@Ferry

"Real-World" tests are the Final Test that you use when everything else has been debugged. The problem is that, with so many other things happening at the same time (interrupts, DMA, etc), if something goes wrong, you have no way of isolating it to a cause.

@Atheist

Nothing so difficult. Many people are using 1 GB RAMs, I know one person using two 1 GB RAMs for a total of 2 GB.

Run Prefs/UBoot, click the "Hardware" tab and at the bottom of the window, make sure that "Limit memory size reported to OS" is not ticked, or that the "Limit, MBytes" is the right size for your 1 GB RAM.

Remember to Save the new setting and do a cold reboot from the Reset button. If you still have problems after that, then it might be worthwhile to drop the memory bus speed from 133 to 100 MHz and try again.

@gregthecanuck

I've tried a couple of registered DIMMs in the past and I still have one here, but I don't see any difference between its "readiness to work" and that of a non-registered version. As usual, others may have different experiences.

@Ferry

So the question remains: are your and my A1s different, or are the DIMMs different? No one has yet compared two A1s side-by-side with DIMMs that work in one but not in the other, AFAIK.

I keep thinking that there must be a marginal hardware problem in there somewhere, but I don't have expensive enough equipment to go looking (My CRO only goes to 100 MHz) and I'm not confident that you could improve matters anyway.

Investigations are not helped by the complete lack of hardware diagnostics. In order to investigate such problems, we would need a proper memory tester, CPU tester, DMA tester, interrupt tester, PCI tester, etc.

You can't run diagnostics at the same time as an operating system and expect an exhaustive test. A memory test program has to check every part of memory, not just a random block that the OS thought it could spare. A memory test program should be run from an external box that connects to the CPU socket. If you have to run the test program on the CPU itself, it should test a block of memory at a time, relocate itself to another part of memory space and retest from there, until it has tested all parts of memory. When I used to design hardware and write such diagnostics back in the 1970s, memory was small (a megabyte was unheard of) and a full memory test on 64kB of RAM would take an hour per pass (CPUs were slow then, too ).

You could re-write the GPL memtester to boot from U-Boot and run stand-alone, but it would be a big job and you'd get no thanks for it. I've thought about it in the past but the need is not great enough.

@Paul

Your post is refreshing, to say the least. There is another possibility - that the people who post here are those that are sick to death of petty arguments started by teenaged sociopaths. We have learnt the futility of argument and know that at least here we can remain free of such annoyances.

@acefnq

Hi Ace, no, I only have the one left. I bought two but sold one to a mate and it works well in his G3 XE.

I can't help wondering if all those people out there with two modules running OK received their XEs with the FSB set to 100 MHz, and have left it there. It might explain why some people have a lot of trouble with DIMMs and some people have none.

I couldn't see any apparent difference in performance between 100 and 133 FSB. Presumably the few apps I tried manage to fit their "fast" bits into the CPU caches.

I don't think there is any difference between the two memory slots, I would be very surprised if an ECC DIMM behaved differently in one of them. ECC is not supported by the motherboard, anyway.

I'm not posing a question or asking for help here, just talking about recent experiences. They may have no relevance to others' experiences or they may strike a chord. But it might help someone to hear what I've found out about my system.

Firstly, I have never been able to run two DIMMs at the same time in my XE. The symptoms have usually been that U-Boot seems to run OK but as soon as the OS (Linux or OS4) takes over and enables both DIMMs, the hardware starts giving errors, hangs or generally won't run reliably. [U-Boot only enables one of the DIMMs if it is 256 MB or more] I know this is not the same that other people experience.

I have had until recently a single 256 MB Legend DIMM, but have always wanted more, like about 512. But I can't use 2x256 MB and all the 512 MB DIMMs I've tried before have not got past the U-Boot stage.

Recently I decided to put some time into the problem, and to document the limitations if possible. I bought a pair of new 512 MB DIMMs so that I had four altogether:
1x512 MB Legend (ECC, registered);
2x512 MB Infineon (plain, non-registered);
1x512 MB Samsung (plain, non-registered).

Advice to eager experimenters: DON'T TOUCH the settings unless you know what you are doing. It is easy to make a mistake and cause a disaster.

My old 256 MB DIMM was operating at 133 MHz FSB, and my G4 CPU was operating at 800 MHz as it has been for several years. Some years ago I put a decent heat sink on it and ran it for a few days at 1066 MHz without failures or crashes, but put it back to 800 for beta-testing and it has remained there ever since.

To cut a long story short, I tried all the 512 MB DIMMs again and found that all would function properly if I dropped the FSB (and memory speed) from 133 to 100 MHz (you do this by changing J13 from 1-2 to 2-3). I could even run two at once, giving 1 gig of memory (not that I need that much). I had to alter the CPU clock multiplier switch from x6 to x8 to get my 800 MHz back, but that was no problem.

However, when I tried to increase the CPU speed above 800 MHz, I had no success at all, it just would not boot. U-Boot would run OK, Kickstart would load, but it would not get past the "now launching Kickstart" display and the WB would not appear. Even going back to my old trusty 256 MB DIMM gave the same result - if the FSB is 100 MHz, it can't run with a multiplier of more than x8. If the FSB is 133 MHz, it will run with a multiplier of x8.5 (1066 MHz).

I tried reverting to Update4 (just to be sure that it was not a "new memory system" problem, but same result, so it's not something new.

I tried going back to the old 256 MB DIMM and making sure that I could still get up to 1000 MHz, and found that the CPU would not even work at its rated 933 MHz. The core voltage (previously set to 1.85 volts) had fallen to 1.80 volts with age. I cleaned around the regulator and worked the switches on/off a few times, but eventually I had to set the switch pack to a nominal 1.89 volts in order to get the right 1.85. I'm not happy about that setting, it might suddenly start giving out 1.89, but it's not a great overload if it does. Anyway, I could run the CPU at 1066 MHz again with that core voltage, so that has not changed over the years.

Leaving the core voltage at 1.85, I rechecked the 512 MB DIMMs, but the limit of x8 at 100 MHz FSB seems to remain.

So it seems that (for my XE at least):
1) I can use two memory DIMMs if I reduce the memory speed to 100 MHz;
2) I can use 512 MB DIMMs by reducing to 100 MHz;
3) When the memory speed is set to 100 MHz, my G4 will not run with multiplier settings greater than x8 (800 MHz);
4) One of my 512 MB DIMMs (the Samsung) will run at 133 MHz FSB and 800 MHz CPU speed, so I have left it in that state.

Again, if anyone feels like trying similar tests, be very careful how you go about it. It is easy to damage DIMM sockets (they are designed for only a few insertions in their lifetime, not hundreds). It is also easy to make mistakes in DIP switch settings, mistakes that might damage your CPU. If you are going to check core voltage, you need an accurate meter and very steady hands so that you don't short anything. Don't touch things unless you know what you are doing. Always switch off the machine at the power input, not just the start/stop button. You want all voltage to the motherboard killed while handling DIMMs. But don't pull the plug out of the wall, you want to leave the computer earthed while you are near it.

I would be interested if anyone else has made any such tests recently, and with what results.

@AmiGame

Yes, it will, but make sure you:

1) Wipe any fingerprints off the battery with a Kleenex before you install it;
2) Check the contacts inside the battery holder for corrosion;
3) Don't use metal tweezers/pliers to hold the battery, even for an instant, you will short circuit it and shorten its life.

@aldur

The only thing you need to know is that 2.5" drives don't have a separate power connector like their big brothers. Power is supplied through extra pins on a longer version of the 40-way connector (it's 44-way).

That link that Severin posted shows a cable (right at the bottom) that allows you to connect a standard 40-way connector to a 2.5" drive and have a flying lead that connects to a spare power connector. That might be what you want.

Should be a piece of cake.

@joerg

I'm in favour of the cpu.library idea. I think a consistent interface would benefit not only those dockies which already exist, but dockies and other applications in the future.

Question re measuring CPU activity: currently the method used is to run a lowest-priority task that estimates how much of the time it has control of the CPU, right? Surely this calculation would be easier to implement, less invasive and more accurate if built into the idle task itself?

@Raziel

Didn't he get called up for military service? Or am I confusing him with someone else?

@PowerAmiga

Hippo birdie, old mate.

@Mikey_C

Oi! What about us on the other side of the world? Or are you still mad at us for winning our Ashes back?

@Severin

Ah, Marble Madness! My first game, I think. My first A1000 was early in 1987 - like JurassicC, had to get the upgrade to get KS1.3 and the extra 256 kB RAM.

At the time I had had a C64 for about 3 years and my own home-brewed computer in a 19" rack (B&W text only) for about 12 years. It wasn't long before I had to buy the kids their own A500 so that I could get the A1000 back.

Then the first A4000 in 1993, the second a year later, the A1 in 2003. Never had a 1200.

Gave away the A1000 some years ago - it had 2 MB fast RAM, built-in SCSI + HD, WB 3.1 ROMs and a switch to fall back to 1.3.

@Chris

Yes, there is some inconsistency out there. I think I might increase my budget and go for Postscript (perhaps QMS/Minolta).

@Detlef

Thanks, that was the answer I originally wanted.

@FuZion

Yeah, as Detlef said, that is the normal start to a Postscript file. you've got the Postscript driver selected.

@Mikey_C

Yikes! And I thought my A1 was an expensive toy.

You'd want to get a lot of usable hardware for that price. In other words, all of the hardware in the machine had better be supported by your "alternate OS".

@kvasir

It's unlikely since Matrox will not release any documentation for their products to outsiders.

@Hans

Ah, so it's one of them! Thanks for that warning.

[just another means of locking the customer into Windows]

I'm thinking of buying an HP 1022N LaserJet. It sports PCL 5e protocol but is too new to appear in the list of printers in OS4.

Does anyone know of a printer driver in OS4 that can talk PCL 5e?