The proliferation of storage devices and external hard drives means many of us have gigabytes to spare, possibly hanging off a key ring or in a wallet or purse as well as the removable cards in our phones, MP3 players, cameras and notebooks.

This year the confusing array of memory cards, for cameras in particular, seems to have been whittled down. Although you can still get CompactFlash, xD and all their variants, the SD card; mini and micro, highly secure and HD video optimised, now seems supreme.

However, Sony and some of its partners are sticking with Memory Stick format, some devices have dual slots, and there are adapters so microSD cards can fit in the old xD slots.

Meanwhile capacity continues to expand with 2Gb cards ($14-$20) commonplace, 4Gb-8Gb fairly standard ($15-$45), and higher capacity 16Gb-32Gb cards varying in price depending on security and speed ($56-$150).

USB thumb drives have similar capacity and pricing. In fact low end 1-4Gb drives often appear in bowls like assorted sweets beside the checkout counter for under $20 each, in case you find yourself a few gigabytes short.

With removable or portable storage, music, movies, photos and documents can be easily moved between PCs, laptops, netbooks, phones, cameras, handheld devices, MP3 players and even car and home stereos.

Remember 4 inch floppy disks, which really were floppy? And their successor the 2inch disk which hasn’t been supported on new PCs for several years? If you do have floppy disks make sure you copy the data to hard disk, CDs or DVD so you don’t end up with orphan information as the format, like Zip drives, is already a distant memory.

Capacity gluttons

Meanwhile the capacity of hard drives on both laptops and desktop PCs remains standard at around 320Gb but there’s no huge outlay to go to 500Gb or double that again to a terabyte if you’re a serious media minder. An increasingly compact and affordable alternative for back-up and portability are high capacity external disks.

There’s growing interest in solid state drives (SSDs) across consumer and business sectors because they’re more shock-resistant, compact, silent, have fewer potential points of mechanical failure, use less energy and generate less heat than current magnetic disk technology.

While the evolution of flash storage continues, it can’t keep going at its current pace says, SanDisk founder Eli Harari. If it did, by 2013 you would be able to buy a 250Gb solid state disk that was 10 times faster than a current computer hard drive, for around $100.

There’s only one problem no-one could afford to make them, he told a Flash Memory Summit in California. The cost of manufacturing a gigabyte of flash memory for thumb drives, SD cards and SSDs has halved in price every year since 2005 but the price has fallen even faster.

If this trend continues manufacturers won’t have the capital to reinvest in the production plants to keep up with the demand analysts are forecasting. Harari predicts either a slowdown in the price curve or relief for the industry through breakthroughs in new technology.

That could be on the way with 3D read/write being developed by SanDisk and Toshiba with product likely in 2012 to keep the cost curve trending down. This technology is expected to reduce manufacturing costs while bolstering the capacity, speed and reliability of solid state disks, making them more attractive as a replacement for computer hard drives.