derosa@cell.mot.COM (John DeRosa) (02/20/90)
I am in the process of getting a very old program running on a Plus. The software does not work with 6.0.X so I figured to boot from a floppy and then run the old program that is resident on the hard disk. I tried various old systems back to 3.x with no luck. I feel that the problem is that the system is "switching" on me. That is when I invoke the old program it starts up the system on the hard disk, 6.0.4. I have not found a definitive reference to how this works with the various systems, only oblique references to the switching of systems. In MacUser, March 1990, page 205, there is a reference (item 1 on the right) to the switch ing of systems but this still does not make things clear. Can anyone illuminate me? Thank you in advance.
clarson@ux.acs.umn.edu (Chaz Larson) (02/20/90)
In article <1325@diamond2.UUCP> derosa@cell.mot.COM (John DeRosa) writes: >I am in the process of getting a very old program running >on a Plus. The software does not work with 6.0.X so I >figured to boot from a floppy and then run the old program >that is resident on the hard disk. I tried various old >systems back to 3.x with no luck. > >I feel that the problem is that the system is "switching" >on me. That is when I invoke the old program it starts >up the system on the hard disk, 6.0.4. > >Can anyone illuminate me? Thank you in advance. I'll give it a try... This is indeed the problem. When you launch the program, which is on the HD, the Mac OS sees the System Folder sitting on the HD and figures it better switch to using that one. This has been a "feature" of the Mac OS since a long time ago [day one, I think]. On a floppy-based system devoid of INITs, this makes a lot of sense. However, on a hard-drive based system, it is, as you have discovered, a real pain. The mechanism was changed slightly in System 5.0 [?]. Now, the Mac will not allow a "switch-launch" to a version of the System software older than the version being switched from. In other words, you could not switch from 6.0.4 to 3.2, though you could go the other way. Whew! Now, there are several ways to get around this, none of them very painful: 1. Before booting from the floppy, drag the Finder out of the System Folder on the hard drive. This will "de-bless" the HD's System Folder, so when you launch that old program, the Mac won't have a valid System to switch to. 2. Put the old program on the same floppy as the old system. This way, the Mac will never be tempted to switch. 3. Copy the old system to the HD, and use a program like "Blesser" to switch between them. Blesser allows one to have more than one System FOlder on any given volume [usually a No-No (tm)]. I've never used it, but apparently you run it before shutting down or restarting and tell the Mac to use System Folder A or B or C or whatever. It has recieved good press in MacUserWorldTutorWeek, so it would appear to be fairly stable. I'm sure my tortured prose has made this simple situation as opaque as can be, but hopefully some useful information can be extracted from it... <chaz> -- ---------------------------------------------------------------------- Chaz Larson - clarson@ux.acs.umn.edu "Great Scott! This 9 foot alien woman is a swinger! ...and she has the hots for me!!!" - Flaming Carrot