If you haven't seen the Toshiba HD-A1 tear-down, you should start there.
New this time is a quick one-minute video which shows my quest to get the M-Systems USB flash drive recognized under XP. This was filmed before my last post which talks about some initial findings inside the firmware.
Now that I had a few more minutes to dig a little deeper, I found a great freeware ext2fs Installable File System Driver that was able to recognize the USB flash disk under XP.
After looking at the size of various files and folders, I found that there is one specific file named pstorage under /usr that is pretty large: exactly 129.5 megs. This consumes a little over half of the entire space on the firmware flash disk. Messages in other parts of the firmware indicate that "pstorage" refers to "Persistent Storage", and apparently there are some menu features to manage what gets stored inside this file. Inside it's organized as a mountable virtual disk.
Looking at the start of the pstorage file, it looks like a FAT16 partition created with mkdosfs. The first 512 bytes are the boot sector with the standard messages "FAT16", and "This is not a bootable disk. Please insert a bootable floppy and press any key to try again". Also the common hex signature at the end of any boot sector: 55 AA. The next sector has the common signature for the start of a FAT table: F8 FF FF FF, which indicates a FAT16 table. The FAT table is filled with zeroes, so nothing allocated. There is the second FAT is at offset 0x10600, and of course has the same signature and no entries. It ends at 0x20A00, and the rest of the virtualized disk is all zeroes. No directory entries whatsoever. So it's formatted and ready, but just not used for anything out of the box.
There are four configuration files found in /usr/local, one called "capability.conf" with some interesting settings:
Also in this file are 32 System Parameter Registers (SPRM). These settings are the default parameters for the player, and were around with the original DVD format. With the old DVD format modifying them allows for things like configuring a player to be region-free. As far as I'm aware there were only 24 settings available before, so what's interesting now is that here the settings range from 0 to 31, meaning there's now 8 more to learn about. They've already got values in them, so there's something there.
In terms of testing the actual HD-DVD IDE drive, I installed Vista Beta 1 on a machine and got the same kind of results as with XP. It can recognize any DVD or CD, but not the HD-DVD movie I tried with it. Perhaps when Beta 2 is released it will recognize the high def media. I haven't tried to look sector by sector.
I wish I had more time to dig in further, but work and preparation for the Desert Code Camp are keeping me pretty busy these days. Plus my curiosity quota is now fully satisfied for this week! Maybe next week I'll put the unit back together again and actually power it up for once.