FAT File System for Memory Cards

As well as the RAM file system, The Venom language has a Windows-compatible FAT file system for use on memory cards, and drivers for Secure Data (SD) or MMC (Multi Media Card) to work with it.

The file system enables memory cards formatted in Windows or by other compatible devices such as digital cameras to be used in the VM-1. Use of memory cards gives much higher data capacity and more robust non-volatile storage than RAM disk. In addition the use of removable media enables applications not possible with RAM disk. The file system supports:

• Reading, creation, writing and deletion of files
• Long file names
• Subdirectories (including creation of subdirectories)
• Detection of media removal and replacement
• Partitions (though we've never seen a memory card with more than 1 partition on it)
• FAT12 or FAT16 formats, which covers card capacities up to 2Gb
• The same file data types and object messages as the RAM file system
• Wildcards in file specifications for finding, counting, listing or deleting
• Files can be renamed or moved between directories without copying data
• cacheing of frequently/recently used blocks in memory to improve speed and reduce card wear when writing
• The FTP and HTTP objects can use this file system too. (see networking)

Hardware Interface

• The VM-1's standard SPI bus connections.
• Serial port 2 - faster but makes the serial 2 asynchronous port unavailable.

We also offer compatible hardware: the 5815 Memory Card Interface which is configurable to use either of the above sets of interface connections.

Documentation