All talk on technology is generally focussed on how processors are getting faster, facilitating smoother and slicker user interfaces across a range of gadgets. What we've somehow begun to take for granted, however, are the huge advances in the field of electronic memory or storage devices.

Just a decade ago, a file that was a few hundred megabytes was considered ‘too heavy', USB drives that could store a few hundred MBs were expensive and almost a luxury item.

Today, we think in terms of many gigabytes, be it storage on our computers, mobile devices or even on USB drives. Indeed, the technology — and the evolution curve — behind this electronic rendition of memory is fascinating and is one of the niche domains in the semiconductor and fabrication industry that involves sophisticated manufacturing processes.

The most widely used non-volatile memory devices are, of course, the now-ubiquitous flash memory devices. What started as complex “electrically erasable programmable read-only memory”, or the EEPROM in geek parlance, are today widely used for plug-and-play applications.

More to come

In fact, many of us can't even imagine how we functioned without these hugely convenient and simple-to-use devices.

If Moore's Law — the thumb rule in the semiconductor industry which predicted back in the sixties that the number of transistors that could be housed in an integrated circuit would double approximately every 18 months — can be applied to our storage devices, then a simple extrapolation would indicate that a 128 GB flash drive is not too distant a reality.

Technically, flash memories are of three types; they differ from each other only in the electronic concepts they use. Based on the physical size of the device and the protocols it uses to communicate with the host or the parent device (in this case, your computing device), memory cards come in many shapes and sizes. With the onset of the multimedia-enabled phones and now the smartphones, Mini SD (Secure Disk) and Micro SD cards have emerged as favourites.

A Micro SD memory card comes in a standardised size and can store tens of GB of data.

This communicates with the parent device using a standard, embedded system communication protocol — Serial Peripheral Interface or the SPI — and can be used to store data of all kinds ranging from multimedia to documents. A design engineer, who works with a leading flash memory company, is all excited about the technology that is on the drawing board and recent developments in the field.

“The latest addendum to the Micro SD family — a 64 GB capacity card — is as good as technology gets. These Micro SD cards have eight layers of NAND array-based storage section and one layer of processor in that compact shell, allowing users to carry a huge chunk of their data, even on their cellphones,” he says.

The missing space

Often when you click on a 1 GB memory card, you find that it shows a capacity of just above 900 MB. The ‘missing space' is where the manufacturer embeds the Digital Rights Management (DRM) implementations. This space is used to verify the authenticity of the applications, protect ‘read only' content and in some cases prevent copying of copyrighted material already loaded onto the disks. A Micro SD memory card has memory arrays and a layer of circuitry implementing the processor.

Apart from reading or writing data into these arrays, the processor is also used to lock a certain portion of memory to implement the DRM protection.

The way ahead

With the ever increasing demand for storage and functionality, flash memory devices are pushing boundaries and are also trying to integrate more capabilities, going beyond merely storing data. This includes Wi-Fi capabilities, allowing these mini-devices to directly communicate with the host (or your gadgets).