RAM question

[qbasicking]

Memory locations 1264 to 1279 are not used by either DOS or
BASIC. Does anybody know if they are used by windows?

 

[Alt255]

I assume you want to use that area for the purpose it was originally intended... inter-application communication. If I am not mistaken, 4F0h to 4FFh has been a "dead" area in ROM-BIOS memory since the early days of DOS. It was just too small to store any meaningful data (maybe big enough for a few pointers and flags, but that's about the extent of it).

If memory serves me correctly, there was once an interrupt intended to facilitate use of this area, but I have long since lost the documentation. I tried to dig it back up by scanning through my old DOS programming tomes and searching Ralf Brown's Interrupt list but I couldn't locate more than a passing reference to it.

I don't believe you will find documentation for use of this area by Windows or any modern application. It probably serves no useful purpose.

One might be tempted to try....

DEFINT A-Z
V$ = "16 bytes of data"
Ch = 1
DEF SEG = 0
FOR Address = &H4F0 TO &H4FF
    POKE Address, ASC(MID$(V$, Ch, 1))
    Ch = Ch + 1
NEXT
DEF SEG

...in one program and then attempt to read the data with...

DEF SEG = 0
FOR Address = &H4F0 TO &H4FF
    Vr$ = Vr$ + CHR$(PEEK(Address))
NEXT
DEF SEG
PRINT Vr$

...in another program.... But Windows isn't going to allow you to do that any more than it will allow you to pass variables through either the local environment or the master environment. (Remember the master environment table? We used to find it by tracing through the PSP chain until we found the first running copy of the command interpreter, searching for the name of the environment variable we wanted to modify, and then poking the values directly into memory. That stragegy hasn't worked since Win3.11.)

As it turns out, the easiest and most reliable way for two 16-bit apps to exchange "effective" amounts data under Windows, is to write and read the data using the file methods.

Sorry I couldn't be more helpful... it appears that you have excavated the fossilized remains of a prehistoric horse. It's going to take a lot more than CPR to bring it back to life.

Do no harm.​

 

[robherc]

Alt255- Hmmm... you ASSuME? We both know VERY well how dangerous that is ;-)
Anywise, drop me a line & maybe we could catch back up w/each other. I've moved to Akron now, so e-mail me at robherc@hotmail.com.

qbasicing- Did Alt255's post answer your question, or is there something else you were looking for? (Alt255 is the most knowledgeable QB4.5 programmer I've ever met...if he can tell exactly what you're wanting to do, and it's possible in QB4.5; I bet he'll be able to tell you how to do it ;-) -Robherc
robherc@earhtlink.net

http://shared.freeservers.com/searchmaster.html

(Anybody remember me? ;-)