Memory test

As Bob alluded to, the built-in hard drive controller on the G4 MDD is an ATA/100 interface, not SCSI. If you were to buy a PCI SCSI card (and make sure it's mac compatible - not all are) THEN you could put in a SCSI hard drive.
 
Elliotjnewman said:
so how about one of these - http://www.clubmac.com/clubmac/shop/cat/Storage/InternalSCSIDiskDrives/category.asp

would I be able to replace my hard drive with a scsi hard drive? (if its the HD thats causing the problem)
Click to expand...
Club Mac is a good reliable dealer, but they are definitely the high priced spread when it comes to prices. There are many dedicated Mac sources selling the same drives and other products at lower cost. Two of my favorite lower cost, high value sources are SmallDog Electronics and Other World Computing. FWIW I have had excellent results with the "house brand" RAM from both of those sources too. There are others that may be even less expensive but these both have excellent customer service and both specialize in Macs.

You would have to add a SCSI card and there are issues with SCSI and OS X. Many SCSI controllers will not work with OS X. I don't know where you would find a list of supported SCSI cards but you might try checking the users reports database at XLR8YourMac for more information. Personally I am not sure the greatly increased price of SCSI would be worth it. Especially in your G4/1.25 MDD with an ATA 100 bus as well as an ATA 66 bus and even an ATA 33 bus for the optical drives. For best performance with two drives put your main drive on the ATA 100 bus and the secondary drive on the ATA 66. It seems counter intuitive to use to slower bus but it eliminates bus contention and will noticeably improve the I/O performance of both drives. That is how I have my G4/1.25 MDD configured.
 
Ok I have just run TechTool Pro 4. Initially I ran a basic test under Suites. Everything passed except the memory - it got half way through and crashed. I will try this again after I post this. Second I did a hardware test - everything passed (including SMART) accept surface scan which came back as:


Model: ST380024A
Mount Point: /dev/disk0
Capacity: 74.53 GB
Writable: Yes
Ejectable: No
Removable: No
Bus: ATA
Bus Location: Internal
Revision: 3.31
Socket Type: Internal
Serial Number: 3KB0SR8W
Connection: Master
ATA Version: ATA-6
disk0s9: Macintosh HD

Bad blocks are areas of media that cannot store data reliably. All hard disks have a few bad blocks when they are created, but these are "mapped-out" by the manufacturer when the drive is formatted. Mapping out bad blocks prevents data from being written to these defective areas of the media. Occasionally a good block will go bad. If this occurs and a file resides on that block, the file may be damaged. TechTool Pro will scan your drives for bad blocks and report if any are found.

Surface Scan
The Surface Scan test reads data from every block on the drive to check the integrity of the drive surface.
2 Bad blocks found

Surface Scan <Failed! (-4)>

Tests Completed

This test checks your hard drive for bad blocks. Blocks are sections of your drive which hold data. It is not unusual for a drive block to eventually fail. All drives employ a mapping scheme which allows bad blocks to be "mapped out" so that they are no longer recognized by the file system. ATA drives should do this automatically unless their bad block table is full or the bad block is in a critical area of the drive.

If bad blocks are reported the only cure is to reinitialize the drive with the option to zero all data. First back up any data since this will erase the drive. Use Apple's Disk Utility or another disk formatter with all checking and mapping options enabled.

Surface Scan <Failed! (-4)>
 
All hard drives have some bad blocks. Not only that but they also have spare blocks available as well. The idea is when the drive attempts to write to a bad block it verifies the write and if there is still an error after a given number of retries the drive itself flags the data block as bad and remaps that location to one of the spare blocks that is placed on the drive for just that purpose. Unfortunately blocks can go bad after there is already data written there. The TechTool Pro surface scan detects these bad blocks and in some cases is able to remap them on the fly, but if there is data written on the block it may have already been corrupted.

The only permanent fix for this condition is to backup everything you can, then erase the drive using either zero all data or 8 way write option to force remapping the bad blocks. This works as long as there are remaining spare data blocks. Once you run out of spare data blocks or data blocks start going bad quite rapidly this should show up in the S.M.A.R.T. values although there are no guarantees.

TechTool Pro detected a similar situation on my wife's G4/733 that had a so called Deathstar drive in it. I solved the situation by:
  1. Purchasing and installing a second hard drive that was quite a bit larger than the original
  2. Used Carbon Copy Cloner to clone the bad drive to the new drive
  3. Booted from the newly cloned drive
  4. Erased the original drive using the 8 way write option
  5. Tested the old drive with TechTool Pro and it got a clean bill of health.
The old drive is now used for backups and has perked along happily for over a year now. :D

If you decide to go this way, I would switch the old drive from the ATA100 bus to the ATA66 bus and put the new drive on the ATA100. That avoids bus conflicts and optimizes drive I/O. The jumpers on your new drive should be set to cable select and not Master or slave. The jumpers on your existing drive are already cable select and you can leave them alone. This is true even if you elect to put both drives on the same bus.

Let us know the results of rerunning the TechTool Memory Test. If that fails again there may be an underlying reason that both the HD and RAM would go bad. :eek:
 
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