Nonvolatile Flash Memory Storage
5/10/2007
Flash semiconductor memory can be configured to serve as the mass storage device for a computer. Because there is no mechanical track seek and rotational delay, read access time can be superior to a hard disk drive. Also, form factor is typically smaller and power consumption is usually lower than a mechanical drive.
If you want to allow the flash device to behave as a typical writable storage device, you may need a custom file system implementation to accommodate the flash memory page erase characteristics.
The following table shows some flash form factors that you can use in your device.
| Flash form factor | Description |
|---|---|
Single chip flash disk |
Memory packaged into one chip that can be installed on a computer motherboard. |
Flash drive SCSI / IDE |
Linear flash memory packaged with a SCSI or IDE controller to emulate a SCSI or IDE hard disk drive. |
Type I/II PCMCIA flash cards |
Linear flash memory packaged into PC Cards that emulate a PCMCIA ATA device. |
CompactFlash device |
Smaller than a PC Card with electrically compatible connector interface. Removable, and provides PCMCIA-ATA and TrueIDE functionality that is compatible with ATA/ATAPI-4. For more information, see CompactFlash. |
MultiMediaCard |
A stamp size flash device that resides on a MultiMediaCardserial bus. Typically nonbootable. |
MemoryStick |
A Sony high-density flash memory device that resides on a serial bus. Typically nonbootable. |
Windows XP supports the devices in the table that emulate a disk using SCSI or IDE interface through an ATA or SCSI driver.
Be aware of the following considerations before deploying to nonvolatile flash:
- You can write-protect your device by using the Enhanced Write Filter (EWF) component.
- You can use the MultiMediaCard and MemoryStick as system storage, or to deploy your run-time image to a device.