Apple II File Type Notes _____________________________________________________________________________ Developer Technical Support File Type: $E0 (224) Auxiliary Type: $8004 Full Name: Davex archived volume Short Name: Davex archived volume Written by: Dave Lyons May 1990 Files of this type and auxiliary type contain an archived image of a ProDOS volume. _____________________________________________________________________________ Davex is a ProDOS 8 command-line shell and program launcher compatible with all Apple II computers that can run ProDOS 8. It supports stuff like wildcards, command history, print spooling, sorted directory listings, and operations on whole directory structures. You can add your own assembly- language commands, too. Davex also allows (coincidentally) saving an image of any ProDOS volume into a file and restoring it later. For more information on Davex, contact: DAL Systems P.O. Box 875 Cupertino, CA 95014 Attention: Davex Technical Support File Structure The first 512 bytes of a Davex archived volume are a header, described under "File Format" in this Note. After the header comes 512 bytes for each block on the saved volume, from zero on up. For blocks that are unused, you can just set the file mark ahead 512 bytes instead of writing 512 zero bytes--this way the unused blocks do not take up disk space, so the resulting file is only a few blocks larger than the number of used blocks on the original volume. If you run out of room while you are creating an archived volume file, close the file and start another one with the same name on a new disk. The fileNumber field in the header is one in the first file, two in the second file, and so on. This file format is suitable for ProDOS, but it is less useful on a file system (such as AppleShare) that does not allow for sparse files. A Davex archived volume file on an AppleShare server always takes up more blocks than the original volume contains. File Format identityCheck (+000) 16 Bytes These 16 bytes are required for historical reasons (there didn't used to be a special file type and auxiliary type to identify these files). The required value is $60 followed by "VSTORE [Davex]" and a $00. The characters have their high bits off. fileFormat (+016) Byte Must be $00. A nonzero value means the file format has changed in a way that isn't compatible with the current definition. vstoreVers (+017) Byte Version of Davex vstore command used to create this file (others use $00). vrestoreVers (+018) Byte Minimum version of the Davex vrestore command needed to read this file. Use $10 (version 1.0). reserved (+019) 13 Bytes Reserved for future use. deviceNum (+032) Byte ProDOS 8 device number of the device that this file is a volume image from. Informational only. totalBlocks (+033) Long Number of blocks on the saved volume. usedBlocks (+037) Long Number of used blocks on the saved volume. volumeName (+041) String Name of the saved volume, with a leading length byte. This field is 16 bytes long. If the name is shorter than 15 characters, the remaining bytes are unused and should be zero. reserved (+057) 7 Bytes Reserved for future use. fileNumber (+064) Byte This field contains one for the first file of an archive, n in the nth file (see above). startingBlock (+065) Long Block number corresponding to the data starting at offset (+512) in this file. reserved (+069) 443 Bytes Reserved for future use. theBlocks (+512) 512*n Bytes 512 bytes of data for each block of the saved volume recorded in this file where n is the number of blocks. Further Reference _____________________________________________________________________________ o ProDOS 8 Technical Reference