[Coco] NitrOS9 L2 CoCo 3 question: Display settings/modifications

[Bill Pierce]

Ok, changed a byte in the "dir" command, and it loads and fails miserably LMAO
I tried both typing the command directly and manually loading it. NitrOS9 allowed the module to load, though it failed when run. In fact, not only did hang up VCC, but DW4 as well... I had to restart both.
So no CRC checking is done at all. I may heve been remembering seeing CRC errors from the old days before Nitros9 LOL

My questions would be, is this a good thing or bad? A lot of crashes could be avoided with CRC checking was "On". Why was it turned off? Was it off in the original OS9?
I know "boot", "REL" and "Krn" have modified headers (mainly for the "dos" loading and relocation code) and will not check properly until they are "in place" after booting. Maybe this is why it was turned of (??). I would think since these modules are loaded and executed before anything else that crc checks on them (after the boot) would be redundant.

 

 


Bill Pierce
"Charlie stole the handle, and the train it won't stop going, no way to slow down!" - Ian Anderson - Jethro Tull

 

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-----Original Message-----
From: Bill Pierce via Coco <coco at maltedmedia.com>
To: coco <coco at maltedmedia.com>
Cc: Bill Pierce <ooogalapasooo at aol.com>
Sent: Fri, Jun 17, 2016 9:56 am
Subject: Re: [Coco] NitrOS9 L2 CoCo 3 question: Display settings/modifications

Tormod, it could be that after a module fails, OS9 tries to error check it (??), though I don't think it's THAT smart :-)I do know that when loading (not booting) a module with a bad CRC, it usually errors with one of the 3 errors, usually 236 (Bad Module Header). This also happens with bad header parity or corrupt headers. This check "may" be done by the "load" command/syscall (??). I'm not really sure, I just know a module with a bad CRC and/or header will not load.Since I'm actually messing with NitrOS9 this morning, I'll change something with ded in a module with no verify and see if it loads. I may be seeing this on just corrupt headers or bad parities, but I'm sure I've seen "Bad CRC" errors when loading modules (externally, not booting).  Bill Pierce"Charlie stole the handle, and the train it won't stop going, no way to slow down!" - Ian Anderson - Jethro Tull My Music from the Tandy/Radio Shack Color Computer 2 & 3https://sites.google.com/site/dabarnstudio/Co-Contributor, Co-Editor for CocoPediahttp://www.cocopedia.com/wiki/index.php/Main_PageGlobal Moderator for TRS-80/Tandy Color Computer Forumshttp://www.tandycoco.com/forum/E-Mail: ooogalapasooo at aol.com  -----Original Message-----From: Tormod Volden <lists.tormod at gmail.com>To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>Sent: Fri, Jun 17, 2016 9:37 amSubject: Re: [Coco] NitrOS9 L2 CoCo 3 question: Display settings/modificationsOn Fri, Jun 17, 2016 at 2:34 PM, Bill Pierce via Coco wrote:> Tormod, I find that odd, unless you're referring to loading system modules. If I try to load a program with a bad CRC, it will usually fail. Usually "Error 205 - Illegal Module Header", "Error 232 - Incorrect Module CRC" or "Error 236 - Bad Module Header".> I know OS9Boot files with bad CRCs will load and "attempt" to execute, but bad CRCs usually mean something is corrupt and the boot (or the bad module in some cases) will fail.> Ident & Id will check module headers (even in merged files like OS9Boot) and report bad CRCs.This is the check in Level2 F$VModul which I think is used for all modules:https://sourceforge.net/p/nitros9/code/ci/default/tree/level2/modules/kernel/fvmodul.asm#l269But the proof is in the pudding, of course.Tormod-- Coco mailing listCoco at maltedmedia.comhttps://pairlist5.pair.net/mailman/listinfo/coco-- Coco mailing listCoco at maltedmedia.comhttps://pairlist5.pair.net/mailman/listinfo/coco