Thomas Harte wrote:
Hmmm, so Sam DOS numbers tracks from 0, but sectors from 1? Or am I suffering a deficit of logic?
Most systems use 1-based sector numbers, though the BBC Micro and Opus Discovery both use 0-based. SAM track numbers are still 0-79 on both sides, and the 128-207 numbering Colin mentioned is just a SAMDOS concept to have the head number in bit 7.
Follow-on questions - does Pro-DOS use 9 or 10 sector tracks and/or is there a CP/M tool for imaging Sam format disks, I guess to multiple floppies if necessary?
Pro-Dos uses 9-sector disks with 1-based sector numbers. It won't work directly with some +3 and CPC disks because they use bits 6+7 of the sector number to indicate different disk types. Steve Parry-Thomas has been using a Spectrum emulator to convert CPC CP/M images to a format that Pro-Dos can read. Edwin has also been working on storing CP/M images in Atom records, so no floppies needed there either.
it sounds like a compact flash formatted for use with the Atom is readable only by Sim Coupe?
It's a SAM-specific format, comprising of a boot sector, record index, and an array of 800K disk-sized records filling the rest of the disk. Most of the Spectrum based IDE projects seem to go for FAT16/32 support, though often for read-only access to tape images or snapshots. Building a list of SAM disk images, then giving read/write random access to them is a bit more involved. A question for Edwin maybe ;-)
And I guess a Trinity Ethernet thingy from Quazar is equivalent to an Atom Lite from a storage point of view?
For basic storage I think they're fairly equivalent, though BDOS version differences might mean some feature differences. The Atom Lite has an optional DALLAS chip for file times, if you don't have a clock on a different board. I'm not sure how they compare speed-wise, though the Lite is faster than the original Atom due to a difference in byte order.
I was actually thinking of getting a compact flash for my Nintendo DS and trying some homebrew - have you any opinion on the ease of porting Sim Coupe?
At a basic level it was quite easy to get running, but it's far from usable yet. I'm still not even sure about running speed, though some crude benchmarks suggested it was maybe just below normal speed. Some core changes I made for the desktop version did help, but it needs further work. I've been a bit out of the loop for months with Real Life, so it's not been looked at since the end of Jan. If you get a SD adapter for your DS, you're welcome to join the fun!
The DS's native screen resolution of 256x192 is almost begging for it
Indeed! http://simonowen.com/images/simcoupe_ds.jpg Si
