Flash Disks and Memory Cards

Most flash memory devices consist of interface electronics or controller and flash memory chips. The controller provides interface to the outer world, processes data and accesses memory chips. Because the controller interface is exposed to the elements it can easily be damaged.

The interface can be USB, SATA, Compact Flash, SD or any other type. The removable device size, speed and capacity varies.

USB flash disks or pen drives are small portable devices with USB type A plug on one side. They can be very small without the outer USB plug jacket or embedded into some toy or case. But the internal structure is the same for all types of USB flash disks: small PCB with USB plug, controller chip and flash memory chip. The price of USB flash disks is very low. They are often given away as a present.

Solid state disks have external dimensions compatible with 2.5" hard drives. But the internal structure is very different. SSD disk contains printed circuit board with flash memory chips and SATA interface electronics. From the outside it behaves exactly as classical hard drive and from the SATA interface you can not determine what kind of device is on the other side. Flash SSD drives are faster but more expensive.

Similar internal components are in memory cards. The only difference is that they can not be opened so easily and they may contain integrated interface/memory chip.

The biggest consumers of memory cards are digital cameras. They are cheap and can store thousands of images. To transfer images from the camera to the computer you simply remove the memory card from the camera and insert it into any integrated or external USB card reader.

Unfortunately removable devices are often exposed to various electrical shocks and other damaging elements. Sensitive electronics can easily be damaged and the controller is on the first front line. This is why flash devices fail. Not because of faulty memory chips but because of damaged interface electronics. This fact can help us to recover the data even if the disk is not accessible by the computer. Here you can read more about practical methods for flash disk and memory card data recovery.