Should I install 64MB or 65MB in my SE/30?

[djc6]

I acquired an SE/30 with only 1MB of RAM - four Apple branded 256KB SIMMs in bank A. I purchased four 16MB SIMMs from OWC.

I have a Garrett’s Workshop GW4402B replacement ROM SIMM for 32-bit clean support.

My question is, do I:

1. Leave the 1MB in Bank A, install 64MB in Bank B, for a total 65MB?
2. Remove the 1MB in bank A, install the 64MB in bank A and leave bank B empty?

I came across this related thread: https://tinkerdifferent.com/threads/se-30-ram-banking-question.2262/

The only advantage I saw of option #1 was that I could boot the machine with the stock ROM by using the layout in option #1 - perhaps for troubleshooting down the road?

I wasn’t sure if there was a disadvantage to the 65MB layout by mixing SIMMs of such disparate ages and capacities.

 

[phipli]

I acquired an SE/30 with only 1MB of RAM - four Apple branded 256KB SIMMs in bank A. I purchased four 16MB SIMMs from OWC.

I have a Garrett’s Workshop GW4402B replacement ROM SIMM for 32-bit clean support.

My question is, do I:

1. Leave the 1MB in Bank A, install 64MB in Bank B, for a total 65MB?
2. Remove the 1MB in bank A, install the 64MB in bank A and leave bank B empty?

I came across this related thread: https://tinkerdifferent.com/threads/se-30-ram-banking-question.2262/

The only advantage I saw of option #1 was that I could boot the machine with the stock ROM by using the layout in option #1 - perhaps for troubleshooting down the road?

I wasn’t sure if there was a disadvantage to the 65MB layout by mixing SIMMs of such disparate ages and capacities.

Put 65MB in it, the SE/30 can be a little weird and doesn't always boot if you put 16MB SIMMs in one bank, and nothing in the other. It should work, but... it doesn't.

My question is, do I:

1. Leave the 1MB in Bank A, install 64MB in Bank B, for a total 65MB?
2. Remove the 1MB in bank A, install the 64MB in bank A and leave bank B empty?

I believe you should put the 64MB in bank A, and the 1MB SIMMs in Bank B, so I guess option 3?

Apparently there are fewer issues if you have an aftermarket ROM.

There isn't an issue in having mixed RAM in terms of different types in each bank (as long as they are all the same within the bank, and all meet the minimum specs).

 

[djc6]

I believe you should put the 64MB in bank A, and the 1MB SIMMs in Bank B, so I guess option 3?

In the thread above, at least with a stock ROM, user JDW could only boot with the 16MB in bank B and something else in bank A. He tried reverse and it wouldn't boot, so thats why I didn't consider Option 3.

Putting the 16MB in Bank B also has the advantage of more physical space - the 16MB modules are taller, and there is more room in the case above bank B. I think they would physically fit in bank A though, its just tighter. I've read various posts of people not being able to fit 16MB SIMMs in bank A depending on the orientation of the ICs on the SIMM module and the number of ICs on the module.

 

[djc6]

Is there a good stress test / memory checker I should run on my 65MB setup? I just wanted to confirm its good before I go and button up the enclosure. Right now I am bench testing the system with an ATX extension cable.

 

[phipli]

Is there a good stress test / memory checker I should run on my 65MB setup? I just wanted to confirm its good before I go and button up the enclosure. Right now I am bench testing the system with an ATX extension cable.

The issue everyone is talking about results in the computer not booting, if it is booting, I wouldn't be too worried, but, I'd use Mac Test Pro...

http://download.macintoshgarden.org/apps/MacTest_Pro_October_1995.iso

In the thread above, at least with a stock ROM, user JDW could only boot with the 16MB in bank B and something else in bank A. He tried reverse and it wouldn't boot, so thats why I didn't consider Option 3.

OK, but that contradicts what others have said. There are likely more variables at play. I think it would be easier to test and see what happens than worry about it. You won't cause any harm due to what is being discussed specifically.

 

[JTRetro]

I like even numbers when it comes to the memory in my computers. In my main SE/30 I have 128MB of RAM; in my test SE/30 board I have 64MB. Either configuration runs well and has no problem running many different programs, including Microsoft Excel 5.0, Photoshop 3, graphics converter, or playing games such as "Return to Zork"!

 

[JDW]

In my main SE/30 I have 128MB of RAM...

When 128 isn't enough, 256 is now an optiion...

https://tinkerdifferent.com/threads/synchr030-s-256mb-sdram-accelerator-for-the-se-30.3840/

It's neat because it's accelerated RAM too.

 

[djc6]

So, I installed the Qty four 16MB SIMMs in Bank B and everything is fine. I'm am curious about trying different arrangements - but I want to minimize flexing the plastic tabs on the SIMM slots, so I'm not going to move anything around.

One interesting thing is how the amounts of free/used memory appear on various versions of the OS. For example, why on System 6.0.8 does it look like almost all of the memory is used with no applications open? Same on System 7.1? But 7.5.3 and 8.1 seem to report free/used correctly. I've run into no problems yet using the systems, just a curiosity:

System 6.0.8 - what is difference between the black and white utilization bars?

System 7.1 - Largest unused block is only 7MB? Why is system using 59MB ?

System 7.5.3 looks accurate:

System 8.1:

 

[JDW]

So, I installed the Qty four 16MB SIMMs in Bank B and everything is fine. I'm am curious about trying different arrangements

But in addition to 4pcs of 16MB SIMMs in Bank B, you also have 4 SIMMs in Bank A, correct? You always need to have something in Bank A when filling Bank B.

 

[JDW]

One interesting thing is how the amounts of free/used memory appear on various versions of the OS. For example, why on System 6.0.8 does it look like almost all of the memory is used with no applications open? Same on System 7.1? But 7.5.3 and 8.1 seem to report free/used correctly.

System 6 requires 24-bit addressing, so anything beyond 8MB isn't free memory that apps can take advantage of, although extra RAM can be used as a RAM disk with third party software.

In System 7.1 and 7.5.3/7.5.5, if you have 32-bit addressing OFF, it's basically the same situation as if you were running System 6. When you open the Memory Control Panel and enable 32-bit addressing and restart, then most of that RAM will appear in Largest Unused Block and be available to all apps.

Systems 7.6 and 8.1 require 32-bit addressing. You cannot change to 24-bit addressing.

Mode32 was a popular way to make SE/30's 32-bit clean.

Some people install a non-stock ROM SIMM to make their SE/30 32-bit clean, and in that case, Mode32 is no longer needed. But when using such ROM SIMMs, a hack to the System File for 7.5.5, 7.6.1 and OS 8.1 is required.

 

[djc6]

But in addition to 4pcs of 16MB SIMMs in Bank B, you also have 4 SIMMs in Bank A, correct? You always need to have something in Bank A when filling Bank B.

View attachment 18980

Yes, I have 4x256KB in Bank A.

 

[djc6]

Some people install a non-stock ROM SIMM to make their SE/30 32-bit clean, and in that case, Mode32 is no longer needed. But when using such ROM SIMMs, a hack to the System File for 7.5.5, 7.6.1 and OS 8.1 is required.

Yes, I watched your excellent video and picked Garrett's Workshop GW4402B replacement ROM SIMM. Its great having both System 6 and System 7 ROM disks available via a DIP switch - at first I had some 2MB SIMMs installed where the 16MB are - and the system wouldn't boot into System 7, but it would into System 6 which was very helpful for troubleshooting. System 6 showed 13MB so I knew the SE/30 didn't like those SIMMs (It should have totaled 9MB since I have 4x256KB in bank A). All of the screenshots above regarding free/used memory are with the replacement ROM SIMM installed.

 

[JDW]

System 6.0.8 - what is difference between the black and white utilization bars?

Black is the RAM used right now.
White is the RAM that still can be used.
Black + White together is the total RAM allocated to the Finder, System, etc.

And don't forget that you can change the RAM allocation for apps merely by selecting the app, then open the Get Info box (screenshot below was made in System 6.0.8)...

Setting a size lower than "Suggested" often triggers a crash. But there are times when I need to set a higher number, as shown above, in some graphics apps like Canvas, when I want to open unusually large or complex documents.

 

[JDW]

Yes, I watched your excellent video and picked Garrett's Workshop GW4402B replacement ROM SIMM.

When I made my ROM SIMM video in Sept.2023, only the GW4402A SIMM was out, but @Zane Kaminski revised it and that is what we know as the "B" edition. It's an incredible SIMM, and I want to do a video about that SIMM alone. Right now though, I'm waiting for an answer from Zane about how to properly re-concatenate my own customized 3.5MB System6 disk image with the stock IIsi ROM image, the IIx ROM image, and the base ROM file (which is seems to be a customized version of Rob Braun's base ROM file). But in terms of feature set, the GW4402B ROM SIMM is amazing. You get a total of 16MB on the SIMM and convenient DIP-switch changing among 4 different ROMs, so it's truly one of the most amazing ROM SIMMs available. Glad you got one!

 

[djc6]

System 6 requires 24-bit addressing, so anything beyond 8MB isn't free memory that apps can take advantage of, although extra RAM can be used as a RAM disk with third party software.

In System 7.1 and 7.5.3/7.5.5, if you have 32-bit addressing OFF, it's basically the same situation as if you were running System 6.

Thanks for this explanation. Now I understand why 6.0.8 shows the amount of free memory it does. This also explained my issue with System 7.1. I have the 32-bit clean replacement ROM installed, but the Memory Control Panel had 32-Bit Addressing set to OFF. Once I turned it ON, now I see 64MB free instead of 7MB free I saw before under System 7.1:

 

[djc6]

But in terms of feature set, the GW4402B ROM SIMM is amazing. You get a total of 16MB on the SIMM and convenient DIP-switch changing among 4 different ROMs, so it's truly one of the most amazing ROM SIMMs available. Glad you got one!

Plus its at the lower end of the price spectrum if you're in the USA

Another feature that was important to me was the board thickness - which you raised in your video. I wanted to minimize chances of issues. I used my digital calipers and the GW4402B is actually a few hundredths of a millimeter thicker than my stock ROM! Initially I viewed the inclusion of the 3D printed ROM clips as a negative, thinking it meant the board was on the thinner side and that they were required. But thats not the case at all (I don't use them), and their facebook post announcing the product details how they beefed up the thickness of the ROM SIMM by using a thicker dielectric inside the board. Reading the facebook post illustrated to me the care they took in designing it.

And I wanted a stock boot logo and stock chime - this ROM SIMM checked all the boxes for me.

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[JDW]

Yes, so not only is the PCB thick from the get-go, and not only does it include two sets of ROM clips (for the 2 ROM socket types that lack metal tabs), you also get little stickers too, just in case the already-thick PCB isn't quite thick enough. Fantastic solution overall!

 

[djc6]

I thought this was interesting. I enabled 32-bit addressing in System 7.1.1 "Memory" Control panel. Later, I booted BlueSCSI from an SD card with System 6.0.8 and I received this message:

This Macintosh is set for 32-bit addressing. You may switch to 24-bit addressing and use this disk or restart and use a newer startup disk. (System 6.0.8 does not work with 32-bit addressing.)

If I click "24-bit" then I can start System 6.0.8 - but when I go back to 7.1.1, then 32-bit addressing is off again and I can only utilize 8MB of RAM - until I change setting within 7.1.1 Memory Control Panel and reboot again. So I'm guessing this setting is maintained in the NVRAM (I have a CR3202 adapter).

 

[Nixontheknight]

indeed it is. Mac OS 8 does automatically enable 32-bit addressing if it is off, I believe

 

[djc6]

The issue everyone is talking about results in the computer not booting, if it is booting, I wouldn't be too worried, but, I'd use Mac Test Pro...

http://download.macintoshgarden.org/apps/MacTest_Pro_October_1995.iso

So, I am curious about testing my RAM. I've had a couple programs hang/crash (says "error 1" - which google says is check memory) and just wanted to make sure it wasn't the RAM I purchased. So I downloaded ISO from link you provided. I'm running the RAM test but it hangs the system immediately. I'm booting from my own System 7.1.1 image and running the test off the iSO. I tried disabling extensions.

I can't boot from the ISO - it hangs at "Welcome to Macintosh". The README on the ISO says it includes a System 7.5.3 bootable installation on the CD. I think because of my replacement ROM, I'd need to update the "gusd" in the boot image, which I had to do for my hard drive image. Except the ISO is read only since its a CD device Instructions I used for my HD image are these:

Mac SE/30 with Upgraded ROM | Big Mess o' Wires

www.bigmessowires.com

If I use my stock ROM, the system shows 2MB of RAM instead of 65MB - it will boot the MacTest ISO - but it won't run because not enough free memory.

If I use Snooper 2.0 it crashes immediately when booted from my System 7.1.1 image - doesn't even show the application. If I use the Snooper 2.0 boot image, its based on System 6.0.8 so its only using 24-bit addressing. It claims to test up to 8MB of memory this way and passes, but even the extended march test is rather quick.

Here is where MacTest Pro hangs - I turned off the VRAM test to only do RAM test. Out of curiosity, I disabled RAM test and tried to do VRAM only - hangs in the same spot.