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Electronic Design

The Right Form Factor Means Everything

I have a bunch of M-System's USB-based DiskOnKey flash-memory devices. They're great for moving stuff between systems when a network isn't handy. I even have a 1-Gbyte version, in which I installed Linux, but it's tough finding a machine with a new BIOS that will boot.

The big problem isn't the speed or capacity, but the form factor. This is true for any existing USB flash device. Using it with a desktop is a royal pain unless there's a handy, device-specific docking station attached. This is especially the case when getting to the back of the PC, where the USB slots are normally hidden.

Have no fear. I have seen the future and it is ExpressCard. This new standard for removable devices is based on USB 2.0 and PCI Express. ExpressCard uses a mere 26 pins and is smaller than existing PCMCIA cards. But size is only part of the issue. The big change is the interface.

PCI Express and/or USB will be part of almost every microcontroller or processor on the planet. Okay, let's just say 16 bits and above. This means the only support necessary for ExpressCard will be a connector. Expect to see ExpressCard slots on the front and back of new desktops, as well as on the sides of every laptop.

Will the embedded market follow suit? I expect to see single-board computers with ExpressCard slots for USB and even PCI Express in the future. The advantages are significant: lower cost, higher reliability, smaller footprint, and lower power. Why would you put a CD-ROM drive or other removable media on an embedded device when a single ExpressCard slot offers an even more flexible alternative?

ExpressCard isn't the only technology that embedded developers will wrangle with in 2004. Serial ATA, Serial SCSI, PCI Express, and USB-on-the-Go will start to replace their older counterparts. Developers will be forced to react as legacy connectors, cables, and devices slowly disappear.

I can't wait until ExpressCard slots are ubiquitous on desktops and laptops. It means that I may eventually be able to carry everything I need in my pocket instead of lugging around a laptop. Finally, a decent replacement for the venerable floppy disk drive has arrived.

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