At 11:38 PM 4/26/2004 +0200, Aitor Santamarķa Merino wrote: >>The first option is X=TEST. This option tests all UMB blocks after X=<range> and >>I=<range> qualification by examining all bytes of the ROM block memory image. >>X=TEST will discard a block from being used as a UMB if it detects any byte value >>other than 0 or 0FFh, since those two values typically are found in unused upper >>memory. >> >I don't know if I get this, so what is the use of X=TEST after X=<range>? If you have >already explicitely forbidden that range...
X=TEST checks all remaining UMB candidates after X=<range> has excluded whatever you want. The only way X=TEST wouldn't test anything is if you had X=<range> exclude your entire upper memory region along with the automatic ROM scanning. X=TEST is a double-check that the UMB's you are going to get are safe(r) than without the option. >(maybe naive question) but why not simply adding this new second scanning algorythm >to the existing one? (for the range specified with RAM= or for the default scanned >range is no RAM present). Thought seriously about it, but I had three reasons not to: First, even in my small test user case, not everyone wanted to use X=TEST because they felt it was overly conservative and turned off UMB's that they could safely use. Just because there is a non-zero non-FF byte value at an upper memory location doesn't necessary means it's ever going to be used, needed, or even noticed. Second reason is that it's a significant behavior change and I didn't want to spring that big of a surprise on everyone. I mean, significant behavior changes are okay when they provider better MS compatibility or fix problems, but X=TEST didn't always and it's probably not what Microsoft EMM386 does, so I left the option behavior as a choice. Third reason, hmmm, what was that one. Oh yeah. There is a rumored small chance that old machines would misbehave if you directly probed certain addresses in their upper memory. Those stories my be all legend, but I figured I wouldn't risk on an late-release change. Safety freaks can always stick in X=TEST everywhere they distribute. ------------------------------------------------------- This SF.net email is sponsored by: The Robotic Monkeys at ThinkGeek For a limited time only, get FREE Ground shipping on all orders of $35 or more. Hurry up and shop folks, this offer expires April 30th! http://www.thinkgeek.com/freeshipping/?cpg297 _______________________________________________ Freedos-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/freedos-user
