What is Mac OS 7.6.1 RAM Disk Fix?

The text below is from the read me built into the splash screen.

What does this patch do?

This patch alters the System File (one of the essential pieces of software your computer uses to operate) of Mac OS 7.6.1, so that it will not crash at shutdown when a RAM Disk is in use.  The problem was identified on  Ted Landau’s web site, MacFixit (www.macfixit.com), which by the way is an incredible resource for ALL Mac users.  Alex Maluta, a reader, found a fix that worked for him, however it involved using ResEdit and finding offset codes.  ResEdit scares most people,  even those who understand its nature, and as such, this patch will apply the same fixes to the appropriate file without using ResEdit.  Users can patch their System in a matter of seconds and have the problem fixed.  

According to MacFixit and Apple, the crash occurs when a non-PowerMac or 680x0 (and in some RARE cases possibly a PowerMac or clone computer) tries to erase the contents of a RAM Disk before restarting or shutting down.  The changes this patch makes, bypasses that process, thus eliminating the crash.  The erasure is not necessary, because the moment the computer restarts or shuts down the contents of RAM are lost anyway.  Users that have a program to save their RAM Disk to a hard disk should not be affected by this patch.  This is often called a persistent RAM Disk.  The persistent RAM Disk should work correctly with the patch installed.

Download Mac OS 7.6.1 RAM Disk Fix for Mac

Architecture

Motorola 68K

Compatibility notes

The text below is from the read me built into the splash screen.

What are the requirements?

System 7.6.1 and a 680x0 Macintosh computer.  This includes any non-PowerMac Apple computer with a 68030 clean ROM or better.  This includes the Color Classic, Color Classic II, MacIIci, MacIIvi, MacIIvx, MacIIfx, any Centris, any Quadra, any Powerbook 100 series, any Powerbook Duo (except the 2300c), any Powerbook 500 series (except those upgraded with the Newer™ PowerPC Upgrade), any Powerbook 190 series, and the following Performa Models: 200, 400, 405, 410, 415, 420, 430, 450, 455, 460, 461, 463, 465, 475, 478, 477, 550, 560, 565, 567, 568, 575, 577, 578, 580, 600, 630, 631, 632, 633, 634, 635, 636, 637, 638, and 640.  (Also included is any LC series that has the same number as a Performa, such as a LC 580.)

If your computer has a four digit model number, such as a 6400 or 7600, the patch is most likely not necessary.  If you have any clone model from any clone vendor, the patch is not very necessary either.  The problem affects PowerMacs (this includes all clones) rarely, so do not patch their system file unless you have the problem.

Emulating this? It could probably run under: SheepShaver