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Dog Cow

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  1. Hard drives of the time (and still today of course) were engineered to be able to run continuously for months on end. But there are different factors at play now because this equipment is 25, 30+ years old. I'll leave my compact Macs on for long periods, unattended, but only if I'm still awake and in the house. Yes, I turn down the brightness. If I leave the house, I switch them off. When I go to sleep, I switch them off. The concern is that a RIFA safety capacitor blows up, or a flyback transformer blows up, or some other component melts down and causes a problem with
  2. There's a small detail missing here: the Segment Loader does not unilaterally unload (purge) segments. According to Inside Macintosh, it will only purge a segment by an application's directive: when an application calls UnloadSeg for a particular segment. UnloadSeg marks the segment as unlocked and purgable in the heap. But it won't actually be purged unless more heap memory is needed. As far as PowerPC code fragments, so long as Virtual Memory is active, these are never truly loaded or purged from the heap in the sense of how things were done under 68K systems. Instead, Virtual Me
  3. Error 41 usually means "can't load the Finder" typically because the Finder file is missing from the blessed System Folder. But you might see that error if the Finder is present, but can't be loaded into RAM for some other reason.
  4. They say you're not supposed to use dish soap when you wash a board. But if you do a thorough rinse job, you're probably OK.....
  5. I don't believe this is a correct description of how the Mac operating system works. Under a 68K-only system, the Segment Loader will typically only load CODE resource 0 (the jump table) and CODE resource 1 (the main segment) into the application heap when you launch an application. If the application has additional CODE segments (and many applications do), they won't be loaded at launch time unless the preload flag is set. Under a PowerPC system, the PowerPC instructions are stored in the data fork of the application file, and not in CODE resources. The Process Manager
  6. The original series LaserWriter uses a Canon marking engine.
  7. Beta 5 is now out for testing. Features the first real TCP/IP application, a prototype POP3 email client. It logs in and downloads messages and saves them as text files on your disk. Email me if you'd like to beta test.
  8. Yup. But I don't have a 512k schematic, so that should have a 'for what it is worth' rider. Here's the followup from some research I did, because I'm not an expert on all things, and I am still learning. The Sony Sound chip was new with the Macintosh Plus and Macintosh SE. The original Macintosh logic board has an Analog Sound Generator chip. From its pinouts found in this schematic, it does not appear to interface with the 68000's reset line.
  9. I don't believe that the original Mac 128K and 512K motherboard has a sound chip. Inside Macintosh volume III shows how sound is generated on these models.
  10. Once you've enabled AppleTalk on both computers and connected them with a cable, they're networked! That was the big innovation of AppleTalk in 1984 and 1985: it was the world's first zero-conf networking system. You are right in saying that AppleTalk is standard on all Macintosh models back to the Mac 128K. But file sharing has a more complicated history (because it's complicated to implement file sharing because of permissions, locking, etc), and AppleShare did not emerge until 1987, though third parties had file sharing and disk sharing systems before then. Apple in 1984 also ha
  11. I don't know. And when I say CPU, I also mean with its supporting components like the oscillator.
  12. Here are his photos in JPEG format:
  13. Try this article: Macintosh Startup Revealed: From Boot Blocks to Finder See also, Inside Macintosh, volume III, page 42 As to your particular problem, the ROM clears the screen to black very early in the boot process, even before the boot chime. So if you're seeing those bars, it means the video buffer in RAM is not being cleared. Likely it's not being cleared because the code in ROM is not being executed. Therefore, I would suspect the problem most likely lays between the Motorola CPU and the two ROM chips. Since you indicated in your earlier thread tha
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