On Wed, Sep 16, 2020 at 4:40 PM RETRO Innovations <go4re...@go4retro.com> wrote:
> On 9/16/2020 4:46 PM, John R. Hogerhuis wrote: > > > > >> Right now, (since you're listening), most of the TPDD.cs I grok, but I am >> wondering about a few things: >> >> - In FOrmatDirResponse, 0x1e is for a file larger than $ffff, I >> assumed that's an extension. >> >> > Nope. It's real TPDD behavior I reverse engineered long ago. Not saying no > one else did, but at least I also did. > > Hmm, interesting. I realize 1e is the number of bytes sent back (differs > by 2), so that answers that, but the 'P' seems odd, as I would think it > would still be the free numbers of sectors. During testing, was it always > 'P' on various disks with different numbers of sectors free? > > > No recollection. It was like 2004 or 2005 I think. Likely the disk was blank though. I'm not sure it matters much... there are no "sectors" to report on a TPDD service that isn't over a real floppy. And I don't know that it is actually referring to free sectors. I always figured the 'P' and the 'F' were structural components of the message when dealing with a 64K or greater file size. > > >> >> - If the file < ffff, you send 0x9d as the sectors free, but I see >> other guidance saying just send 0x80 back. Why 0x96d? >> >> Is there a reason you send x09d as opposed to 0x80 here? > > >> - I assume the 'P', the len >> 24 and the len >> 16 is to send the >> upper 2 bytes of the > ffff size file, but why big endian when the >> original >> code was small endian? And, is this part of the extension previously >> defined? >> >> What original code was little endian? > > Ah, you're right. I was looking at seek, which is little endian. > > Seek is definitely an extension. > > >> >> - In SelectFile, it looks like the select code always tries to look >> for matches in the root dir that of DOS*.CO format. Is there a reason? >> >> > Turns out I write very little code without a reason ;-) > > It's so that DOS100.CO TS-DOS tpdd client (RAM version) can be found even > if it's not your current directory based on changing directories using the > TS-DOS directory extension. > > I figured there was a reason, but it's always good to leave the question > open ended. But, the response doesn't clarify, at least for me. What is > the use case that the read needs to see TS-DOS even when you're not in that > directory? > > Probably the bootstrap programs that inload the DOS100.CO isn't directory aware. It's for compatibility. I added it for Kurt McCullum I think > > >> >> - Is reference.previous an extension? Regardless, is there an app >> that uses it (PDDuino doesn't have that functionality, but I would like to >> add and test). >> >> No. It's a real TPDD feature. I added when I found the WP-2 using it. > WP-2 traverses the directory backwards if you move the cursor backwards in > the file list. > > OK... Hmm, don't have one of those to test with, so will have to write > some test code > > >> >> - Not sure I see why there is an option for a FilteredRead in >> RequestReadBlock. Is there more docs on this? >> >> > Feature... NUL and EOF in .DO files will corrupt a model t's memory file > system. So they get filtered out when interacting with a model t. > > It looks like you filter them out regardless of platform (Model T, etc.), > correct? > Maybe. Not in my local copy. Being able to turn it off / on easily is being changed for CP/M compatibility. > Wow, it looks like when the file is opened for reading, you read it fully, > counting bad chars, deducting those from the total, using that as the total > for the filelength. Hmmm, that's doable on uCs, but expensive... I wonder > if there's a way to just replace with another non printing char. > Yeah, it's complicated but negligible on a desktop. Other option is just don't filter them. A real TPDD doesn't do it. I do it because I have come to consider LaddieAlpha a Model 100 to PC file transfer service, not a disk emulator per se. So conversion filters particularly for safety are a reasonable feature and weren't to tricky to add. The bigger problem has been turning them off. BTW, the other filtering I do is extension correction for BA versus DO files. Many BA files around on Club100 are not real, tokenized BA files, and if you try to inload them with TS-DOS you'll crash your Model 100. So LaddieAlpha detects them and presents them as DO files if they have DO content. I'll warn you a couple of our members don't like the fact that LaddieAlpha has filters. So if you do implement it you may want to add an option to turn it on / off. -- John.
