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BD-R with UDF filesystem - FS redirector with 64-bit sizes (Miscellaneous)

posted by bretjohn Homepage E-mail, Rio Rancho, NM, 27.12.2020, 16:40

I thought I might go into my idea in a little more detail since I didn't explain it all that well and it didn't generate a lot of conversation when I thought it might.

The way MSCDEX (and its clones) work now is that you first need to install a hardware-specific device driver for the CD drive. This is usually done in CONFIG.SYS, and the installed driver is a character device rather than a block device (that is, it is installed with a device name like "SCSI_CD" rather than installing as a drive letter like "E:"). When you load MSCDEX, you must tell MSCDEX which character device (name) you want it to "attach" to on the hardware side, and MSCDEX sets up what amounts to two interfaces on the DOS side -- a drive letter (like "E:") and a special interface that lets DOS access audio CDs.

In the days when MSCDEX was created, this did make sense since things like DVDs and BDs and USB and UDF and even FAT32 didn't yet exist. Even though it made sense at the time, though, it wasn't very flexible and can't handle the hardware that we have today.

I think the problem is that MSCDEX was essentially designed backwards. MSCDEX "attaches" to the character device drivers when you install it, and I think MSCDEX should simply provide two interfaces (one for audio the the other for data). The hardware-specific part is installed after MSCDEX (or at least attaches to MSCDEX after MSCDEX is installed), but there shouldn't be a "permanent" attachment or binding between MSCDEX and the hardware-specific driver like there is now. MSCDEX provides "virtual slots" that hardware can attach to and detach from on-the-fly, and which "virtual slot" gets plugged into depends on what kind of media is inserted into the hardware.

In the same modern optical driver, e.g, you can insert almost every kind of CD, DVD, or BD that has ever existed (audio CD, data CD, DVD+, DVD-, DVD-RAM, BD, read-only, writable, and rewritable, potentially formatted in all kinds of different ways). I don't think the binding between MSCDEX and the hardware should be "permanent" the way it is now.

This is conceptually what I'm trying to do with my USB drivers, where I create "virtual slots" for the USB disks that get inserted and removed and are "attached" to DOS based on how they are configured and formatted in quasi-real-time rather than making a permanent connection when the program is installed. Making permanent connections for things that are purposely designed to be removable (like optical and USB media) doesn't make a lot of sense.

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