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The CompactFlash for USFiles add-on product supports CompactFlash cards as ATA FlashCards when used with PCMCIA controllers. It can also be used in True-IDE mode when the CompactFlash card is configured for that mode by the hardware. Besides CompactFlash cards, ATA PCMCIA flash cards are also supported.
PCMCIA support for USFiles The CompactFlash add-on product to USFiles provides support for CompactFlash and ATA FlashCards when used with PCMCIA controllers that are register compatible with the Intel 82365 PCMCIA controller. During the file system initialization, the PCMCIA controller is set up to allow the PCMCIA card to be accessed as an ATA hard drive. PCMCIA support on a Personal Computer uses layers of software to access the PCMCIA cards. These layers are socket services, card services, and the hardware drivers. All of these layers are designed and built for use on a PC running a Windows OS and are not usable with USFiles. Other types of PCMCIA memory cards may be usable with USFiles but will require the customer to customize the product. For example, a customer may want to configure a PCMCIA controller to allow memory-mapped access to a SRAM PCMCIA card with battery back-up. Once the PCMCIA controller is configured, the USFiles ramdrv.c device driver can be used to access the SRAM card. Linear flash cards are used with Flash Translation Layer (FTL) software that allows applications to access the linear flash card as a standard ATA disk drive. The FTL software takes care of the special access requirements of the linear flash cards such as the requirement that the flash memory be erased in blocks. USFiles does not support the FTL capability. A customer wishing to use linear flash cards with USFiles would have to write a driver for the device. USFiles for CD-ROM is an add-on product to USFiles and includes CD File Manager and ATAPI CD-ROM drivers. It is designed to be used with or without RTOS, which can be accessed through macros. MultiTask! and TronTask! have been integrated, but use of other multitasking executives requires minimum customization (editing macros and changing driver calls to make a task sleep, wake up a task from an ISR, and return from an ISR). USFiles for CD-ROM allows multiple tasks simultaneous use of the file system. CD-ROM drive can be placed on the primary or secondary IDE cable.
Compatibility and Support Platform
The USFiles - 32 add-on product to USFiles extends the capabilities of USFiles to support very large hard disks. This is done by using 32-bits to specify FAT entries. In addition, more root directory entries are allowed on a FAT32 drive, and clusters may be allocated to the root directory.
Directory entries in the FAT32 file system only allow 32 bits to specify the file size. Even though the disk geometry may allow it, the file size is limited to less than 4 GB. If the user attempts to write a file larger than this, an error will be reported The FAT32 file system BPB specifies the following items that USFiles ignores:
In addition, FAT32 uses a sector to keep track of file system information. In particular it keeps track of the number of free clusters and the last cluster allocated. USFiles will update this sector. It does not use the last cluster information, but when free_clust_cnt() is called, USFiles will try to access the file system information sector and read the number of free sectors, instead of scanning the entire FAT. Insignia
Solutions - Jeode Embedded JVM |
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©National Data Mux 2002. - All products and brand names mentioned are trademarks
or registered trademarks of their respective owners
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