Hi Georg, thanks for your detailed explanations of Bret's point!
> So again, the block device driver interface is not limited to FAT disks. Correct, but non-FAT devices, be it raw BIOS or supported by a block device driver, do not directly allow DOS to do things with the files on those devices. For that, another driver would alledgedly be required. The advantage would be to separate device hardware access and the file system processing layers into two distinct drivers. Also, generic disk processing tools for DOS could enjoy having access to any block device driven entity, be it FAT oriented or not. For example a block device cache can be effective for BIOS and non-BIOS (e.g. certain USB devices) drives and cover both the FAT and the non-FAT partitions on such drives, as long as the block device driver gives you access to them. For the current topic of supporting exFAT, UDF, HFS+, ext2 or other more-modern-than-FAT filesystems in DOS, you always need some sort of file system engine for the specific non- FAT file system to actually access files and directories. It is possible to let that directly access BIOS drives and give a CDEX or "network redirector" API based view of the contents to DOS. Another possibility is to combine a block device for the low level access with another layer to access files. Yet another possibility is a "transforming" block device, where DOS sees a block device with a FAT filesystem, generated as on the fly "FAT shaped view" of the actual non-FAT storage. In my personal opinion, the third option is mostly interesting for compressed variants of FAT, either on a dedicated partition or in some image file, or for letting DOS access file systems of the "quite similar to FAT" category with a bit of magic :-) The first option has the disadvantage that raw disk I/O has to be done by the same driver as the file system processing itself. This can also be an advantage if the driver is able to access a disk or partitioning scheme (such as GPT) that DOS itself cannot normally access. The middle option combines advantages and disadvantages: A driver which understands GPT and USB can make both FAT and non-FAT disk partitions visible to DOS as block devices. However, the non-FAT set of partitions would just sit around in the device chain until another driver provides the corresponding file system engine and gives DOS access to the actual files and directories - proabably using the "network redirector" interface of DOS for that step. Regards, Eric ------------------------------------------------------------------------------ Full-scale, agent-less Infrastructure Monitoring from a single dashboard Integrate with 40+ ManageEngine ITSM Solutions for complete visibility Physical-Virtual-Cloud Infrastructure monitoring from one console Real user monitoring with APM Insights and performance trend reports Learn More http://pubads.g.doubleclick.net/gampad/clk?id=247754911&iu=/4140 _______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
