Miscellaneous Ramblings

The S900 Diaries: New Year Edition

Charles W. Moore - 2001.01.17

My now-legendary SuperMac S900 weathered the holiday season with a few new developments, the most notable of which being that it is now networked with my PowerBook at its main workstation, which is located on the other side of the house from the SuperMac. When my son was here for Christmas, he brought what had been a 1000 foot coil of ethernet cable left over from a renovation job he'd been working on, and we spent an evening running a long crossover cable behind baseboards and trim moldings.

Having the two machines networked is very convenient, as for the past eight months I have been using the S900's cranky hard drive for file backups (with a second backup for really important stuff on Zip disks). Crossover cable networking is about a simple as it gets. Just plug it in, turn on AppleTalk and File Sharing, select the other machine in the Chooser, and you're off to the races.

Systems-wise, I think in our last episode I was still running Mac OS 8.1, which is nice and fast on the 200 MHz 604e SuperMac, but I have taken a liking to an iMac USB keyboard that I have, and I missed my USB pointing devices.

Consequently, I took another crack at installing a later system. As usual on the S900, the Mac OS 8.5 installer crapped out before the installation was complete, but it got enough of 8.5 installed over 8.1 to boot from. I then ran the OS 8.5.1 updater, which worked with no problem, and left me with a seemingly complete system.

The dilemma then was whether to try installing the OS 8.6 update as well. I decided to go for it, but the updater quit before the install was complete. Nevertheless, it seemed to have gotten the important stuff down, and I now have a system that works better than anything I've had on the S900 in the past three months or so. The only anomaly I've noticed is that the Desktop Pictures control panel is nowhere to be found.

In the previous installment, I described my booting drill, which involved putting a bootable CD in the drive, waiting until the boot process froze, hitting the reset button, and ejecting the CD, which would usually goose the machine into booting successfully. With the mongrel OS 8.6 installation, I am now usually able to dispense with the CD ritual, and the machine will commence booting from cold and then freeze before the extensions start to load. After a reset try or two, it will usually boot.

I haven't had time yet to experiment with some of the suggestions that you can read in the messages below, but here is what has been tried:

The hard drive has had a low-level reformat using Apple's Drive Setup - unfortunately while booted from an OS 9 CD, which may have rendered the wrapper error bug, a possible source of some of my difficulties. When I get a chance, I want to reformat the drive using a different version of the Mac OS.

A bug in one version of the wrapper System file startup code can prevent the real System file from being found when the disk directory or the real System file is fragmented into more than 8 extents on startup disks that are initialized when running under Mac OS 9.0 through 9.0.4. The result can be an inability to start up from the disk.

However, since the problem manifested on a fresh system install and a newly reformatted drive, I don't think fragmentation is the issue here.

We have zapped the PRAM and tried the CUDA reset button on motherboard.

SCSI termination was suggested by the Seagate web page and by an S900 savvy reader, but more experimentation may be in order.

I have ordered another hard drive, and it will be interesting to see how that addresses the boot issue.

Meanwhile, the big, noisy machine is usable and actually works quite well once you manage to get it booted.

Before we get to the letters, I would like to bring your attention to an S900 Web site posted buy a guy named Mike.

Mike's Ultimate S900 (link no longer available) is dedicated to those who would like upgrade, repair, or modification advice on their S900 or Tsunami-based Macintosh - the most powerful pre-G3 Macs - and documents the configuration and descriptions of upgrades he's done to his S900, which are quite extensive.

Mike's S900 started out with a 180 MHz 604 processor, was upgraded to a hand-me-down 200 MHz 604e, and currently is running a 350 MHz Metabox JoeCard G3 that Mike is borrowing from a friend (Norton System Info benchmark of 728 overall/944 CPU, vs. 378/419 respectively for the stock S900. The numbers compare to a PowerMac 6100/60 scratch machine representing a value of 100). He has also added an IBM DFHS 4.2 GB 7,200 rpm drive, an ixMicro GameRocket 16 MB Voodoo Banshee video card, and a bigger power supply.

If you're a SuperMac fan, you will definitely find this page worth a visit.

The Letters

From Bradley Dichter:

Use only FWB Hard Disk Toolkit version 4.0 with Mac OS 9.0.x Also use CDT 4.0.1 to work with this. Alternately use Intech's HD SpeedTools 3.1.1 and CD/DVD SpeedTools 5.6. These work correctly with OS 9, older versions do not.

Also regarding the jumpers, TP stands for termination power, which means the drive supplies termination power to the SCSI chain. TE stands for termination enable. It's OK for any device to supply termination power, but only the last one on the chain should have termination enabled. Usually the arrangement is to have the HD at the end of the chain and terminated and the CD-ROM not terminated in the middle.

The motherboard is terminated. As for SCSI ID, it is best to have the hard drive at SCSI ID 0 as the Mac is designed to use this as the first SCSI address to look for at startup, contrary to the PC standard of going straight from 6 to 0. The Mac checks zero first, then from 5 to 1 on internal SCSI bus or bus 0. It then checks from 6 to 0 on the external SCSI bus. It is true to avoid SCSI ID 5 on either bus due to a design flaw.

Also most scanner software won't find a scanner on the external SCSI bus if the same SCSI ID is in use on the internal SCSI bus. The S900 has two internal connections for SCSI, the hard drive should be on the bus 0 which is rated at 10 MB/sec where the second or external SCSI bus is rated at 5 MB/sec. The slower CD-ROM drive should connect to the second SCSI bus to avoid slowing down the hard drive. Only fast SCSI devices should connect to the bus 0 for best speeds.

Hope these tips help.

From David Walker:
Hello Charles,

Five years ago I did sales and technical work for an Apple Dealer. I dealt with a lot of Macs that wouldn't boot, new scanners that wouldn't work, new Internet connections, etc.

In those days there were still lots of machines that lacked CD-ROM drives so I had an external 2 gig hard drive with a "universal" System Folder and several different drive repair tools. After your experiences with the S900 I'm sure you can appreciate what it was like to arrive at a customer's home or business and be unable to boot their machine because the computer wouldn't recognize my external drive. Power Mac 7500's were the absolute worst. No matter how I set the termination there was a game to be played just to get the external drive to spin up let alone get it recognized.

I found a very strange SCSI conflict with Power Macs of that era: I could not use ID 2 for any external device. This, of course makes no sense given that the stock internal devices, SCSI bus 0, were set to 0 and 3. As I encountered systems with more and more devices attached I discovered a pattern. The machines rejected a SCSI ID if the total of the bus number and ID number was the same as another device. Thus the internal CD-ROM at bus 0 ID 3 prevented use of bus 1 ID 2 because both add up to 3. A Mac with a second internal hard drive at bus 0 ID 1 prevented me from using bus 1 ID 0 because both total 1. This pattern held for disk drives on all the dual bus Macs I encountered. Scanners, of course, had to be different. Most of them didn't recognize the existence of a second bus and would block their ID on both chains. I also found that some 7500's and 7600/120's had SCSI "black holes". There were certain combinations of SCSI bus and ID numbers that just didn't work, despite being free of conflicts.

In that job I also heard lots of myths. One is that scanners should always be the last devices on a SCSI chain. As you can see below, my scanner is the first item on my external chain and it uses the "evil" SCSI ID 5. I've yet to have a problem with it.

My experiences with Seagate hard drives have been mixed. When I was in retail I sold dozens of 1 gig Seagate drives as replacement drives for 040 and PPC 601 based machines, but since then I've had two bad experiences with clients' Macs. The first was a stock PowerCenter 150. The drive would become corrupted within hours of being reformatted. I tried 4 different hard drive formatting tools and checked the SCSI chain for problems, but could never get it working reliably. Eventually the client sent the whole machine back to Power Computing and bought an Apple product. The second was a 7200 rpm Medallist in a 7600/120. The drive wasn't totally unreliable but it did tend to get corrupted and need reformatting every 6 months. It was also slower than the external 5400 rpm Digital Equipment Co. drive I used for my service work. Those old DEC drives were noisy and they ran hot, but they were fast and reliable. I still remember the DEC DSP3540 hard drive I bought for my Centris 610 in 1994. That 540 MB drive had better seek times than today's best ATA100 devices!

Today my UMAX J700 has 3 SCSI chains, a massively overclocked G3 upgrade, a Formac video card and a wild mixture of RAM including a SIMM to DIMM converter, and yet it's very stable. I usually boot up under 8.6, but I have a prerelease version of MacOS 9.1 on a spare partition and it's rock solid too. Here are the ID numbers and associated devices:

  • SCSI bus 0 (fast internal): 0 Quantum hard drive, 3 internal Toshiba CD-ROM, 4 internal Yamaha CD-RW (term)
  • SCSI bus 1 (external): 5 UMAX scanner, 6 Iomega Zip drive (term) SCSI bus 2 (UW PCI card): 6 IBM hard drive (UW drive automatically termination)
I remember a time in the past when I tried to put both my portable hard drives on the external SCSI chain. In several configurations the scanner was invisible. If the scanning software could see the scanner it was only a matter of time before one of the hard drives would hang with its drive activity light permanently on. The only time I got it to work was when I turned termination on in both the second and fourth devices. I certainly can't recommend that, however. I blame having 12 feet of assorted cable between the Mac and the last device. Today when I want to transfer data to/from one of my portable drives I unplug the scanner and Zip drive.

My rules are:

  • Never use the same SCSI ID number as a scanner on any bus. Never let the total of the bus number and ID number equal the same total for another device.
  • Never exceed SCSI cable length recommendations, either for a single cable or total length of the chain.
  • Follow the standard practice of terminating only the last device on a SCSI bus.
When possible I connect SCSI devices in numerical order. It helps me keep track of what number corresponds to what device, but probably offers no other advantages.

Good luck with your S900. At this point I'd be looking for a different brand of hard drive.

From Maxwell Cabral:
Dear Mr. Moore,

I read your article SuperMac S900 Hard Drive Woes Continued, and what you need to do is to use the "Wish I Were" program to set your S900's Gestault ID to that of a 9600 at the closest MHz as your S900's.

From Owen Jeffries:
Hi Charles,

The HD in your SuperMac is dying.

I have had this happen to me a few times with many machines and suspect HD's.

I replace the HD and the problem goes away....


From Ian R. Campbell:

I recently acquired a used S900 at an excellent price, and the reason I got it so cheap was because it had issues similar to those that you are experiencing.

At first, it was unable to recognize any hard drives. Fortunately, setting the jumpers on the hard drive at terminate managed to do the trick. Also, 9.0.4 is incredibly unstable on it, so I have it running 9.0. Which, so far has been rock solid. I have a 9 GB external drive hooked up to it. This has managed to help the machine act as my backup server/machine/mp3 jukebox. And it has a level of expandability that my little Bondi blue iMac could only dream of.

Have a great day, and best of luck.

From Randy Dickson:
Have/had the same problem with mine. Eventually got around it by putting an external drive on it and booting for it. No problems (other than it's a slower chain than the internal) since then and can use the internal drive with no problems for data and apps.

Never have been able to figure out why the internal drive won't boot. System is intact and blessed but machine just looks stupid at me. Have managed to milk another 1.5 years out of the machine using the external.


From Chris Higgins:
I had a Radius 81/110 that gave me some of the same issues. I found out it was a bad CD-ROM. Have you tried unhooking the CD-ROM and having the HD the only device on the chain and see if the problems persist (if they don't try it for a couple of days.

From Chris Hart
Here's some things to try...

You don't say anything about reformatting the hard drive. It's not uncommon for a drive to have a file structure, or driver partition, so screwed up that a full reformat is the only fix.

I would strongly suggest that you perform a reformat using low-level formatting. Apple's Drive Setup should work for that drive, I believe. And Apple's is the most compatible driver out there. If that won't work with that drive then use the latest version of whatever formatting utility you have access to.

Have you zapped your PRAM, or used the CUDA reset button on the motherboard?

Have you tested the PRAM battery for voltage?

How about removing all PCI cards?

You also do not mention whether or not you tried having the HD as the _only_ device on the SCSI chain. Try it with no CD, Zip, or other devices - it could actually be the fault of another device.

As I said before, reformatting the HD would definitely be one of the steps I would try. If the format fails then the drive is dead. I wouldn't buy a 500 MB HD that is many years old. I realize this is just a spare machine, and you don't want to spend a lot, but 500 MB is not only small but S L O W. If you are interested, contact me for some HDs at cheap prices. I have several slightly used drives hanging around.

Chris Hart
Independent Macintosh Computer Consultant

From BK:
Hope you're doing better w/ your UMAX

I've had my S900 for a number of years w/o much trouble It's now equipped with a G3/500 MAXpowr (rest their business-acumen-disadvantaged souls ) upgrade card and 480 meg of RAM. It flies !!!!! ( My brand new G3/500 w/256 PowerBook can't touch it )

FireWire PCI card
USB PCI card
Digital Audio PCI card
Graphics PCI card

and have just installed a second 10,000 rpm HD (in a neat DataStor cooling bracket) all 7 drive bays are full, wherein lies my problem I wonder, in your cyber travels , if you've come across a UMAX HotRodder who might offer some insight into upgrading the power supply. As the 250w standard issue won't power up all 7 drives

I do hope you persevere w/ your UMAX. I've found it resists change at first but, with a little patience, it eventually comes 'round.

I always enjoy reading your ramblings.

For HotRodding, check out Mike's Web page referenced above.

Thanks to everyone who wrote. At least my S900 travails seem to be an entertaining problem.