a project supplying Casio handheld devices with MicroDrives that had data pre-installed for selling tickets on trains. It was a great idea, but sadly the MicroDrives consumed the handheld device’s battery rather too quickly, and because they were mechanical drives they tended to skip as the train jiggled about. I successfully advised switching to CompactFlash cards, which, though more expensive, did not skip and were less power hungry.  

What next for flash memory form factors? Well, they can get smaller than microSD, as Huawei has shown with its Nano Memory, though in terms of using them for swappable memory expansion there is a logical endpoint when cards become too fiddly for us humans to handle. There might be more proprietary form factors coming onto the scene, and removable flash may well become much more commonly used in household technologies as the Internet of Things (IoT) really takes off (security cameras, TVs, connected fridges and more). 

The drivers of what happens with flash memory formats in the future will be very similar to those that have featured in the past. Form factors are usually successful because they are easy to use, affordable and meet a need. That need isn’t necessarily about the end user. Sometimes form factors are developed because an OEM can see an opportunity to make money. Meanwhile engineers are always coming up with better ways to do things and manufacturers are always trying to reduce manufacturing costs to make technology more affordable.  

Whatever the future holds in terms of specifics, flash itself is here to stay, and is likely to spread its wings wider as our need to store, access and use data in different scenarios grows.  

Author: Paul Norbury

Date: Friday 8th July 2020