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Installing Mac OS 8 on a Performa 6400/180 - Only 8MB RAM Detected?

TheMightyMadman

Active member
Hi all,

I've got my Macintosh Performa 6400/180 up-and-running after quite a bit of work (power supply rebuild, replacing dead IDE HDD with a CF card and adapter, replacing the non-working CD-ROM drive), and I want to install Mac OS 8 from CD. I have an original UK install disc, and although I can boot the machine from it, unfortunately it won't let me install the OS as "there isn't enough RAM available" - only 8MB RAM is shown under system information, which I am guessing is the RAM soldered on the mainboard. Both DRAM module sockets are populated, so surely there should be plenty more RAM available than that. Is this an installer software limit, or could there be a hardware issue? Or, am I overlooking something simple?

I greatly appreciate any assistance!

Many thanks,

Adam
 

TheMightyMadman

Active member
Thanks for the advice, all :) It looked like the two modules had managed to work themselves out of their sockets on one side. With them cleaned and refitted, the Performa is showing 104MB RAM, and Mas OC 8 has been successfully installed.
 

Snial

Well-known member
... I want to install Mac OS 8 from CD. I have an original UK install disk...
I understand you're running Mac OS 8 (not 8.1) from the CD? I too have that CD - there's a lot of enjoyment in re-installing the OS authentically! Mac OS 8 has a free upgrade to Mac OS 8.1 and I wanted to install that version because it supports HFS+ which means massive drive partitions with small cluster sizes.

I was wondering if you wanted to do the same, since you have a CF card, if in fact you have Mac OS 8.0 rather than 8.1. After a bit of sleuthing I found the actual British 8.1 update, which you can read about it in this post:

Nov 28, 2022

Mac OS 8 (and 8.1) itself will need to be in a HFS partition, but you can format the other partitions for HFS+.

-cheers from Julz
 
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