More on Mac OS X system freezes: hard drive problem?

Posted by Pierre Igot in: Macintosh
April 18th, 2004 • 11:14 pm

I recently wrote about a problem I have been experiencing in the past couple of weeks or so, with my G4 (MDD) seemingly freezing during the night while the displays are asleep (but not the CPUs or the hard drive).

Well, there have been a few developments over the week-end, which might yet help me narrow it down.

First of all, I’ve started noticing the following behaviour in the day time, while I am working at the computer. All of a sudden, while I am working, the hard drive in the computer starts making a very weird noise, that I can best describe as a loud “blip shling plonk gzzz”. The noice stops after a second. Nothing seems to happen in my work environment. I can continue to work as if nothing had happened. Then, after approximately 15 seconds (i.e. not immediately after the noise), the entire screen freezes, with the exception of the mouse pointer. There is no noise coming from the G4, no hard drive activity, nothing. No amount of clicking with the mouse produces anything either.

This happened to me twice over the week-end. The strange thing is that the freeze lasts approximately 1 minute, and then things go back to normal, as if nothing had happened.

Then this morning, the noise happened again. This time, knowing what would happen 15 seconds later, I started moving my mouse in all directions, clicking on menus, etc. just to see what would happen. The freeze started after 15 seconds, right when I was in the process of pulling down a menu.

The problem is that, this time, the freeze never stopped. I waited for several minutes, to no avail. I went to the PowerBook and tried to ping the G4. Pinging worked just fine, with 0% packet loss. I tried to ssh into the machine. No response.

After a few minutes, I ended up doing a hard reset.

Now I have every reason to suspect that this is exactly what has been happening during the night while I was gone. (The “blip shling plonk gzzz” is not loud enough to wake me up in the middle of the night in the bedroom next door.)

I have DiskWarrior installed on this machine, and the utility’s “S.M.A.R.T.” feature is supposed to warn me if the hard drive is starting to show signs of malfunction. I haven’t received any warnings yet.

After this morning’s incident, I started from the DiskWarrior CD and rebuilt the startup volume’s directory, just in case. But I somehow doubt that this will help in any way. The “blip shling plonk gzzz” noise is not a typical symptom of directory corruption as far as I know (from my experience with such corruption on various machines).

Needless to say, this is rather worrisome, because it seems to indicate some kind of impending hard drive failure. I am making sure I have backups of all the important stuff, but still… I don’t like this one bit. The G4 (MDD) is one and a half years old, so it’s not like the hard drive is at the end of its normal lifespan.

Yup, “blip shling plonk gzzz”. Eeek.

17 Responses to “More on Mac OS X system freezes: hard drive problem?”

  1. Henry Neugass says:


    “blip shling plonk gzzz”? Sounds something like the heads moving to the storage position followed by a re-seek to some extreme track. Or something like that.

    First thing that came to mind is this: I recall that, a while ago, some Mac hard drives commonly made alarming noises for no apparent reason. This was before Unix, when you could depend on correlating disk actions with something you did. The explanation turned out to be a specific hard drive model that needed to be exercised periodically, kept warm as it were, to operate correctly. Maybe ten years ago (or more!). Certainly should no longer be directly relevant, but possibly a clue.

    Second thing that came to mind is a global system slowdown that I ultimately tracked to a poorly-mated SCSI connection to a secondary drive that wasn’t even being accessed. This was on a PC, and was SCSI-specific, but it reminds me of signs on both OS’s that there are a multitude of functional layers between the operator and the media, and strange things sometime result.

    Hard disk drives themselves both SCSI and IDE et al. contain very high-performance microprocessors. There’s a significant amount of computing going on, and who knows what might happen in response to some odd condition found by the embedded program?

    How about doing an entire re-build of the disk in question? I guess Panther does some automatic compaction, but I’d be tempted to do a complete off-line housekeeping.

    If it was my primary work machine, though, what you’ve described would convince me to immediately order a new drive, clone the current one to that, and relegate the suspect drive to secondary use, e.g., let a proto-geek at your local elementary school take it apart.

    It would be nice to pin down the problem, but –given the complexity of the storage subsystems– I wouldn’t have much confidence in this being possible. Drives are very cheap these days. In fact, you might consider buying two if your machine has a spare bay and connector, so you have a fast back-up at hand. I’ve got three drives in my G4 Sawtooth: A 20GB SCSI drive dedicated to the OS and user storage, a 20GB IDE drive for routine work, and a 40GB secondary drive for fast backup.


  2. Pierre Igot says:

    Thanks for the added tips… As a matter of fact, I just happen to have ordered a second internal HD (Seagate 120 GB) that I was planning on using as a second drive… It sounds like I’ll probably take the opportunity of the installation of this second drive (when it arrives) to do what you recommend.

    Interestingly, the more I think about it, the more I am convinced that this particular noise is not new, and that I have been hearing intermittently, in fact, since the very beginning, when I first purchased the G4. It never resulted in a freeze, however. It was just one of these weird unexplained noises that I just associated with the new machine (which had more than its share of noises, as we all know).

    It just seems that this particular noise has become more frequent (almost once a day now) and that now there is a freeze associated with it.

    The problem here is that, since I first purchased the machine, I already did one complete rebuild — when I installed Panther last fall. I wiped the entire startup partition and rebuilt it from scratch. Then again, I did not wipe the other two partitions…

    Oh well. I guess it’ll be time for spring cleaning soon!

  3. Henry Neugass says:


    Great minds think alike?

    Instead of consigning the old drive to oblivion after cloning from it, you might want to simply leave it hooked up and see (a) if as a secondary drive it causes the same problem and (b) if it eventually fails totally.

    Interesting that you’ve heard this noise from the start. I’ll look forward to finding out if the new drive sounds the same.

    The only relevant noises I routinely hear from my G4 is the sound of a drive spinning up or down, at appropriate times. Come to think of it, this representsa change from all previous machines. Before Unix, it made sense to listen to the disks and all their noises to infer what the machine was doing. I recall realizing that this would no longer be possible after installing MacOS X. Maybe I just stopped listening after that. Or, hearing loss associated with increasing age…

    Let me take a wild guess about your issue: All modern disk drives arrive from the manufacturer with bad sectors — that’s unavoidable — and the drives still meet specifications, as well as the needs of most users.

    How? The drive has a supply of extra sectors that it automagically substitutes for bad ones. I believe this is done at format time, but I’ll also assume this is done on the fly during normal use of modern drives. Let’s say your drive arrived with an unusually large number of bad sectors and developed a lot more over time. This would generate extra work, possibly the noises you heard as the disk did additional substitutions. Eventually, if the number of bad sectors rises high enough, the drive may not be able to deliver data at some minimum rate that the disk drivers expect, and this could jam up your system.

    Plausible? It probably isn’t what is going on, but it might be a useful model.

    Hmmm, I wonder if a “hard” format of this drive might fix the problem.

    Does the ambient temperature vary widely in your office? Mine is in the garage, and might swing between 50F and 80F in a day, not much more, and never gets outside 40F to 90F. I’m thinking that bigger extremes might be bad for today’s higher-density drives.


  4. Pierre Igot says:

    Thanks for the additional information. I’ll readily admit that it’s already more than I’d like to know about hard drives :-). Much like other pieces of modern technology, the more you look into it, the more you wonder how it ever manages to work. No wonder our societies suffer from extreme specialization and compartimentalization!

    Once I get my other HD, I’ll probably try to do a complete wipe of this HD, writing zeros on each sector. Then maybe it’ll let me know whether there is a serious problem. (I don’t really trust Norton Utilities.)

    Temperature issues? Well, it does tend to get cold in the winter time, but I am monitoring the temperature inside my G4 on a constant basis (temp displayed in the menu bar), and it always a little over 50 degrees Celsius. It doesn’t change much. (Right now it’s a little higher because I am burning DVDs: 53.5 degrees.) I certainly don’t think the temperature ever varies widely inside the G4 or anywhere near the HD.

  5. Henry Neugass says:


    Thanks for your response. If you think this is overwhelming, try spending some time with a disk drive designer. Truly awe-inspiring. I might have his card somewhere around here…

    I am also surprised at how well technology works. Planes leave continent ‘x’ every day, year in and year out, and arrive at continent ‘y’ with such regularity that, well, we rarely consider the possibility of an accident, and even delays are rare.

    Back to computers, which are not so reliable. All those layers on top of the actual hardware means that the basics are far abstracted from the physical reality. Certainly a necessity, but it leads to some strangeness. In the case we’re discussing, the method of automatically substituting good sectors for bad obscures what’s going on. I suppose the “SMART Drive” mechanisms may make such parameters as rate-of-substitution information available at some level, but I’d expect manufacturers are quite leery of making the details available.

    I guess you leave the computers running 24 hours a day, just sleep the display and the hard disks, right? That’s probably the best strategy and it is borne out by your results you give. (I sleep my machine whenever I’m away for more than an hour or two. Here in earthquake country, I’m concerned that the machine will wake up, spin-up the disks, just in time for the main, devastating shock… bye-by disks. I’m hoping the g-force detectors I’ve heard are built-in to drives these days will protect them.)


  6. Pierre Igot says:

    I guess the reason that computers are not as reliable as planes is that computer crashes rarely cause bodily harm. Still, with more and more human activity depending on computers, I figure it’s only a matter of time…

    Yes, I leave my computer running 24 hours a day. I don’t let it put the hard disks to sleep, though. Maybe I should. I just want to be sure that background activities (maintenance tasks in the middle of the night, phone call logging, etc.) work fine. Earthquakes are not such a concern around here :).

  7. Henry Neugass says:

    I attempted some time ago to figure out how one could easily detect that those maintenance tasks (technically, “cron jobs”) are run, without success. The hard disk sleep mechanism _should_ not interfere with these, but it is certainly reasonable to wonder. Time to post on the Apple Unix board. I’ll let you know.


  8. Pierre Igot says:

    Joeri: I am sure lots of people have hard drive horror stories… It’s probably one of the weakest parts in a computer, because it is still to a large extent mechanical. I doubt, however, that the replacement HD was different because of an “incompatibility”. Hard drives are pretty standard fare these days (although there can be some issues with certain brands/models and sleep behaviours). The more likely explanation is that Apple doesn’t always use the same HDs in all models. These things go by batches, and I am sure Apple doesn’t hesitate to switch brands when they get a better deal.

    Out of curiosity, what were the brands/models of the original and the replacement?

  9. JoeriPruys says:

    Hi there!

    Interesting train of thoughts… This is the first time I read about HDs being shipped to customers with damaged sectors…
    I had a problem with my G4. A month or two after I bought it, the system freezed completely. I had witnessed some freak crashes and quite a few strange noises emanating from my shiny gray apple… but because this was my first osX experience I didn’t know what to think of it. But when things really went down the drain I woke up.
    The freezes & crashes first started while the machine was asleep. I just couldn’t wake my mac up and had to do a forced reboot everytime. Then applications started to behave badly. And finally I got the Blinking Question Mark o’Death.
    As it turned out my HD was rotten to the core. I got the one-in-a-million HD: no doubt checked and doublechecked at the factory, yet completely messed up. The funny thing is that when I got a new HD from Apple (I was well within my warranty) it was a completely different one – not even the same manufacturer. Could it be (or am I being paranoid) that they found out that the HDs they put in G4 machines are not completely compatible and that they started using different HDs?
    Who knows…. No hard feelings though. Great machine with great software. Although… maybe another time I will tell you about the huge crash (after which I had to do a full reinstall) when I tried to open an incomplete stuffit-file?… Sound familiar?

    Best wishes, Joeri

  10. Henry Neugass says:

    First, a follow-up. I’ve collected a lot of information about cron tasks to support automated backups, which I can summarize or discuss off-line. Nothing to suppose that hard-disk sleep will prevent this; I think sleeping drives simply wake up when referenced.

    Joeri: Thanks for your comments. I’m fairly certain about disk media being made with a greater number of sectors than will be available to customers; the extras are available to substitute for “bad” sectors. I’m also fairly certain about this not being anything to worry about. There is a huge number of sectors in, say, a 20 GB disk. (I think it’s 512 bytes/sector.) It’s possible to make an individual drive platter very precisely, with a defect rate in the low parts-per-million. Without bad-sector substitution, all it would take is one defect to ruin a platter. I’m guessing that all drive manufacturers set allowable defect rates very low, so if too many substitutions are necessary, they throw away the platter — it just makes sense to do it this way. About your failure: sorry to hear about that, and glad to hear that you have no hard feelings. Despite all the checking, it’s possible that, say, last deliverperson in the entire chain dropped the computer! It happens. “Crashes are nature’s way of reminding us to keep backups” still applies.

    Pierre: I think the way Apple and most other companies work is they qualify more than one drive manufacturer for each size disk they plan to use in a particular model. Price is, of course, an issue, but keep in mind it becomes extremely expensive to stop a production line because a single company can’t deliver drives. It’s my strong impression, based on some (admittedly out-of-date) direct contact with a disk drive designer, that competition is so fierce in this market that manufacturers are extremely, astonishingly careful about quality assurance.


  11. mare6 says:

    This has been a very edifying discussion.Though unfortunately no conclusions were drawn. I have the Quicksilver. I also get the sleep crashes, the weird noise. That I brought in for what was a supposedly bad power supply noise nearly a year ago. The noise persisted as did the freezes and crashes. The ‘Bad Black Box’. Black screen too, white code. Gosh, I hate that. My locals said maybe the power supply corrupted the HD but I dismissed that. Now I have read alot about the bad HDs. Lots of kernal fails, panics. I still suspect a problem w/ the cinema as my PB gets the same freeze when I work it on the cinema. I have had the G4 on 2 other cinemas. no problem. I am baffled.

    Apple had me do a clean install. New dual proccessor. Problems persist. Crash sometimes every 10 m or sometimes not for 20-24 hrs…… tips???


  12. Shelly says:

    I have no helpful comments to add, except that my Quicksilver G4 does the same things. I have always gotten many crazy noises, but I read online this is not unusual. With the install of 10.2, the noises abated somewhat. Then the crashes started. The endless spinning ball complete with loud, clunking hard drive noises, what sound like rushing into a wall and then backing up with lots of metal sounds that sound like clunks. It’s hard to describe these sounds. The G4 now no longer sees the hard drive at all. I can’t get it to mount. I bought DiskWarrior yesterday and used it and it temporarily seemed to fix the problem. After retrieving some files with North Unerase however, suddenly 2 hard drives appeared on my desktop and 3 CDs (I had one inserted) and I couldn’t get them to “go away” no matter what I did. Then the final crash and now today I am again searching for the hard drive. This computer is only 2 years old, and I’ve already had to replace the power supply. What gives with these things? I used to love this machine – now I can barely look at it without deep sadness. I want a new G5 of course, but not if problems like these still occur within Apple machines. I guess I’ve lost my trust of Apple products. (Too bad, because my Performa lasted years and years…. I had to force myself to part with it, and when I sold it, it still worked great.)
    If anyone knows how to magically fix a hard drive, old before its time, please share your wisdom.

  13. Shelly says:

    Thank you Henry, I will do just that. In fact it was on my list, but I have to give this one more try before I can accept all my data is gone. (No, my last backup unfortunately was a quickie that didn’t include all my critical things, like digital photos. Bad me, I know, and consider myself “reminded”.) Right now the G4 is “resting”, unplugged. It has sometimes found the internal hard drive after one of these apparently rejuvinating “rests”. Anyway, one more try and it’s on to finding a new hard drive. Do you have a recommendation for a good brand and place to buy it? I’ve never had to buy one before. Also, will I have to have a professional install it or is this something I can do myself? If I can do it myself I will have to look up how to do it today, since I’m losing this temporary laptop tomorrow!
    Thank you very much for your help.

  14. Henry Neugass says:


    <Sigh of relief> I’m glad you weren’t irritated by my advice and admonition. <Sigh of relief>.

    It’s easy … if you know how to do it. (I consider it easier than changing the washer on a faucet.) But if you don’t, I would call the local WeFixMacs store –or its equivalent– and ask them how much it would cost. Two prices: they supply the drive, or you do.

    There’s a really good article at

    I always start by finding out what kind of drive I have, and then I look for an identical one or one in the same family with larger capacity. If you do get your machine to boot up, and you are using 10.3, Disk Utility will tell you all you need to know. For example, it tells me my primary drive is a Quantum FireballP LM20.5, ATA bus. 19.1 GB. I would look on the website…

    Ummm, maybe we should take this offline to spare Pierre the gory details.

    Feel free to email me at, but be sure to remove the snoring first.


  15. Henry Neugass says:

    Hey, Shelly, I’m really sorry to hear about your disk problems.

    As I try to imagine the sounds you’re describing, my hair stands on end. Yuck!

    Hard drives are complex, high-performance computers themselves, but the most important factor to keep in mind is that they are electro-mechanical in nature. Mechanical stuff fails. Sorry, but that’s the way it is.

    Apple doesn’t make hard drives themselves — wisely, as you can’t imagine how exacting a task it is. Some years ago I hung around with a hard disk drive designer for a bit and I was blown away. It’s a remarkably competitive industry, and I’ll bet what they are doing these days is even more impressive than then.

    Of course, Apple picks the vendors from which to buy drives, and you could potentially fault them for choosing a sleazy vendor or some off-the-wall practice like re-using surplus drives in new equipment. I’ve never seen any evidence of Apple doing anything of the kind. The drives I’ve seen in new machines have been from the most reputable vendors. In at least one or two cases, Apple authorized repair centers have replaced drives on mere suspicion of a problem. Yeah, OK, the replacements might not have been brand-new.

    Note: No, I don’t work for Apple. But I’ve owned a number of Macs, starting with a 512KE and I’ve worked in the computer industry. I hated taking my IICi out of service– it was built like a tank and just kept ticking. My G4 Sawtooth has had only one problem — a noisy fan on the video card. Apple sent someone to replace it, and the new one went noisy too, so I bought a different, more advanced replacement.

    Your Quicksilver will probably be fine if you replace your hard disk with a new one from a major vendor. Even better, get two, and use one for backup only. Make CDROM and or DVD backups. Often.

    I know it’s frustrating! In the old days, we used to say, “disk crashes are nature’s way of reminding you to back up…” I have definitely had my share of reminders. But not recently, and not often with Apple equipment.


  16. Nick says:

    Hi Shelly,

    I’ve just read all these articles about freezes, crashes etc. Your articles seem to be the closest to the problems I’ve been experiencing since buying my G4 just over a year ago. The noises, the question marks, crashes in sleep, they all sound very similar to yours. I also thought that the hard drive was on its way out, but after a year I couldn’t believe it.

    The only way it seems to come back to life from being unseen is to open the cover and touch the ribbon, or disconnect and wait for an hour or a day!

    My problems seemed to begin with the Panther update, which I stupidly thought was the full version, on offer through Apple. Panther was a nightmare, with strange things happening all the time, including grey screens. I was advised to reset PRAM which, if anything, made things worse. Since then I have done an archive and install and eventually a clean install back to 10.2. I am still having problems with crashes, mainly from the Apple Help screens.

    It sounds like the hard drive could have been a constant problem, does anyone know how to check it for bad sectors?? i am willing to buy another drive but would like to know for sure that it is troublesome.

    Any ideas please let me know

  17. Pierre Igot says:

    Nick: For the price you’d pay for software to test your hard drive for bad sectors, you can get a new hard drive. But there is a variety of software titles that can test your hard drive: Norton Utilities, Drive10, etc. Personally, I mostly use DiskWarrior to repair damaged directories. If I suspect I have bad sectors, I get a new hard drive. No point in living dangerously.

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