VRT file format

[eslapion]

I have a hard time understanding the necessity of this VRT file format.

Back in the early 80s, a few people noted that VIC-20 autostart carts never use BLK2. They either use only BLK5 or a combination of BLK1 and 5 or BLK3 and 5.

For that reason, it was easy to save carts as a single file by transferring the content of BLK5 into the BLK2 area to prevent the cart from autostarting and saving the data as a contiguous block of either BLK1 and 2, only BLK2 or BLK2 and 3, depending on the configuration of the cart.

If VICE is smart enough to look for the CBMA0 indicator in that file (a PRG file, I must add) and use the 2 byte address locator at the beginning to know what parts go where then these old files effectively constitute a workable .vrt file.