rose@shorty.CS.WISC.EDU (Scott Rose) (05/09/89)
1. For various reasons too ugly to publicly admit, I wish to be able to follow the chain of memory control blocks. I have a very lovely little program that does just that, and in a very informative fashion: mapmem, particularly useful in conjunction with its /v switch. It works every time, which is evidence that if an entirely elegant technique is not available there is at least some repeatable way to find the head of the chain. While I can find *some* of the MCBs- that associated with the PSP of my program and any that follow- these beasties are not doubly-linked, and no documentation that I have found describes how to find the root. 2. Another lovely little program that has fallen into my hands keeps a little queue of events in memory and eyes the system clock to determine when to execute one. Called 'at', it only executes a job if it is determined that the machine is at the DOS prompt. HOW DOES IT KNOW? 3. Alright, I've asked this before... How, specifically, do I move back into real from protected mode, on an AT? Yes, I know, it requires a reset. Yes, there is a way to get the keyboard to generate the required signal. Yes, a PC Tech article back in 1985 tells just how to do it. I don't have access to this issue of PC Tech (you remember PC Tech, don't you?), and *still* want to know how to do this? Thanks, in advance, to anybody who can provide me with answer(s) to these burning questions of the day.
ellisond@gtephx.UUCP (Dell Ellison) (05/16/89)
In article <7495@spool.cs.wisc.edu>, rose@shorty.CS.WISC.EDU (Scott Rose) writes: > ..., I wish to be able to follow > the chain of memory control blocks. I have a very lovely little program that > does just that, and in a very informative fashion: mapmem, particularly > useful in conjunction with its /v switch. It works every time, which is > evidence that if an entirely elegant technique is not available there is at > least some repeatable way to find the head of the chain. While I can > find *some* of the MCBs- that associated with the PSP of my program and any > that follow- these beasties are not doubly-linked, and no documentation that > I have found describes how to find the root. I understand that there is a DOS or BIOS call that will give you the address of the head of the linked list.
everett@hpcvlx.HP.COM (Everett Kaser) (05/19/89)
The current issue of PC Magazine has part 1 of a two part article by Ray Duncan on this subject. Part one doesn't give any code details, but concentrates on the theory of how to use extended memory. Part two, next issue, should have all the code listings for this stuff (not the memory block stuff, but the protected mode stuff :-). Everett Kaser !hplabs!hp-pcd!everett everett%hpcvlx@hplabs.hp.com