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Thread: Memtest question

  1. #1
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    Default Memtest question

    I confess to having a rather unknown quality of RAM which came with the machine bought used, so I thought it might be useful to run this Memtest and/or Rember to see what's what.

    I haven't had time yet to run a full test with Rember, but it starts and progresses OK. The read-me with Memtest 4.04M states that more RAM can be tested than that available to test when running in Terminal, either by booting in Safe Boot and logging in as ">console" (which I can, but don't understand), or running Memtest in Single User Mode.

    If I use Rember in my User account, I can test 814MB of the installed 1024MB.

    If I run Memtest after Safe Boot, logged in as ">console", I can test 903MB. This is from the Memtest Read-Me; "By booting into Safe Mode, I've been able to test all but about 100M of the installed memory. You can add another 30M or so to the testable amount of memory by logging in as user ">console" without a password. This will drop you into console mode and turn off the window manager, freeing up the additional memory for testing. Now you should be able to test all except the approximately 70M of memory that OS X requires to run in this mode." I can only test all but 121MB using this method.

    If I boot normally and log in as ">console", I drop into the CLI, and shortly thereafter the screen goes clear blue and I have to hard restart to escape.

    If I boot in Single User Mode, the prompt is frozen, or freezes after entering 3 or 4 characters, and again I have to hard-restart to escape. I want to use the S.U.M. to try and test all but 2.3% of the installed RAM, which is about 1000MB.

    I guess my question really is about why I can't successfully boot in Single User Mode. There seems to be something rotten in the State of Denmark, and maybe I should have posted this in OS X General.
    "illegitimis non carborundum"

  2. #2
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    Lightbulb Can't boot to Safe Mode

    Boy... I never saw this one! and I didn't find the juicy stuff until the end.

    boot from Panther CD and use the Restore tab to clone your drive to backup.
    Create a BootCD with all your goodies like Disk Warrior.
    You can run memtest from CD also. Or various apps.

    Will DIMM First Aid run on your PC133 G4? yes. give it a try first so we have some idea what you are dealing with.

    What does Disk Utility say about your hard drive when you repair it? from CD or backup system?

    Gremlins. Odd that a Safe Boot hangs. That would say the underlying OS is hosed.

  3. #3
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    Default DFA result

    TZ,

    I have a back-up, but haven't tried it yet since this stuff with Single User.

    These are the DFA results:

    Model: PowerMac3,4
    PowerMac G4 (Digital Audio)
    DIMM0/J21
    DIMM configured for 512MB
    8008040D0A02400001755400800800018F04060101000E7054 0000140F142C40
    15081508000000000000000000000000000000000000000000 00000000001294
    00000000000000000000000000000000000000000000000000 00000000000000
    00000000000000000000000000000000000000000000000000 000000000064F5
    7.5ns PC133-233
    DIMM checks out OK

    DIMM1/J22
    DIMM configured for 256MB
    8008040D0A01400001755400820800010F04060101000E7554 00000F0E0F2A40
    15081508FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFF12F3
    C1494E46494E454F0836345633323330304755374420202020 20200332025108
    A3D12CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFF64AF
    7.5ns PC133-222
    DIMM checks out OK

    DIMM2/J23
    DIMM configured for 256MB
    8008040C0A02400001755400000800018F04060101000EC090 0000140F142C20
    15081508000000000000000000000000000000000000000000 0000000000127F
    7F7FB5FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFF011E19
    9D6700FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FFFFFFFFFF64FF
    7.5ns PC133-333
    DIMM checks out OK

    DIMM3/J24
    DIMM not configured
    no DIMM present

    All your DIMMs checked out OK

    You've gotta love these machines! I don't have OS 9 installed so I ran DFA from the install CD and saved it as a Text Edit file in my Panther User Doc's folder, and voila! there it is in OS X. I knew I had this 222/223/333 mix, but it's all 7.5ns PC133 and didn't think it would be a problem, but maybe it is.

    I'll run DU from the install CD next and see what gives.

    Single User definitely hangs once the CLI screen has finished opening, sometimes the prompt is D.O.A. and sometimes I can enter a few characters before it freezes, but freeze it does.

    A hosed OS seems likely, and that's easy enough to fix, but it does beg the question "Why?"

    The other symptom which persists has to do with logging in as ">console".
    If I try that after a normal boot, the CLI goes to a clear blue screen shortly after appearing. If I try it in Safe Boot, it works OK. I just ran Memtest for 12 hours using that method. But...

    After running through 6 sequences with all OK results, testing 945MB of 1024, I quit and ran it again, and this time it locked down 950MB. So I quit and ran it again; this time it locked 970MB, but then went loopy with the constantly scrolling message "WARNING. No physical memory suitable for pageout or reclaim, pageout thread temporarily going to sleep."

    Seems like each time I run Memtest it grabs a bit more RAM until finally it goes unstable. Maybe that has more to do with Memtest than my machine.

    One other symptom, which may be unrelated, is that Help Viewer is hosed too, and not for the first time. In fact, it's hosed in my back-up too, so I've got a ground-up OS install coming anyway.

    biggles.
    "illegitimis non carborundum"

  4. #4
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    Default

    Interesting stuff there. When you get a stable system, would be fun to burn a CD with more goodies as I said earlier.

    There are a lot of threads out there (MacINtouch etc also) on Help Viewer and what happened. With Apple Updates and bugs and backing up before applyiing, and always go in and rerun the combined update if at first you don't succeed....

    Backup - make sure it is bootable etc. Then run 10.3.5 Combined Update would be a "quick fix" perhaps.

    While a mix of RAM "should" in theory work, I'll leave that to Costa and you and whether throwing some PC133 512MB in there and pulling the slowest.

    ASP in OS X never shows PC133 as anything but PC100. AHT reports it correctly. Obviously different code and programmers were on that project. I forget, and you wouldn't even be able to boot and run with PC100.

    A G4 MDD doesn't have OS 9 CDs to boot from - glad you had one handy.

  5. #5
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    Default

    Dear Biggles,

    to me, your RAM seems fine. The Uni-North Memory Controller you have fitted inside your DA, is happy to handle CAS 3 RAM modules (PC133-3xx).
    The only thing I might want to suggest you is to move the DIMMs so as they show in this order:
    1. J21 - PC133-333
    2. J22 - PC133-233
    3. J23 - PC133-222

    And test your machine out.
    That should force the MC to set it's timing programming to suit the worst DIMM spec you have, for all the others too; but, as the other DIMMs bear better specs anyhow, they should take it easely.

    J24 is empty, right?

    IMHO, that memtest won't tell you much else that you already don't know about your DIMMs.

    If you want the full spec breack down, so as to compare it to your systems minimum requirements, while you are handling the DIMMs to shovel them around (if you want to do that), write down the small in-print you can read on those "little, black, bug-like" chips soldered on them, for each module (every DRAM device on each, single module should bear the same in-print).
    Then post that info here back for me to investigate.

    Your other arguments, about OSX stuff, are so very much interesting to me.... I am LEARNING (GREAT!!).

    Let me know.

    Ciao

    Costa
    Last edited by Costa; 10-04-2004 at 10:45 PM.

  6. #6
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    Default

    Ciao Costa,

    thank you for your kind words elsewhere.

    There is no J24 in a DA, only 3 slots. If I'm going to keep this DA for a while I will put 3x512 in it, but for the moment 1GB is enough, and what I have should be OK, if it isn't damaged, and I suppose that's what Memtest is designed to check.

    I'll arrange the DIMM's as you suggested, just on principle, although I can't see that the present arrangement would hose the OS, and that's what's happened. An inability to successfully boot in Single User mode points to something seriously amiss, but what caused it?

    As my ol' Dad used to say, "#1 Stoppage! Stop Firing! Cock Gun. Recommence Firing Procedure."

    So it's out with the Panther install disks and start afresh.

    I'll post what's on the DRAM chips, 'cause I've always wanted to do that but never had a reason; now I do!

    Ciao,

    biggles.
    Last edited by biggles; 10-01-2004 at 08:13 AM. Reason: spelling
    "illegitimis non carborundum"

  7. #7
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    Default

    Costa,

    I shuffled the RAM as you suggested, damned if things don't feel just a bit quicker!

    From the DRAM's I have these data;

    333: S80016LK7TW

    233: NT5SV32M8AT-7K

    222: HYB3YS256800DT-7

    biggles.
    "illegitimis non carborundum"

  8. #8
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    Default

    ...and, booted into Single User on the supposedly hosed OS. At the second character entered at the prompt, "x", the x's ran across the screen ad infinitum! Hmmn. Seen this before in a CLI. Unplug keyboard, connect keyboard, recommence firing procedure. Single User now serviceable!

    Macally iMediaKey; before you ask, it came with the used DA. Not the nicest K/B in the world, but hey! it was cheap. Is cheap! Something in the Macally USB driver?

    Costa, the RAM shuffle produced a most unexpected result which may be entirely unrelated and will probably remain a deep mystery.

    I think I'll have a beer now.

    biggles.
    "illegitimis non carborundum"

  9. #9
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    Lightbulb

    Even when you think you've done everything and it can't do anything and doesn't make sense...

    now if only - with all the USB problems and potential problems (USB keyboards are a *hub* and hubs can cause mischief) and get an Apple Pro kb in there.

    So even though the memory controller "knows" - it doesn't know as much as Costa does!! Makes sense now when you think about it. Also like to have DIMM output to help sort these things out.

    has anyone said that RAM is the first thing to always look at when troubleshooting?

  10. #10
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    Default

    TZ,

    ain't that the truth! It's definitely the Macally k/b causing the Single User mischief, I'm using an ol' B&W k/b now and it's just fine. I really don't like the Macally board and will replace it post haste, it's only on account of laziness and parsimony that I haven't done so before now. Much the same reasons for not replacing the RAM mixture, appropos of which...

    Costa,

    if I read you aright then the MC takes it's timing cues from whatever is installed in J21.

    Am I right in thinking that the first number in CAS (Column Address Strobe) is the Clock Latency (CL) which describes how many clock cycles for the DIMM to respond to the MC, and the other two are Row Address Strobe (RAS) and RAS precharge time which describe how data are managed within the DIMM? And is it the case that the MC uses all three numbers of whatever's in J21 to control the DIMM's?

    biggles.
    "illegitimis non carborundum"

  11. #11
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    Dear biggles,

    I apologize for not posting any sooner my reply to you, but I was away for the weekend and had to manage a 10-years old birthday party with some SCREAMING 35-40 kids around.... For a moment I felt like having done 2 rounds in a ring with Mike Tyson.....
    I was exausted.... (Where do they get all that energy from???)

    Now, back to your memory modules.

    233: NT5SV32M8AT-7K
    These DRAM devices are built by a Company named Nanya Technology Corporation, which is one of the Big five world producers of semiconductors and DRAM devices for the computer markets.

    Your specific DRAM device is now considered an EOL (= End Of Life) product by NTC and, according to their specification data sheet, they bear the following main specs:
    • They can clock up to 133MHz, but are also backward compatible to the 100MHz frequency.
    • The 7K items have a CAS Latency @ 133MHz of 2.
    • They have also being tested @ 143MHz with a CAS Latency of 3.
    • They can be programmed by the Memory Controller to run with a CAS Latency of 3 @ 133MHz.
    • They are self refresh at 7.5 ns rate with CAS Latency of 2, and 7.0 ns. rate with CAS Latency of 3.
    • They are unbuffered non ECC.
    • From what I understand, they were last produced on the 2nd. Quarter 2003.

    Glossary:
    • CAS = Column Address Strobe (or Select)
    • Refresh Rate = it consists of these activities:
      1. Identifying each row and column (row address select, or RAS, and column address select, or CAS)
      2. Keeping track of the refresh sequence (counter)
      3. Reading and restoring the signal from a cell (sense amplifier)
      4. Telling a cell whether it should take a charge or not (write enable)
    • Unbuffered = It means that the RAM expansion module bears no additional device between the chipset (Memory Controller) and the physicall memory stored inside the DRAM devices as they communicate. In other words, the expansion module allows direct communication between the Memory Controller and the RAM cells.
    • Non-ECC = It means that the module must be built without the Error Correction Code feature. The ECC feature is a method used to check the integrity of data stored in memory . ECC memory improves data integrity by detecting errors in memory and is more advanced than parity because it can detect both multiple-bit errors and single-bit errors (parity only detects single-bit errors). ECC is typically found in high-end PCs and file servers where data integrity is key.

    The above is a high quality SDRAM module.

    222: HYB39S256800DT-7
    You have erroneusly transcribed HYB3Y.... Should have been a "9".
    This DRAM devices are built by a Company called Infineon Technologies AG, which is the n 3 biggest DRAM producer in the world.

    Your specific DRAM device is still in production by Infineon and, according to their specification data sheet, they bear the following main specs:
    • They can clock up to 133MHz, but there are no tests showing they are backward compatible to the 100MHz frequency.
    • The 7 items have a CAS Latency @ 133MHz of 2.
    • They have also being tested @ 143MHz with a CAS Latency of 3.
    • They can be programmed by the Memory Controller to run with a CAS Latency of 3 @ 133MHz.
    • They are self refresh at 7.5 ns rate with CAS Latency of 2, and 7.0 ns. rate with CAS Latency of 3.
    • They are unbuffered non ECC.


    These are also excellent quality DRAM devices.

    333: S80016LK7TW
    For this last DRAM device I have found no details. It is NOT produced by any of the Big names. The only possibility is that it is a Powerchip Semiconductor Corp. product, as their site does not provide any information about their part numbers....
    Otherwise, the above part number does NOT match any of the other big producers.

    Quote Originally Posted by biggles
    Am I right in thinking that the first number in CAS (Column Address Strobe) is the Clock Latency (CL) which describes how many clock cycles for the DIMM to respond to the MC, and the other two are Row Address Strobe (RAS) and RAS precharge time which describe how data are managed within the DIMM? And is it the case that the MC uses all three numbers of whatever's in J21 to control the DIMM's?
    Yes, to your first question.
    Almost there...., to your second question: the 2nd number represents the number of additional clock cycles the DRAM device takes to react to the Memory Controller's request of a RAS pre-charge; the 3rd number represents the number of additional clock cycles the DRAM takes to react to a write(/refresh) command by the MC.
    Mmmm.... yes, in simple terms is correct: the MC will set it's own clock signal on the J21 DIMMs parameters. In your case, it is making it easier for all the remaining DIMMs to "answer" in time to the MC.

    How is it going now your DA? Better?

    Hope you can make good use of the above specs.

    Ciao.

    Costa

    P.S.: If you run DFA now, what does it tell you about your SDRAM modules?
    Last edited by Costa; 10-05-2004 at 06:18 AM. Reason: Missed out on an explanation

  12. #12
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    Costa,

    you asked "if you run DFA now, what does it tell you about your SDRAM modules?".

    All the data are exactly the same, just the DIMM order changed, slowest in J21 thru fastest in J23.

    Ciao,

    biggles.
    "illegitimis non carborundum"

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