68k Macs can't disable the bootup RAM test, at least the IIci can't. With a Turbo 601 I was only able to disable the test when booting to the PPC card. Since it is possible to set a flag in the PRAM on a IIci to bypass the boot RAM test, with a 601 upgrade that enables the hidden function in Apple's Memory control panel, why hasn't anyone written a software utility to set that PRAM flag without a 601 upgrade installed?
For someone to do that they'd need software capable of reading out the PRAM with a Turbo 601 installed, in enabled and disabled states. Read it with PPC enabled and RAM test on, then with PPC enabled and RAM test off. Compare both VS PRAM state with the PPC installed and disabled. The bits that are different between the PPC enabled and test on and test off are what needs to be set without a PPC to disable the test. Different bist between PPC enabled and disabled are what the Turbo 601 CP toggles. Then for more fun, read the PRAM immediately after booting from a PRAM zap. Of course the PRAM reader for that state would need to be 24 bit compatible. (See next paragraph.) An odd thing I noticed with the Turbo 601 is when I had it set to boot to PPC and did a PRAM zap, it would boot Mac OS 7.6 in 24 bit mode. The amount of available RAM was way low, with most of the 128 meg taken up by "System" - and the Memory control panel gained a 24 - 32 bit switch. I never tried running any software requiring 24 bit mode, I'd always just flip that switch to 32 bit, re-enable the PPC and reboot. The switch on the Memory panel would vanish, only to return again with a PRAM zap. I thought many times about investigating that further, getting screen shots of 7.6 in 24 bit mode, but ehhh, I just wanted to get back to to PowerMac mode ASAP. I never just rebooted to see if 24 bit mode would stick or if it would reset itself to 32 bit. Had to be something weird the Turbo 601 did in PRAM because unlike other CPU upgrade cards, once enabled it didn't need a control panel to switch to the PPC, it completely bypassed the 68030 from power on. The 601 control panel was only needed for turning on a couple of performance boosting options. Apple's 601 Upgrade control panel could *disable* 3rd party 601 upgrades but once turned off, Apple's CP would say "601 upgrade? I don't see any 601 upgrade." Apparently it would check the PRAM state with a Turbo 601 enabled, and could set the state to normal, but to turn it on it'd first check for an Apple 601 upgrade (which IIRC they only made for 68040's) and not finding one would not enable a 3rd party one. On Tuesday, April 25, 2017, 12:45:56 AM MDT, Clark Martin <[email protected]> wrote:Give it plenty of time to boot. The RAM test for 64 Mb will take quite a while. Try letting it boot for an hour, that should be more than enough time. There is a way to stop it from running the RAM test at startup. IIRC you hold down the Command key while opening the Memory control panel and an additional option appears. Clark Martin A designated driver on the information Super Highway -- -- ----- You received this message because you are a member of the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To leave this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/vintage-macs Support for older Macs: http://lowendmac.com/services/ --- You received this message because you are subscribed to the Google Groups "Vintage Macs" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
