You need to substantiate your claim. Which Apple computers don't have ROM debuggers or monitors? -- Derek

1. Combination and degree. If one person claims that all X have Y, and then you claim that not all X have Y (= no X have Y (which we agree is false in this case) or some X don't have Y (which is in dispute)) immediately afterward without giving evidence, that doesn't have the same effect as making your claim first. Also, your claim is totally opposite from the previous claim (that's what I meant by "degree"). So if you want me to believe you, sub- stantiation is nice. Also, you wrote "certainly". That just makes a naked claim even less appealing to me. 2. Prejudice. I read your argument and wanted to counter it right away. ("Hmph! Is he thinking that old Macs don't have ROM debuggers? That's not true in my experience. Is he thinking that new Macs don't have ROM debuggers? That's also not true -- I *know* the iMac has Open Firmware, for example.") 3. Proving your claim. Unless you've disassembled the ROMs, you don't *know* there isn't a debugger in there. If I claim there *is*, I may be able to show it to you easily. Yes. I asked you because of reason 4: I think you're at least partially wrong. This I doubt. You could be right (especially in the case of the Performas) which I will admit if it's true. No. Many of the older models had a plastic switch that snapped into the ventilation slots; it would reset the machine or bring up a debugger. I vaguely remember using the SE's debugger to look at a picture of the development team that was hidden in ROM. And as it turns out, Apple has a Tech Note (#1136) on the subject. (I vaguely remembered it before reading your post; afterward I went and looked it up. So I'm not trying to be *too* unkind or to have all the evidence beforehand and bait you.) It says: About MicroBug MicroBug was first introduced with the Mac Plus and has been a standard component in the ROM of all Mac OS computers since then. MicroBug is invoked when the system takes a Non-Maskable Interrupt (NMI) and there is no other debugger (e.g., MacsBug) installed. MicroBug is not present on the Macintosh 128, Macintosh 512, and Macintosh XL computers. So you're right about the 128, 512, and XL, but wrong about the Plus, SE, II, IIx, and IIcx. I just saw the debugger on my 7100/66 the other day when I hit Cmd-Shift-Power instead of Cmd-Ctrl-Power. I doubt it's been updated to handle the PPC. I know many newer machines have Open Firmware (hold down Cmd-Opt-O-F when turning on -- the letter O, not zero) which could be used for debugging, if you're evil and know FORTH. :) I'm not going to reboot my machine while I'm writing this message! So I could be wrong but I doubt it. -- Derek

Hmm... what did I mean by "totally opposite"? Well, I'm not sure so maybe we should say you're right and drop the point. But your claim was rather abrupt. Let's just say that substantiation always helps. I read your point (here and in another post) about finding one counterexample -- which is true. I would have understood your point a lot quicker if you had said, "I only need to find one counterexample and here it is." Having the correct counterexample is nice too. :) Well, yes, but as it happens they do have debuggers. The reason I mention the switch is that without it one would almost certainly be unaware that the de- bugger was there. (Unless some sort of crash caused an NMI.) Probably not entirely by choice, right? (as in, "Damn, here I am looking at the debugger again... stupid memory errors... stupid hard-drive setup... stupid copy protection...") :) Is it more or less useful than the one in the Macintosh? hmm... FORTH gives you low-level access to memory; you could write all the features of "real" debugging monitors if they weren't already there (e.g., hex dumps). I guess the potential is there, and it's there with FORTH a lot more than with BASIC. I want to slip this in -- I was annoyed at how completely useless the HELP command appeared to be, so I typed SEE HELP and got something like this -- I forget the exact syntax: ." HELP for " print-string ." is not available." cr Is this allowed by the standard? -- Derek

On 2 Nov 1998, Eric Smith wrote: And I think you are wrong about the Mac 512K. I can't guarantee that the debugger is at all useful, or even that it's in ROM (how can I check?), but my Mac 512K does have the INT button on the side which brings up the little window which lets me examine and change registers. Whether or not I can play with memory, I don't know... I haven't played with the debugger very much. I would check to see if I could bring up the debugger without having put in a system disk, but that would involve waking up my mother, within who's room the Mac 512K currently lives. But even if that doesn't work, that wouldn't prove that the debugger isn't in ROM. Old Amigas, at least, had ROM debuggers that could be accessed via a terminal connected to the serial port at 9600bps, but you would never know it was there without reading some of the thicker manuals. (The debugger activates upon a system crash, or via certain system calls, or by selecting a menu item from the hidden menu on old versions of Workbench.) (But of course, the original Amiga model didn't have a ROM debugger, because Kickstart was loaded into the WOM from disk. Does anyone know if it's possible to find the Amiga 1000's actual ROM in memory?) -- Doug Spence ds_spenc(a)alcor.concordia.ca http://alcor.concordia.ca/~ds_spenc/