Mac OS 9.2.2 Memory Limit of 1.5 GB... Some Answers

[GaryN]

I'm here with:

2003 MDD M8570
Titanium Powerbook  1Ghz  A1025
Powerbook G3 Lombard M5343

[nanopico]

Awesome guys.
With the holidays and such coming up (and my kid not having school for a week or so, making me daycare for a week!) I probably won't have anything until the beginning of January.
I'll let you know when I have something ready.

[Protools5LEGuy]

Just wanted to add the machines that boot MacOS9 and allow 2 Gigs of RAM:

PowerMac G4 Sawtooth http://www.everymac.com/systems/apple/powermac_g4/specs/powermac_g4_450.html


PowerMac G4 Gigabit Ethernet http://www.everymac.com/systems/apple/powermac_g4/specs/powermac_g4_400_2.html


PowerMac G4 MDD http://www.everymac.com/systems/apple/powermac_g4/specs/powermac_g4_867_dp_mdd.html


PowerBook G4 1.0 17" (Al) http://www.everymac.com/systems/apple/powerbook_g4/specs/powerbook_g4_1.0_17.html


I've also made this post sticky

[DieHard]

PT5,

Thanks for the list

But under OS9 we are limited to 1.5 GB on ALL Models...

http://macos9lives.com/smforum/index.php?topic=2101.msg10763#msg10763

[Mat]

PT5,

Thanks for the list

But under OS9 we are limited to 1.5 GB on ALL Models...

But that doesn´t change the fact that there are some Macs that allow 2 GB for other Operating Systems. And that is exactly what the list is about: Macs that boot Mac OS 9 AND allow 2GB Ram.

[DieHard]

Just to clarify for the members new to PPC G4 Macs...

YES, many can physically handle an install of up to 2 GB RAM, and YES the OS will show 2 GB RAM, and YES, OSX can utilize the entire 2 GB, but unfortunately Mac OS 9 can only utilize 1.5 GB of the physical 2 GB RAM.

[Protools5LEGuy]

But under OS9 we are limited to 1.5 GB on ALL Models...

http://macos9lives.com/smforum/index.php?topic=2101.msg10763#msg10763

Built-In Memory. 1.99. I want to know more about that supersized Mac OS System itself using 811.9 MB instead of 68.1MB. I am keeping the faith in that we will recover some of this memory back to the user. In fact "256" Megs are taken for the RAM disk.

I can always pull out memory to make 1.5 or even 1 Gig. of RAM, but OSX benefits from that extra 0.5 RAM.  We have 4 slots.

On the AL 1.0 GHz 17" Powerbook you have only 2 slots.

We should look if having more than 1.5 Gigs of RAM we make the system more prone to crash.

Also if 1kWindows test shows a slower system when using with more than 1.5 Gigs of RAM.

Imagine we can use that nanopico BootX loader to fool OS9 think it only has 1.5 and the virtual RAM Disk is made before loading OS9. We could call it "2 Gigs patch for OS 9" or "512 Meg RAM disk for 2 Gigs RAM". The benefits of that neglected 0.5 Gig in a RAM Disk for DAW or Photoshop would do wonders. Probably I am delusional with the possibilities.
 
OFFTOPIC: I hate to pull off memory. It reminds me an x86 P4 triple boot I had with W'98 (Needed less than 768 Megs), XP + XXX 10.4.11. 

[DieHard]

HA ! That screenshot always cracks me up; 811.9 MB for the Mac OS, Mactron would have a heart attack if that was accurate !

He works for days if he wastes .000002 MB and re-writes extensions... LOL

[Protools5LEGuy]

I would pay an 800 Meg Mac OS system TAX gladly if it would allow true multitasking, protected memory, USB 2.0 and FW-800. 

In the meantime, it makes sense to have under 1.5 G of RAM for a pure OS9 setup.

[nanopico]

I had a new stupid theory earlier this week on this.
Some of the pre-g3 macs that are supported in 9 had 12 ram slots.  They official supported 128 MB dims but others found that 256 ones worked.
This only equates to 768 mb though. I think Apple probably knew that 256 would technically work, but for whatever reason stated only 128 would work.  With 256 used in each slot you get 1.5 GB.  I think that this is the driving force behind the reason for the limit.  That or I'm just crazy.  Still doesn't help solve the problem though.

[MacTron]

HA ! That screenshot always cracks me up; 811.9 MB for the Mac OS, Mactron would have a heart attack if that was accurate !

He works for days if he wastes .000002 MB and re-writes extensions... LOL

 

Not at all. This is a very known picture. It only has to do with the Finder way to compute memory. It clearly knows that there is 2 GB installed, but it only can use ( RAM addressable ) 1.5 GB.

[nanopico]

HA ! That screenshot always cracks me up; 811.9 MB for the Mac OS, Mactron would have a heart attack if that was accurate !

He works for days if he wastes .000002 MB and re-writes extensions... LOL

 

Not at all. This is a very known picture. It only has to do with the Finder way to compute memory. It clearly knows that there is 2 GB installed, but it only can use ( RAM addressable ) 1.5 GB.

Because the Mac OS usage is calculated by the total ram - what the process manager has allocated to it. Now how to change that allocation and what other ramifications that will have are the problem.

[DieHard]

Sorry, lost a little in the translation, I KNOW it's NOT accurate, but if it was.... we would have about 10 threads explaining what extensions/control panels to turn off

[nanopico]

Quick update here.
I found some older documentation on MacsBug that outlined the mmu and memory map info.
It was older documentation for some of the earlier OS, but the commands in MacsBug haven't changed other than there are some PPC specific alternatives that require that (such as the dissembler).
So between that and system calls asking to for logical to physical translation I can identify a clearer vision of the address space and where the ram sits with in it to find out what regions of physical ram are mapped to what logical address and figure out exactly what parts of the ram it is not using.  Possibly then sending a couple instructions to the MMU to ask it to map the missing ram.  Crazy idea yes, but moving in the right direction.

[Protools5LEGuy]

The folks from sheepshaver will thank any info on MMU.

[ELN]

Anyone ever used the Potatoswatter's Ephemerboot? It gave you a bootable RAM disk on NewWorld systems. I quote from the docs:

This also gets around basic limitations in the Mac OS, like the 1.5 gig limit. A 500 meg Ephboot disk should let a 2 gig machine use all of its memory.

[Protools5LEGuy]

https://groups.google.com/forum/#!topic/comp.sys.mac.programmer.help/UH78zG9cmPA

Current Multiprocessing SDK from Apple contains
version 1.5d16 of PowerMacInfo tool. Undertstand
there is a version 1.7d5 (post by Rene A. Vega
on 10-25-2001). Does anyone know where this can
be downloaded ?

Also, where might I find additional documentation
on the nanokernel (if any exists) ?

Thanks for any help, Nick Burgoyne    14 Feb 2003
<[email protected]>

It's up to you to figure what's going on inside the nanokernel. You
might have fun with the source from my hack Ephemerboot, at
http://homepage.mac.com/potswa/source .

You could ask Rene for 1.7d5. Or you could ask me.

   - Potatoswatter

[Philgood]

Please post this little app, tool, whatever it is...

[Protools5LEGuy]

Wayback machine can't help with http://homepage.mac.com/potswa/source

Googling ephemer boot lead to openstack info

http://docs.openstack.org/user-guide/cli_nova_launch_instance_from_volume.html

https://wiki.openstack.org/wiki/BlockDeviceConfig

[Protools5LEGuy]

If we can't reach Rene A. Vega maybe we can with Potatoswatter

http://stackoverflow.com/users/153285/potatoswatter

http://math.stackexchange.com/users/9317/potatoswatter

http://everything2.com/user/Potatoswatter/writeups/opcode

https://www.facebook.com/Potatoswatter

http://www.potswa.org/

http://everything2.com/title/opcode